Chemical agent for forming solid lubricating film, method for producing chemical agent, method for applying chemical agent, oil and gas tubular products and threaded joint for oil and gas tubular products

Abstract

FIELD: lubricants.SUBSTANCE: present invention relates to a chemical agent for forming a solid lubricating coating film on a metal surface, a method for producing it, a method for applying it, as well as to a tubular product for the oil and gas industry and a threaded connection of tubular products. The chemical agent comprises solid lubricant, binder resin and solvent as its main components. The solvent comprises water as a main component and a lower alcohol having three or less carbon atoms, which is added as an additive to water, and said additive has a volume of 0.5 or more to 45 or less based on 100, given as the volume of water. Water and additive make up 95% or more of the solvent volume. At least metallic soap is used as a solid lubricant, and the metallic soap accounts for 95% or more of the total mass of the metallic soap and alkali soap components. The size of the metal soap particles does not exceed the thickness of the solid lubricating coating film. The binder resin is formed from a water-soluble or water-dispersible polymer or copolymer, wherein the polymer or copolymer having an acrylate or methacrylate structure makes up 90% or more of the total weight of the binder resin.EFFECT: resulting chemical agent is environmentally friendly, and the solid lubricating coating films produced using it have lubricating properties that can withstand use in a real well.20 cl, 8 dwg, 13 tbl, 4 ex

Description

[0001] Field of technology to which the invention relates

[0002] The present invention relates to a chemical agent for forming a solid lubricating coating film that imparts lubricity and corrosion resistance to a metal surface, and to a technology using this chemical agent. Furthermore, this invention also relates to a chemical agent capable of simultaneously improving lubricity and preventing rust on two sliding objects formed from metal surfaces, and to a solid lubricating coating film formed using the chemical agent. This invention primarily relates to a solid lubricating coating film designed for lubricating and preventing rust on joints of oilfield tubular goods.Furthermore, this invention is designed to simultaneously provide adequate lubrication and prevent rust formation under operating conditions, even during make-up / break-out conditions in a real well. Furthermore, this invention is designed to enable early drying during film formation, including drying in an undisturbed environment, blower drying, hot air drying, infrared irradiation, ultraviolet irradiation, and heat treatment.

[0003] At the same time, a problem occurring in a well or during a workover is considered. Accordingly, a case is considered where actual-length nipples are taken individually or in groups of 2 or 3 nipples and assembled near the well. Then, for example, in an onshore well, the actual-length nipples are retrieved one by one. For example, in an offshore well, the actual-length nipples are retrieved in blocks of 2 or 3 nipples. In this case, the oilfield tubular goods are laid side by side and cleaned. The present invention is also intended for use as a chemical agent applied to the thread surface for rust protection, and as a coating film formed in the process.

[0004] State of the art

[0005] Examples of technologies close to the present disclosure include technologies described in PTL (Patent Literature) 1-3.

[0006] PTL 1 provides an example of a threaded joint for a steel pipe having an acrylic-silicone coating film on the surface layer, wherein the surface layer film is mainly made of an ultraviolet-curable resin. PTL 1 provides an example of an epoxy acrylic resin as the ultraviolet-curable resin, and an example in which an oil-based resin or a water-based resin can be used, but it is clearly stated that an oil-based resin is preferred. That is, a water-based resin is not actively used. In addition, PTL 1 provides a quick-drying varnish-based film as the acrylic-silicone surface layer film, and a case in which a metal soap is included as a solid lubricant.

[0007] PTL 2 describes an example of a threaded connection for oilfield tubular goods that additionally contains a dry solid film formed on a viscous liquid or semi-solid lubricating coating film. PTL 2 shows that the dry lubricating film is formed by either a water-soluble or water-dispersible polymer compound, or an organic solvent-based composition. PTL 2 provides an example in which a metallic soap is used in the viscous liquid or semi-solid lubricating coating film. However, PTL 2 presents an example in which the metallic soap is added as a thickener. Furthermore, PTL 2 does not intend the metallic soap to function as a solid lubricant.

[0008] PTL 3 defines a lubricating coating film containing one or both of rosin and calcium fluoride, a metal soap, wax, and a basic metal salt with aromatic organic acids. Optional additional components include thermoplastic resin and acrylic resin. An example of the use of a volatile organic solvent is given.

[0009] In addition, as technologies proposed taking into account screwing on a real well in the relevant field of technology, there are, for example, PTL 4 and 5, NPL 1 and the like.

[0010] PTL 4 describes that the test is performed at 6 degrees as the initial setup using a 7" short nipple and a vertical pipe wrench, allowing for misalignment.

[0011] PTL 5 is an example in which the misalignment was checked and evaluated at 5 degrees using a vertical pipe wrench and a short nipple with a size of 9-5 / 8".

[0012] NPL 1 (Non-Patent Literature) is an article evaluating lubrication using a vertical pipe wrench. Accordingly, NPL 1 describes applying a force of 5 kN to the front end of a short nipple on the side opposite the make-up side, that is, to the upper end of the nipple, when the nipple is raised vertically and being made-up.

[0013] List of references

[0014] Patent Literature

[0015] PTL 1: JP 2016-028211 A

[0016] PTL 2: JP 2008-537062 A

[0017] PTL 3: JP 2009-057754 A

[0018] PTL 4: JP 2002-327874 A

[0019] PTL 5: WO 2017 / 110685.

[0020] Non-patent literature

[0021] NPL 1: Tsuru et al., Journal of the Japanese Association for Petroleum Technology, Vol. 61, No. 6 (1996) pp. 527 to 536.

[0022] NPL 2: KAWAMURA KASEI INDUSTRY CO., LTD., Solubility of Metal Soap, on the Internet https: / / www.kawamura-kasei.co.jp / solubility_table.html

[0023] Disclosure of invention

[0024] Technical problem solved by the invention

[0025] The present invention relates to a chemical agent that simultaneously improves the lubrication of two sliding objects and prevents rust, as well as to a solid lubricating coating film obtained using such a chemical agent. The present invention is mainly aimed at producing a solid lubricating coating film designed to lubricate and prevent rust on a joint for oil and gas tubular goods. The present invention aims to simultaneously ensure sufficient lubrication and prevent rust formation under operating conditions, even under make-up / break-out conditions in a real well. To ensure lubrication and prevent rust formation, the present invention uses a chemical agent in which a metal soap-based component as a solid lubricant is contained in a water-soluble or water-dispersible polymer.The present invention also relates to a solid lubricating coating film formed using such a chemical agent. Furthermore, the water-soluble or water-dispersible polymer is a water-based polymer.

[0026] The water-based polymer mentioned in this application refers to a polymer that has hydrophilicity due to containing a polar or charged functional group in the polymer structure. For example, the water-based polymer refers to a polymer containing a carboxylic acid group, an amino functional group, a sulfonic acid, or the like in the main chain or side chain.

[0027] On the other hand, the prior art faces the following problems.

[0028] (1) No technology has been developed to mix metal soap with a solvent formed from water in a water-based polymer without using oil, ether or a chemical agent from the volatile organic compound (VOC) group, which are also called thinners.

[0029] In the technical field to which the invention pertains, it was not known how to obtain a metallic soap, which is considered to be insoluble in water and alcohol by nature, and how to cloud the metallic soap when mixed with an aqueous acrylic polymer.

[0030] (2) When alkaline soap is added to a water-based polymer, the soap is water-soluble. Therefore, when alkaline soap is added to a water-based polymer, water, which is a solvent, tends to form a highly viscous gel. No research has been conducted in this area of ​​technology related to oilfield tubular goods.

[0031] (3) In the case of a chemical agent using a water-based polymer and a solvent formed from water, there is a serious problem that it takes a long time to dry.

[0032] At the same time, when it comes to solvents other than water, volatile organic solvents such as xylene, toluene, benzene, and the like should be avoided. These substances should not be used in conditions that prohibit the use of fire, and worker safety and health should be considered, including ventilation arrangements, etc. Therefore, it is preferable to avoid the use of volatile organic compound (VOC) chemicals, also known as thinners. The methods cited in the examples in PTL 1-3 are technologies that use volatile organic compounds (VOCs) and do not meet the fire safety requirements applicable at the wellhead. Therefore, they cannot be used for oilfield tubular goods.

[0033] Furthermore, a fluorine-based solvent or fluorine-based binder resin, which is highly volatile but nonflammable, can be used to speed up or accelerate drying. However, these substances are virtually impossible to use. According to the US Toxic Substances Control Act (TSCA), following a rule revision at the end of April 2021, a set of chemicals containing perfluoroalkyl and polyfluoroalkyl substances (PFAS) cannot be used, even with previous approvals. PFAS refers to a group of fluorinated acrylic compounds, including perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). Furthermore, in response to the recent increase in environmental protection requirements, it is likely that every country will follow this trend.Therefore, although a water-based polymer cannot be dried immediately after application, it is preferable to achieve drying properties within 30 minutes in an environment where the object being dried is left at room temperature using a method other than fluorine-based or VOC-based chemicals. Early drying properties refer to the degree of drying, preferably within 15 minutes, and more preferably within 5 minutes. Furthermore, near oil and gas well drilling sites, there are extreme conditions, such as environments where the use of fire is prohibited. It is necessary to consider conditions in which the object being dried is left only in the atmosphere, without the use of a heat treatment oven or electricity. Therefore, it is impossible to envisage performing the solvent removal process by heat treatment at temperatures of 50 to 300°C at the well site.This means that the UV-curable resin described in PTL 1 also requires a device capable of emitting ultraviolet rays at the well site. Therefore, a device capable of drying and electrically connected equipment must be provided, and therefore PTL 1 is considered to have a low probability of implementation.

[0034] A factory producing a product with a solid lubricating film on the surface is not in a fire-prohibited environment, such as a well. In this case, blowing equipment, such as a large fan, hot air drying device, heat treatment, and drying-enhancing equipment using infrared light, ultraviolet light, and the like, are readily available. When drying using such a device to accelerate drying, drying is preferably carried out for 5 minutes, preferably 3 minutes, and more preferably 1 minute. To ensure drying without reducing the line speed, which is consistent with the state-of-the-art technology, drying should be carried out within the working time of the production line.

[0035] (4) With the recent increase in environmental protection requirements, the challenge of designing for a variety of chemicals, including heavy metals and PFAS, has arisen. However, it is believed that the requirements are naturally met when the above-mentioned issue is addressed.

[0036] (5) When the inventors evaluated whether the lubricating properties are exhibited by applying the solid lubricating coating film and the chemical agent described in the present application using an evaluation method suitable for the conditions used in an actual well, it was found that it is important to set the upper and lower limits of the parameters.

[0037] That is, when conducting laboratory evaluation using a short nipple with a length of about 1 meter in the relevant technical field, there is a problem that the evaluation method does not correspond to the actual conditions of use.

[0038] For example, as with the methods described in PTL 4 and 5, even when performing a make-up test using a short nipple with a misalignment setting of five or six degrees, the parameters at the test failure level are likely to be mistakenly determined to be pass-test parameters. As a result, the methods disclosed in PTL 4 and 5 have the drawback of not confirming the upper and lower limit definitions of the parameters. In fact, the case is considered where the make-up / break-out test is performed using a short nipple with an offset of five or six degrees. In this case, the inclination of the nipple connection is mechanically determined on the imperfect threaded portion of the coupling connection and on the conical portion of the front end of the nipple connection. Therefore, due to the thread structure, it is difficult to insert even when the inclination angle is set to five or six degrees.Connections for oil and gas tubular goods have a tapered thread design, and the taper angle is approximately equal to this inclination. However, structurally, inclining the nipple at such an angle relative to the coupling is completely impossible.

[0039] However, the thread can only be inserted without engaging. However, this is unrelated to the behavior during lubrication. The initial installation position changes only momentarily, and then tightening is performed only along the thread cone.

[0040] Furthermore, the nipple connection must be inserted and positioned along the thread cone. Consequently, due to the gap between the lugs that occurs during insertion, an inclination is inevitable. When the nipple connection is inserted into the coupling connection, it is structurally difficult to consistently maintain an inclination angle of approximately 5 degrees. It is assumed that, due to the gap between the profile peaks, only an inclination angle of approximately 1-2 degrees can be maintained. In practice, even from this state, when the threads are engaged, the nipple connection immediately rises vertically. Therefore, it has been established that when the threads are almost not engaged, damage to the solid lubricating film is minimal at an inclination of approximately 5 degrees, and this condition in a real well cannot be simulated.

[0041] Furthermore, the method of applying a 500 kN load to the nipple joint and applying a load equivalent to one actual nipple, as described in NPL 1, also has a problem in evaluation. The initial installation position, which will be described in detail in the following embodiments of the invention, is important for simulating the chattering of the nipple joint in a real well. In NPL 1, as shown in Figure 5, when the nipple is screwed to a position where the nipple can be screwed in approximately half a turn by hand, the load becomes a stabilizer, and makeup is performed in the ideal state of the nipple. Therefore, it is impossible to simulate a serious situation in which the nipple is screwed in and out while chattering due to slight bending of the long nipple in the elastic region in a real well. A serious situation is, for example, a situation similar to a real well.

[0042] Here, the inventors discovered that unless the initial installation position of the nipple connection is intentionally set as described below and makeup / breakout is performed, it is impossible to evaluate the result suitable for the actual situation in a real well or a simulated well. This setup involves setting the nipple connection in a position where the nipple connection extends beyond the coupling connection, and applying a load equivalent to one to three actual-sized nipples to the end of the nipple.

[0043] Here, it is important to note that the lubrication performance of a solid lubricating coating film tends to differ from the results obtained in a real well when evaluated using a simple short nipple, compared to lubrication with a conventional viscous fluid-like compound. Specifically, the evaluation result is too good. That is, even a "meets requirements" rating in the short nipple test does not necessarily mean it meets the requirements in a real well. Therefore, it has been found that for a solid lubricating coating film, unless lubrication is rigorously evaluated, defining upper and lower parameter limits does not ensure lubrication properties that can withstand the environmental impacts of a well.

[0044] The present invention was made by focusing on the above-mentioned problems. Accordingly, the aim of the present invention is to provide an environmentally friendly chemical agent and a solid lubricating coating film with lubricating properties that can withstand use in a real well, even when the chemical agent contains a water-soluble or water-dispersible polymer as a binder resin, a solid lubricant containing a metal soap as the main component, and a water-based solvent.

[0045] Problem solution

[0046] In recent years, in the lubrication of oil and gas tubular goods joints, there has been a tendency that the components of the chemical agent or the lubricating film obtained from the chemical agent are limited due to the increasing awareness of environmental issues.

[0047] In the technical field to which the invention pertains, lubrication of oil and gas tubular joints is achieved, for example, by combining lubricants containing harmful heavy metals and surface treatment on the coupling's connection side. Furthermore, the surface is treated with a manganese phosphate base or a galvanic layer. However, widely used API-mod formulations, i.e., wet lubricants, are already difficult to use in areas with high environmental protection levels. In particular, API-mod formulations contain harmful heavy metals such as Pb and Zn as their main components. Therefore, during pipe make-up, harmful heavy metals can be washed away or splashed out, leading to marine pollution.

[0048] The present invention utilizes a solid lubricating coating film instead of these lubricating compositions. Furthermore, the present invention utilizes a water-soluble or water-dispersible polymer as the binder resin for the solid lubricating coating film. Thus, the present invention aims to eliminate the problem of harmful heavy metal leakage.

[0049] First, in the chemical agent for forming the solid lubricating coating film, which is the objective of this application, the solvent is water, and it is considered that water itself does not pose a problem in terms of environmental resistance. The binder resin and solid lubricant can comply with international standards and regulations for chemical reagent systems. Therefore, in order to simultaneously ensure the safety and health of workers, replacing traditional oilfield tubular joint lubrication with a solid lubricating coating film is also an effective solution to the HSE problem. HSE stands for "health, safety, and environment."

[0050] As for the wet composition used in the general lubrication method, in many cases the composition used in lubrication is different from the composition used in storage.

[0051] The technology for replacing wet-based lubrication with a solid lubricating film must be completed by producing a dry film, i.e., a dry film that also prevents rust during storage. Furthermore, using a conventional wet-based lubrication to prevent rust and protect the nipple connection is less preferable except in emergency situations.

[0052] Therefore, it is considered that the solid lubricating coating film is preferably formed as a coating film having the property of preventing rust formation during storage and also as a lubricating film.

[0053] Furthermore, it should be noted that the technologies used in this field of technology involve both lubricating compounds and corrosion-resistant compounds in the form of viscous liquids. Consequently, these compounds function in a wet state. Therefore, with a wet compound, there is no need to consider drying time.

[0054] On the other hand, a solid lubricating coating film is a dry film and functions in a dry state. Therefore, when forming a solid lubricating coating film, it is necessary to develop a chemical agent, including the work required to evaporate the solvent from the applied chemical agent to form the film, and the time required for this work.

[0055] The art discloses a technology for producing a dry, soft, polymer-based resin film using a chemical agent containing a water-soluble or water-dispersible polymer as a matrix component. Specifically, the technology utilizes the film for surface lubrication of threaded joints in oil and gas tubular goods. Furthermore, with regard to solid lubricants, the art discloses a technology for using a metallic soap as the main component to achieve high lubricity.

[0056] However, a resin obtained by dispersing a metallic soap as the main component of a solid lubricant in a dry film of a soft polymer-based resin formed using a simple water-soluble or water-dispersible polymer, or a combination thereof, is unknown. Furthermore, the polymer-based resin film is a component of the matrix.

[0057] Because no oil or diluent is mixed in, it has been recognized in the relevant art that it is difficult to add a water-repellent and water-insoluble metallic soap to an aqueous solvent as a single substance. This is not to say that the idea of ​​using a metallic soap as a solid lubricant in an aqueous solvent does not exist, but this idea is difficult to implement under the conditions addressed by this invention. The metallic soap has water-repellent properties and simply floats to the surface without dispersing or dissolving, even when attempting to mix the metallic soap with water.

[0058] The present invention relates to a structure in which a water-soluble or water-dispersible polymer is used to form a dry, soft film of a polymer-based resin, and a solid lubricant is dispersed and distributed within the film. Furthermore, the present invention positions a metallic soap as the main component of the solid lubricant.

[0059] Metallic soap itself is water-repellent and insoluble in water. However, metallic soap itself is considered insoluble in alcohols. The substances in which metallic soap itself is considered slightly soluble belong to the group of volatile organic compounds (VOCs), also known as thinners. However, these chemicals are often considered harmful to health and are often widely referred to as thinners. However, these chemicals are classified as toluene, xylene, benzene, a VOC group related to white spirit, a group of esters, and an oil commonly known as mineral oil. This information is generally known.

[0060] However, in the art, it is believed that metallic soap itself does not mix well directly with a water-based polymer. Therefore, in the art, the metallic soap is dissolved in the aforementioned VOC and then turbidified in a solvent formed from water as the main component. A method of using a diluent or the like is described, for example, in PTL 1-3. However, as will be discussed below, there is a high probability that this method cannot be used for worker and environmental safety reasons, as well as environmental protection considerations, and also in areas where the use of fire is prohibited, such as during oil and gas drilling.

[0061] The present invention also contemplates a case in which an alkaline soap is also dispersed. Here, the alkaline soap is a soap formed from either one or both of a Na salt and a K salt of a fatty acid. Hereinafter, the alkaline soap is also simply referred to as soap. The present invention also contemplates using a trace amount of alkaline soap to facilitate or enhance lubrication. Again, the present invention provides a structure for dispersing and distributing a solid lubricant in a film in a state in which the water-soluble or water-dispersible polymer is a dry, soft film of a polymer-based resin.

[0062] Unlike metallic soap, alkaline soap is, on the contrary, water-soluble. Therefore, alkaline soap has the disadvantage of being difficult to use for the chemical agent and solid lubricating coating film discussed in this invention. Furthermore, few application examples have been found in the relevant technical field. When a certain amount of alkaline soap is added to an aqueous polymer, the entire liquid gels and solidifies. As a result, the fluidity inherent in an aqueous system increases. This means that the ease of application disappears, and rapid drying is generally difficult.

[0063] On the other hand, many soap-based lubricants used in a wet state are commercially available worldwide, even for industrial use. However, this is achieved by using lubrication in a solid gel-like state without drying. Therefore, their technological system differs from the present invention.

[0064] As described above, in this technical field, a water-based polymer refers to a polymer in which the solvent is water, and drying and removal of the aqueous component is necessary to form a film. A water-based polymer is a water-soluble or water-dispersible polymer. Because the solvent is water, a water-based polymer heats the object being applied. Conversely, there is also a method in which the target area is heated before coating. In any case, unless a process is implemented to promote volatilization and evaporation of water, the applied product remains in the manufacturing plant until it dries. This significantly reduces production efficiency. Therefore, when drying in the atmosphere, a long drying time is required, and a protected drying area must be provided.Consequently, if measures are not taken to dry the water-based polymer early, production efficiency decreases, and production costs increase. Therefore, a drying unit and a heat treatment oven are required when drying is performed early using a device. However, this increases installation and operating costs.

[0065] On the other hand, a technology is also known in the relevant technical field for early drying of an aqueous polymer, which involves adding a volatile organic solvent and forming a film by effectively utilizing the heat generated by the volatile organic solvent. PTL 1 describes that, since an acrylic silicone surface film forms a dry coating film at a relatively low temperature in a short time, an oil-based surface film can be selected, and an ambient temperature-curable type film can be particularly preferably used. Therefore, PTL 1 is an example of attempting early drying by utilizing the evaporation of an oil solvent without selecting an aqueous solvent.

[0066] Furthermore, PTL 2 only covers water-based films, films based on water and volatile organic solvents, and films using UV-curable resin. Of the three, the latter two can be dried early. However, when using the former, a water-based resin only, the water must be evaporated using a specific method. However, PTL 2 does not clearly describe this method.

[0067] Furthermore, PTL 3 discloses a measure to accelerate drying time by using a volatile solvent and a chemical agent with a flash point of 30°C or higher. However, when the flash point is approximately 30°C, in the presence of a hazard such as a spark in a hot area such as a hot desert, there is a high probability of a fire occurring at the wellhead. Furthermore, even if processing is carried out in a workshop located near the wellhead, the possibility of a fire cannot be ruled out. In this regard, a material with a low flash point carries a high risk of fire and other accidents if not used under sufficiently controlled conditions. Therefore, the question remains as to how safely and early drying is carried out. A material with a low flash point is a material that is easily ignited.

[0068] On the other hand, the present invention includes, as a solid lubricating coating film, a solid lubricating coating film based on a water-soluble or water-dispersible polymer.

[0069] To accelerate the drying of water-based solvents, one approach could be to utilize the volatility of volatile organic compounds (VOCs), also known as thinners. However, given VOC emission control regulations and to prevent workers from being exposed to contaminated environments, the inventors decided to avoid the use of organic solvents such as toluene, xylene, or benzene, even if the organic solvent is highly volatile and effective for early drying. Even manufacturing an exhaust system can entail significant investment in equipment. Furthermore, the chemical agent used to form the solid lubricating film does not use a volatile organic solvent, which is harmful to humans.Thus, the inventors determined that a group of chemical agents from volatile organic compounds (VOCs), which are also called thinners, are harmful to health and have too high volatility, and cannot be used to ensure rapid drying.

[0070] Furthermore, fluorine-based solvents, which inherently have quick-drying properties, and fluorine-based resins, which can be dissolved in fluorine-based solvents to form a resin binder from the coating material, are generally no longer used. Fluorine-based solvents are alternatives to CFC-based or similar materials.

[0071] In the technical field to which the invention pertains, fluorine-based compounds have the property of drying quickly immediately after application and are good for lubrication and corrosion prevention, so they are mainly used for surface treatment. However, due to recent tightening of regulations, fluorine-based compounds have become unsuitable for use. In the United States Toxic Substances Control Act (TSCA) and REACH, including the European Union's Restricted Chemicals Act (REACH), perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) are the only regulated chemical compounds (chemical compounds containing fluorine compounds with eight C) of the F-based alkyl compounds (F-(CF2)n-). Compounds with a C number of less than eight were suitable for use without causing any special problems.However, as a result of the April 2021 revision of TSCA in the United States, the importation, use, or production of chemical agents containing organofluorine compounds (PFAS: perfluoroalkyl compounds and polyfluoroalkyl compounds) into the United States is almost completely prohibited. Consequently, binder resins containing fluorine compounds (PFAS) cannot be used. Therefore, only Teflon (registered trademark) (PTFE: polytetrafluoroethylene) and perfluoropolyether (PFPE) are now exempt from the scope of TSCA for chemical agents and products that can be used with fluorine. Accordingly, the international trend toward developing fluorine-free solid lubricating coating films is no longer ignored.

[0072] In view of the above, in the present invention, it is considered that a solid lubricating coating film is formed by using water as a solvent to solve environmental problems, converting a binder resin into a chemical agent containing a water-soluble composition, producing a chemical agent from an appropriate solid lubricant or other additives, and using the chemical agent.

[0073] However, water as a solvent is difficult to evaporate, and the problem is that it takes time to evaporate. Furthermore, many problems arise from the large capital investment required for drying, as a heat treatment oven is required.

[0074] Furthermore, when applying a solid lubricating coating film to the threaded portion of an OCTG connection, the OCTG must be manufactured and transported away from the oil / gas well. Therefore, by producing a solid lubricating coating film based on a water-soluble or water-dispersible polymer at a production facility, all problems associated with rapid drying can be solved. Since water-based polymers are difficult to dry, it is possible to adopt measures such as setting up a drying system over time or organizing the drying process using a heat treatment device or similar equipment. During this time, when the heat treatment device is not in use, a volatile organic solvent can also be added to promote drying.In addition, it is often possible to provide an exhaust device and take measures to prevent ignition.

[0075] However, when a chemical agent for forming a solid lubricating film and a solid lubricating film formed using the chemical agent are used for a threaded connection of oil and gas tubular goods, and the threaded connection of oil and gas tubular goods is used in a well, the following problems arise. That is, the solid lubricating film is not necessarily manufactured or formed only at a production facility away from the well.

[0076] When a problem or similar issue with the lubricating film formed on oil and gas tubular goods is suspected, it must also be assumed that the chemical agent for forming the solid lubricating film is being used at the well. The well site is located in a fire-prohibited zone, and there is also a situation where the scaffolding is not strong. Furthermore, when a water-soluble or water-dispersible polymer is applied at the well site, rapid drying is required.

[0077] This is due to the fact that when a problem occurs at a well, the pipe connections are lifted near the well and unscrewed into blocks of one to three nipples. In this case, it is necessary to arrange the lifted nipples (oil and gas tubular goods) side by side, clean the nipple surfaces with water, steam, or a similar substance, and apply a coating similar to a storage coating to prevent rust. On the other hand, in the method for connecting oil and gas tubular goods, it has been established from methods known in the art that a wet lubricating compound containing Pb and Zn, such as API-mod, is not used; instead, a compound called a wet storage compound is applied to solve this problem.

[0078] On the other hand, with a solid lubricating film coating, unlike with a wet coating, a solid film base must be formed that can be quickly dried at the well site to complete the coating application using solid lubricating film coating technology alone. However, lighting fires in the well area is strictly prohibited. Due to the risks, the use of organic solvents with a low flash point and good volatility, which facilitate rapid drying, is not possible.

[0079] The descriptions of PTL 1-3 illustrate such cases; however, in the relevant technical field, an organic solvent with a low flash point and high volatility is used to rapidly form a film. Accordingly, it is assumed that the design of the chemical agent will be based on the assumption that oil and gas tubular goods are manufactured and transported away from oil / gas wells. A chemical agent based on a chemical with a low flash point is extremely dangerous to use near oil / gas wells, where fire is strictly prohibited.

[0080] The present invention provides a chemical agent that minimizes the use of a highly volatile organic solvent.

[0081] Furthermore, the inventors do not intend to evaluate the anti-corrosion and lubrication issues of the present invention using simple laboratory experiments or simulations, which are often performed on a daily basis. The inventors examined a typical laboratory test and concluded that a test capable of withstanding even the harshest conditions imaginable is necessary.

[0082] In the present invention, regarding the anticorrosion properties, a situation in which the solid lubricating coating film is damaged is assumed, rather than the anticorrosion properties of a simple film in its original state. It is assumed that, under the most severe and possible operating conditions, the surface of the solid lubricating coating film of an oil and gas tubular joint should maintain corrosion resistance after make-up / break-out with a protector. That is, the present invention assumes that the solid lubricating coating film should be able to maintain corrosion resistance even in a damaged state caused by contact with a protector.

[0083] At the same time, in the present invention, regarding lubricity, it is necessary to ensure good lubricity under sliding conditions under high loads. Considering a real well, it must be assumed that the solid lubricating film is inevitably scraped off to some extent during make-up or break-out. The inventors discovered that scraped off fragments cause scuffing wear problems in the following cases. For example, this case includes a situation where the gap between the coupling joint and the pin joint is clogged, a situation where a high load and unbalanced load are applied to the connecting portion, a situation where part of the film is completely removed, and so on.Accordingly, the present inventors have found that unless the upper and lower limits of the solid lubricating coating film components are established with respect to lubrication characteristics by simulating a real well or near-well conditions, their definitions will not be meaningful for a real well.

[0084] In the related art, a commonly used test is a laboratory make-up test using only a short nipple of approximately 1 m in length. In the make-up test concerning the lubrication of a solid lubricating coating film, which is the subject of this disclosure, the lubrication determined as NG (not meeting the requirements) is also NG in an actual well. However, in a test in the related art, the inventors found that although the evaluation in the test using a short nipple of approximately 1 m in length is acceptable, such a determination does not guarantee that the result will be acceptable in an actual well. However, with regard to the determination range of the lubricity of a solid lubricating coating film, there are very few reports in the patent literature in previous years on selecting the determination range of a solid lubricating coating film taking this aspect into account.

[0085] Furthermore, a viscous, liquid-like lubricant typically used to lubricate oilfield tubular goods connections in the relevant field of engineering does not show significant differences between the make-up / break-out performance results using a short nipple in the laboratory and under actual wellbore operating conditions. Furthermore, the actual wellbore performance is generally determined in accordance with the laboratory test results. It should be assumed that the composition is a viscous, liquid-like lubricant and is therefore effective for movement in parallel with make-up / break-out.

[0086] On the other hand, in the case of a solid lubricating film, the inevitably scraped-off fragments do not necessarily move in parallel with the make-up / break-out process. Therefore, in a real well, where numerous fragments inevitably form, they can cause clogging. Furthermore, if significant peeling occurs, scuffing wear occurs in the area where the solid lubricating film becomes thin or in the area where the solid lubricating film disappears. Based on these results, the inventors concluded that when evaluating a solid lubricating film, it is necessary to make a determination based on the aspect described above.

[0087] The results obtained will be described in more detail.

[0088] In a real well, the situation in which a nipple connection of actual length is screwed into a coupling connection does not occur in the ideal state, as described in the textbook. The ideal state depiction assumes that the actual-sized nipple is installed vertically and inserted directly into the coupling connection. However, in practice, this does not occur. The design of oilfield tubular goods connections has a non-ideal threaded section, where the nipple connection is inserted into the coupling connection by insertion. Consequently, in many cases, during initial installation, the nipple is installed slightly at an angle due to clearance (play, offset) in the section. Consequently, at the beginning of make-up, the nipple connection wobbles with a runout equal to the amount of play.Therefore, until the threads engage, the solid lubricant film is subject to the weight of the pin, which is a heavy and unbalanced load, causing eccentric movement of the pin. This poses a serious risk of the solid lubricant film being abnormally scraped off or completely peeling off. On the other hand, since the wet lubrication compound is a viscous lubricant, similar to a liquid, it moves with the make-up / break-out process. Therefore, with regard to the lubricant compound, the lubrication evaluation method in the laboratory using a short pin and the results in a real well are virtually identical, which is a good contrast.

[0089] This is particularly illustrated in Figures 2A-3B.

[0090] The examples shown in Figures 2A-3B are examples of conditions under which the make-up / break-out tests are performed at a rotation speed of 15-25 rpm before increasing the torque and at a speed of 2.5-1.5 rpm with increasing torque. This is the result of testing under severe conditions, that is, at a high rotation speed exceeding the conditions specified in the connection manual, that is, the make-up description in the technical kit. The examples shown in Figures 2A-3B represent an example of evaluating the solid lubricating coating film on a JFELION (trademark) connection made of 9-5 / 8” 53.5# material and Q125 as the downhole make-up material and strength grade.

[0091] Figure 2A shows a torque / speed diagram when makeup is performed using a short nipple, approximately 1 m in length, with a vertical pipe wrench based on a laboratory evaluation method known in the art. Since the nipple is short, it is easy to handle and can be installed straight. Therefore, the nipple can be manually set to a position where the apex of the nipple profile is almost invisible (Figure 2B). In this case, in the torque / speed diagram, the torque begins to increase from the start of makeup, and makeup is performed beyond the bending point of the torque arm. That is, in this case, a very general diagram is obtained (Figure 2A). Here, the torque on the nipple immediately increases because the nipple connection and the coupling connection are sufficiently engaged with each other at the initial stage of installation, and makeup is performed from a predetermined position.

[0092] On the other hand, Figure 3A shows a torque / RPM graph obtained using one actual-size nipple with a range of 3, i.e., 40 feet or more (12 meters or more). Accordingly, Figures 3A and 3B illustrate the result of a test conducted in a simulated well. Here, the unit (size) of the horizontal axis is different from that shown in Figure 2A. In addition, the simulated well is not a well that actually produces oil and gas, but an experimental well that is drilled in a simulated manner so that three actual-size nipples or more can enter the well in a subsurface direction, i.e., downward. At the same time, the simulated well means a group of devices and an experimental setup, which has a drilling rig on which 2 to 3 connected nipples can be suspended and installed in the upper chamber, and a make-up / break-out test can be carried out.This example typically represents a condition where the nipple is installed similarly to a real wellbore installation, but differs from the case shown in Figures 2A and 2B for a short nipple. In this example, the steady-state torque does not increase until approximately 6.3 revolutions, and uneven, intermittent torque peaks are occasionally observed during rotation. The inventors found that this phenomenon is directly related to damage to the solid lubricant film and highlights the importance of evaluating the solid lubricant film based on the data obtained.

[0093] This example of a torque diagram is shown in Figure 3A. This occurs when a Range 3 nipple, i.e., 40 feet plus (12 meters plus), is installed. In this case, since the actual nipple size is approximately 12 meters plus, the nipple cannot be installed completely level, and in most cases, the nipple is inserted at an angle. Furthermore, this condition is similar to that of a real well. Therefore, even if the nipple is installed manually, the nipple connection and the coupling connection are partially too tightly pressed against each other. Therefore, five or more profile peaks on the nipple, and in many cases, approximately half of all profile peaks, cannot be further advanced manually when they are visible from the coupling. From this state, make-up and insertion with a wrench begins.Accordingly, the threads are not sufficiently engaged with each other, and some threads unintentionally press against each other too hard and, in most cases, no longer advance. Therefore, until the actual size pin threads are sufficiently engaged with each other, the coupling joint and the pin joint will adhere to each other in a state where the load is unbalanced. This means that damage occurs. Taking this into account, the inventors of the present invention found that, as described above, if the solid lubricating coating film is not evaluated, a film determined to be NG (failure) in the evaluation using a short pin is also determined to be NG in the actual well, but a film determined to be OK (pass) in the evaluation using a short pin does not necessarily mean "OK" in the evaluation in the actual well.Therefore, in the previous invention, it was found that a film determined to be “OK” when evaluated using a short nipple will not necessarily be in a favorable range in an actual well when determining the upper / lower limit of components, conditions and other parameters.

[0094] Here, PTL methods 4 and 5 are examples of test scores using short nipples and will not necessarily be in the favorable range.

[0095] Furthermore, in the NPL 1, when the nipple is installed vertically and made up, a load of 5 kN is applied to the upper end of the nipple to evaluate lubrication. In this case, it is considered that in the NPL 1, a weight equal to one nipple of the actual length, that is, a nipple of approximately 40 feet (approximately 12 m) in length, as determined based on the torque / turn chart for the 7" / 29# nipple, is intentionally applied. However, when the determination is made based on the turbine tightening torque table, that is, based on Fig. 5 of this document, it is considered that the NPL 1 is based on the assumption that the test is carried out with make-up parameters close to Figs. 2A and 2B, rather than Figs. 3A and 3B.That is, NPL 1 is considered to be based on the premise that the test is defined as a test of the make-up condition, starting from a specified initial position, in which the nipple connection is manually tightened to a level where the nipple connection is no longer visible from the coupling connection, with the nipple connection and coupling connection sufficiently engaged. Therefore, it is not always possible to obtain a favorable range.

[0096] From the above description, the problems identified in the present invention will be described below.

[0097] The present invention is based on the premise that no oiling agent or volatile organic compounds (VOCs) contained in the diluent are used. Based on this premise, the present invention considers producing a chemical agent by dispersing a solid lubricant component based on a metallic soap in a binder resin formed from a water-soluble or water-dispersible polymer. Furthermore, the possibility of using the chemical agent to form a lubricating film formed from a solid lubricating coating film and having corrosion resistance is considered.

[0098] This configuration was found to have the following issues. Therefore, it was determined that additional measures are necessary.

[0099] The first problem

[0100] This is a problem that occurs when metallic soap is mixed with a water-based polymer. That is, when mixing metallic soap, which is insoluble in water, measures must be taken to make the mixture cloudy without the use of volatile organic compound (VOC) chemicals, also known as thinners.

[0101] The second problem

[0102] When alkaline soap is added to an aqueous polymer, because alkaline soap is water-soluble, the solvent tends to convert to a highly viscous gel-like state. Therefore, even though the alkaline soap has lubricating properties, film formation may take time. At the same time, it is necessary to determine the appropriate amount of alkaline soap to obtain a solid lubricating film in the dry state.

[0103] The third problem

[0104] Since the polymer is water-based and the solvent is water, there's a significant problem with drying time after application. Therefore, certain measures must be taken to ensure rapid drying. In short, it's preferable to apply the coating anywhere and ensure drying as quickly as possible.

[0105] Extreme situations, such as fire-prohibited environments, also include environments where neither a heat treatment furnace nor electricity is used, and the coating film only needs to remain in the atmosphere. However, the present invention is based on the assumption that the solid lubricating coating film and chemical agent can be used not only at the production site of oil and gas tubular goods but also at the wellsite. Therefore, to improve the efficiency of rapid drying, it is necessary to avoid the use of VOC thinners at wellsites where fire is strictly prohibited. At the same time, worker safety and health, as well as ventilation design, must be considered. Therefore, it is necessary to develop a solid lubricating coating film and chemical agent based on the assumption that the use of VOC thinners should be avoided.

[0106] The Fourth Problem

[0107] To meet the demands of recent increased environmental awareness, it is necessary to stop using a number of chemicals containing heavy metals and PFAS (a group of fluorinated acrylic compounds, including PFOS and PFOA). PFAS is also a group of fluorinated acrylic compounds, including PFOS and PFOA.

[0108] The Fifth Problem

[0109] Regarding the solid lubricating coating film and chemical agent described in this invention, it is important to establish the upper and lower limits of the parameters by evaluating the presence or absence of lubrication, or something similar, using an evaluation method suitable for the conditions used in a real well. However, when evaluating using a short nipple of approximately 1 meter in length, the evaluation method in the relevant technical field does not correspond to actual application conditions.

[0110] Next, means for solving each problem described in this disclosure will be described.

[0111] The present invention provides a chemical agent comprising a water-soluble or water-dispersible polymer, i.e., a water-based polymer, as a binder resin, a metallic soap as the main component of a solid lubricant, and a solvent containing water as the main component. This invention further provides a solid lubricating coating film formed from said chemical agent. 0112 A metallic soap acts as a solid lubricant with water-repellent properties. Water-repellent properties mean that the soap is not water-soluble. It is believed that good properties such as lubricity, corrosion resistance, and rapid drying ability are achieved within the range defined in this invention, provided that the metallic soap can be properly incorporated into the chemical agent. To solve the above problems, this disclosure is defined using the following solutions and configures the invention.

[0113] The solution method for the first problem refers to the technology of successfully mixing metal soap with water-based solvent.

[0114] Typically, metallic soap is described as insoluble in both water and alcohol and reportedly soluble in viscosity-lowering volatile organic compounds (VOCs), ethers, and oils. For example, NPL 2 clearly states that metallic soap is insoluble in ethyl alcohol, methyl alcohol, and butyl alcohol. This means that when water is selected as the solvent and a VOC solvent is used, which easily volatilizes even at room temperature and is a viscosity-lowering solvent requiring a special mask or exhaust equipment for the worker, the metallic soap will melt. However, in the relevant technical field, it was believed that there was no way to dissolve metallic soap in water unless such a substance was added.

[0115] Furthermore, considering the lubrication of oil and gas tubular joints and assuming that the chemical agent is used at the well site, a problem arises: the use of a thinner is strictly prohibited in well site conditions where fire hazards are high and fire is strictly prohibited. A viscosity-reducing solvent cannot be used, even though no solvent remains in the resulting film.

[0116] The inventors conducted experiments investigating the mixing of a water-insoluble metallic soap with water, which is a solvent for a water-soluble or water-dispersible polymer, i.e., a water-based polymer. In the experiments, the metallic soap was insoluble in both water and ethanol. However, during actual dissolution, observations of the experiment revealed that the dispersion of the metallic soap differed in water and in a group of lower alcohols, including ethanol, when comparing water and a lower alcohol.

[0117] In particular, it was found that in a group of lower alcohols, including ethanol, metallic soaps are virtually non-clumping and readily dissolve into solid particles, allowing the metallic soaps to persist as fine particles. Metallic soaps can be mixed with alcohol and then vigorously shaken or ultrasonically treated. However, in water, metallic soap particles associate with each other and become larger, forming clumps, making it impossible to achieve a homogeneous dispersion of metallic soaps.

[0118] From this, it was discovered that metallic soap could be dispersed in an insoluble state by temporarily dissolving the metallic soap in lower alcohols, such as ethanol. It was then discovered that such a mixture could be developed and mixed with a water-based polymer, thereby creating a metallic soap mixture that approximates a homogeneous chemical agent.

[0119] When the chemical agent described in the present invention is left unstirred, the metallic soap separates over time. However, it has been verified that by removing the aqueous solvent, i.e., evaporating the water, after application, a uniform, solid lubricating film is formed. This is the case when the solvent is applied after re-turbidification by shaking the container containing the chemical agent of the present invention or by the like at the time of use (i.e., application).

[0120] In addition, when the metal soap is directly dissolved in water, it tends to form lumps, so there is a great danger that the metal soap will form a heterogeneous film when it forms a solid lubricating coating film.

[0121] The reason for the above is not very clear.

[0122] Qualitatively, water is merely a polar solvent. On the other hand, lower alcohols, including ethanol, are soluble in water and generally slightly soluble in oil. Metallic soaps are described as insoluble in water and generally insoluble in alcohol. However, metallic soaps can be dissolved in oil or VOCs, called diluents. Therefore, it is assumed that the level of insolubility differs at the molecular level and, therefore, is effective in accounting for the differences in the phenomena described above.

[0123] On the other hand, lower alcohols, including ethanol, are also highly volatile and are classified as volatile organic compounds. Therefore, there is concern that they may cause combustion in environments where flames are prohibited. Therefore, it is necessary to determine the upper limit of the useful amount of lower alcohol used to dissolve metallic soap and the concentration of lower alcohol in the chemical agent. From this perspective, the present invention defines an upper limit for the lower alcohol content.

[0124] Furthermore, the greater the amount of dissolved metallic soap, the better its performance as a solid lubricant. However, the maximum amount of dissolved metallic soap is determined by the upper limit, which depends on the maximum amount of solvent alcohol, volatility, and flash point. Accordingly, the lower limit of metallic soap content is determined based on the minimum amount at which lubrication can be achieved.

[0125] The second problem is how to mix a trace amount of alkaline soap as an auxiliary component for lubrication.

[0126] That is, the method for mixing trace amounts of alkaline soap is based on the premise that VOC such as diluent is not added to the system in which a water-based polymer is used as a binder resin, a metal soap is used as the main component of a solid lubricant, and water is used as a solvent.

[0127] Alkaline soap is water-soluble, so it can be mixed. However, when alkaline soap is dissolved in excessive quantities, water, as a solvent, tends to become a highly viscous gel. Therefore, when a chemical agent is applied, it is difficult to dry, and it takes time for the chemical agent to dry into a solid film. Furthermore, when the film dries, it turns into a semi-solid film with high viscosity. Consequently, the semi-solid or viscoelastic film retains its stickiness on the surface and allows dust or sand to easily adhere. If dust or other particles are present, they are difficult to remove. Dust or other particles will cause resistance during tightening and loosening, and there is a risk that the necessary lubrication will not be achieved.

[0128] From the above description, it is necessary to add alkaline soap in a small amount and set an upper limit to maintain the additive amount sufficient to maintain the solid lubrication effect of the alkaline soap without changing the viscosity of water as a solvent. From this perspective, the present invention determines the amount of alkaline soap added.

[0129] The third problem is that since the water-based polymer uses water as a solvent, there is a possibility that it will take time to dry when applying the chemical agent.

[0130] In this description, the use of large quantities of VOCs and water evaporation due to the volatility of VOCs are not considered in fire-prohibited environments. VOCs based on toluene, xylene, and benzene, which are known as thinners, should not be used where worker health and safety are at stake. Furthermore, safe drying of the film must be ensured, including situations where the film is formed solely by drying in an environment where the use of an electric heater is not possible, or outdoors in field conditions.

[0131] In the present description, the lower alcohol mentioned in the first problem, i.e., a group of alcohols such as ethanol, methanol, isopropyl alcohol, normal propyl alcohol, and industrial ethanol, is used to dissolve the metallic soap. Currently, as described above, the lower alcohol can be included in the composition within a range that does not pose problems with volatility and flash point, so the chemical agent can be used even in environments that prohibit the use of fire.

[0132] For use in a fire-resistant environment, the following conditions must be met. The flash point of the chemical agent must be 60°C or higher, preferably 150°C or higher, and more preferably 250°C or higher. Accordingly, under these conditions, a lower alcohol is added in an amount greater than that required to dissolve the metallic soap, taking advantage of its volatility.

[0133] However, this means that the higher the flash point, the lower the amount of alcohol added / the alcohol content. However, the preferred lower alcohol content is at least 0.5% or more.

[0134] At the same time, the addition of ammonia water and its volatility can be used.

[0135] Ammonia water can be used to adjust the pH of the coating material. When used for pH adjustment, ammonia water is additionally added to adjust the composition to the upper limit of the prescribed pH of the chemical agent, that is, to a high pH level. Furthermore, when ammonia water is not intended for pH adjustment, volatility can be increased by adding ammonia water (28 to 30%) at an upper limit of 1% by volume relative to the water-containing solvent. In the present invention, the conditions for the simultaneous use of ethanol and ammonia were clearly determined through experiments to clarify the optimal range. Commercially available ammonia water also includes ammonia water with a low ammonia content of 10% or 5%. However, in the present invention, concentrated ammonia water (28% to 30%) is used as the basis for discussion.

[0136] At the same time, this invention selects a metallic soap with a small particle size. Accordingly, by dispersing the metallic soap in a chemical agent so that it does not stick together, the contact surface area of ​​the metallic soap is increased and drying is achieved earlier.

[0137] By using a metallic soap having an average particle size of 10 μm or less, preferably 5 μm or less, and more preferably 1 μm or less, the drying of the applied agent is accelerated. Furthermore, to disperse and mix the metallic soap with the chemical agent as described in the method for solving the first problem, the chemical agent is obtained by dissolving the metallic soap in a lower alcohol such as ethanol.

[0138] Furthermore, it is important to regulate the viscosity of the chemical reagent. It is also important to reduce the viscosity to achieve a thin film application while also preventing the film from being applied in thick layers.

[0139] If a chemical agent is applied to the metal surface of the cylinder while rotating, excess chemical agent will inevitably fall from the 6 o'clock position, the lowest position. Similarly, when the cylinder is not rotating, even though the 6 o'clock position tends to be slightly thicker, excess chemical agent will inevitably flow down from the 6 o'clock position. Even when applying a chemical agent to an object such as a plate, the excess chemical agent will flow downward due to its own weight when the object is tilted. This allows for rapid drying to be easily achieved.

[0140] Therefore, for rapid drying, even in situations where the metal surface coated with a chemical agent remains indoors or outdoors in an atmospheric environment, rapid drying can be achieved under the following conditions. This condition involves combining alcohol and ammonia, selecting the particle size of the metal soap, ensuring that the metal soap does not clump or form lumps, adjusting the viscosity of the chemical agent, and ensuring that the chemical agent is not applied in a thick layer.

[0141] The fourth issue concerns the method of developing a chemical agent that does not use heavy metals and a set of chemical reagents containing PFAS. PFAS refers to a group of fluorinated acrylic compounds, including PFOS and PFOA.

[0142] On the other hand, since the present invention does not use a harmful substance in the aqueous polymer, the problem can be naturally solved by realizing the solution to problems 1-3.

[0143] The fifth problem is that it is necessary to determine the upper and lower limits of each material by evaluating the performance of lubricating and anticorrosive films through the appropriate evaluation method.

[0144] First, regarding the anti-corrosion properties and corrosion resistance according to the present invention, the threaded joint lubricant for oil and gas tubular goods is designed for the most severe operating conditions. When evaluating the corrosion resistance in a state in which the film is simply attached to the plate, or the lubrication performance using a short nipple, a negative result may be obtained, but the plate cannot be said to have passed the test.

[0145] In the present invention, with respect to the anti-corrosion properties, it is necessary to consider not only the corrosion resistance of the film as it is after applying the chemical agent for forming the film, that is, with respect to the anti-corrosion properties, it is necessary to consider that the film is brought into partial contact with the tread and the film is damaged when screwing with the tread.

[0146] Furthermore, regarding lubrication, a nipple of actual length corresponding to Range 3, that is, a nipple approximately 40 feet (approximately 12 m) long, is installed vertically in a real well, suspended using a drilling crane or similar device, and screwed together. In the worst case, the entire dead weight of the nipple of actual length falls on the coupling side. Furthermore, the equivalent weight of one 9-5 / 8" 53.8# nipple is approximately 1 ton. Due to the heavy load, it is necessary to anticipate a situation in which the solid lubricating film will be significantly damaged.

[0147] Furthermore, regarding the initial installation position of the actual length nipple, unlike the short nipple, a situation is assumed in which almost all of the profile peaks of the nipple cannot be screwed in until they are hidden in the coupling connection. Therefore, it is necessary to evaluate lubrication by assuming a situation in which the nipple can only be inserted to a position at which the thread cannot advance further during rotation, that is, to a position at which the profile peak remains exposed. For example, in an actual well, the nipple connection can only be installed to a position corresponding to 1a (10) in Fig. 3B.

[0148] However, it is unrealistic to evaluate the lubricating properties of the connection of oil and gas field tubular goods in a real well or in a simulated well from the point of view of the costs and time for organizing the experiment.

[0149] The solution to this problem is as follows.

[0150] A load equivalent to the weight of one to three actual-length nipples is applied to the upper end of the short nipple. Furthermore, the initial installation position of the connection is such that approximately half of the nipple's profile peaks protrude from the coupling connection. Therefore, the load is applied during makeup, but no load is applied during breakout. The upper and lower parameter limits are determined based on actual conditions after simulating makeup in a real well.

[0151] That is, in the present invention, the initial position of the nipple connection is intentionally set so that the nipple connection protrudes (is visible) from the coupling connection. Furthermore, in this description, a weight equivalent to the weight of one to three actual-sized nipples is placed on the end of the nipple, and make-up / break-out operations are performed for evaluation. During make-up, a weight equivalent to the weight of one to three actual-sized nipples is used. Furthermore, it is assumed that a weight equivalent to one nipple is located in an onshore well, and a weight equivalent to three nipples is located in an offshore well. During break-out, the weight is suspended from an overhead crane to adjust the load, and the load is reduced, including the zero load, to perform break-out. If the weight is applied as is during break-out, the weight, on the contrary, becomes a balancer, and the nipple rises straight without rattling.Thus, the solid lubricating film is in a situation where neither the coupling connection nor the nipple connection is damaged at all, and it is impossible to simulate the real situation in a real well.

[0152] Advantages of the invention

[0153] The chemical agent of the present invention is a chemical agent that contains a metal soap as a main component of a solid lubricant, a water-soluble or water-dispersible polymer as a main component of a binder resin, and water as a main component of a solvent.

[0154] According to the chemical agent of the present invention, under the condition of such a configuration as described above, it is possible to obtain an environmentally friendly chemical agent without using a group of chemical agents called diluents, heavy metals, and a set of chemical agents containing PFAS.

[0155] Furthermore, the chemical agent described in this invention also enables faster drying without the use of a group of chemical agents known as thinners. Thus, the chemical agent can be used even in conditions that prohibit the use of fire. PFAS refers to a group of fluorinated acrylic compounds, including PFOS and PFOA.

[0156] Further, the chemical agent described in the present invention can provide a solid lubricating film having lubricating properties and corrosion resistance that can withstand use in an actual well.

[0157] Brief description of drawings

[0158] Figure 1 is a view illustrating oil and gas tubular goods and a threaded connection of oil and gas tubular goods;

[0159] Figure 2A is a graph illustrating a screwing pattern in a laboratory test in the relevant technical field, and Figure 2B is a view illustrating the initial installation position at that time;

[0160] Figure 3A is a graph illustrating a make-up pattern in an actual well, and Figure 3B is a view illustrating the initial position of the installation at a given time;

[0161] Figures 4A and 4B are schematic diagrams illustrating make-up diagrams, where Figure 4A shows an example of a real well, and Figure 4B shows an example of a laboratory test in the related technical field;

[0162] Figure 5 is a view for explaining the conditions (pipe wrench with load) of the new laboratory test;

[0163] Figure 6 shows an example of installing the load according to the conditions (pipe wrench with load) of the new laboratory test;

[0164] Figure 7 is a schematic view illustrating the installation state of a nipple connection and a coupling connection, and in Figure 7, the description of the profile top and the like is omitted; and

[0165] Figure 8 is a schematic view illustrating an example of a method for performing application to a pipe using a brush.

[0166] Implementation of the invention

[0167] The present invention relates to a solid lubricating coating film formed on one or both sides of lubricated surfaces and to a chemical agent for forming the solid lubricating coating film, for example, in a situation where two objects made of the same metal and facing each other must slide, and high lubricity is required. The present invention relates to a solid lubricating coating film and a chemical agent for forming the solid lubricating coating film, in particular for thread lubrication and, further, for thread lubrication of oil and gas tubular goods.

[0168] At the same time, the present invention is designed to simultaneously provide anti-corrosion properties to the lubricating film. This invention is intended to ensure sufficient lubrication of the threaded portion even under make-up / break-out conditions in actual oil and gas wells.

[0169] The present invention utilizes a solid lubricant component containing a metallic soap as the main component, and a water-soluble or water-dispersible polymer as the binder resin. Furthermore, when applying a chemical agent to form a solid lubricant film, instantaneous drying, such as drying at the application site, is not expected. However, the present invention aims to achieve early drying to the extent that drying can be completed in approximately 30 minutes, even if the chemical agent is applied and left to dry in the atmosphere.

[0170] This invention provides corrosion protection by coating with a soft film. Furthermore, this invention aims to provide lubrication by using the soft film as a film that simultaneously performs a lubricating function. Accordingly, this invention aims to provide a chemical agent for forming the film. The present invention also focuses on environmental resistance and compliance with international chemical reagent conventions, as well as a design that incorporates quick-drying properties and practical use.

[0171] Furthermore, the chemical agent described in the present invention is also designed to address the conditions when a problem occurs in a well or when a major workover is performed. Therefore, the chemical agent of the present invention is also intended to be used as a coating film that is formed on the thread surface for rust protection when actual-length nipples, individually or in blocks of two or three nipples, are assembled and positioned near the well and washed. It is assumed that the actual-length nipples are disconnected individually in a land well, and the actual-length nipples are disconnected in blocks of two or three nipples in an offshore well.

[0172] Next, embodiments of the invention will be described.

[0173] In one embodiment, the description describes oilfield tubular goods as metal components having a surface that is imparted with lubricating properties. The invention can be applied to other metal components.

[0174] Configuration

[0175] Chemical agent

[0176] The chemical agent of this embodiment is a chemical agent for imparting lubricity and corrosion resistance to a metal surface of a metal component such as oilfield tubular goods.

[0177] The chemical agent is composed of solid lubricant, binder resin and dissolving component, and may contain a small amount of additional additive component depending on the situation.

[0178] Dissolving component

[0179] The solvent component contains water as its main component. A lower alcohol containing three or fewer carbon atoms is added to the water as an additive. The volume of the additive, calculated as water, is from 0.5 or more to 45 or less per 100, specified as the volume of water.

[0180] One of the characteristics of the solvent composition of the present invention is that 95% or more of the volume of the solvent is formed from water and a lower alcohol, and the solvent is a component system containing water as the main component.

[0181] Lower alcohol is one or more kinds of lower alcohols selected from methyl alcohol, ethyl alcohol, isopropyl alcohol, normal propyl alcohol and industrial ethanol.

[0182] At least one of ammonia water and a primary amine may be further contained as an additive. The content of at least one of ammonia water and a primary amine is, for example, 2 or less based on 100 times the volume of water.

[0183] A lower alcohol, ammonia water, and a primary amine are added to accelerate the drying of the coating film by utilizing their volatility. At the same time, the lower alcohol functions as follows in a solvent characterized by water solubility according to the present invention, i.e., a solvent containing water as the main component. That is, when dissolving a solid lubricant, the lower alcohol effectively dissolves the solid lubricant with water-repellent properties. Accordingly, the lower alcohol serves to disperse and dissolve the solid lubricant throughout the solvent, while avoiding excessive thickening.

[0184] When a lower alcohol containing 3 or fewer carbon atoms is not added in an amount of 0.5 or more per 100 volumes of water, the solid lubricant with water-repellent properties cannot be uniformly dispersed, and phase separation from the water occurs. In many cases, the lower alcohol floats on the water surface. On the other hand, the lower alcohol group has a low flash point. A situation is considered where a lower alcohol is used to lubricate the joint of oil and gas tubular goods, and the alcohol is used in a well under conditions prohibiting the use of fire. In this case, the lower alcohol can cause a fire and can be a highly hazardous chemical. Therefore, the upper limit for adding lower alcohol was set at 45.

[0185] In this case, the solid lubricating film formed as a result of drying does not contain any solvent, including lower alcohol. The solvent issue is only related to the drying time of the chemical agent. Therefore, if the chemical agent is not used in conditions that prohibit the use of fire, a large amount of lower alcohol can be used to accelerate drying.

[0186] Furthermore, the permissible addition range of lower alcohol is 20% or less. Although this correlates with the evaporation temperature described below, rapid drying is easily achieved at 20% or less. Furthermore, this range ensures that the evaporation temperature is 70°C or higher, or that the chemical agent is nonflammable and safe for use in fire-prohibited areas downhole. Furthermore, if a sample containing a large amount of lower alcohol is unsuccessful and relies on rapid drying, the following problems arise: There is concern that the film will dry too early, the film will become uneven, the film will deteriorate, and the film quality will deteriorate.

[0187] Solid lubricant

[0188] The solid lubricant contains a soap component comprising at least a metallic soap component and an alkaline soap component. The metallic soap component accounts for 95% or more of the total weight of the metallic soap and alkaline soap components. That is, the main component of the solid lubricant is the metallic soap.

[0189] The mass of metallic soap accounts for 95% or more of the total mass of metallic soap and alkaline soap. When a large amount of alkaline soap is contained, there is a concern that the alkaline soap may dissolve in the aqueous solvent, causing the solvent's viscosity to become excessively high, making it difficult to achieve uniform application and delaying film drying. Therefore, reducing the amount of alkaline soap component in the soap alleviates this problem. However, if the amount of alkaline soap is zero, the lubrication improvement effect of alkaline soap cannot be expected, so it is preferable for the component composition to contain alkaline soap.

[0190] At the same time, it is necessary to ensure that the particle size of the metallic soap does not exceed the film thickness of the solid lubricating coating. An acceptable range is preferably an average particle size of 10 μm or less. A particle size exceeding the film thickness of the solid lubricating coating indicates that the metallic soap penetrates the film. In this case, when tightening / loosening with a high torque, the film of the solid lubricating coating is more severely damaged than when the metallic soap is dispersed within the film. For example, there is concern that significant peeling or other similar effects may occur, resulting in deterioration of the lubrication performance. Therefore, the particle size should be equal to or smaller than the film thickness of the solid lubricating coating.On the other hand, assuming the solid lubricating film is thin enough to provide lubrication and prevent rust, the film thickness is at least approximately 10 μm. Therefore, the particle size is preferably 10 μm or less.

[0191] Furthermore, the metallic soap and alkali soap components constituting the solid lubricant include one, two or more kinds of soap, which are compounds formed from a fatty acid selected from the following group A and a metallic element selected from the following group B.

[0192] Group A: stearic acid, behenic acid, lauric acid, 12-hydroxystearic acid, oleic acid, montanic acid.

[0193] Group B: Na, K, Mg, Ca, Zn.

[0194] Binding resin

[0195] The binder resin is formed from a water-soluble or water-dispersible polymer, and is a polymer or copolymer containing a polymer having an acrylate or methacrylate structure in an amount of 90% or more of the total mass of the binder resin.

[0196] The water-soluble or water-dispersible polymer constituting the binder resin is, for example, a polymer formed from a monomer selected from the following (1) to (4), or a copolymer formed from two or more monomers.

[0197] (1) Monomers including acrylates, methacrylates and individual derivatives of acrylates and methacrylates as main components.

[0198] (2) Monomers, including acrylates and methacrylates, and individual derivatives of acrylates and methacrylates, and alkyl esters, vinyl esters, styrene esters, carboxylic acid esters, and individual derivatives of these esters.

[0199] (3) Monomers grafted with respect to the above (1) and (2).

[0200] (4) One or both monomers of vinyl compound and urethane compound.

[0201] Here, in this specification, "formed from a water-soluble or water-dispersible polymer and containing a polymer having an acrylate or methacrylate structure in an amount of 90% or more of the total weight of the binder resin" means the following. That is, in the case of a copolymer, when a part of the copolymer structure contains only a part of an acrylate or methacrylate structure, the binder resin of the copolymer is considered to be a "polymer having an acrylate or methacrylate structure", regardless of the weight other than the weight of the included acrylate or methacrylate structure.

[0202] When the content is less than 10%, the polymer suitable for blending refers to a polymer that does not form a copolymer with a polymer having an acrylate or methacrylate structure, which is the focus of this application. That is, a structure having an acryloyl group, vinyl group, or the like in the monomer composition is excluded.

[0203] Furthermore, since the chemical agent of the present invention is a chemical agent dissolved in an aqueous solvent, it is necessary for the polymer suitable for blending to have a water-soluble composition in addition to the information described above. Examples of the polymer include polyamide imide resin, phenolic resin, urea resin (urea formaldehyde), and the like, which are water-soluble.

[0204] The mass of the solvent is required to be, for example, 0.7 times or more to 100 times or less of the total mass of the solid lubricant and the binder resin when the volume of the solvent is converted to a mass with a specific gravity of the solvent of 1.

[0205] In addition, the solid lubricant has a mass of 0.1 times or more and 1.0 times or less relative to the mass of the binder resin.

[0206] It is preferable to adjust the flash point of the chemical agent to a temperature higher than 60°C, or make the chemical agent flame retardant (non-flammable) by selecting the components.

[0207] In addition, it is preferable to adjust the viscosity of the chemical agent to 1000 mPa s or less by selecting the components.

[0208] The corresponding range and allowable value of these parameters can be determined as follows.

[0209] First, regarding the mass fraction of the solvent, the lower limit of 0.7 or more is defined as the amount of solvent required to dissolve the solid lubricant. In fact, the metal soap as the main component of the solid lubricant can be dissolved at a rate of up to 0.7, as in the examples described below. Furthermore, since a mass fraction of 0.5 results in insufficient dissolution of the lubricant components to be mixed, 0.7 is used as the lower limit. The lubricant components to be mixed include a metal soap component, an alkaline soap component, and the like. Regarding the upper limit, it is assumed to be 100 times or less, but the preferred range is 10 times or less. A high mass fraction of the solvent indicates a large amount of the chemical agent and thin film components. The film components include a binder polymer component, a solid lubricant component, and the like.There's no particular problem with the upper limit being set at 100 times, where multiple recoatings are desired, such as repeated coating and drying. On the other hand, excluding the time and effort required for multiple coatings and drying, the solvent content can be greater than 100 times the original amount. However, since the chemical agent is applied in a thin layer, there's a high risk of deteriorating the film quality. Therefore, the number of times the coating can be screwed / unscrewed is somewhat reduced, but the film can still be used.

[0210] Hereinafter, the “number of times of screwing / loosening” is also called “number of times of C / R”.

[0211] The preferred range is 10 times or less. When the S / P ratio is 10 times or less, the required film thickness can be easily obtained by a suitable application method, for example, by applying one to three times, the S / P ratio is good, and no deterioration in quality is observed. In the examples described below, it will be found that a solid lubricating coating film can be formed without problems at a mass ratio of 7.6 or less, and the required lubrication properties and the like can be realized. Therefore, it can be said that 7.6 or less is a more preferable range. As will be described below, it is also preferable that the mass of the solvent be low to prevent rust formation. In the present application, the solvent contains water as the main component.Therefore, in order to avoid the formation of rust on the insufficiently dried part, it is more preferable that the mass ratio is two times or less. 0212. Furthermore, regarding the mass ratio of solid lubricant to binder resin, the lower limit is preferably 0.1 times or more, and the upper limit is preferably 1.0 times or less. When the mass of solid lubricant relative to the mass of binder resin is small, the total amount of solid lubricant, which plays a major role in lubrication, is small, and thus lubrication tends to deteriorate. Conversely, when the mass of solid lubricant is excessively large, more solid lubricants may be contained than necessary, and they interact with each other, causing the tendency to improve lubricating performance to be saturated or impaired.In the following Examples, regarding the actual deterioration of performance to the level at which the number of times of C / P meets the requirements of the lower limit of the allowable number of times, the mass ratio of the solid lubricant is 0.08 at the lower limit and 5.0 at the upper limit in the experimental range.

[0213] The desired flash point range is preferably 60°C or higher, and it is even more preferable for the chemical agent to be non-flammable. On the other hand, in an oil / gas well, if there is a location or zone that can be used in a temperature range of less than 60°C depending on the operating conditions, the chemical agent can be used to form a solid lubricating coating film and the film of the present invention. These parameters are determined solely from the perspective of worker safety and well location. These parameters do not affect lubrication, which is evaluated by the number of C / P times. With the exception of chlorofluorocarbon substitutes, a low flash point often means high volatility, which affects the chemical agent's ability to quickly dry and form a film.For downhole operating conditions, the flash point is set at 60°C or higher, and preferably much higher, or the chemical agent must be non-flammable.

[0214] The viscosity of a chemical agent is determined relative to the chemical agent obtained by mixing with a solvent, solid lubricant, binder resin, and other additives. The viscosity depends on the concentration of the composition. In the present application, the viscosity is preferably 1000 mPa s or less to reduce uneven application and film thickness unevenness of the chemical agent. This is because high viscosity is likely to cause uneven film thickness. In the following examples, no significant deterioration in quality is observed at 740 mPa s or less, and thus it can be said that this range is more preferable.

[0215] In addition, the case where the chemical agent is applied to the metal surface in an amount of 0.1 g / mm is considered 2 or less by selecting the components. In this case, the components are preferably selected so that the chemical agent has rapid drying properties, allowing for complete drying within 30 minutes when the chemical agent is left to dry in a windless atmosphere at ambient temperature.

[0216] As an alternative, the case is considered where the chemical agent is applied to the metal surface in an amount of 0.1 g / mm 2 or less by selecting the components. In this case, the components are preferably selected such that the chemical agent has rapid drying properties, allowing for complete drying within 5 minutes when the chemical agent is dried with an air flow of 1 m / s or higher in an atmospheric environment at ambient temperature.

[0217] Furthermore, the term “normal temperature” used in this application refers to a temperature in the range of 15 to 30°C.

[0218] The amount of material applied is 0.1g / mm 2or less, means the typical amount of applied material realized by the application method with a JIS 20 brush with a brush width of 50 mm when coating with rotation in one stroke of the brush in one direction. The drying time in this case is determined accordingly. Drying is preferably carried out for 30 minutes while leaving the chemical agent and for 5 minutes while drying with air blowing at a speed of 1 m / s or higher. The method is implemented using a variety of parameters defined in this application. Drying is improved by adding at least one of lower alcohols and ammonia water to utilize their volatility, as well as by dispersing and containing a metallic soap of a solid lubricant with an appropriate particle size to increase the surface area over which evaporation occurs.

[0219] Method for manufacturing a chemical agent

[0220] The chemical agent is preferably obtained by introducing a metallic soap into the composition by dispersing and clouding the metallic soap in a lower alcohol and then adding the metallic soap to an aqueous solvent.

[0221] Method of applying chemical agent

[0222] It is preferable that the container containing the chemical agent be shaken and stirred before application, and then the chemical agent be applied.

[0223] Furthermore, when the chemical agent according to the present embodiment is applied to the surface of the tubular member, it is preferable to apply the chemical agent in a circumferential direction while rotating the tubular member axially.

[0224] Oil and gas tubular goods and threaded connections for oil and gas tubular goods

[0225] Oil and gas field tubular goods include a coupling 2 having an internal thread 2a and a nipple 1 having an external thread 1a, as shown in Fig. 1.

[0226] As shown in Fig. 1, a threaded joint of oil and gas tubular goods is formed by a coupling 2 having an internal thread 2a and a pin 1 having an external thread 1a. A lubricating coating film including a solid lubricating coating film of the present invention is formed on a contact surface (fastening surface 10) of a threaded portion in at least one component of the coupling 2 and the pin 1.

[0227] A lubricating coating film including a solid lubricating coating film is formed on a threaded portion of an oil and gas tubular product according to an embodiment.

[0228] The solid lubricating coating film contains a binder resin and a solid lubricant dispersed in the binder resin.

[0229] The solid lubricant contains a soap component containing at least a metallic soap of metallic soap and alkaline soap components, wherein the metallic soap component accounts for 95% or more of the total mass of the metallic soap and alkaline soap components.

[0230] Furthermore, the metallic soap and alkali soap components constituting the solid lubricant include, for example, one, two or more kinds of soap that are compounds formed from a fatty acid selected from the following group A and a metallic element selected from the following group B.

[0231] Group A: stearic acid, behenic acid, lauric acid, 12-hydroxystearic acid, oleic acid, montanic acid.

[0232] Group B: Na, K, Mg, Ca, Zn.

[0233] For example, the mass of metallic soap accounts for 95% or more of the total mass of metallic soaps and alkaline soaps.

[0234] The particle size of the metal soap is preferably 10 μm or less.

[0235] The binder resin is formed from a water-soluble or water-dispersible polymer, and said polymer is a polymer or copolymer containing monomers belonging to acrylates or methacrylates in an amount of 90% or more.

[0236] The water-soluble or water-dispersible polymer constituting the binder resin is, for example, a polymer formed from one or more monomers selected from the following (1) to (4). The copolymer is a copolymer formed from two or more monomers.

[0237] (1) Monomers including acrylates, methacrylates and individual derivatives of acrylates and methacrylates as main components.

[0238] (2) Monomers, including acrylates and methacrylates, and individual derivatives of acrylates and methacrylates, and alkyl esters, vinyl esters, styrene esters, carboxylic acid esters, and individual derivatives of these esters.

[0239] (3) Monomers grafted with respect to the above (1) and (2).

[0240] (4) One or both monomers of a vinyl compound and a urethane compound.

[0241] Hereinafter, "formed from a water-soluble or water-dispersible polymer and containing a polymer having an acrylate or methacrylate structure in an amount of 90% or more based on the total weight of the binder resin" referred to in this application means the following. That is, in the case of a copolymer, where a part of the copolymer structure contains only a part of an acrylate or methacrylate structure, the binder resin of the copolymer is considered to be a "polymer having an acrylate or methacrylate structure", regardless of the weight other than the weight of the included acrylate or methacrylate structure. Mere weight does not mean the weight of "acrylate or methacrylate".

[0242] For example, the solid lubricating coating film has a film thickness of 1 μm or more and 100 μm or less, and the pencil hardness of the soft film is H or lower.

[0243] In addition, a base film (not shown) may be provided on the lower layer of the solid lubricating coating film.

[0244] At least one oil and gas field tubular product of a coupling and a nipple is formed by an oil and gas field tubular product on which a lubricating coating film according to the present invention is formed.

[0245] When one of the oil and gas tubular goods of the coupling and the nipple is an oil and gas tubular goods on which a lubricating coating film according to the present invention is formed, it is preferable that a coating film having a higher hardness than said solid lubricating coating film is formed on the threaded portion of the other of the oil and gas tubular goods.

[0246] The lower limit of film thickness, set at 1 μm or more, is determined to meet the definition that the film thickness is suitable for lubrication and the particle size of the metallic soap is equal to or less than the film thickness at which the metallic soap cannot protrude beyond the solid lubricating film. The upper limit, 100 μm or less, is determined based on the clearance between the internal and external threads (coupling / pin) of the oil and gas tubular goods connection. During make-up / break-out, the solid lubricating film is inevitably scraped off to some extent.Furthermore, there is a serious problem associated with the fragments generated by scraping off the solid lubricating film, which cause the migration of powdery substances during make-up / break-out. These particles are either reformed and reattached, or cannot be restored and reattached, clogging the thread gap and thus causing scuffing wear. Depending on the thread type, the gap between the "pin thread crest and the coupling thread root" may be empty and approximately 100 μm. On the other hand, the gap between the "pin thread root and the coupling thread crest" has a dense contact structure. When the solid lubricating film size exceeds 100 μm, it is assumed that the absolute amount of the solid lubricating film, which is inevitably scraped off to some extent during make-up / break-out, increases and exceeds the amount that can be absorbed by the gap, and scuffing wear often occurs.Therefore, the upper limit was set in the preferred range of 100 µm or less. When the solid lubricant film size exceeds 100 µm, it is difficult to say that the result will always be NG, but the S / P number does not satisfy the definition, and scuffing wear is likely to occur.

[0247] As described above, the chemical agent of the present invention contains a binder resin component mainly composed of a water-soluble or water-dispersible polymer. Furthermore, a metallic soap is contained as the main component of the solid lubricant, and a trace amount of alkaline soap and additional additives are added to it to serve as a solid lubricant other than alkaline soap. Furthermore, the chemical agent of the present invention includes a component system that allows the addition of a solvent containing water as the main component and a small amount of an organic solvent.

[0248] A chemical agent configured in this manner ensures rapid drying after application and, in addition, provides lubrication and rust protection that can withstand downhole use, thanks to the solid lubricating film formed using the chemical agent. The present invention achieves lubrication of threaded connections in oilfield tubular goods, taking into account the harshest environmental conditions in which they will be used.

[0249] Below will be detailed the definition and so on for each item.

[0250] In the present invention, it is expected that the chemical agent and the solid lubricating coating film formed using the chemical agent will have the property of rapid drying, corrosion resistance and lubricating performance.

[0251] However, the parameters that ensure individual necessary properties are related to the necessary properties and are thus implemented within the upper and lower limits defined in this specification. The target necessary property will be described first, followed by the range of each parameter and its value.

[0252] "Regarding the target characteristics of quick drying, corrosion resistance and lubrication"

[0253] The term "rapid (early) drying property" used in this specification indicates that drying can be completed in 5 minutes or less, and, if necessary, in 1 minute or less, without heating and air blowing. Alternatively, the quick-drying property means that drying can be completed in 30 minutes or less, preferably in 15 minutes, and more preferably in 5 minutes, when the object to be dried is outdoors or indoors at ambient temperature.

[0254] The term "drying" referred to in this application refers to the semi-cured state or the cured state after touch-drying. Furthermore, paint terms such as "touch-dry" and "semi-dry" are defined in accordance with JIS K5500-2000.

[0255] However, the present disclosure is an invention aimed at creating a chemical agent having low viscosity and good fluidity when applied to a connecting structure for oilfield tubular goods. Therefore, it is also assumed that the applied chemical agent inevitably accumulates at the 6 o'clock position, that is, the lowest position, and the liquid accumulates or partially drips. Therefore, the dry state of the threaded portion on the upper side of the clock, from 8 to 4 o'clock, will be discussed in relation to the aforementioned early drying property. The portion where the chemical agent remains without drying due to accumulation, dripping, etc. of the chemical agent at the 4 to 8 o'clock position, or more precisely, the 5 to 7 o'clock position, is excluded from rapid drying. The reason why problems do not arise even if this portion is excluded is as follows.This means that although the applied chemical agent may remain semi-dry, there is a portion where a solid lubricating film forms in the bottommost layer of the coating fluid applied to the semi-dry part, and thus, there are no film retention issues from a rust prevention perspective. This means that the only portion that remains insufficiently dry is the area between the dried film of the bottommost layer on the pipe surface and the film of the outermost layer on the part exposed to the atmosphere. Therefore, from a corrosion prevention perspective, a strong lubricating film formed by the drying of the bottommost layer can be achieved.

[0256] Corrosion resistance in this description does not refer solely to the corrosion resistance of a surface to which a chemical agent for evaporating water has been applied. Corrosion resistance according to the present invention is a target property when used in a tubular structure with a threaded crest, such as a connection for oil and gas tubular goods, which are intended for the most severe operating conditions. Furthermore, this invention relates to corrosion resistance in a state where, for example, a protective cap, such as a protector, is screwed on and screwed on, that is, attached, removed again, and the protector is removed. These conditions are assumed to be somewhat more severe than the actual required property.

[0257] When connecting actual oil and gas tubular goods, it is possible that the solid lubricating film partially adheres to the protector, and the film is damaged during installation of the protector after the solid lubricating film has formed. This occurs because the protector is secured in this position and is not touched either outdoors or indoors.

[0258] In the present invention, the lubrication characteristics are provided by evaluating the lubrication characteristics using the evaluation results in a real well or in a simulated well, or by using a tong-type make-up test that can be approximated to the evaluation results.

[0259] The present invention does not evaluate the superiority or inferiority of lubricity using a conventional short-nipple make-up / break-out test. The inventors found that the solid lubricating film cannot be properly evaluated using a conventional short-nipple test.

[0260] Here, when lubricating threaded connections of oilfield tubular goods, lubrication achieved with a lubricating compound has been and remains the primary focus. Because the lubricating compound is like a viscous fluid, it moves in conjunction with the make-up / break-out process and works in the direction that optimally achieves lubrication. Therefore, evaluation can be performed without significant differences between lubrication evaluation in the laboratory using a short nipple and evaluation in a real well. However, when lubricating with a solid lubricating film, as in this invention, the solid lubricating film can inevitably be scraped off, and its fragments and powder may not move with the make-up / break-out process, unlike the lubricating compound.As will be described in detail below, a method for conducting an evaluation under conditions close to those actually found in a well has been developed based on laboratory data, and the suitability of the solid lubricant coating film is determined by the lubrication characteristics evaluated in the developed test.

[0261] "Regarding water-soluble or water-dispersible polymer"

[0262] In this description, a water-soluble or water-dispersible polymer is used as the binder resin.

[0263] The present invention provides a polymer that forms a film after water evaporates, i.e., evaporates. Therefore, the polymer in the present invention refers to a synthetic polymer in the narrow sense. The polymer of the present invention does not include pectin, agar, starch-based materials, cellulose-based materials, and natural gums (based on alginic acid), which are well-known natural polymers. Furthermore, the polymer of the present invention does not include a material that maintains semi-dry moisture during the drying stage, i.e., after removing water. Furthermore, if carbon steel is coated with an incompletely dried material, there may be a risk of corrosion due to exposure to water.

[0264] In particular, the water-soluble or water-dispersible polymer in this specification includes a polymer formed from a single polymer and a copolymer formed from two or more monomers. The individual monomers correspond to the monomers in the following sections (1) to (4).

[0265] (1) Monomers including acrylates, methacrylates and individual derivatives of acrylates and methacrylates as main components.

[0266] (2) Furthermore, monomers including, insofar as they are water-based, alkyl esters, vinyl esters, styrene esters, carboxylic acid esters and individual derivatives of these esters, as well as acrylates and methacrylates, and individual derivatives of acrylates and methacrylates.

[0267] (3) Monomers grafted with respect to the above (1) and (2).

[0268] (4) One or both monomers of a vinyl compound and a urethane compound.

[0269] In the present invention, the polymer includes at least one polymer defined according to (1) to (4), a copolymer formed from two or more monomers, or one or both of a polymer formed from one monomer according to (1) to (3), or a polymer formed from a copolymer according to (1) to (3), which is formed from a polymer forming a copolymer with (4) or another compound.

[0270] Other compounds refer to maleic acid, sulfonic acid, styrene, carboxylic acid and their salts, and their monomers.

[0271] Hereinafter, "formed from a water-soluble or water-dispersible polymer and containing a polymer having an acrylate or methacrylate structure in an amount of 90% or more based on the total weight of the binder resin" referred to in this application means the following. In the case of a copolymer, where a part of the copolymer structure contains only a part of an acrylate or methacrylate structure, the binder resin of the copolymer is considered to be a "polymer having an acrylate or methacrylate structure", regardless of the weight of the structure other than the acrylate or methacrylate structure. Mere weight does not mean the weight of "acrylate or methacrylate". In addition, the water-based polymer mentioned herein refers to a polymer having hydrophilicity due to containing a polar or charged functional group in the polymer structure.For example, a water-based polymer refers to a polymer containing a carboxyl group, an amino functional group, a sulfonic acid, or the like in the main chain or side chain.

[0272] The binder resin of the present invention is dissolved in a solvent containing water as a main component, and when a chemical agent is applied, the water is removed, that is, evaporated, to form a film.

[0273] Furthermore, since the present invention is based on the basic premise that the environment is taken into account, the chemical agent of the present invention is developed without using heavy metals including lead and a material containing an alkyl group containing fluorine (F) from a group of compounds called PFAS, which has become a problem recently.

[0274] The definitions that enable the rapid drying property of the film after applying the chemical agent directly or indirectly affect the characteristics of the chemical agent film.

[0275] The following will describe in detail the group of products related to quick drying property.

[0276] It is desirable to use a polymer or copolymer containing 90% or more of monomers belonging to acrylates and methacrylates in the final film formation stage. In addition, a polymer obtained by copolymerizing monomers including acrylates and methacrylates and another monomer during copolymerization is considered an acrylate polymer and methacrylate polymer and satisfies the definition of 90% or more.

[0277] A ratio of 90% or more indicates that the majority of the polymer is composed of acrylate polymer or methacrylate polymer, and 10% or less of the other polymer is allowed. Essentially, the copolymer is considered to consist of approximately 100% acrylate or methacrylate polymer.

[0278] "The reason why quick drying is required and the reason why the target value is set"

[0279] The reason why the quick-drying property is required is that, in fact, the chemical agent of the present invention and the solid lubricating coating film formed using this chemical agent are used in production to form the film and are also required for use on-site.

[0280] In particular, when applying a coating to a threaded joint of oil and gas tubular goods, the following chemical agent is also contemplated. That is, it is also contemplated that the chemical agent is used, particularly in cases where the oil and gas tubular goods are temporarily pulled out for casing due to a problem at the well, or when scuffing wear occurs, and the oil and gas tubular goods are removed and sent to a workshop. In this case, it is necessary to perform the entire operation using a clean and environmentally friendly solid lubricating film. The oil and gas tubular goods removed from the well are washed with water or the like, and to prevent corrosion of the threaded portion, it is also possible to form an anti-corrosion film of a solid lubricant with the chemical agent described in the present invention.Such a need naturally arises during well operation.

[0281] In this case, when a conventional wet compound is used, a storage preservative is usually used. For example, a viscous, liquid-like, oil-based compound such as KENDEX (trademark) or OCTG ORANGE corrosion and storage compound. Additionally, if a storage compound is not available, a lubricating compound containing the heavy metals Pb and Zn is applied to prevent corrosion. In this case, the compound is not environmentally friendly, meaning it contains compounds containing harmful heavy metals.

[0282] On the other hand, in the present invention, the chemical agent for forming a solid lubricating coating film is designed with the application of the chemical agent in the wellsite environment in mind. That is, according to the present invention, under fire-prohibiting conditions, the solid lubricating coating film must be dried as quickly as possible without using anything that could cause combustion, including a heater.

[0283] On the other hand, there is a measure for the case where the production system of each individual workshop is incomplete when the thread cutting is performed on-site.

[0284] The thread-cutting shop has sufficient equipment for machining. When using a conventional compound, surface treatment of the coupling joint is often outsourced, less often in-house. Surface treatment is performed, for example, with manganese phosphate or Cu coating. However, this is not a nipple joint, which is coated with a viscous liquid for storage and does not require drying. Therefore, the nipple joint is usually supplied with a protector attached after application, without a drying process.

[0285] When the chemical agent described in the present invention is used on-site, it is difficult to expect the presence of a blower, hot air dryer, or heat treatment device. Therefore, it is determined that the chemical agent of the present invention dries in 30 minutes or less, preferably 15 minutes, and more preferably 5 minutes or less when left indoors or outdoors.

[0286] It is assumed that one worker will repeat the process of unwrapping and positioning approximately 30 pin or box connections over a 30-minute period, sequentially coating one end section of each oilfield tubular goods from one end, returning to the starting position, and sequentially coating the end section from the opposite side. Accordingly, it is assumed that the worker will return to the starting position within 30 minutes, which is required for the coating to be almost completely dry. Furthermore, once the protectors are prepared and in order, a 30-minute time period is established during which the work can be performed without waiting. A drying time of 15 minutes will not cause problems, even if fewer threads are to be processed. A drying time of 5 minutes or less is the preferred target.

[0287] However, in a factory or similar facility producing products with a lubricating film, blowing equipment and the like are expected to be present. Therefore, drying can be facilitated not only by exposure to the atmosphere but also by air blowing devices such as a jet fan, a heated air blower capable of blowing hot air, a heat treatment oven, and the like. In this case, drying is preferably carried out for 5 minutes, more preferably for 3 minutes, and even more preferably for 1 minute. It is preferable that the drying time be within a range that does not reduce the line speed and does not hinder processing in the area where products with a solid lubricating film with good lubricity and anticorrosive properties are produced, or that the line speed is maintained and processing is not hindered even at a low level when obstacles are unavoidable.

[0288] Furthermore, regarding the air volume of the fan and blower, the starting speed of a typical electric fan is 2 to 4 m / s. However, in this description, since drying is assumed to be accomplished even with a weak hand-held fan or similar device, the drying time is estimated for drying with an air blower speed of 1 m / s.

[0289] "Method of applying a chemical agent"

[0290] The main composition of the chemical agent of the present invention is a solvent (water + lower alcohol, ammonia, primary amine as an auxiliary additive), a binder resin (water-based polymer as the main component) and a solid lubricant (metal soap + alkaline soap as an auxiliary).

[0291] The viscosity of the chemical agent is also an important parameter. Therefore, to achieve rapid drying, it is preferable to use a liquid formulation with a low viscosity chemical agent. When applied to an inclined surface, the chemical agent tends to flow rather than remain on the inclined surface. Therefore, it is preferable to adjust the viscosity of the chemical agent so that it flows after application.

[0292] For example, the viscosity is preferably 1000 mPa s or less. This level is a level at which, when a member or tubular member arranged at an angle is coated with a chemical agent, the chemical agent flows at an angle. In addition, the viscosity in this specification refers to the viscosity of the chemical agent in a non-dried state or at the beginning of application. According to this definition of viscosity, the formation of an unintentionally thick film when applying a chemical agent can be avoided. The lower limit of the viscosity is not specified, but is, for example, 40 mPa s or higher. When a water-soluble or water-dispersible polymeric material is added to a water-based solvent, its viscosity does not become equal to the viscosity of water (1 mPa s) and tends to increase. Therefore, the viscosity is set at a level of at least about 40 mPa s.

[0293] Setting the viscosity of the chemical agent at 1000 mPa s or lower makes it difficult to overcoat or apply a thick layer, and provides the advantage of achieving a uniform and low coating film thickness. Viscosity is adjusted by selecting the monomers that make up the aqueous polymer, the concentration of the metallic soap or alkaline soap, and the proportion of the solvent-containing composition.

[0294] On the other hand, since the viscosity of the chemical agent is 1000 mPa s or lower, the viscosity is low and the chemical reagent flows easily. Therefore, the chemical agent flows onto the uncured portion, and the chemical agent solution tends to accumulate at the 6 o'clock position. Consequently, since this portion inadvertently thickens, even though the base has dried and formed into a film, only the accumulated portion may not dry during the drying process.

[0295] Therefore, when lubricating a tubular structure, the specified drying time should be checked at the 12 o'clock position, broadly speaking, in the upper half of the 9 to 3 o'clock position. Indeed, the solution accumulates at the 6 o'clock position, but only the uncured chemical agent accumulates on the already dried portion. Therefore, the lower portion dries during the initial stage of application.

[0296] Application by any method is permitted, including brushing, spraying, dipping, manual application, and machine application. After coating, by actively exploiting the flow tendency, the object coated with the chemical agent can be directed downward or tilted at an angle to allow the coating material to flow downward. Furthermore, it is preferable to apply the coating to the tubular metal part by brushing or spraying while rotating, rather than while stationary. This also improves drying. Furthermore, the remaining amount of chemical agent that has not formed a film ensures uniform re-coating of the metal surface and supports the formation of an even film when the tubular metal part rotates. Furthermore, accumulation in one position can be avoided.

[0297] "Measures for Realizing Early Drying Ability"

[0298] In the present invention, in order to realize the rapid drying ability of a water-soluble or water-dispersible polymer, a necessary configuration and a preferred configuration including the following four configurations were developed and used.

[0299] Basic Configuration

[0300] The main configuration is lower alcohol.

[0301] That is, since a lower alcohol is intended for use even in conditions prohibiting the use of fire, a lower alcohol, which is a volatile organic solvent, the concentration of which is selected so that the flash point is 60°C or higher, is used to ensure rapid drying. The concentration can be adjusted until the flash point of the chemical agent reaches the desired value of 150°C or higher, and even more preferably 250°C or higher. In addition, VOC thinners should not be used. This is necessary to ensure the safety and hygiene of workers, and allows them to work without the need for exhaust devices such as a hood.

[0302] Another component selected is ammonia water.

[0303] According to the situation, the volatility of ammonia water is also used, and its concentration is adjusted within the appropriate range to a level at which the chemical agent can be used without using an exhaust device.

[0304] One of the configurations is the concentration and particle size of metal soap.

[0305] The concentration and particle size of the metallic soap contained in the chemical agent are adjusted within appropriate limits to ensure rapid drying. The particle size of the metallic soap is 10 μm or less. Preferably, the particle size is 5 μm or less, and more preferably, 1 μm or less, which improves drying by increasing the surface area of ​​the metallic soap.

[0306] In this case, metallic soap particles clump together and form lumps, requiring measures to prevent the apparent size of the lumps from exceeding their individual size. This is achieved by dissolving the metallic soap in the lower alcohol described above and then mixing the metallic soap with a solvent formed from water or a water-based polymer mixed liquid.

[0307] Metallic soap also serves as the main component of the lubricant, so that the metallic soap accounts for 95% or more of the total mass of the solid lubricant when combined with the following alkaline soap. Regarding the overall mixing ratio, when the solvent evaporates to form a solid lubricating film, the total mass of the solid lubricant is 0.05 to 1.0 times the mass of the binder resin. Furthermore, the total mass of the solid lubricant is 95% or more composed of metallic soap.

[0308] In the present invention, alkaline soap can be used as a lubrication aid. However, adding alkaline soap, which is readily soluble in water, conversely causes water, the solvent, to become highly viscous and gel-like. This has the side effect of increasing the viscosity of the chemical agent, requiring time for film formation. If the chemical agent thickens too much, water is not completely removed, and a solid lubricating film cannot be formed in a dry state. Therefore, the upper limit of the permissible amount of alkaline soap should be set at a trace level. Accordingly, the viscosity is set within the viscosity range specified below.In addition, in the solid lubricant described above, the upper limit of the content of the metallic soap as the main component is 95% or more, that is, the upper limit of the content of the alkali soap component is 5% or less.

[0309] The viscosity of the chemical agent is adjusted to 1000 mPa s or less.

[0310] When a water-soluble or water-dispersible polymeric material, an additive such as a metallic soap, and the lower alcohol described above are combined into a composition as a chemical agent, it is necessary to have the following viscosity. In short, the chemical agent should have a low viscosity and be uniform in viscosity throughout the liquid. The lower limit of viscosity is not specified, but it is approximately 40 mPa s or higher. When adding a water-soluble or water-dispersible polymeric material to an aqueous solvent, the viscosity does not become equal to the viscosity of water (1 mPa s) and tends to increase. Therefore, the viscosity is set at approximately 40 mPa s.

[0311] Preferred Configuration

[0312] When applying a chemical agent to a metal tubular structure, it is preferable to apply the chemical agent while rotating the tubular structure. It is preferable to continue rotating even after application. This is because it can achieve a similar effect to accelerating drying using a blower or similar method, without the accumulation of undried chemical agent after application at the 6 o'clock position due to rotation.

[0313] Furthermore, in the case of a tubular metal part (structure), the solution accumulates at the 6 o'clock position, requiring drying time for only the outermost layer. Complete drying, including drying of the accumulated portion, takes a long time. Therefore, it is preferable to use a drip from the 6 o'clock position when applying to the outside of the pipe. Alternatively, it is preferable to remove the chemical agent, which tends to accumulate at the 6 o'clock position, by rotating the pipe at an angle, both from the outside and inside.

[0314] Furthermore, accelerated drying can be achieved by using drying-enhancing processes such as blower drying, hot air drying, infrared irradiation, ultraviolet irradiation, or heat treatment. In this case, synergy with the above configuration can also be expected.

[0315] "Use of lower alcohol, ammonia or primary amine and flash point of all chemical agent"

[0316] The present invention utilizes the volatility of lower alcohols and ammonia, and selects a fine-particle metallic soap as the main component of the solid lubricant. This increases the surface area for faster drying, while reducing the viscosity of the chemical agent itself to improve fluidity. This ensures water vaporization and evaporation, preventing film thickening.

[0317] The lower alcohol mentioned herein is a combination of one or more kinds of lower alcohols selected from methanol, ethanol, isopropyl alcohol, normal propyl alcohol, and industrial ethanol.

[0318] Among lower alcohols, those with four or more carbon atoms, such as butanol, are hardly soluble in water. Therefore, the present invention utilizes a lower alcohol with three or fewer carbon atoms. However, lower alcohols have a low flash point at high concentrations and cannot be used under fire-prohibiting conditions. Therefore, the chemical agent is prepared so that it has a flash point of 60°C or higher, and preferably 150°C or higher, after final preparation of the chemical agent. It is more preferable to prepare the chemical agent at a level at which it is classified as a non-flammable material. When the lower alcohol content is at least 0.5% or more, faster drying can be achieved by utilizing its volatility.It is most preferable for the chemical agent to be one for which a flash point does not exist or is not measurable and to be in a state defined as non-flammable.

[0319] The lower alcohol group helps to accelerate drying and, at the same time, helps to incorporate metallic soap into the composition as an additive without forming lumps, and avoids the accumulation of metallic soap while maintaining the particle size from the moment of addition.

[0320] When metallic soap is simply dissolved in water, the metallic soap particles do not mix in the water and stick together, forming clumps due to their water-repellent properties. Despite attempts to mix metallic soap with a particle size equal to or smaller than the specified value with the coating material, the metallic soap is insufficiently dispersed when directly mixed with water. Therefore, even in the film state, the film has a slope, and this slope is detrimental to both lubrication and corrosion resistance.

[0321] According to the present invention, a metallic soap is first dissolved in lower alcohols. Accordingly, a method is used to prepare a mixture in which the lower alcohol and metallic soap are mixed with a liquid dispersion formed from a water-soluble or water-dispersible polymer and water. In this case, it is necessary to adjust the concentration of the lower alcohol and the content of the metallic soap so that they are within the ranges defined by the present invention.

[0322] In addition, to accelerate the drying, the volatility of the lower alcohol, which is the main one, and additionally ammonia and primary amine can be used.

[0323] The ammonia referred to here is ammonia water. Commercially available ammonia water with an ammonia content of 28% to 30% can be used as a chemical reagent. Incidentally, ammonia water itself is non-flammable. Furthermore, commercially available ammonia water with low ammonia content—10% or 5%—also exists. However, in the present invention, concentrated ammonia water (28% to 30%) is used as the basis for discussion.

[0324] Ammonia water can be used as a chemical agent for the preparation of formulations in the neutral pH range preferred by water-based polymer, in particular, in the pH range of 5 to 9. Ammonia water can be used with the effect of volatilizing lower alcohols.

[0325] Furthermore, the use of primary amines, which belong to a group characterized by high volatility, is also permitted under conditions not exceeding the pH level described above. Primary amines can be added to shift the pH toward the alkaline side. Consequently, volatility is combined and utilized by ammonia and primary amines added to change the pH from neutral to alkaline.

[0326] However, with regard to primary amines, special care must be taken when handling methylamine. Ammonia water can be classified as nonflammable. On the other hand, since methylamine is highly flammable, there is a serious risk that large quantities of methylamine could cause an accident. Therefore, primary amines can be used in small quantities, but they must be handled with care. To improve evaporative drying, the content of lower alcohols, ammonia, and primary amines should be 30% or less of the total solvent. This upper limit is limited by the flash point or similar.

[0327] The chemical agent of the present invention does not contain an alternative chlorofluorocarbon solvent that is poorly soluble in water, a halogenated solvent such as trichloroethylene or tetrachloroethylene, and a group of chemicals called diluents. These chemicals should not be used due to their global environmental impact, including health hazards. In addition, the group of chemicals called diluents includes chemicals classified as toluene, xylene, benzene, white spirits, ether group, and oils, commonly known as mineral oils, which are often harmful to health.

[0328] The flash point of the chemical agent described in this invention is set at 60°C for the following reason. Under actual wellbore operating conditions, the temperature that can be considered the temperature encountered during make-up of a threaded joint for oilfield tubular goods is considered to be below 60°C at the very least. Therefore, firstly, the temperature is prevented from dropping below this temperature. Thus, the risk of ignition and combustion due to volatile chemicals is reduced to virtually zero. The reason why the flash point is preferably 150°C, and more preferably 250°C, is as follows.That is, in exceptional cases, the highest temperature at the wellhead, 250°C, is taken as the temperature at the wellhead, and 150°C can be taken as the maximum possible temperature, which is the temperature at the wellhead after heat transfer. To minimize the risk, the flash point of the chemical agent is set so that it cannot be measured, and the agent is classified as non-flammable.

[0329] "Particle size and concentration of metallic soap and alkaline soap content"

[0330] In the present invention, metallic soap and alkaline soap serve as solid lubricants. Furthermore, the metallic soap has a small particle size, which increases the surface area and promotes rapid drying. The alkaline soap, after being dissolved in a solvent containing water as the main component, is then incorporated into the film, or the soap is deposited on the surface of the film or within the film. However, alkaline soaps do not transform into a liquid state in the final stage and are thus considered solid lubricants.

[0331] In the following description, solid lubricant means a soap component containing metallic soap and alkali soap.

[0332] In the present invention, the early drying process is improved by combining multiple factors. An appropriate amount of an additive comprising the above-described volatile lower alcohols, ammonia, and primary amines is added to the solvent, utilizing their volatility. Accordingly, the particle size of the metallic soap is determined by promoting the volatilization and evaporation of the aqueous solvent, and the metallic soap is uniformly dispersed without forming lumps. Furthermore, the viscosity of the chemical agent is set to 1000 mPa s or less to prevent the chemical agent from being applied in a thick layer. At the same time, to simultaneously ensure lubricity and corrosion resistance, it is necessary to adjust the addition amounts of the metallic soap and alkaline soap.

[0333] Regarding the particle size of the metallic soap, metallic soaps with an average particle size of 10 μm or less are used, preferably 5 μm or less, and more preferably 1 μm or less. This increases the surface area of ​​the metallic soap and improves the drying process. The smaller the particle size of the metallic soap, the faster the chemical agent dries. However, it is important that the metallic soaps be distributed separately from each other to maintain the particle size of the metallic soap and prevent the formation of metallic soap lumps. At the same time, to ensure the integrity of the solid lubricating coating film, it is necessary that the particle size of the metallic soap not exceed the film thickness of the solid lubricating coating. When the particle size exceeds the film thickness, the metallic soap particles appear to protrude from the film.Accordingly, when a strong torque is applied, the film suffers significant damage, i.e. peels off, gets scratched, etc.

[0334] On the other hand, the particle size of alkaline soap is not determined because alkaline soap is soluble in water.

[0335] Metallic soap is the main component of the solid lubricant and plays a key role in accelerating drying. Alkaline soap, on the other hand, is included in the composition to provide a supporting role in lubrication.

[0336] In a real well, when a nipple of a real size is installed in a coupling joint, the nipple joint is inserted directly into the coupling joint, and the apexes of the nipple joint profile are rarely manually inserted into the coupling joint, as is assumed in an ideal state. In practice, the nipple joint is inevitably installed at a slight angle. Therefore, even if the nipple joint is installed manually, the nipple joint can only be installed in a state in which approximately half of the apexes of the nipple joint profile remain exposed. Therefore, during the initial make-up stage with a wrench, the threads are unbalanced, and the surface of the solid lubricating film is prone to damage.During this time, the alkaline soap is expected to maintain lubrication so that the coupling joint and the nipple joint slide into a stable position until the coupling joint and the nipple joint are fully engaged. As shown in Figs. 3A and 3B, alkaline soap lubrication is assumed so that peak torque does not occur until torque is generated.

[0337] At the same time, metallic soap has water-repellent properties. Therefore, even with minor damage to the solid lubricating film, the water-repellent effect is expected to be maintained, thereby enhancing corrosion resistance. Thus, metallic soap provides corrosion resistance.

[0338] The solid lubricant is composed of 95% or more by weight of metallic soap and alkaline soap. Briefly, approximately 5% of another solid lubricant may be mixed in, but it is assumed that the majority of the solid lubricant is composed of a material belonging to the soap family in the broad sense.

[0339] As described above, the content of metallic soap or alkaline soap is determined based on the balance of the entire chemical agent. In this case, when the volume of the solvent is converted to a mass with a specific gravity of 1, the metallic soap and solvent are prepared at a ratio of 0.7 to 100 times the mass of all solid lubricant components forming the film. The mass of all solid lubricant components is equal to the sum of the masses of the solid lubricant and the binder resin. That is, a solvent containing water as the main component can be used over a wide range, except in a highly thick or diluted state. If the content exceeds 100, the amount of water is excessive, making it difficult to dry. Furthermore, since there is concern that water itself will cause rust, the ratio is preferably 10 times or less, and more preferably 2 times or less.

[0340] Because the solvent disappears during drying, what forms as a film is a component of the binder resin and a solid lubricant.

[0341] It is desirable that the mass ratio of solid lubricant to binder resin be between 0.1 and 1 times, and the metallic soap content should account for 95% or more of the solid lubricant mass. If the lower limit is 0.1 times or less, the portion supporting solid lubrication is too small, and no lubrication improvement effect can be expected. In this case, when a large force is applied to the binder resin, there is a high probability of complete film peeling. This is because, as a result, the likelihood of scuffing wear increases. The reason why the upper limit is set at one time is that the amount of metallic soap relative to the solvent is too large, the integrity of the film itself is lost, and there is a high risk of cracking under light loads and exposure to the environment.Furthermore, it can be said that such a concentration is the limit for maintaining a small particle size of metallic soap without the formation of lumps of metallic soap particles.

[0342] "Concerning the types of metallic soap and alkaline soap"

[0343] In the present invention, metallic soaps and alkaline soaps are defined as follows. That is, the metallic soaps and alkaline soaps include one kind or a combination of two or more kinds of soaps comprising a compound formed from group A fatty acids and group B metal elements described below.

[0344] · Group A (stearic acid, behenic acid, lauric acid, 12-hydroxystearic acid, oleic acid, montanic acid)

[0345] · Group B (Na, K, Mg, Ca, Zn)

[0346] In the present invention, the metallic soap is formed from salts of one or more metals, such as a Mg salt, a Ca salt, and a Zn salt from Group B with a fatty acid from Group A fatty acid. The metal salt of the alkali soap is formed from metal salts of one or both of a Na salt and a K salt from Group B.

[0347] Other alkali metal salts are commercially available, but other metal salts were excluded because the salts of these metals are not used in the so-called applications in which the metal salts are dissolved in water and used for washing.

[0348] "The amount of chemical agent applied and the drying time"

[0349] The above description indicates that drying acceleration is achieved through the simultaneous action of multiple factors. Specifically, an appropriate amount of volatile lower alcohols, as well as ammonia and primary amines, are added to the solvent, while ensuring that the flash point does not drop too low. This is achieved by enhancing the volatilization and evaporation of the aqueous solvent by utilizing the volatility described above, as well as by the small particle size of the metallic soaps, which disperses the metallic soaps uniformly without forming lumps. Furthermore, the viscosity of the chemical agent is adjusted to 1000 mPa s or less to prevent the chemical agent from being applied in a thick layer.

[0350] In addition, as a condition to ensure early drying, it is preferable that the coating be applied virtually homogeneously in an amount of 0.1g / mm 2or less under the above conditions. Under these conditions, if the chemical agent is left in the atmosphere at a normal temperature, drying can be expected to be completed at a normal temperature (from 15°C to 30°C, e.g., 24°C) within 30 minutes. Furthermore, in the case of hot air drying, when drying is carried out with an air flow rate of 3 mm / s or higher, earlier drying can be expected, allowing drying to be completed within 5 minutes at a normal temperature.

[0351] It is preferable that the amount of the applied agent is, for example, 0.2-0.05g / mm 2 When the chemical agent is applied thicker, the drying time increases, and the chemical agent inevitably runs off. Consequently, only the surface layer of the part may not dry. Furthermore, when applied less than 0.05 g / mm 2 Drying is usually accelerated, but the resulting film has unreliable anti-corrosion properties.

[0352] "Film characteristics: film thickness, pencil hardness"

[0353] In the present invention, when the chemical agent is dried to form a solid lubricating coating film, the film is preferably soft with a film thickness in the range of 1 μm to 100 μm and a pencil hardness of H or less.

[0354] Initially, a uniform film thickness of approximately 10 to 50 μm can be used. However, when a chemical agent with the viscosity described above is applied, the viscosity is low, and therefore the coating material, which cannot be formed into a film, tends to shift when flowing, even when drying is intensified. In the case of a structure with a profile crest, such as the thread structure of oilfield tubular goods, it is undeniable that the chemical agent tends to further accumulate at the bottom of the profile crest, especially at the 6 o'clock position. In addition, the corner portion of the profile structure protrusion tends to be thin due to the surface tension of the chemical solution. Therefore, the film thickness is preferably set within the above range to ensure both lubrication and corrosion resistance. If the thickness is less than 1 μm, there is a high probability of scuffing wear at the thinnest point.Furthermore, at film thicknesses greater than 100 µm, the film is scraped off during lubrication, and a loose piece or powdery substances can cause scuffing wear. Furthermore, there is a risk that the film may peel off completely, causing scuffing wear.

[0355] Here, as described above, the film thickness is the film thickness at the stage where the chemical agent has dried and formed a solid lubricating coating film. The film thickness is determined, for example, by observing each cross-section of the threaded portion at four points (e.g., at four positions every 90 degrees) along the circumference of the threaded portion in the longitudinal direction using a microscope. During this observation, the thickness of each film is determined at the thickest and thinnest parts of the coating film. Accordingly, each film thickness is checked to see if it is within the range described above.

[0356] Next, once the film thickness distribution trend is determined from the previous measurement results, the film thickness can be estimated as follows. That is, when the chemical agent application and drying methods are the same, it is also possible to estimate the maximum and minimum film thickness values ​​over the entire threaded portion by measuring the film thickness in a predetermined area using an electromagnetic film thickness gauge.

[0357] The solid lubricating coating film preferably has a pencil hardness of H or lower.

[0358] This is because the solid lubricating film of the present invention intentionally has a soft film quality and provides lubricating performance under the assumption that the solid lubricating film itself is slightly scraped off under strong contact. Furthermore, if the pencil hardness exceeds H and is hard, there is a risk that the film may completely peel off, and scuffing wear may intensify.

[0359] Next, the film hardness is measured by pencil hardness analysis. The measurement is performed according to the method specified in JIS K 5600-5-4 (1999). JIS standards state that this standard is a translation of ISO / DIS 15184, Paints and varnishes - Determination of film hardness by pencil hardness. The pencil hardness determination method described in the present invention is based on the JIS standard. That is, films having a pencil hardness of 6B to B, HB to F, and H to 9H as evaluation targets, and a hard film having a pencil hardness of 9H or higher are evaluated as ≤ 6B and ≥ 9H, respectively.

[0360] "The case of applying a coating on both sides of oil and gas tubular goods including a threaded joint, the case of applying a coating on one side, and the case of applying a coating on one side and having another type of solid lubricating coating film on the opposite surface."

[0361] The present invention covers all of the cases where the solid lubricating coating film of the present invention, formed from the chemical agent of the present invention, is applied to both sides of the lubrication symmetry plane, and the case where the solid lubricating coating film is applied to only one side, and the film is not applied to the other side.

[0362] When the solid lubricating coating film according to the present invention is formed on only one part, the pencil hardness of the solid lubricating coating film according to the present invention is preferably lower than that of a different type of lubricating coating film on the opposite surface. The solid lubricating coating film according to the present invention is designed to form a soft film. This is because the lubricating properties are realized under the condition that the lubricant is lightly scraped off when lubrication is required, and thus this effect cannot be realized when the film is hard.

[0363] “Method for Evaluating the Corrosion Resistance of a Solid Lubricant Coating Film”

[0364] In the corrosion resistance assessment in this specification, the protector used to protect the profile tip is first screwed onto and then removed from the structure to which the profile is attached, such as an oilfield tubular goods joint attached to a steel pipe. Salt water is then sprayed onto the solid lubricating coating film after the protector is removed. Accordingly, based on the criterion, it is determined that red rust appears on the entire surface and is assessed as NG (non-compliant). In short, the corrosion resistance assessment is conducted by spraying salt water after the film has undergone predictable damage.

[0365] Next, regarding the salt water spraying conditions, spraying was carried out by the method in accordance with JIS K 5600-7-1, under the spraying conditions of neutral salt water containing 5% NaCl (35°C, humidity 98-99%, spraying at 1 to 2 ml / hour / 80 cm 2 , pH from 6.5 to 7.2), based on an 8-hour assessment.

[0366] Here, the metal surface of the metal part that is the subject of the present invention includes, for example, a surface subjected to turning or cutting, a polished surface, and the like. Furthermore, to evaluate the corrosion resistance, the portion on which mill scale remained was removed. Depending on the roundness or eccentricity of the tubular structure, the sample may have mill scale attached to the profile structure. However, with regard to mill scale, during cleaning or similar operations before the formation of a solid lubricating coating film, water penetrates into minute defects, holes, and areas such as scratches on the mill scale. Accordingly, when a solid lubricating coating film is formed on the mill scale, even if the solid lubricating coating film is intact, pitting rust may occur on the base steel.However, since pitting rust is not solid lubricating film rust, this rust is excluded from the evaluation.

[0367] "Method for Assessing Lubrication Quality"

[0368] Of all the environments in which the solid lubricating film described in this invention is used, the most severe lubrication conditions are applied. That is, the lubricant is evaluated under make-up / break-out conditions of oil and gas tubular goods, consistent with make-up in a real well.

[0369] However, it is unrealistic to evaluate the lubricating properties of a connection for oil and gas tubular goods in a real well or in a simulated well in terms of the cost and time involved in organizing the experiment.

[0370] Therefore, in the present invention, the evaluation was carried out using the devices shown in Figures 5 and 6.

[0371] To solve this problem, a weight equivalent to approximately one to three actual nipple lengths can be attached to the upper end of the short nipple. Furthermore, the initial installation position of the connection is adjusted so that approximately half of the nipple profile vertices remain open to the coupling connection, and makeup is performed using a tong. Accordingly, the weight is applied during makeup, but not during breakout, so the nipple connection is unstable. This simulates the makeup situation in a real well. In this way, the upper and lower limits of each parameter determining lubrication characteristics can be set to values ​​corresponding to actual conditions. This evaluation method is also referred to as "loaded tong evaluation."In addition, according to the findings of the inventors, it was confirmed that the evaluation using a pipe wrench with a load can sufficiently simulate the evaluation during make-up / break-out in a real well.

[0372] The prior use of evaluation using a load-bearing tong is as follows. That is, when the determination is made based on the evaluation performed by a horizontal tong using a short nipple approximately 1 m long, or the evaluation simply performed by a vertical tong using a short nipple, the "solid lubricating coating film evaluation," which is the purpose of this description, is erroneously defined as good. That is, the upper and lower limits of the parameters defined by the invention are evaluated.

[0373] Regarding the solid lubricating film, in some cases the solid lubricating film is inevitably damaged during fastening / loosening, and then the peeling piece or powdery object does not always move in tandem with the fastening / loosening process. When this does not occur, the threaded gap becomes clogged, leading to scuffing wear. However, when evaluating using a short nipple, as in the related art, since the short nipple is less likely to be damaged, there is a concern that a defective nipple in the related art will be evaluated as good. On the other hand, regarding lubrication when using a composition in the related art, since the composition is a viscous compound similar to a liquid, it moves in tandem with the fastening / loosening process.Thus, there are no significant differences between the short nipple evaluation results and the actual well evaluation results.

[0374] Furthermore, in many patent publications of previous years, during lubrication tests based on the application of a solid lubricating coating film, there are indications that the number of make-up / break-out times can reach 15-20 times even with a large diameter of 9-5 / 8" or 13-3 / 8". However, with a solid lubricating coating film, which has poor lubricating properties compared with grease, the above-mentioned number of make-up / break-out times is practically impossible. Such conditions apparently arise from the evaluation using short nipples and horizontal or vertical pipe tongs, which are often found in laboratories. In this case, it is possible to obtain values ​​​​for evaluating the performance; however, in the example of large-diameter oilfield tubular goods using a solid lubricating coating film, the level of 15-20 make-up / break-out times in a real well is rarely encountered.

[0375] Based on the above idea, in the evaluation method given in the Examples to be described below, the evaluation was carried out by a load-testing test with a pipe wrench using the device shown in Figures 5 and 6. Simulation was performed to evaluate the lubricity of the solid lubricating coating film by simulating the make-up conditions as shown in Figures 3A and 4A under the conditions of a simulated make-up / break-out test that is carried out in a real well or in a simulated well.

[0376] Since a real-sized nipple (approximately 12 m long) is used in a real well, it is impossible to "install the nipple perfectly level" during initial installation, and the nipple is generally inserted at an angle. The nipple connection of the actual length cannot be installed perfectly level, even if an attempt is made to install the nipple connection level using either a landing guide or a compensator. The nipple connection is installed at a slight angle. In fact, it is impossible to tighten the crests of the nipple connection thread profile until they are hidden by the coupling connection. At the point where the nipple connection can be inserted into the coupling connection for further manual tightening and installation, the threads partially touch each other. Therefore, the crests of the nipple thread profile do not advance further when five or more crests, or about half of the total crests, are exposed.Thus, when making up with a wrench, the nipple connection and the coupling connection begin to engage in the normal position after several turns (up to approximately 6.3 turns in Fig. 3A) until the load is released. Since oilfield tubular goods threads, like many other threaded structures, have a conical structure, the threads can eventually engage each other in a stable position. As shown in Fig. 7, in the enlarged view, the circled parts are severely damaged. That is, cracks, peeling, and the like always occur at the microscopic level. That is, since the nipple connection 1a is installed slightly inclined relative to the threaded portion 2a of the coupling connection 2, the following occurs.The location where the nipple connection is inserted tends to be significantly damaged near the front end of the nipple connection 1a, the center of the protrusion of the threaded portion 2a of the coupling connection, the center of the nipple connection 1a, and the mouth of the threaded portion 2a of the coupling connection. "Proximity to the thread center" means the proximity to the location where the nipple connection is inserted and abuts the coupling connection. "Proximity to the mouth of the threaded portion 2a of the coupling connection" is the proximity to the mouth of the coupling connection 2a when the nipple connection is inserted.

[0377] Figure 3A shows an uneven increase in torque, peaking over several revolutions, that is, increasing from a constant torque until reaching a stable position. This behavior is directly related to the uneven contact between the pin joint and the coupling joint, which leads to damage to the solid lubricating film. Based on this, it is necessary to evaluate the lubrication degree of the solid lubricating film. When the threads are unevenly contacted, the solid lubricating film is inevitably scraped off. Flaking pieces and debris do not necessarily move with the threads. Accordingly, when the debris clogs the gap between the threads, this clogging is the main factor in scuffing wear. The chattering noise caused by the initial set position of the pin joint and the dead weight of the actual pin length are superimposed.Thus, uneven and unbalanced loading affects the pin and coupling connections, and the solid lubricating film inevitably peels off or disintegrates into powder. Accordingly, the effects of thread clogging and scuffing wear were assessed using a laboratory simulation.

[0378] Figure 5 shows the overall conceptual view of the test method, and Figure 6 shows an enlarged view of the part to which load 3 is applied. A vertical pipe wrench 4 is used for the load test with a pipe wrench. Accordingly, the connection 1 of the short nipple and the connection 2 of the coupling are secured by the profile peaks of the threaded portion 1a of the nipple and the profile peaks of the threaded portion 2a of the coupling. At this time, in order to simulate the situation where the profile peaks do not engage with each other, the initial temporary make-up position is set so that half of the total number of profile peaks of the threaded portion 1a of the nipple are visible from the connection 2 of the coupling. This is one of the causes of chatter. From this state, make-up is started using pipe wrench 4.

[0379] At this time, weight 3 is attached to the opposite side of the make-up thread of nipple 1. The weight of weight 3 is set by calculating the load equivalent to 1-3 actual-length nipples based on the actual-length nipple having the outside diameter and wall thickness of the nipple. In the case of 9-5 / 8” and 53.5#, one nipple weighs approximately 1 ton (2200 lbs), and the equivalent weight of three connected nipples is approximately 3 tons (6600 lbs). It is assumed that the equivalent weight of one nipple corresponds to an onshore well, and the equivalent weight of three nipples corresponds to an offshore well.

[0380] As shown in Figure 6, the load 3 in Figure 5 is formed by connecting the insert rod 13, welded to the load body 3A, to the axisymmetric position of the load. The insert rod 13 is inserted into the nipple 1 from above, and the load is installed on the upper end of the nipple 1. Through holes 1d and 13a are pre-made in the nipple 1 and the insert rod 13, respectively. A penetrating rod 12 is inserted and installed in through holes 1d and 13a to connect the load 3 and the nipple 1. A rotating hook 11 is welded to the axial central position of the upper part of the load 3 and has a structure for suspension from a ceiling suspension device 20 using a suspension chain 21. During make-up, a load of the load is applied to the coupling connection, and the coupling connection is make-up at a speed of 5 to 20 rpm until the torque increases. The initial temporary make-up position and high-speed revolutions during make-up / unmake-up simulate rattling.As soon as the torque increases, the rotation speed is reduced to 0.5-2 rpm and screwing is performed to reach the screwing position.

[0381] To simulate the make-up / break-out test in a real well, a load in the form of weight 3 may be applied, or weight 3 may not be applied, particularly when loosening make-up. It is preferable not to apply weight 3 during break-out. In the following examples, weight 3 is not applied during break-out. When break-out is performed while the load is applied, the weight becomes a "weight" or balancer when it is released from the make-up completion position, and the weight is removed similar to the state when a straight nipple connection is lifted. Therefore, if the nipple is loosened without chattering, the solid lubricating film is not damaged. Even under conditions where the load is not zero, the test is performed by lifting the weight.The test can be conducted under conditions where pronounced chattering occurs when the load is released, including when the load is not completely reduced to zero, and there is a high risk of damage to the solid lubricating film. Regarding the rotational speed during loosening, as the torque increases, the rotational speed begins to decrease to 0.5-2 rpm, and when the torque reaches approximately 1 / 10 of the initial torque, the rotational speed is reduced to a high speed of 5 to 20 rpm. In this example, the evaluation was performed by separating the pin joint and the coupling joint from each other by loosening. After loosening, the corresponding surfaces were checked by blowing air over the surfaces to remove fragments, etc., formed from the solid lubricating film, and then make-up was resumed.

[0382] Lubrication evaluation is performed using the following methods and criteria.

[0383] According to ISO 13679 standards, the casing size is determined to be adequate when make-up / break-out is performed three or more times, and the tubing size is determined to be adequate when make-up / break-out is performed ten or more times. However, when considering lubrication using a solid lubricating film, the number of make-up / break-out times is generally lower than that of lubrication using grease known in the art. The reasons are as follows. In the method using grease in the relevant art, each time make-up / break-out is performed, the grease applied to the surface is washed with an organic solvent to check the surface, and then the grease is applied again. In other words, the main part of the lubricant is reapplied.On the other hand, when using a solid film lubricant, the thread surface is cleaned by blowing air or something similar, but the lubricant component is not added during the testing process. As a result, it's undeniable that the number of make-up / break-out cycles using a solid film lubricant will inevitably be limited.

[0384] Therefore, as the criterion for the number of make-up / break-out times in the present invention, the casing diameter is defined as meeting the requirements when the number of make-up / break-out times is three or more. The tubing diameter is defined as meeting the requirements when make-up / break-out is performed five or more times. In addition, the casing diameter is defined as 7" or more, and the tubing diameter is defined as less than 7". In addition to the number of C / P times, when the nipple connection is completely pulled out after break-out, the nipple is lifted to the top, and the nipple connection surface and the coupling connection surface are directly visually inspected after blowing with air to check whether scuffing wear occurs.At the same time, the torque-turn diagram was checked and a determination was made based on whether an abnormal point was observed.

[0385] The NG (non-conformance) determination was performed as follows. If the connections were not loosened after the specified number of times of make-up / break-out, the scuffing wear was determined to be the number of times of make-up / break-out, and this number of times of make-up / break-out was determined to be the previous number of times. For the case where the threads were completely loosened and the surfaces were visible, if slight scuffing wear occurred on the sealing part, the case was determined to be NG on-site. Accordingly, the number of make-up / break-out times was determined based on the scuffing wear for the next time, and make-up tests with a pipe wrench under load were performed on-site. If the scuffing wear on the threaded part was very slight, repairs were performed, and the testing was continued as before.Thus, good and bad results are sorted by the number of screwing / unscrewing operations performed in accordance with the determination criteria described above.

[0386] Examples

[0387] Next, examples according to the present invention will be described.

[0388] Example 1: Technology of incorporating metallic soap into the composition and the method of uniformly mixing the metallic soap

[0389] In the test group of Example 1, the conditions were sorted according to how the metallic soap was mixed with the liquid for the metallic soap mixing method. The state of the metallic soap in the composition was tested using a chemical agent with the following component ratio.

[0390] A mixture of water as the main component, industrial ethanol, and ammonia water was used as the solvent. Calcium stearate (a metallic soap with a particle size of 8 to 10 μm or less) and sodium stearate (an alkaline soap) were used as the solid lubricant at a weight ratio of 99:1. A vinyl acetate-methacrylic acid copolymer formed from a monomer obtained by using 10 parts by weight of methacrylic acid per 100 parts by weight of vinyl acetate was used as the binder resin. Furthermore, the copolymer mentioned here corresponds to 100% of the "polymer having an acrylate or methacrylate structure" described in the present invention.

[0391] Regarding the component ratio, the amount of solvent (water) (measured by volume and converted to mass with a specific gravity of 1) was calculated to be three times the combined mass of the solid lubricant (metallic soap + alkaline soap) and binder resin. Furthermore, the mass fraction of the solid lubricant in the composition was 0.1 times the mass of the binder resin.

[0392] To formulate the composition, a mixture was prepared by mixing the monomer to produce a vinyl acetate-methacrylic acid copolymer with water. As described below, industrial ethanol was used to incorporate the metallic soap into the composition, followed by the addition of ammonia water to adjust the pH to 7-8. Finally, sodium stearate was added and mixed. An attempt was made to mix the metallic soap with the base agent.

[0393] Condition 1

[0394] Condition 1 is an example in which calcium stearate was directly added to the base agent and mixed according to the component ratio described above. Condition 1 is an example in which industrial ethanol is not used at all.

[0395] In Condition 1, the metallic soap was not sufficiently mixed, and the metallic soap particles floated on the surface and adhered to each other. This means the metallic soap could not be mixed thoroughly and uniformly. The results confirmed the generally accepted notion that metallic soap is insoluble in water.

[0396] Condition 2

[0397] In Condition 2, calcium stearate was added to the base agent and mixed according to the component ratio described above. Industrial ethanol was then added to water at a ratio of 20:100 by volume.

[0398] In Condition 2, the calcium stearate was not sufficiently mixed, and the calcium stearate particles floated on the surface and adhered to each other. This means the metallic soap could not be mixed thoroughly and uniformly.

[0399] Condition 2 indicates that the metal soap does not mix well even when subsequently mixed with ethanol.

[0400] Condition 3

[0401] Condition 3 is an example in which the ratio of industrial ethanol to water was set to 20:100, and calcium stearate was mixed with industrial ethanol in a separate container, that is, stirred until uniform, and then the mixture was added to the main agent and stirred.

[0402] Condition 3 can be cited as an example of a substantially homogeneous mixture. Although calcium stearate is reported to be insoluble in both water and alcohol, it has been confirmed that a situation can be realized in which calcium stearate disperses to form fine particles in alcohol (ethanol) without forming lumps due to the aggregation of calcium stearate grains. Therefore, it was discovered that a situation in which metallic soap is uniformly dissolved can be achieved by first dissolving the metallic soap in ethanol (alcohol) and then processing and stirring the dissolved metallic soap in a basic agent.

[0403] Condition 4

[0404] In Condition 4, the ratio of industrial ethanol to water was set at 1:100, and calcium stearate was thoroughly mixed with the industrial ethanol in a separate container before being added to the main agent. Condition 4 represents an example in which an amount of industrial ethanol (19%) was subsequently added to the main agent and mixed.

[0405] In Condition 4, during the step of placing the metallic soap (calcium stearate) in a small amount of ethanol and causing it to become cloudy, the metallic soap was insufficiently mixed, and some metallic soap grains floated to the surface and clumps together, forming lumps. In other words, Condition 4 is an example in which the metallic soap is mixed with the base agent, but Condition 4 corresponds to an example in which the metallic soap cannot be mixed well and homogeneously.

[0406] Condition 5

[0407] In Condition 5, the ratio of industrial ethanol to water was set at 15:100, and calcium stearate was thoroughly mixed with the industrial ethanol in a separate container before being added to the main agent. Condition 5 represents an example in which an amount of industrial ethanol equal to 5% was subsequently added to the main agent and mixed.

[0408] In the system corresponding to Condition 5, the metal soap (calcium stearate) was already in a state of homogeneous mixing with industrial ethanol in an amount of 15. Therefore, based on this state, Condition 5 can be taken as an example, in which, even with the additional addition of industrial ethanol, the metal soap is essentially homogeneously mixed.

[0409] From Examples of Conditions 1 through 5, the following was established. That is, a mixture obtained by initially homogeneously dissolving an appropriate amount of metallic soap in a corresponding amount of a suitable lower alcohol—that is, in an amount sufficient to sufficiently mix the metallic soap—is prepared, placed in the chemical agent itself, and stirred. In this case, the metallic soap can be mixed with a solvent containing water as the main component. Accordingly, in the case of an amount of metallic soap that cannot be uniformly mixed in the volume of the lower alcohol, it was found that there is a high tendency for the metallic soap to remain unmixed even when industrial ethanol is added after the metallic soap is added to the main agent.

[0410] In addition, the following examples are described on the basis that the chemical agents are agents in which the metallic soap is uniformly mixed.

[0411] Example 2: Quick-drying property, application amount and drying method

[0412] The test group in Example 2 was divided into good and poor dryness levels by applying a chemical agent to the joint structure of oil and gas tubular goods. The ratio of alcohol to ammonia water in the composition, the difference in alcohol type, and the size of the metallic soap were studied. Specifically, the following individual agents were systematically prepared under different conditions, and their rapid drying properties were studied.

[0413] The solvent was formed from alcohol and ammonia water, with a ratio of 100 to the aqueous solvent, and the solid lubricant was formed from metallic soap and alkaline soap. The binder resin was a copolymer obtained by using 6 parts by weight of polyvinyl alcohol as the monomer per 100 parts by weight of acrylic acid. The polyvinyl alcohol used is, for example, Poval, which is obtained by saponifying polyvinyl acetate prepared by polymerizing vinyl acetate monomer.

[0414] Their calculated ratio corresponds to the details of the current study. Accordingly, in a solvent system with a solvent (water) content of 100 (measured by volume and converted to mass with a specific gravity of 1), conditions were created to change the formulation conditions for industrial ethanol and ammonia water.

[0415] At the same time, a chemical agent was prepared by varying the total mass ratio of the solid lubricant (metallic soap + alkaline soap) to the binder resin and solvent, as well as the mass ratio of the metallic soap to the alkaline soap in the solid lubricating coating film. Furthermore, metallic soaps with different particle sizes were prepared. Each drying condition was then studied.

[0416] As a preparation method, sodium stearate was obtained and mixed in the penultimate step. Finally, ammonia water (approximately 28%) was added to adjust the pH to 6.5-8.5.

[0417] The method used was the same as that confirmed in the test group of Example 1 described above, namely, a method of mixing a metallic soap after pre-mixing the metallic soap with a "lower alcohol (ethanol: Example 1)". The industrial ethanol mentioned in this application is high-purity ethanol. Here, industrial ethanol refers to industrial ethanol mixed with methanol or isopropyl alcohol in an amount that does not violate the Alcohol Tax Act.

[0418] As the general conditions of the experiment, an OCTG joint with a 5.5" and 23# carbon steel nipple joint of L80 grade was prepared, and this joint was a JFEBEAR (trademark) nipple joint, and both ends were processed to make them short in length from 700mm to 1000mm. Regarding the method of applying the chemical agent, a general paint brush (Japanese brush standard No. 20: brush width 50mm) was first dipped into the chemical agent. Then, the short nipples were placed on two rollers rotating at the same speed, and the coating was applied while rotating at a speed of about one revolution per 10 to 20 seconds (see Fig. 8). These two rollers were two rollers rotating around an axis, where the 5.5" and 23# nipples were placed and touched at approximately at the 5 o'clock and 7 o'clock positions.In addition, brush 30 applied the chemical agent in such a way that it shifted only 1 degree in one direction and did not coat the same section of the thread located at the same position of the brush. Brush 30 touched the thread perpendicular to the thread rotation in the longitudinal direction of pipe 31. The coating was applied to the entire thread, the end surface of the front end of the nipple connection, approximately 10 mm inward and approximately 30-50 mm in the area without a profile protrusion on the ridge runout area. Both ends were evaluated as one set. In addition, the brush rotates, and thus the coating is inevitably applied approximately 10 mm inward.

[0419] First, as an example of how the chemical agent was left to dry in the atmosphere, one side was coated and then left to dry. Subsequently, as an example of how the chemical agent was left to dry in the atmosphere, the other side was similarly coated while rotating and dried under atmospheric exposure, for example, at a flow rate of 1 m / s, as the bottom side of a two-level air volume switch in the air blowing mode of a hand dryer, while continuing to rotate. The drying time was then recorded. After this, the tube rotation was stopped, and the drying time on the stationary drying side was also recorded. A sample that was not sticky and did not show fingerprints from hand contact was considered dry.

[0420] Regarding the position at which drying was determined, drying was determined at the top of the pipe, between 8 and 4 o'clock clockwise. The same determination position was also set on the side that was left to dry. When a large amount of chemical agent was applied, the agent accumulated at the 6 o'clock position as a steady state. However, since other parts, except the surface, had already cured, drying of the coating material was determined to be unaffected and used as the determination criterion.

[0421] The stationary drying time was 30 minutes or more, while drying cannot be considered complete within 30 minutes. Furthermore, the room temperature that day was between 25 and 28°C, and drying was conducted at nearly the same temperature. The forced-air drying mode was set to simple air blowing, as drying is slower than with hot air blowing, which is a harsh condition. However, if this drying mode is determined to be good, drying can be determined to be satisfactory under any forced-air drying mode, meaning the test is conducted under the harshest conditions imaginable.

[0422] The coating weight was calculated based on the difference in brush weight. However, since the chemical agent had low viscosity and high fluidity, the semi-dry coating material appeared to accumulate at the 6 o'clock position, especially on the side where the chemical agent remained after application. Finally, there was also a part where the chemical agent flowed down from the 6 o'clock position, but the applied amount was calculated without taking this flowed amount into account, and was simply based on the difference in brush weight before and after application. In addition, the viscosity of the solution was approximately 850 mPa s, except for the exception, and no significant change was observed under all conditions. The exception was less than 850 mPa s with an increase in the solvent mixing ratio. The exceptions with low fluidity are Nos. 2-10 to 2-14 listed below. A case where the solvent ratio is increased is, for example, a case where a chemical agent is used mixed with an aqueous solvent in a small amount.

[0423] In the following cases, the film weight will be described, but the film thickness will not be discussed. Only one case in which the film thickness was measured is given, and the cross-sectional microscopy is provided for No. 2-5. The connection for oilfield tubular goods was in the form of a pin joint with a thread root of 20 to 50 μm and a thread crest of approximately 20 to 40 μm. In addition, the pilot / flank portion (the part of the longitudinal wall of the thread that bears during make-up) and load / flank portion (the part of the longitudinal wall of the thread that bears during break-out) were 5 to 10 μm. For example, depending on the contact point of the brush, the brush coating line may vary. The brush coating line is an irregular part formed at a certain time, etc.Applying the coating solution after re-dipping the brush in the chemical or applying firm pressure to force the coating solution out of the brush when the yield of the coating solution decreases. Furthermore, in the examples, the pipe itself is also rotated during brush application. Thus, uniform application was intended. However, since the viscosity of the solution itself is low, a film forms on the dried area. On the other hand, the coating material tends to accumulate on the wet area of ​​the coating material during rotation. This means that the coating material migrates into the thread root groove, but apparently the coating material accumulates due to the difference in film thickness. The performance was evaluated taking this level of film thickness difference into account.However, with regard to the evaluation of the drying itself, since drying is generally carried out uniformly as long as the tube rotates, the determination of the completion of drying was made based on the drying time at the location where drying is slowest.

[0424] Detailed information about this is provided in Tables 1-3.

[0425] These are experimental examples concerning drying time. Furthermore, the lubrication characteristics of oilfield tubular goods joints represented by the number of C / P times in Tables 1-3 are not subject to evaluation. The “*” sign in the tables indicates a result that deviates from the definition. “**” indicates a result that exceeds the preferred range.

[0426] In the present application, evaluation and determination were made as “inventive examples” (drying OK (normal)) / “inventive examples” (∆: drying time different from the preferred range) / “comparative example”.

[0427] In the examples of the invention (drying is normal), the drying time is within the acceptable range defined in claims 10 and 11 of the formula of this application, and the range defined in claims 1-9 of the formula is justified.

[0428] The examples of the invention (∆: drying time differs from the preferred range) are examples that include the NG state in terms of drying time. That is, the examples differ from the preferred range. However, the examples given are within the scope of the invention defined in this specification. However, the tightening / loosening test is not described.

[0429] The comparative examples are rated as NG (unsatisfactory) in terms of drying time or hard coating film formation, and these examples cannot be expected to achieve an acceptable C / R rate. In this regard, the examples are NG because they are difficult to use for the actual make / break test. Furthermore, the comparative examples refer to examples that fall outside the scope of the invention defined in this specification.

[0430]

[0431]

[0432]

[0433]

[0434]

[0435]

[0436] Nos. 2-1 through 2-3 are examples that do not contain alkaline soap. Meanwhile, No. 2-1 is an example in which the solvent does not contain either alcohol or ammonia water.

[0437] No. 2-1 is an example for investigating the dry state of the binder resin (acrylic acid-vinyl alcohol copolymer) discussed in Examples in a state in which coating is performed by slightly exceeding the coating thickness limit. This property of the binder resin composition ensures drying. This example corresponds to the comparative example. Specifically, the solvent is only water and does not contain alcohol, ammonia water, or similar substances. Because only water is used, calcium stearate, which has water-repellent properties, cannot be uniformly distributed and dissolved even at the chemical agent stage. Therefore, even in the form of a solid coating film, many components of calcium stearate are not incorporated into the film but are located on it, and the film cannot be said to be good as a solid lubricating coating film.In addition, this is an example in which the drying time is also long and is considered as a comparative example.

[0438] In both #2-2 and #2-3, the volume ratio (v / v) of ethanol to water is 6:100. The former is an example in which ammonia water is not contained, while the latter is an example in which ammonia water is mixed in a ratio of 0.5. In both examples, the amount of the applied agent is within the specified range, and both hot air drying and drying in an undisturbed environment meet the specified value. In other words, both examples correspond to the claimed invention (good drying). Variant #2-3 has a slightly shorter drying time and is an improvement. This indicates that volatility may lead to a slightly improved result due to the influence of ammonia water content.

[0439] No. 2-4 is an example in which an alkaline soap component was slightly added to No. 2-3. Metallic soap (calcium stearate) and alkaline soap (sodium stearate) were added at a weight ratio of 99:1. The drying time is not inferior to that of No. 2-3, and this example is an example of the invention.

[0440] No. 2-5 is an example in which methylamine, a primary amine, is added instead of the ammonia water of No. 2-4. This example has the same drying level as No. 2-4 and is an example of the invention.

[0441] No. 2-4 described above and Nos. 2-6 to 2-9 are examples in which the proportions of industrial ethanol are increased to 6, 10, 25, 250, and 43 with respect to 100 volumes of water, in that order. In addition, these examples correspond to examples of 0.5, 1.0, and 1.0, without addition, and 2.0 ammonia, in that order.

[0442] Overall, drying time was reduced in variants #2-4, #2-5, #2-7, #2-8, and #2-9, in that order, both when drying with an air dryer and when drying in an undisturbed environment. These examples demonstrate that the more industrial ethanol, the faster the drying process. All of these examples are in accordance with the invention (good drying).

[0443] Example #2-7 demonstrates that drying can be improved solely by the evaporation of industrial ethanol without ammonia. Examples #2-4, #2-5, #2-6, and #2-8 demonstrate that ammonia has a positive effect on rapid drying.

[0444] In addition, Example No. 2-9 means that the sum of the alcohol content and ammonia water is 45 relative to the volume of water, and there is no problem with drying to this level.

[0445] Examples Nos. 2-10 to 2-15 are the results of investigating the mass ratio of solvent to solid (mass of solid lubricant component + total mass of binder resin). In addition, the mass of solvent refers to the mass obtained by converting the volume of solvent formed from water, alcohol, and ammonia with a specific gravity of 1.

[0446] No. 2-10 and No. 2-11 are test examples in which industrial ethanol was used at a ratio of 25 to 100, specified as the volume of water. Nos. 2-12 to 2-15 are test examples of industrial ethanol at a ratio of 40. In the first group, the mass ratio of solvent to solid is 0.7 and 30, in that order. In the second group, the examples have a water ratio of 20, 50, 100, and 130, in that order.

[0447] When the solvent-to-solid mass ratio reaches 100, the target drying time specified in this specification can be achieved, which corresponds to the inventive example (good drying) (Nos. 2-11 to 2-14). On the other hand, in Example No. 2-15, which has a value of 130, which is greater than 100, the target drying time cannot be achieved when dried in an undisturbed environment, which is the inventive example (∆: drying time deviates from the preferred range). This means that the basic structure of the present invention meets the requirements, although the standard drying time is not met. However, Example 2 does not describe the lubrication behavior.

[0448] Nos. 2-16 to 2-20 represent the test results with increasing alkaline soap content. This is also a study example (solvent mass ratio is 2.5) in which the amount of solvent is increased, and an example in which the alcohol content is also high. In the examples, the mass ratios of metal soap and alkaline soap are 99:1, 99:1, 95:5, 90:10, and 80:20, respectively. In addition, in Examples No. 2-16 and No. 2-18, the mass ratio of alkaline soap is indicated. 2-17, the amount of applied material is different, and in the former case it is 6 g, while in the latter case it is 12 g, and the amount of applied material is slightly higher than the target value of 0.1 g / mm 2 .

[0449] Nos. 2-16 and 2-17 comply with the standard for hot air drying. However, when drying in an undisturbed environment, the former is an example in which the standard is met, while the latter is an example in which the standard is not met. Since the amount of material applied in the latter case is twice that of the former, it is assumed that the amount of material applied exceeds the standard drying time. When the amount of material applied exceeds the prescribed value: 0.1g / mm 2 , it is indicated that the sample may not meet the standard of the preferred drying time range, especially when dried in an undisturbed environment. The first example corresponds to the example of the invention (good drying), and the second corresponds to the example of the invention (∆: drying time deviates from the preferred range). This is due to the fact that the range defined by the present application is met, with the exception of the suitable drying time.

[0450] No. 2-18 is an example that specifies the upper limit of the specified alkaline soap content. The drying time is longer than in No. 2-15, but the target value is achieved. This corresponds to the example of the invention (drying is normal).

[0451] On the other hand, in Nos. 2-19 and 2-20, the amount of alkaline soap component (sodium stearate) exceeded the specified amount and was added in excess, increasing the viscosity of the solvent, making it difficult to apply the chemical agent evenly. Furthermore, even if the chemical agent was applied, it took too long to dry, and the specified value could not be achieved. Therefore, this example shows that using too much alkaline soap is not recommended. In particular, No. 2-20 is an example in which the drying time exceeds the standard value of the preferred drying time range, and the viscosity is excessively high, making the application uneven and difficult. In No. 2-20, uneven or dripping drying was very slow, and the drying time could not be accurately determined. Thus, Nos. 2-19 and 2-20 correspond to comparative examples.

[0452] Examples No. 2-21 to No. 2-26 represent a series of studies of lower alcohols.

[0453] No.2-21 is a methanol test example, No.2-22 to No.2-24 are isopropyl alcohol test examples, No.2-25 is a normal propyl alcohol test example, and No.2-26 is an isobutyl alcohol test example.

[0454] Nos. 2-22 to 2-24 are the results of the study on the influence of the film thickness of the solid lubricating coating.

[0455] Nos. 2-21 to 2-25 are examples of components containing up to three carbon atoms. When using methanol, ethyl alcohol (examples No. 2-2 to No. 2-20), isopropyl alcohol, or normal propyl alcohol, a certain amount of metallic soap is contained. At the same time, when a value of 0.1 g / mm is reached 2or less, which is the target film thickness value, this indicates that the drying objective can be achieved. Nos. 2-21 to 2-23 and No. 2-25 correspond to examples of the invention (good drying).

[0456] On the other hand, No. 2-24 is an example in which the film thickness exceeds the predetermined value with isopropyl alcohol, and is an example in which the film thickness does not satisfy the predetermined value in the preferred drying time range. Since the basic structure of the present invention has been achieved (experimental data omitted), this example is an example of the invention (∆: drying time deviates from the preferred range).

[0457] No. 2-26 was an example for isobutyl alcohol, which has four carbon atoms. The problem was that the metallic soap was not sufficiently mixed with the aqueous solvent during the preparation of the chemical agent before application, and thus this example corresponds to a comparative example. As the number of carbon atoms increases, the solubility of the solid in water gradually decreases. Based on this result, even when the metallic soap can be uniformly dispersed and dissolved in isobutyl alcohol, the following can be said when considering the metallic soap as a coating material in a state of dissolution in water and miscibility. That is, it is assumed that dissolved isobutyl alcohol and metallic soap are poorly miscible in the aqueous solvent. Therefore, a uniform coating film was not formed before the drying time was discussed, and therefore, the coating film was used as a comparative example.

[0458] Examples 2-27 through 2-33 show the results of studying the effects of the types of metallic soap and alkaline soap, as well as the particle size of the metallic soap. Examples 2-27 through 2-29 are for calcium stearate and sodium stearate. Example 2-30 is for zinc stearate and sodium oleate. Example 2-31 is for magnesium stearate and potassium stearate. Example 2-32 is for calcium montanate and sodium 12-hydroxystearate, and Example 2-33 is for calcium behenate and sodium laurate. Accordingly, the effect of fine particles of metallic soap is studied.

[0459] As in Example 2-29, when the particle size of the metallic soap is 25 μm, the drying time becomes longer than the target. However, with a particle size of 10 μm or less in other examples, the preferred drying time range is satisfied, and early drying is possible. It was found that, although drying is generally enhanced by adding metallic soap, setting the particle size to 10 μm or less achieves the target drying time. Furthermore, it was found that various types of metallic soaps and alkaline soaps can be used without any particular problem within the scope of the present invention.

[0460] No. 2-29 can be defined as an example of the invention (∆: drying time is different from the preferred range), and Nos. 2-27 to 2-34 correspond to an example of the invention (drying is normal).

[0461] The reason why No. 2-29 corresponds to the invention example (∆: drying time differs from the preferred range) is as follows. That is, the particle size of the metal soap (calcium stearate) is 25 μm. As described above, there is often a region where the film thickness of the longitudinal wall-like portion of the oilfield tubular goods joint, the film thickness of the joint / side surface, and the bearing / side surface are smaller than the particle size of the metal soap. Therefore, it can be assumed that the film integrity cannot always be maintained during lubrication, and long-term rust protection may be impaired.

[0462] Example 3: Effect of each condition in terms of lubricity

[0463] Test Group Example 3 describes an invention based on the results of a study of lubricity by applying a chemical agent to a joint structure of oilfield tubular goods to form a film and conducting a load-bearing test using a pipe wrench.

[0464] When tightening, the entire load's weight was applied. When loosening, the rattling sound of lifting with overhead crane 20 (Fig. 5) was simulated to bring the load's load close to zero. Evaluation details were systematically prepared to test combinations of various conditions, and the correctness of their application was determined by the nature of the lubrication, i.e., the number of times the load was lubricated.

[0465] The metal soap component was pre-dispersed in low molecular weight alcohol to achieve uniform dispersion and uniform dissolution to obtain a chemical agent, which reflects the details discussed in Example 1.

[0466] As described above, the criteria for determining the lubrication performance using a load-bearing tong were that the casing size was determined to meet the requirements when make-up / break-out was performed three or more times. The tubing size was determined to meet the requirements when make-up / break-out was performed five or more times. In addition, the casing size was determined to be 7" or greater, and the tubing diameter was determined to be less than 7". According to connection testing standards such as API-5C5, the tubing material is based on achieving 10 or more times the C / P with the normal lubrication performance of the API-mod compound.However, in the case of a solid lubricating coating film, since gradual scraping of the film itself is inevitable, the number of repetitions tends to decrease, and thus 5 or more times is used as a measure of suitability in this case.

[0467] In addition to the number of times of S / R, after completely loosening the pin after make-up, the pin was lifted to the top. Accordingly, the pin connection surface and the coupling connection surface were inspected after blowing with air to directly visually check for scuffing wear. At the same time, the torque-rotation relationship chart was checked, and a determination was made based on whether an abnormal point was observed. The determination method was as follows. When the connection was not loosened after a certain number of times of make-up / break-out, it was determined that scuffing wear was determined by the number of times of make-up / break-out, and this number of times of make-up / break-out was determined as the previous number of times.

[0468] Regarding the case where the thread was completely loosened and the surfaces were visible, if slight scuffing wear occurred on the sealing portion, this case was considered minor. Accordingly, the number of make-up / break-out repetitions was determined based on the scuffing wear during the next test, and the number of make-up / break-out test repetitions using a pipe wrench with a load was recorded on-site, and the make-up / break-out test was terminated. If no scuffing wear occurred on the sealing portion, but very slight scuffing wear was observed on the sealing portion, repairs were performed, and the test was continued as before. Thus, good and bad results were classified according to the number of procedures performed in accordance with the determination criteria described above.

[0469] The conditions and results are shown in Tables 4-12. The "*" symbol in each parameter in the table indicates a result that deviates from the definition. The "**" symbol indicates a result that is outside the preferred range.

[0470]

[0471]

[0472]

[0473]

[0474]

[0475]

[0476]

[0477]

[0478]

[0479]

[0480]

[0481]

[0482]

[0483]

[0484]

[0485] In the tables, "solid lubricating coating films A with a pencil hardness of 3H" frequently appearing in the description below are as follows. That is, for carbon steel, a chemical conversion film of manganese phosphate was formed as the base layer, and for stainless steel, a galvanic Cu-Sn film (Sn; 45-47%) was formed, and then a solid lubricating coating film was formed on the base layer. In this case, the structure is formed by substantially uniformly dispersing a binder resin (polyamide imide film), a solid lubricant (PTFE), and a small amount of MoS2 (1 to 3%). Accordingly, the solid lubricating coating film refers to a solid lubricating coating film having a thickness of 50 to 80 μm. The film thickness is the measured value of the film thickness at the profile peak. The solid lubricating coating film belongs to the ordinary and uniform solid lubricating coating films with a pencil hardness of 3H.Furthermore, the film thickness on each section of the profile shoulder is distributed as follows. That is, the profile shoulder design of the oil and gas tubular goods connection has an inverted hook structure. Consequently, although the chemical agent is designed and applied to achieve a uniform film thickness, it is impossible to avoid a decrease in film thickness in the longitudinal wall section of the profile shoulders of the working / side section and in the thread / side section. However, thanks to a sophisticated method for forming the solid lubricant film, the film thickness is formed in such a way that it can be half or more the film thickness of the measured film thickness at the profile top, even in the vertical wall section.

[0486] Nos. 3-1 to 3-12 are examples in which a 7” 38# JFELION (trademark) joint made of P 110 grade carbon steel was produced, and styrene-acrylic acid copolymer (500 parts by weight of styrene to 100 parts by weight of acrylate) was used as a chemical agent. Accordingly, they are examples in which a solid lubricating coating film is formed on the connection side of the pin. In addition, the examples provide a condition in which a “solid lubricating coating film A having a pencil hardness of 3H” is formed on the connection side of the coupling. In this case, a chemical conversion film of manganese phosphate is formed on the base. To determine whether make-up / break-out can be performed, a test was conducted using a load of 2 tons, which is equivalent to make-up for three connected nipples.

[0487] In Examples Nos. 3-1 through 3-8, the solvent contains industrial ethanol and ammonia water in a ratio of 15:2, respectively, based on 100 parts water. The component ratio is generally accepted, and the composition is prepared under conditions within the specified range. This is a study example in which the particle size of the metallic soap, the presence or absence of alkaline soap, and the film thickness are varied. Examples in Nos. 3-1 through 3-4 show particles of metallic soap (calcium stearate) with sizes of 5 μm, 1 μm, 10 μm (alkaline soap is not contained in this example), and 10 μm, respectively. Nos. 3-1, 3-2 and 3-4 demonstrate good lubricity when the number of times of C / R using a pipe wrench with a load is 10 or more times (stopping at 10 repetitions) and correspond to the example of the invention. No. 3-3 corresponds to the example of the invention, in which the number of times of C / R is only 3 times.However, the lubricating properties of No. 3-3 deteriorated to a greater extent than those of Nos. 3-1, 3-2, and 3-4, which contained an alkaline soap component. This indicates that the addition of alkaline soap effectively improves lubrication.

[0488] In Nos. 3-5 to 3-8, the metal soap had a particle size of 25 μm. However, in these examples, the film thickness of the solid lubricating coating was 20 μm, 50 μm, 100 μm, and 180 μm, in that order. In addition, these examples were examples in which the drying time was 7 minutes with air flow drying, 23 minutes with air flow drying, 8 minutes with hot air drying, and 10 minutes with hot air drying, in that order. In Nos. 3-7 and 3-8, drying was performed using a hot air blower (power: 1000 W).

[0489] In general, the drying time is generally longer than in Nos. 3-1 through 3-4. This change is believed to be influenced by the increase in the film thickness of the solid lubricant coating and the particle size of the metallic soap. When the particle size of the metallic soap is small and the metallic soap is dispersed, the number of drying spots in the film increases as the surface area increases. As a result, one would expect the drying process to accelerate. However, in these examples, this can be explained by the fact that since the particle size is large and therefore a reduction in drying time is not expected, the volume to be dried increases due to the influence of film thickness.

[0490] No. 3-5 is an example of a 20 μm thick film and is an example in which the metal soap particle size is larger than the film thickness. In this example, where the metal soap particle size is larger than the film thickness, there is a section where it is difficult to maintain the film integrity, and this section is damaged, causing scuffing wear. No. 3-6 (film thickness: 50 μm) correspond to the invention example with a C / P number of 6 or 7 times. Nos. 3-7 and 3-8 are examples of studying the effect of film thickness. In the former case, the film thickness is 100 μm, and the C / P number can be achieved, but in the latter case, the film thickness is 180 μm, and some sections of the film may not meet the C / P number of 3 as a standard. That is, this indicates that when the film thickness is more than 100 μm, the lubrication performance may deteriorate.

[0491] Nos. 3-9 and 3-10 are comparative studies conducted using different drying methods. They will be described in comparison with No. 3-1. No. 3-1 described above is an example in which the S / P rate was 10 or more times (stopping at the tenth rotation). No. 3-9 is the same, with up to one brush application while rotating the pipe. However, in this example, only the pipe with the nipple connection as is is rotated and dried in the atmosphere, with drying completed for 15 minutes. No. 3-10 is an example in which drying was carried out in a state where rotation was stopped, but the coating film remained after coating with rotation, requiring additional drying time.

[0492] Next, as described above, the degree of drying on the upper side of the pipe at the 8 to 4 o'clock position was determined. This determination can be made because the lower portion of the coating film has already formed into a film, which can be evaluated by drying at the 8 to 4 o'clock position. Furthermore, in this case, the surface remains dry in addition to the lower portion of the coating film at the 5 to 7 o'clock position, where the chemical agent accumulates, but the surface does not completely dry from the inside, so it can be considered that there is no problem with corrosion resistance. As shown in this example, the lubrication performance is slightly inferior to that of No. 3-1 or No. 3-9, but is within the acceptable range. The lubrication can be considered to be in a good range, and this example can be considered an example of the invention.The cause was apparently related to the fact that the chemical agent was more fluid due to its lower viscosity, and the coating material, which was not completely dry at the end of application, contained liquid running (dripping) down the edges. Although the position between 5 and 7 o'clock shows a dry surface but not a completely dry interior, this position is within the acceptable range.

[0493] Examples Nos. 3-11 and 3-12 are experimental examples in which the binder resin contains a binder resin component other than an acrylate-based or methacrylate-based binder resin component. These are examples in which 11 parts by mass and 35 parts by mass of a water-soluble phenolic resin are contained relative to 100 parts by mass of a binder resin component other than a methacrylate-based resin. The former corresponds to the example of the invention, and the latter corresponds to a comparative example in which the amount of components exceeds the standard upper limit.

[0494] In the examples, the mass proportions of the binder resin other than the acrylic resin or methacrylic resin in the total mass of the binder resin are 90% and 74% (* less than 90% of the standard), in that order. The first example is an example of the invention in which the number of times of S / P satisfies the definition. The first example is an example in which the mass ratio of solvent / (solid lubricant + binder resin) is 1.8, the mass ratio of solid lubricant / binder resin is 0.12, and the viscosity is 650 mPa s. The last example is an example having values ​​of 1.8, 0.12, and 1300 mPa s, in that order.

[0495] On the other hand, in the last example, the solid lubricating film was applied at a specified thickness of 25 μm, but the solid lubricating film was not completely dried. Consequently, since the film was not dried even one night after application, it was in a semi-wet state, and the make / break test could not be performed. Therefore, this example was used as a comparative example.

[0496] Examples 3-13 to 3-17 use a 9-5 / 8” 53.5# JFELION (trademark) joint made of Q125 carbon steel, and vinyl acetate butyl acrylate, polyvinyl polymer (420:100:75) was used as the chemical agent. This is an example in which a solid lubricating coating film is formed on the connection side of the nipple. In addition, the examples provide a condition in which “a solid lubricating coating film A having a pencil hardness of 3H” is formed on the connection side of the coupling. Accordingly, when the conditions are met, a chemical conversion film of manganese phosphate is formed on the base. In order to determine whether make-up / break-out can be performed, a test was conducted using a load of 3 tons, which is equivalent to make-up for three connected nipples. This is an example of a study in which To increase volatility and improve drying, the amount of lower alcohol (ethanol) was increased.

[0497] The solvent contains industrial ethanol in the ratio of 35, 35, 35, 45, 60 to 100 water, in that order. In addition, the following application methods are used: rotary application / air drying, rotary application / air drying, stationary application (hand application) / stationary drying, rotary application / stationary drying, stationary application (hand application) / stationary drying, in that order.

[0498] Only #3-17 contains a lower alcohol content of 60, exceeding the upper limit of 45. This definition does not meet the standard for the number of make-up / break-out times. When the make-up / break-out test was conducted using a load-bearing pipe tong, the number of make-up / break-out times was generally low, although the examples were at the compliance level, such as 5 times, 1 time, and 2 times. Therefore, this example is consistent with the comparative example. This indicates that the film may have dried too early and the film thickness may be uneven. Furthermore, assuming a flash point of 40°C and the chemical agent is applied at the wellsite, there is a risk of accidents such as explosions, and therefore this example may also be considered unsatisfactory in this regard.

[0499] In Examples other than 3-17, the number of C / R times met the standard requirements. It is believed that the reason why the number of C / R times for No. 3-13 was only 3 times, which is the lower limit, is that the solid lubricant / binder resin ratio exceeded 1.0, which is higher than the preferred range. In the case where the solid lubricating coating film contains a large amount of solid lubricant, it is believed that this is due to the fact that the film integrity is slightly reduced. In addition, from Experimental Examples Nos. 3-15 to 3-17, which were coated manually and / or statically (without air blowing), the number of C / R times generally decreased slightly. It is believed that this decrease is due to the unevenness of the film thickness during film formation, while the undried chemical agent gradually flows down to the 6 o'clock position during drying.

[0500] In Examples No. 3-18 to No. 3-34, a JFELION (trademark) joint of size 9-5 / 8" 43.5# was manufactured using HP2-13CR-110 martensitic stainless steel (13Cr-5Ni-2Mo based) by using an ethylene methacrylic acid copolymer resin as a chemical agent. Here, the ethylene is a polymerized ethylene methacrylic acid of a random copolymer of ethylene oxide and propylene oxide, and a solid lubricating coating film is formed on the connection side of the pin. On the connection side of the box, a galvanic indicator film having a Cu-Sn binary system is formed on the base, under the condition that “solid lubricating coating film A having a pencil hardness of 3H” is formed. Here, a make-up / break-out test was performed with using a 2 ton load to determine whether make-up / break-out can be accomplished provided that a weight equivalent to make-up of less than three nipples on an actual well is applied.

[0501] In Examples No. 3-19 to No. 3-22 and No. 3-24 to No. 3-33, the number of times of tightening / loosening in the tightening / loosening test using a weight is within the allowable range, and the examples correspond to the examples of the invention. Nos. 3-18, 3-23, and 3-34 correspond to comparative examples.

[0502] Examples No. 3-18 through No. 3-21 constitute a group of examples that consider the lower limit of lower alcohol content. Example No. 3-18 is an example of a solvent consisting solely of pure water without adding alcohol. Drying was performed with hot air at 100°C, and the drying time was not particularly long. However, the tightening / loosening test with a pipe wrench under load was deemed unsuccessful, and thus this example is considered a comparative example. Because the solvent was solely water, the metallic soap, as the main component of the solid lubricant, had water-repellent properties. For this reason, it is believed that since the metallic soap cannot be properly distributed even when a solid lubricating film is formed, the uneven dispersion is due to uneven film quality.

[0503] Examples #3-19 through #3-21 are examples in which industrial ethanol is contained in ratios of 0.5, 1, and 5, in that order. From #3-19 (industrial ethanol: 0.5), it can be confirmed that the C / P ratio is within the acceptable range.

[0504] Examples No. 3-22 to No. 3-24 are experimental examples containing a third solid lubricant other than a metallic soap and an alkaline soap, and are examples in which graphite, graphite, and BN were added in that order. In Examples No. 3-22 and No. 3-24, adjusted within the specified range, the number of times of S / P is within the allowable range, and the examples are inventive examples. No. 3-23 is an example in which a large amount of a third solid lubricant (in this case, graphite) is contained, and the mass ratio of the metallic soap and alkaline soap to the total amount of the solid lubricant does not meet the definition. In these examples, the number of times of S / P does not meet the required criteria, and the example is determined as NG and corresponds to the comparative example. In practice, the graphite formed a ribbon-like product with a thickness of more than 20 mm along the groove of the protruding part of the profile, which led to scuffing wear.

[0505] Examples No. 3-25 to No. 3-27 are comparative analysis examples in which the solvent, binder resin, and solid lubricant are conventional. The solid lubricating coating film is completely dried by changing the application method and drying method, and a part of the solid lubricating coating film remains as a semi-dry part. Thus, these examples correspond to the comparative examples. No. 3-25 is an example in which the pipe was coated with a brush while rotating, and then blown and dried while rotating. When the film is completely dried, the number of times of S / P using a pipe tong with a load is determined to meet the requirements, and this example corresponds to the example of the invention.

[0506] No. 3-26 and No. 3-27 are examples in which the same process as No. 3-25 was followed before application, but the drying process was different, forming a solid lubricating coating film and leaving it to dry in a stationary position. No. 3-26 is an example of complete drying, while No. 3-27 is characterized by an insufficiently dried portion. Specifically, between the 5-7 o'clock positions, there is a portion of the liquid-like coating material that is not completely dry. Furthermore, since the coating material is formed as a film (dried) from the contact surface between the outermost layer (the surface exposed to the atmosphere) and the steel material containing the thread, a semi-dry portion remains near the center of the film thickness. This is an example in which drying occurs even at the contact surface between the thread and the coating film.Although the application and drying times were the same, the application method was slightly different and it is assumed that this change affected the application method, but no lubrication problems were encountered and the examples correspond to the examples of the invention.

[0507] In Examples 3-28 to 3-32, the effects of the solvent mass ratio (in this case, calculated at a solvent specific gravity of 1) and the solid lubricant / binder resin mass ratio relative to the total mass of the solid lubricant and binder resin were compared and evaluated. Both parameters were examined in the order of 100∆-0.6, 150∆-5.0∆, 0.7-0.1, 0.5 -0.08∆, and 0.6 -1.1∆. In addition, ∆ means exceeding the upper limit of the preferred range, and means exceeding the lower limit of the preferred range. All conditions are also examples of the invention. Examples that fall within the preferred range are No. 3-28 with 6 times the C / R and No. 3-30 with 10 times the C / R, indicating a significant number of C / R times. However, examples that exceed the preferred range demonstrate lubrication efficiency with only approximately 3-4 times the C / R.

[0508] Examples Nos. 3-33 and 3-34 are examples in which another solvent is added to the solvent in addition to water and alcohol, and are examples in which dimethyl sulfoxide (DMSO) is added. In the former case, when the volume of water is 100, DMSO is added at a ratio of 6 to the main chemical agent containing industrial ethanol at a ratio of 14 per 100 as the volume of water. Accordingly, in the examples, with respect to the total mass of the solvent, the volume formed by water and a lower alcohol is 95%, and the volume of the other solvent is 5%. This example considers the limit of the solvent composition for this application. These examples use a stable polar solvent that is virtually non-volatile, and the chemical agent can be dried with hot air in about 5 minutes.However, this is an example in which drying cannot be accomplished within the specified 5 minutes under normal airflow conditions, nor can drying be accomplished within 30 minutes even when drying in an undisturbed environment. If film formation is successful, the target lubrication level for this application can be improved, and thus the example corresponds to the example of the invention.

[0509] On the other hand, No. 3-34 is an example in which more DMSO is added and a solvent containing a large amount of DMSO with a high boiling point (approximately 190°C) is studied. Therefore, the film does not dry even when left to dry in the atmosphere or even when dried with an air flow (including hot air), and the chemical agent is unable to form a film. It can form a film through heat treatment at or above 200°C. However, since the viscosity of the prepared solvent is low, the film cannot form instantly during baking, and dripping occurs even during baking. In particular, a thick film forms at the 6 o'clock position, and areas of filling the bottom of the nipple joint grooves are visible, and in some areas, further dripping occurs, resulting in the formation of teardrop-shaped film protrusions.Consequently, even when performing the make / break test, the required number of repetitions is not achieved, and scuffing wear occurs. Therefore, the example is classified as NG and matches the comparison example. These studies determined that the proportion of water and lower alcohol in the solvent should be 95% or more.

[0510] Examples No.3-35 to No.3-39 are examples of a chemical agent obtained by mixing a polymer of diacetone acrylamide (DAAD: a kind of acrylate) and diphenylmethane diisocyanate (MDI: a urethane compound) with 40 parts by mass of MDI per 100 parts by mass of acrylate, and using the resulting mixture as a chemical agent, which is applied to a JFELION (trademark) joint having a size of 5.5" 23# and a material grade of T95 carbon steel. On the coupling side of the base, a galvanic indicator film having a Cu-Sn binary system is formed under the condition that a “solid lubricating coating film A having a pencil hardness of 3H” is formed. A make-up / break-out test using a 1-ton load was performed to determine whether make-up / break-out, provided that a weight equivalent to make-up when connecting less than three nipples on an actual well is applied.

[0511] Examples No. 3-35 to No. 3-39 are examples in which a solid lubricating coating film is formed by changing the application method and the drying method. Five examples of rotary coating - rotary air flow drying, rotary coating - stationary drying, stationary and manual coating - stationary drying, rotary coating - rotary air flow drying, and rotary coating - rotary air flow drying are given in order. The number of times of C / R with a pipe wrench under load is, in order, ≥10 times (stop at the tenth time of C / R), ≥10 times (stop at the tenth time of C / R), 9 times, 8 times, and 9 times, and all of them meet the requirements, and the examples are examples of the invention.Compared with Examples No. 3-1 to No. 3-34, since the screwing torque is small due to the small diameter material, it indicates that the unevenness of film thickness distribution is not significantly affected by manual coating in a stationary state or stationary drying, or static drying.

[0512] In Examples No. 3-38 and No. 3-39, different types of metallic soaps are used as metallic soaps, different from the calcium stearate and calcium / zinc stearate (mixed) used in Examples No. 3-1 to No. 3-37. The first example is an example of using zinc stearate, and the second is an example of using barium stearate. In both examples, the other conditions are examples that fall within the detection range, and the number of times C / P falls within the required range, and thus, the examples correspond to the example of the invention.

[0513] Examples No. 3-40 to No. 3-43 are examples in which an acrylic acid-polyvinyl acetate copolymer is used as a chemical agent, which is applied to a JFEBEAR (trademark) joint having a size of 3.5" 9.2# and a material grade of T95 carbon steel. In addition, a chemical agent obtained by mixing 30 parts by mass of polyvinyl acetate with 100 parts by mass of acrylic acid was investigated. In the examples, as a condition for using "solid lubricating coating film A having a pencil hardness of 3H" for the coupling joint, there is a manganese phosphate chemical conversion film on the base. In addition, the examples include an example of using a pin joint, an example of applying only a chemical reagent to both surfaces of the thread, and an example of using only a manganese phosphate chemical conversion film or the like.To determine whether make-up / break-out could be performed, a test was conducted using a 500 kg load, which corresponds to the condition where a weight equivalent to make-up is applied when connecting three nipples on a real well.

[0514] No. 3-40 is similar to the above series of examples and is an example in which a solid lubricating coating film is attached to the pin joint side, and a "solid lubricating coating film A having a pencil hardness of 3H" is formed on the coupling side. Furthermore, this is an example of the invention in which the number of times of S / P can be ≥ 10 times (stopping at the tenth time). No. 3-41 is an example in which a solid lubricating coating film is attached to the pin joint side, and the coupling joint has only a manganese phosphate film without the "solid lubricating coating film A having a pencil hardness of 3H". However, make-up / break-down can be performed 3 times, and thus, this example is an example of the invention.

[0515] No. 3-42 is an example in which the solid lubricating coating film according to the present invention is attached to both sides of the thread, and the screwing / loosening can be performed 5 times, and thus, the example is an example of the invention. No. 3-43 is an example in which the coupling joint is coated with a solid lubricating coating film, and "solid lubricating coating film A having a pencil hardness of 3H" is attached to the coupling side of the pin. The number of times of S / P can be ≥ 10 times (stopping at the tenth time). This is also an example of the invention.

[0516] Example 4 Corrosion Test Result

[0517] The results are shown in Table 13.

[0518] Table 13

[0519] *: Result deviating from detection range **: Result deviating from preferred range

[0520] № Material The result of spraying salt water Meets / Does not meet requirements Note Comparative examples SPCC (sheet material) Red rust all over the surface Does not correspond Comparative example 3-1 L80 No rust Corresponds Example of the invention 3-13 L80 No rust Corresponds Example of the invention 3-17 L80 Rust in two places of scale residue Corresponds Example of the invention 3-20 L80 No rust Corresponds Example of the invention 3-38 L80 Rust in one place of the scale residue Corresponds Example of the invention 3-42 L80 No rust Corresponds Example of the invention

[0521] In evaluating the corrosion resistance of this invention, a protector used to protect a connecting structure was screwed onto and then removed from the structure to which the profile structure was attached, such as an oilfield tubular goods joint attached to a steel pipe. Salt water was then sprayed onto the solid lubricating coating film in the state where the protector was removed. Accordingly, based on the criterion, it was determined that the case in which red rust appeared on the entire surface was rated as NG. The evaluation was conducted by spraying salt water after applying the expected damage to the film. The corrosion resistance was tested using several materials and conditions listed in Tables 1–12.

[0522] Next, regarding the salt water spraying conditions, spraying was carried out in accordance with JIS K 5600-7-1, under the spraying conditions of neutral salt water containing 5% NaCl (35°C, humidity 98-99%, spraying at 1 to 2 ml / hour / 80 cm 2 , pH from 6.5 to 7.2), and based on an 8-hour assessment.

[0523] At the same time, the metal surface (thread surface of oilfield tubular goods) of the metal part that is the subject of the present invention includes, for example, a surface subjected to turning or cutting, a polished surface, and the like. Furthermore, to evaluate the corrosion resistance, the portion on which scale remained was removed. Depending on the roundness or eccentricity of the tubular structure, scale may be present on the sample on the structure of the protruding portion of the profile. However, regarding the scale, when cleaning or the like is performed before the formation of a solid lubricating coating film, a water-based solvent penetrates into minute defects, holes, and areas such as scratches on the scale. Therefore, when a solid lubricating coating film is formed on the scale, even if the solid lubricating coating film is not damaged, pitting rust may occur on the base steel.However, since pitting rust is not solid lubricating film rust, such rust is excluded from the evaluation.

[0524] The sample number in Table 13 refers to the chemical composition based on the components and configurations used in Tables 1-12. Different from the sample number, the application method is an example in which the coating is applied by brushing while rotating the pipe, and the drying method is an example in which drying is carried out by rotating, blowing with air, and drying, and completely drying. In addition, all of these are examples in which the materials were tested by combining with JFELION (trademark) L80, 3.5" 9.2# nipple (male thread) connections. Accordingly, after complete drying, the HDPE resin protector (made of high-density polyethylene) was screwed and screwed in place, and a saltwater spray test was conducted.SPCC materials made from general-purpose thin steel sheets, as well as materials obtained by applying chemical agents numbered 3-1, 3-13, 3-17, 3-20, 3-38, and 3-42 to the nipple joints, were prepared and tested as comparative materials. However, the SPCC made from the comparative material is not coated with anti-corrosion oil and does not pass the test corresponding to the installation / removal of the protector.

[0525] As a result, it is clear that all the parts coated with the chemical agent of the present invention have good corrosion resistance.

[0526] Other examples

[0527] The present invention can also have the following configurations.

[0528] (1) A chemical reagent for forming a solid lubricating coating film on a metal surface is proposed, containing:

[0529] The main components are solid lubricant, binder resin and solvent, and

[0530] the solvent contains water as a main component and a lower alcohol having three or less carbon atoms, which is added as an additive to the water, and said additive has a volume of 0.5 or more to 45 or less based on 100, set as the volume of the water-containing solvent,

[0531] 95% or more of the solvent volume is formed from water and the specified additive,

[0532] A soap component containing at least a metallic soap from metallic soap components and an alkaline soap is used as a solid lubricant, and the metallic soap component accounts for 95% or more of the sum of the total masses of the metallic soap components and the alkaline soap,

[0533] in this case, the condition is set that the particle size of the metal soap does not exceed the film thickness of the solid lubricating coating, and

[0534] the binder resin is formed from a water-soluble or water-dispersible polymer and a copolymer, wherein the polymer having an acrylate or methacrylate structure and said copolymer account for 90% or more of the total weight of the binder resin.

[0535] (2) As said additive, at least one of ammonia water and a primary amine is further contained.

[0536] (3) The lower alcohol is formed from one, two or more lower alcohols selected from methanol, ethanol, isopropyl alcohol, normal propyl alcohol and industrial ethanol, and the volume of the lower alcohol is 0.5 or more based on 100 set as the volume of the water-containing solvent.

[0537] (4) The metallic soap and alkali soap components constituting the solid lubricant include one, two or more kinds of soap that are compounds formed from a fatty acid selected from the following Group A and a metallic element selected from the following Group B, and the mass of the metallic soap accounts for 95% or more of the total mass of the metallic soaps and alkali soaps:

[0538] Group A: stearic acid, behenic acid, lauric acid, 12-hydroxystearic acid, oleic acid, montanic acid;

[0539] Group B: Na, K, Mg, Ca, Zn.

[0540] (5) Metallic soap has a particle size of 10μm or less.

[0541] (6) The water-soluble or water-dispersible polymer constituting the binder resin is a polymer formed from one or more monomers selected from the following (1) to (4), and the copolymer is a copolymer formed from two or more monomers selected from the following (1) to (4):

[0542] (1) Monomers including acrylates, methacrylates and individual derivatives of acrylates and methacrylates as main components;

[0543] (2) monomers including acrylates and methacrylates, and individual derivatives of acrylates and methacrylates, and alkyl esters, vinyl esters, styrene esters, carboxylic acid esters, and individual derivatives of these esters;

[0544] (3) monomers grafted with respect to the above-described (1) and (2);

[0545] (4) One or both monomers of a vinyl compound and a urethane compound.

[0546] (7) The chemical agent has a flash point above 60°C or is fire retardant.

[0547] (8) When converting the volume of a solvent to a mass with a specific gravity of the solvent equal to 1,

[0548] - the solvent has a mass of 0.7 times or more and 100 times or less relative to the total mass of the solid lubricant and the binder resin, and

[0549] - The solid lubricant has a mass of 0.1 times or more and 1.0 times or less relative to the mass of the binder resin.

[0550] (9) The viscosity of the agent is 1000 mPa s or less.

[0551] (10) When the chemical agent is applied to the metal surface in an amount of 0.1g / mm 2 or less and left and dried at room temperature in a windless atmospheric environment, the chemical agent has a quick drying property, allowing drying to be carried out within 30 minutes.

[0552] (11) When the chemical agent is applied to the metal surface in an amount of 0.1g / mm2 or less and dried by an air flow of 1 m / s or more at ambient temperature under atmospheric conditions, the chemical agent has a quick drying property that allows drying to be carried out within five minutes.

[0553] (12) A method for producing a chemical agent for forming a solid lubricating coating film according to the present invention is proposed, comprising:

[0554] - incorporating metallic soap into the composition by dispersing and clouding the metallic soap in a lower alcohol, and then adding the metallic soap to an aqueous solvent.

[0555] (13) A method is proposed for applying a chemical agent for forming a solid lubricating coating film according to the invention onto the surface of a tubular part, comprising:

[0556] - application of a chemical agent when rotating a tubular part around an axis.

[0557] (14) Provides oil and gas field tubular goods, including:

[0558] - a lubricating coating film having a solid lubricating coating film formed on a threaded portion, wherein said solid lubricating coating film is formed by dispersing a solid lubricant in a binder resin,

[0559] - as a solid lubricant, a soap component is contained that contains at least a metallic soap from metallic soap components and an alkaline soap, wherein the metallic soap component accounts for 95% or more of the sum of the total mass of the metallic soap components and the alkaline soap,

[0560] in this case, the condition is set that the particle size of the metal soap does not exceed the film thickness of the solid lubricating coating, and

[0561] the binder resin is formed from a water-soluble or water-dispersible polymer and a copolymer, wherein the polymer having an acrylate or methacrylate structure and said copolymer account for 90% or more of the total weight of the binder resin.

[0562] (15) The metallic soap and alkali soap components constituting the solid lubricant include one, two or more kinds of soap which are compounds formed from a fatty acid selected from the following group A and a metallic element selected from the following group B, and

[0563] - the mass of metallic soap accounts for 95% or more of the total mass of metallic soap and alkaline soap:

[0564] Group A: stearic acid, behenic acid, lauric acid, 12-hydroxystearic acid, oleic acid, montanic acid;

[0565] Group B: Na, K, Mg, Ca, Zn.

[0566] (16) Metallic soap has a particle size of 10μm or less.

[0567] (17) The water-soluble or water-dispersible polymer constituting the binder resin is a polymer formed from one or more monomers selected from the following (1) to (4), and the copolymer is a copolymer formed from two or more monomers selected from the following (1) to (4):

[0568] (1) Monomers including acrylates, methacrylates and individual derivatives of acrylates and methacrylates as main components;

[0569] (2) monomers, including acrylates and methacrylates, and individual derivatives of acrylates and methacrylates, and alkyl esters, vinyl esters, styrene esters, carboxylic acid esters, and individual derivatives of these esters;

[0570] (3) monomers grafted with respect to the above-described (1) and (2);

[0571] (4) one or both monomers of a vinyl compound and a urethane compound.

[0572] (18) The solid lubricating coating film has a film thickness of 1μm to 100μm, and the soft film hardness is H or lower on the pencil.

[0573] (19) A threaded connection for oil and gas field tubular goods is proposed, connecting a coupling having an internal thread and a nipple having an external thread, and

[0574] at least one of the coupling and the nipple as oil and gas field tubular goods is made from the oil and gas field tubular goods according to the present invention.

[0575] (20) A threaded connection for oil and gas field tubular goods is proposed, connecting a coupling having an internal thread and a nipple having an external thread,

[0576] wherein one of the nipple and the coupling as oil and gas field tubular goods is made from oil and gas field tubular goods according to the present invention, and

[0577] a coating film having a hardness exceeding the hardness of the said solid lubricating coating film is formed on a threaded portion of another of the oil and gas field tubular goods.

[0578] This application sets forth the entire contents of Japanese Patent Application No. 2022-134375 (filed on August 25, 2022), from which priority is claimed, and which is incorporated herein by reference. The description herein is presented with reference to a limited number of embodiments, but the scope of rights is not limited thereto, and modifications to each embodiment based on the above description will be apparent to those skilled in the art.

[0579] List of reference designations

[0580] 1 - nipple

[0581] 1a - threaded part

[0582] 2 - coupling

[0583] 2a - threaded part.

Claims

1. A chemical agent for forming a solid lubricating film on a metal surface, containing as main components a solid lubricant, a binder resin and a solvent, wherein said solvent contains water as a main component and a lower alcohol having three or less carbon atoms, which is added as an additive to water, and said additive has a volume of 0.5 or more to 45 or less based on 100 given as the volume of water, wherein 95% or more of the volume of the solvent is formed from water and the specified additive, wherein the solid lubricant comprises a soap component containing at least a metallic soap from among the metallic soap and alkaline soap components, wherein said metallic soap component constitutes 95% or more of the sum of the total mass of the metallic soap and alkaline soap components, in this case, the condition is set that the size of the metal soap particles does not exceed the thickness of the solid lubricating coating film, and wherein the binder resin is formed from a water-soluble or water-dispersible polymer or copolymer, wherein the polymer or copolymer having an acrylate or methacrylate structure makes up 90% or more of the total mass of the binder resin.

2. A chemical agent for forming a solid lubricating coating film according to claim 1, wherein at least one of ammonia water and a primary amine is additionally contained as said additive.

3. A chemical agent for forming a solid lubricating coating film according to claim 1 or 2, wherein the lower alcohol is formed from one or two or more lower alcohols selected from methanol, ethanol, isopropyl alcohol, normal propyl alcohol and industrial ethanol, and the volume of the lower alcohol is 0.5 or more based on 100 given as the volume of water.

4. A chemical agent for forming a solid lubricating coating film according to any one of claims 1 to 3, wherein the metallic soap and alkaline soap components constituting the solid lubricant include one, two or more kinds of soap that are compounds formed from a fatty acid selected from the following group A and a metallic element selected from the following group B, and wherein the mass of metallic soap constitutes 95% or more of the total mass of metallic soaps and alkaline soaps; Group A: stearic acid, behenic acid, lauric acid, 12-hydroxystearic acid, oleic acid, montanic acid; group B: Na, K, Mg, Ca, Zn.

5. A chemical agent for forming a solid lubricating coating film according to any one of claims 1 to 4, wherein the metallic soap has a particle size of 10 μm or less.

6. A chemical agent for forming a solid lubricating coating film according to any one of claims 1 to 5, wherein the water-soluble or water-dispersible polymer constituting the binder resin is a polymer having an acrylate or methacrylate structure formed from one or more monomers selected from the following (1) to (4), and said copolymer is a copolymer having an acrylate or methacrylate structure formed from two or more monomers selected from the following (1) to (4): (1) monomers including acrylates, methacrylates and individual derivatives of acrylates and methacrylates as main components; (2) monomers in which acrylates, methacrylates, and individual derivatives of acrylates and methacrylates are combined with monomers comprising alkyl esters, vinyl esters, styrene esters, carboxylic acid esters, and individual derivatives of these esters; (3) monomers grafted to monomers from (1) and (2); (4) one or both monomers of a vinyl compound and a urethane compound.

7. A chemical agent for forming a solid lubricating coating film according to any one of claims 1 to 6, wherein said chemical agent has a flash point above 60°C or is fire-resistant.

8. A chemical agent for forming a solid lubricating coating film according to any one of claims 1 to 7, in which, when converting the volume of the solvent into mass at a specific density of the solvent equal to 1, the solvent has a mass of 0.7 times or more to 100 times or less relative to the total mass of the solid lubricant and the binder resin, and the solid lubricant has a mass of 0.1 times or more to 1.0 times or less relative to the mass of the binder resin.

9. A chemical agent for forming a solid lubricating film according to any one of claims 1 to 8, which has a viscosity of 1000 mPa⋅s or lower.

10. A chemical agent for forming a solid lubricating coating film according to any one of claims 1 to 9, wherein when the chemical agent is applied to a metal surface in an amount of 0.1 g / mm 2 or less and left to dry at ambient temperature in a windless atmospheric environment, the chemical agent has a quick drying property that allows drying to be completed within 30 minutes.

11. A chemical agent for forming a solid lubricating coating film according to any one of claims 1 to 10, wherein when the chemical agent is applied to a metal surface in an amount of 0.1 g / mm 2 or less and dried by blowing air at a speed of 1 m / s or more at ambient temperature in an atmospheric environment, the chemical agent has a quick drying property that allows drying to be carried out within five minutes.

12. A method for producing a chemical agent for forming a solid lubricating coating film according to any one of claims 1 to 11, wherein said chemical agent is obtained by mixing said solvent formed mainly from water, said lower alcohol as an additive to water, said binder resin and said solid lubricant containing said metallic soap, wherein in said method: - the said metallic soap is dispersed and clouded in the said lower alcohol, and then the said lower alcohol, in which the said metallic soap is dispersed and clouded, is added to water.

13. A method for applying a chemical agent for forming a solid lubricating coating film according to any of paragraphs 1-11 onto the surface of a tubular part, comprising: application of a chemical agent while rotating a tubular part around an axis.

14. A tubular product of the oil and gas industry, containing: a lubricating coating film having a solid lubricating coating film formed on the threaded portion, wherein said solid lubricating film is formed by dispersing a solid lubricant in a binder resin, wherein the solid lubricant comprises a soap component containing at least a metallic soap from among the metallic soap and alkaline soap components, wherein the metallic soap component accounts for 95% or more of the sum of the total mass of the metallic soap and alkaline soap components, in this case, the condition is set that the size of the metal soap particles does not exceed the thickness of the solid lubricating coating film, and wherein the binder resin is formed from a water-soluble or water-dispersible polymer or copolymer, wherein the polymer or copolymer having an acrylate or methacrylate structure makes up 90% or more of the total mass of the binder resin.

15. Tubular product of the oil and gas field assortment according to clause 14, in which the metallic soap and alkaline soap components constituting the solid lubricant comprise one or two or more kinds of soap which are compounds formed from a fatty acid selected from the following group A and a metallic element selected from the following group B, and in which the mass of the metallic soap constitutes 95% or more of the total mass of the metallic soap and the alkaline soap; Group A: stearic acid, behenic acid, lauric acid, 12-hydroxystearic acid, oleic acid, montanic acid; group B: Na, K, Mg, Ca, Zn.

16. A tubular product for oil and gas industry according to paragraph 14 or 15, in which the metal soap has a particle size of 10 μm or less.

17. A tubular product of the oil and gas field assortment according to any of paragraphs 14 or 16, wherein the water-soluble or water-dispersible polymer constituting the binder resin is a polymer having an acrylate or methacrylate structure formed from one or more monomers selected from the following (1) to (4), and said copolymer is a copolymer having an acrylate or methacrylate structure formed from two or more monomers selected from the following (1) to (4): (1) monomers including acrylates, methacrylates and individual derivatives of acrylates and methacrylates as main components; (2) monomers comprising acrylates, methacrylates, and individual derivatives of acrylates and methacrylates are combined with monomers comprising alkyl esters, vinyl esters, styrene esters, carboxylic acid esters, and individual derivatives of these esters; (3) monomers grafted to monomers from (1) and (2); (4) one or both monomers of a vinyl compound and a urethane compound.

18. A tubular product of the oil and gas field assortment according to any of paragraphs 14-17, wherein the solid lubricating coating film has a film thickness of 1 μm or more to 100 μm or less, and the pencil hardness of the soft film is H or lower.

19. A threaded connection of oil and gas field tubular goods, connecting a coupling with an internal thread and a nipple with an external thread, in which at least one of the coupling and the nipple as an oil and gas field tubular product is made from an oil and gas field tubular product according to any of paragraphs 14-18.

20. A threaded connection of oil and gas field tubular goods, connecting a coupling having an internal thread and a nipple having an external thread, in which one of the coupling and the nipple as a tubular product of the oil and gas field assortment is made from a tubular product of the oil and gas field assortment according to any of paragraphs 14-18, and in which a coating film having a hardness exceeding the hardness of the said solid lubricating coating film is formed on the threaded part of another of the oil and gas field tubular goods.

Images