A cooling coating for deep well drilling, its preparation method and application

Abstract

This invention provides a deep well drilling cooling coating, its preparation method, and its application. The preparation method of the deep well drilling cooling coating includes the following steps: (1) reacting sugar alcohol, esters, and an initiator, and then adding benzene compounds for continuous reaction to obtain a composite phase change core material; (2) reacting silicate ester, zirconium oxide, organic solvent, siloxane, and water, and aging at low temperature; (3) mixing a treated ester diol with isocyanate and a catalyst, then adding additives and regulators, reacting it with the material obtained in step (2), the mixed solvent, and amines, and then adding polyetheramine and water to obtain an emulsion; (4) heating and melting the composite phase change core material from step (1), and then reacting it with the emulsion from step (3) to obtain the deep well drilling cooling coating. The deep well drilling cooling coating obtained by the preparation method provided by this invention has advantages such as stable thermal properties and controllable temperature.

Description

Technical Field

[0001] This invention relates to the field of deep well drilling technology, specifically to a deep well drilling cooling coating, its preparation method, and its application. Background Technology

[0002] In the process of deep well oil and gas drilling and development, increasingly high temperatures pose a challenge. Drilling fluids are prone to dispersion, aggregation, degradation, and cross-linking reactions in high-temperature environments, leading to poor rheological filtration properties and disrupting drilling operations. High or ultra-high temperature environments also affect the service life of drilling equipment, measurement-while-drilling (MWD), and logging instruments. For example, when the downhole ambient temperature exceeds 140°C, the measuring probes of precision instruments such as rotary directional drilling systems will be damaged, with each maintenance costing hundreds of thousands of yuan. To improve the safety and efficiency of deep well operations, drilling companies employ surface cooling methods such as natural cooling, mixing cryogenic media, and forced cooling with cooling devices to lower the circulating temperature of the drilling fluid returning from the wellbore. However, surface cooling methods only indirectly reduce the circulating temperature of the drilling fluid in the wellbore by lowering the temperature at the drilling fluid inlet, and they suffer from problems such as high equipment investment, high energy consumption, and high consumption of cooling media, still failing to fully meet the actual cooling needs of deep well drilling.

[0003] CN112096303A discloses a heat-insulating drill pipe for cooling high-temperature wellbore and its preparation method. It uses phenolic resin as a raw material, injecting closed-cell particles into the annulus inside the drill pipe after high-temperature sintering with the phenolic resin. After cooling and molding, the particles are fully bonded to the drill pipe, forming a dense heat-insulating layer of a certain thickness on the inner wall of the drill pipe. This reduces the overall thermal conductivity of the drill pipe and significantly lowers the bottom hole ambient temperature. The insulating outer coating on the outer surface of the drill pipe further improves its heat insulation performance and extends its service life. However, the cooling coating needs to be applied to both the inner and outer surfaces simultaneously, which is costly and cumbersome. Furthermore, the outer coating is made of polyfluorine material, which only provides heat insulation and does not have temperature control functionality.

[0004] CN102219878A discloses a hydroxyl acrylic resin and its preparation method. Under nitrogen protection, a solvent and a reactive solvent are first added to a reaction vessel, and the temperature is raised to 150℃~160℃. Acrylic acid, methyl methacrylate, ethyl acrylate, hydroxyethyl acrylate, perfluoroalkyl ethyl acrylate monomers, and an initiator are mixed evenly and added dropwise for 3h~4h. The mixture is then kept at this temperature for 1.5h~2h, and finally cooled to 40℃~70℃ to discharge the material, thus obtaining the hydroxyl acrylic resin. The coating film formed by this resin and a curing agent has both the characteristics of acrylic polyurethane and fluorocarbon coatings. However, when used in drilling cooling coatings, the resin still has a high thermal insulation coefficient, and the coating itself does not possess the ability to control temperature through phase change. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, this invention provides a deep well drilling cooling coating, its preparation method, and its application. The deep well drilling cooling coating prepared by the method provided by this invention has advantages such as stable thermal properties, controllable temperature, low thermal insulation coefficient, strong corrosion resistance, and long cycle life.

[0006] The first aspect of this invention provides a method for preparing a cooling coating for deep well drilling, comprising the following steps:

[0007] (1) After mixing and melting sugar alcohols and esters, an initiator is added for heating and reaction. Then, benzene compounds are added for continued reaction to obtain a composite phase change core material.

[0008] (2) The silicate ester, zirconium oxide, organic solvent, siloxane and water are reacted and then aged at low temperature;

[0009] (3) After vacuum treatment, the ester diol is mixed with isocyanate and catalyst for the first reaction, then the auxiliary agent and regulator are added for the second reaction, and then the mixture is allowed to stand for reaction with the material obtained in step (2), mixed solvent and amine, and then polyetheramine and water are added to obtain an emulsion.

[0010] (4) The composite phase change core material of step (1) is heated and melted, and then the emulsion of step (3) is added drop by drop to it to carry out the reaction, so as to obtain the deep well drilling cooling coating.

[0011] Furthermore, in step (1), the sugar alcohol is selected from any one or more of xylitol, erythritol, threitol and mannitol.

[0012] Further, in step (1), the ester is selected from one or more of sucrose fatty acid esters, propyl 3-phenylacrylate and polyethylene glycol methacrylate (average molecular weight 1000-3000), preferably propyl 3-phenylacrylate.

[0013] Further, in step (1), the melting conditions are heating and stirring melting, with a temperature of 120℃~200℃, a stirring speed of 500rpm~800rpm, and a time of 30min~60min.

[0014] Further, in step (1), the initiator is selected from one or more of benzoyl peroxide, sodium peroxide and diethylaniline, preferably benzoyl peroxide.

[0015] Further, in step (1), the reaction temperature of the heating reaction is 150℃~250℃, and the reaction time is 3h~6h; the heating reaction is preferably carried out in a nitrogen atmosphere or an inert atmosphere, preferably selected from any one or more of high-purity nitrogen, high-purity helium and high-purity argon.

[0016] Further, in step (1), the benzene series compound is selected from one or more of toluene, ethylbenzene and xylene, preferably xylene.

[0017] Further, in step (1), after adding the benzene series compound, a continuous reaction is carried out under the same conditions as the heating reaction, for a time of 0.5 h to 3.5 h. Specifically, the reaction temperature is 150 °C to 250 °C, the reaction time is 0.5 h to 3.5 h, and the reaction is carried out under a nitrogen atmosphere or an inert atmosphere, preferably selected from any one or more of high-purity nitrogen, high-purity helium, and high-purity argon.

[0018] Further, in step (1), after the reaction is complete, conventional filtration, washing, and drying can be performed to obtain the composite phase change core material. The filtration is preferably performed under vacuum heating, with a vacuum level of 0.3 atm to 0.6 atm, a temperature of 160℃ to 230℃, preferably 180℃ to 200℃, and a filtration time of 25 min to 40 min. The washing is preferably performed using an organic solvent, selected from one or more of anhydrous ethanol, acetone, and chloroform, with acetone being preferred. The washing is preferably performed first with a low-temperature organic solvent, then after filtration, followed by a room-temperature organic solvent wash. The temperature of the low-temperature organic solvent is -10℃ to 10℃, preferably -2.5℃ to 2.8℃, and the residence time is 3 min to 7 min. The room temperature is 20℃ to 30℃. The drying is preferably performed under vacuum, with a temperature of 100℃ to 170℃, preferably 130℃ to 150℃, and a time of 1 h to 6 h.

[0019] Further, in step (1), the mass ratio of the sugar alcohol, ester, initiator and benzene series is 1:(0.1~1):(0.005~0.05):(0.8~2.4), preferably 1:(0.3~0.7):(0.009~0.03):(1.3~1.9).

[0020] Further, in step (2), the silicate ester is selected from one or more of tetraethyl orthosilicate, tetramethyl orthosilicate and polyethyl orthosilicate, preferably tetraethyl orthosilicate.

[0021] Furthermore, in step (2), the zirconium oxide is selected from one or more of zirconium oxychloride and zirconium oxalate, preferably zirconium oxychloride.

[0022] Further, in step (2), the organic solvent is selected from one or more of anhydrous methanol, anhydrous ethanol and N,N-dimethylformamide (DMF), preferably anhydrous ethanol.

[0023] Further, in step (2), the siloxane is selected from one or more of triethoxysilane, methyltrimethoxysilane and isooctyltriethoxysilane, preferably triethoxysilane.

[0024] Further, in step (2), the mass ratio of the silicate ester, zirconium oxide, organic solvent, siloxane and water is 1:(0.08~0.75):(1~10):(0.06~0.33):(3~14), preferably 1:(0.13~0.35):(3~6):(0.1~0.24):(6~10).

[0025] Further, in step (2), the reaction temperature is 40℃~80℃, preferably 50℃~70℃; the stirring speed is 800rpm~1000rpm; and the time is 25min~40min.

[0026] Further, in step (2), the low-temperature aging is water bath low-temperature aging, wherein the temperature of the water bath is -7℃ to 12℃, preferably 0℃ to 5℃; the aging treatment temperature is 20℃ to 80℃, preferably 40℃ to 60℃, and the time is 5h to 16h, preferably 8h to 13h.

[0027] Further, in step (3), the ester diol is selected from polycaprolactone diol with an average molecular weight of 500 to 2000 and / or polycarbonate diol with an average molecular weight of 500 to 2000, preferably polycaprolactone diol with an average molecular weight of 1000 to 1500.

[0028] Further, in step (3), the vacuum treatment conditions are heating treatment, with a temperature of 80℃~130℃, a vacuum degree of 0.3atm~0.6atm, and a time of 30min~60min; the vacuum treatment atmosphere is preferably nitrogen or an inert gas, preferably any one or more selected from high-purity nitrogen, high-purity helium and high-purity argon.

[0029] Further, in step (3), the isocyanate is selected from one or more of dicyclohexylmethane diisocyanate (HMDI), hexamethylene diisocyanate (HDI) and lysine diisocyanate (LDI), preferably lysine diisocyanate.

[0030] Further, in step (3), the catalyst is selected from one or more of stannous isooctanoate, zinc isooctanoate and bismuth isooctanoate, preferably zinc isooctanoate.

[0031] Furthermore, in step (3), the reaction temperature of the first reaction is 40℃~120℃, preferably 70℃~95℃, and the reaction time is 5min~60min, preferably 20min~40min.

[0032] Further, in step (3), the adjuvant is selected from one or more of dimethylolpropionic acid, dimethylolbutyric acid and trimethylolpropionic acid, preferably trimethylolpropionic acid.

[0033] Further, in step (3), the regulator is selected from one or more of nonylphenol polyoxyethylene ether-6, diisopropyl ketone and 1-phenyl-2-pyrrolidone, preferably nonylphenol polyoxyethylene ether-6.

[0034] Furthermore, in step (3), the reaction temperature of the second reaction is 40℃~120℃, preferably 70℃~95℃, and the reaction time is 5min~40min, preferably 10min~25min.

[0035] Further, in step (3), the mass ratio of the ester diol to the material aged in step (2) is 1:(0.05-0.75), preferably 1:(0.15-0.5).

[0036] Further, in step (3), the mixed solvent is selected from any two of anhydrous methanol, acetonitrile, isobutanol and cyclohexane, preferably a combination of acetonitrile and isobutanol; wherein, preferably, the mass ratio of acetonitrile to isobutanol is (0.5 to 2.5):1.

[0037] Further, in step (3), the amine is selected from one or more of triethanolamine, diethylamine and 1,4-butanediamine, preferably 1,4-butanediamine.

[0038] Furthermore, in step (3), the settling reaction time is 10 min to 80 min, preferably 30 min to 60 min.

[0039] Further, in step (3), the polyetheramine is selected from one or more polyetheramines with an average molecular weight of 200 to 2000 of difunctionality, preferably D-230.

[0040] Furthermore, in step (3), the addition of polyetheramine and water can preferably be carried out under rapid stirring, with a speed of 2000 rpm to 4000 rpm and a time of 1 min to 15 min, preferably 4 min to 9 min.

[0041] Further, in step (3), the mass ratio of the ester diol, isocyanate, catalyst, auxiliary agent, regulator, mixed solvent, amine, polyetheramine and water is 1:(0.9~2.4):(0.003~0.02):(0.008~0.16):(0.001~0.01):(0.73~4.45):(0.06~0.72):(0.01~0.23):(0.003~0.04), preferably 1:(1.2~1.7):(0.008~0.015):(0.02~0.1):(0.004~0.009):(1.46~2.85):(0.1~0.37):(0.05~0.13):(0.01~0.027).

[0042] Furthermore, in step (4), the composite phase change core material is heated and melted at a temperature of 120°C to 180°C for a time of 15 min to 30 min.

[0043] Further, in step (4), the mass ratio of the composite phase change core material to the emulsion is 1:(0.86-2.79), preferably 1:(1.37-1.93).

[0044] Furthermore, in step (4), stirring is preferably carried out during the dripping process, with a rotation speed of 4000 rpm to 12000 rpm, preferably 6000 rpm to 9000 rpm.

[0045] Further, in step (4), the ratio of the composite phase change core material to the emulsion is 1g composite phase change core material: (3mL / min~15mL / min) emulsion, preferably 1g composite phase change core material: (6mL / min~10mL / min) emulsion.

[0046] Furthermore, in step (4), the reaction is a dynamic reaction, wherein the temperature is 120℃~180℃, the stirring speed is 2000rpm~8000rpm, preferably 4000rpm~6000rpm, and the time is 25min~80min, preferably 40min~60min.

[0047] Furthermore, in this invention, the mixing of each material in steps (1)-(4) is preferably carried out under stirring to better promote the mixing effect. The stirring speed is 300 rpm to 500 rpm and the time is 15 min to 30 min.

[0048] A second aspect of the present invention provides a deep well drilling cooling coating obtained by the above preparation method.

[0049] A third aspect of the present invention provides an application of the above-mentioned coating in deep well drilling.

[0050] Furthermore, the application specifically involves spraying the coating onto the surface of a deep well drill and allowing it to cure and solidify.

[0051] Furthermore, the spraying is preferably performed by adding the coating material into a polyurethane spraying device and spraying it onto the drilling (such as drill rods) part, wherein the raw material output of the polyurethane spraying device is 100g / min to 1000g / min, the heating power is 7.5kW to 10kW, and the output pressure is 9MPa to 12MPa.

[0052] Furthermore, the thickness of the spray coating is 5μm to 100μm, preferably 15μm to 25μm.

[0053] Furthermore, the curing temperature is 20℃~30℃, and the curing time is 0.5h~4h.

[0054] Furthermore, the properties of the cured deep well drilling cooling coating were tested and are as follows: phase change temperature is 90℃~170℃, latent heat of phase change is 180J / g~240J / g, supercooling is 5℃~10℃, adiabatic coefficient is 21.5mW / (m·K)~33.9mW / (m·K), compressive strength is 3.5MPa~4.3MPa, tensile strength is 2.6MPa~3.5MPa, and there are no cracks when folded and bent at 180℃.

[0055] Furthermore, after 20 consecutive uses, the coating was tested in deep well drilling, and its properties were as follows: the phase change temperature did not change by more than 4% compared to before 20 consecutive uses; the latent heat of phase change did not change by more than 4% compared to before 20 consecutive uses; the supercooling did not change by more than 23% compared to before 20 consecutive uses; the adiabatic coefficient did not change by more than 14% compared to before 20 consecutive uses; the compressive strength did not change by more than 9% compared to before 20 consecutive uses; the tensile strength did not change by more than 15% compared to before 20 consecutive uses; and the folding and bending at 180°C showed virtually no change compared to before 20 consecutive uses.

[0056] Compared with the prior art, the present invention has the following advantages:

[0057] (1) The present invention uses a grafting modification method to combine sugar alcohols and esters, which improves the thermal stability and latent heat of phase change of sugar alcohol phase change materials. At the same time, it adjusts the phase change temperature of existing sugar alcohol phase change materials, broadens their application scope, and esters can effectively suppress the supercooling phenomenon of sugar alcohols as new nucleation centers.

[0058] (2) In this invention, silicon-zirconium aerogel prepolymer component is added to polyester matrix, so that the two undergo cross-linking reaction to synthesize polyester-aerogel copolymer monomer. This monomer has the advantages of both polyester and aerogel, with high flexibility and tensile strength, as well as low thermal insulation coefficient and wear resistance. As the encapsulation component (shell material) of composite phase change core material, it can effectively prevent core material loss and extend service life.

[0059] (3) The present invention uses sugar alcohols and esters to prepare composite phase change core materials, so that the hydrophilic sugar alcohol phase change materials have both hydrophilic and lipophilic properties, which is beneficial for the shell material prepolymer to carry out the coating reaction. At the same time, some components in the shell material prepolymer, such as nonylphenol polyoxyethylene ether-6 and polyetheramine D-230, can act as surfactants, thus improving its coating effect.

[0060] (4) The cooling coating prepared by the present invention is clean and environmentally friendly, and easy to use. It can be directly sprayed onto the outer surface of key drilling equipment and devices such as drill rods using a polyurethane spraying equipment. The operation is simple and conducive to large-scale promotion and application. Attached Figure Description

[0061] Figure 1 Differential scanning calorimetry (DSC) endothermic melting curve of the cooling coating prepared in Example 1 after 20 consecutive uses;

[0062] Figure 2 Scanning electron microscope (SEM) image of the cooling coating prepared in Example 1;

[0063] Figure 3 The image is a scanning electron microscope (SEM) image of the cooling coating prepared in Example 1 when it is folded and bent at 180°C.

[0064] Figure 4 Scanning electron microscope (SEM) images of the cooling coating prepared in Comparative Example 6 when folded and bent at 180°C;

[0065] Figure 5 The temperature rise curves of the cooling coatings in Example 1 and Comparative Example 1 during the drilling process show their changing trends. Detailed Implementation

[0066] The following examples further illustrate the preparation method and effects of the deep well drilling cooling coating of the present invention. These examples are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following examples.

[0067] Unless otherwise specified, the experimental methods used in the following examples are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following examples were purchased from conventional biochemical reagent stores.

[0068] In this invention, a Shimadzu DSC-60Plus differential scanning calorimeter was used to test the phase transition temperature, latent heat of phase transition, and subcooling of the cooling coating for deep well drilling.

[0069] In this invention, the thermal conductivity of the cooling coating for deep well drilling was tested using a TPS2500S thermal conductivity meter from the Swedish company Hot Disk.

[0070] This invention uses a Hitachi FlexSEM1000II scanning electron microscope to observe the appearance morphology and morphology of the cooling coating for deep well drilling at 180°C.

[0071] This invention uses the HT9801 wear index tester from Beijing Jingcheng Huatai Instrument Co., Ltd. to test the wear rate of cooling coatings used in deep well drilling.

[0072] This invention uses the XWW type micro-controlled electronic universal testing machine from Chengde Kecheng Testing Machine Co., Ltd. to test the compressive strength and tensile strength of cooling coatings for deep well drilling.

[0073] Example 1

[0074] 100g xylitol and 50g propyl 3-phenylacrylate were added to a round-bottom flask and stirred at 150℃ and 650rpm for 45min. The temperature was increased to 200℃ and 2g benzoyl peroxide was added. The mixture was refluxed and kept at a constant temperature for 4.5h. High-purity nitrogen was introduced to protect the reaction components in the round-bottom flask. Then 150g xylene was added and the mixture was reacted for 1.8h. The mixture was then filtered at a vacuum of 0.4atm and 190℃ for 30min. The resulting material was poured into 230g acetone at -1.7℃ and held for 5min. The mixture was then filtered at 25℃, washed with acetone, and finally dried under vacuum at 140℃ for 3.5h to obtain the composite phase change core material. 100g of tetraethyl orthosilicate, 25g of zirconium oxychloride and 500g of anhydrous ethanol were weighed and reacted at 25℃ and 400rpm for 20min. Then, 15g of triethoxysilane and 800g of deionized water were added, the reaction temperature was increased to 60℃, and the mixture was stirred at 900rpm for 30min. The mixture was then transferred to a 2.5℃ low-temperature water bath for aging at 50℃ for 10h. 100g of polycaprolactone diol with an average molecular weight of 1200 was weighed and placed in a reactor. The reactor was vacuum-treated at 0.4 atm and 100°C for 45 min, and protected with high-purity nitrogen. 140g of lysine diisocyanate and 1g of zinc isooctanoate were added, and the mixture was reacted at 80°C for 30 min. 6g of trimethylolpropionic acid and 0.75g of nonylphenol polyoxyethylene ether-6 were added, and the reaction was continued for 15 min. The mixture was then cooled to 25°C, and 25g of the aged mixture was added. The mixture was diluted with 200g of acetonitrile and isobutanol (mass ratio 1:1). 15g of 1,4-butanediamine was added, and the mixture was allowed to stand for 45 min. At 25°C, 8g of D-230 polyetheramine with an average molecular weight of 230 and 1.4g of deionized water were added, and the mixture was rapidly stirred at 3000 rpm for 5.5 min to obtain an emulsion.

[0075] 50g of composite phase change core material was heated and melted at 150℃ for 20min. 75g of emulsion was then added dropwise to the core material at a rate of 1g of composite phase change core material and 8.6mL / min, with a stirring speed of 8000rpm. After the addition was complete, the mixture was stirred and reacted at the same temperature and 5000rpm for 50min to obtain a deep well drilling cooling coating. This coating was then added to a polyurethane spraying device and sprayed onto drill pipes and other components at a raw material output rate of 200g / min, a heating power of 8.5kW, and an output pressure of 10MPa. The coating thickness was 18μm. The coating was cured at 25℃ for 1.5h to obtain the cured deep well drilling cooling coating.

[0076] Example 2

[0077] 100g xylitol and 30g propyl 3-phenylacrylate were added to a round-bottom flask and stirred at 150℃ and 650rpm for 45min. The temperature was increased to 200℃ and 0.9g benzoyl peroxide was added. The mixture was refluxed and kept at a constant temperature for 4.5h. High-purity nitrogen was introduced to protect the reaction components in the round-bottom flask. Then 130g xylene was added and the mixture was reacted for 1.8h. The mixture was then filtered at a vacuum of 0.4atm and 190℃ for 30min. The resulting material was poured into 180g acetone at -1.7℃ and held for 5min. The mixture was then filtered at 25℃, washed with acetone, and finally dried under vacuum at 140℃ for 3.5h to obtain the composite phase change core material. 100g of tetraethyl orthosilicate, 13g of zirconium oxychloride and 300g of anhydrous ethanol were weighed and reacted at 25℃ and 400rpm for 20min. Then, 10g of triethoxysilane and 600g of deionized water were added, the reaction temperature was increased to 60℃, and the mixture was stirred at 900rpm for 30min. The mixture was then transferred to a 2.5℃ low-temperature water environment for aging treatment at 50℃ for 10h. 100g of polycaprolactone diol with an average molecular weight of 1200 was weighed and placed in a reactor. The reactor was vacuum-treated at 0.4 atm and 100°C for 45 min, and protected with high-purity nitrogen. 120g of lysine diisocyanate and 0.8g of zinc isooctanoate were added, and the mixture was reacted at 80°C for 30 min. 2g of trimethylolpropionic acid and 0.4g of nonylphenol polyoxyethylene ether-6 were added, and the reaction was continued for 15 min. The mixture was then cooled to 25°C, and 25g of the aged mixture was added. The mixture was diluted with 146g of acetonitrile and isobutanol (mass ratio 1:1). 10g of 1,4-butanediamine was added, and the mixture was allowed to stand for 45 min. At 25°C, 5g of D-230 polyetheramine with an average molecular weight of 230 and 1g of deionized water were added, and the mixture was rapidly stirred at 3000 rpm for 5.5 min to obtain an emulsion. 50g of composite phase change core material was heated and melted at 150℃ for 20min. 68.5g of emulsion was then added dropwise to the core material at a rate of 1g of composite phase change core material and 8.6mL / min, with a stirring speed of 8000rpm. After the addition was complete, the mixture was stirred at 5000rpm for another 50min at the same temperature to obtain a deep well drilling cooling coating. This coating was then added to a polyurethane spraying device and sprayed onto drill pipes and other components at a raw material output rate of 200g / min, a heating power of 8.5kW, and an output pressure of 10MPa. The coating thickness was 18μm. The coating was cured at 25℃ for 1.5h to obtain the cured deep well drilling cooling coating.

[0078] Example 3

[0079] Compared with Example 1, the difference is that sucrose fatty acid ester, sodium peroxide and ethylbenzene are used instead of propyl 3-phenylacrylate, benzoyl peroxide and xylene, respectively, while other reaction conditions and material composition remain unchanged, to obtain deep well drilling cooling coating and deep well drilling cooling coating after curing.

[0080] Example 4

[0081] Compared with Example 1, the difference lies in the following: In the process of preparing the composite phase change core material after adding benzene compounds, the reaction time after xylene addition ("adding 150g xylene, reacting for 1.8h, and then filtering at 0.4atm and 190°C for 30min") is shortened by 0.6h, and the vacuum heating temperature is increased from 190°C to 230°C. In the process of "pouring the obtained material into 230g acetone, with the acetone temperature at -1.7°C, holding for 5min, and filtering the mixture at 25°C"), the cold acetone temperature is increased from -1.7°C to 10°C, and the holding time is extended from 5min to 7min. In the process of vacuum drying to obtain the composite phase change core material, the vacuum drying temperature is increased to 170°C, and the time is shortened to 1h. Other reaction conditions and material composition remain unchanged, resulting in a deep well drilling cooling coating and a cured deep well drilling cooling coating.

[0082] Example 5

[0083] Compared with Example 1, the difference is that the amount of 3-phenyl acrylate is increased to 100g, the amount of benzoyl oxide is reduced to 0.5g, and the amount of xylene is increased to 240g, while other reaction conditions and material composition remain unchanged, to obtain a deep well drilling cooling coating and a cured deep well drilling cooling coating.

[0084] Example 6

[0085] Compared with Example 1, the difference is that tetramethyl silicate, zirconium oxalate, and isooctyltriethoxysilane are used instead of tetraethyl orthosilicate, zirconium oxychloride, and triethoxysilane, respectively, while other reaction conditions and material composition remain unchanged, to obtain a deep well drilling cooling coating and a cured deep well drilling cooling coating.

[0086] Example 7

[0087] Compared to Example 1, the difference lies in reducing the amount of zirconium oxychloride to 8g and increasing the amount of triethoxysilane to 30g. The description of "adding 15g of triethoxysilane and 800g of deionized water, and raising the reaction temperature to 60°C" is modified by increasing the reaction temperature to 80°C after adding triethoxysilane and deionized water. The description of "then transferring the mixture to a 2.5°C low-temperature water bath for aging, with an aging temperature of 50°C and a aging time of 10 hours" is modified by reducing the water bath temperature to -7°C, lowering the aging temperature to 20°C, and extending the aging time to 16 hours. Other reaction conditions and material composition remain unchanged, resulting in a deep well drilling cooling coating and a cured deep well drilling cooling coating.

[0088] Example 8

[0089] Compared with Example 1, the difference is that polycarbonate diol, hexamethylene diisocyanate and stannous isooctanoate with an average molecular weight of 1200 are used instead of polycaprolactone diol, lysine diisocyanate and zinc isooctanoate with an average molecular weight of 1200, while other reaction conditions and material composition remain unchanged, to obtain deep well drilling cooling coating and deep well drilling cooling coating after curing.

[0090] Example 9

[0091] Compared with Example 1, the difference is that the reaction temperature after adding lysine diisocyanate and zinc isooctanoate is increased from 80°C to 120°C, the reaction time is shortened from 30 min to 5 min, the amount of aged mixture in "adding 25g of aged mixture and diluting with 200g of acetonitrile and isobutanol (mass ratio of 1:1)" is increased from 25g to 75g, and the standing reaction time in "adding 15g of 1,4-butanediamine and standing reaction for 45 min" is extended to 80 min. Other reaction conditions and material composition remain unchanged, resulting in a deep well drilling cooling coating and a cured deep well drilling cooling coating.

[0092] Example 10

[0093] Compared with Example 1, the difference is that dimethylolpropionic acid and diisopropyl ketone are used instead of trimethylolpropionic acid and nonylphenol polyoxyethylene ether-6, respectively, while other reaction conditions and material composition remain unchanged, to obtain a deep well drilling cooling coating and a cured deep well drilling cooling coating.

[0094] Example 11

[0095] Compared with Example 1, the difference lies in the use of anhydrous methanol and cyclohexane combination, diethylamine and D-2000 polyetheramine with an average molecular weight of 2000 instead of acetonitrile and isobutanol combination, 1,4-butanediamine and D-230 polyetheramine with an average molecular weight of 230, while keeping other reaction conditions and material composition unchanged, to obtain deep well drilling cooling coating and deep well drilling cooling coating after curing.

[0096] Example 12

[0097] Compared with Example 1, the difference lies in increasing the amount of lysine diisocyanate to 230g, decreasing the amount of zinc isooctanoate to 0.3g, decreasing the amount of trimethylolpropionic acid to 0.8g, increasing the amount of nonylphenol polyoxyethylene ether-6 to 1g, decreasing the amount of mixed solvent to 73g, decreasing the amount of 1,4-butanediamine to 6g, and increasing the amount of D-230 polyetheramine to 20g, while keeping other reaction conditions and material composition unchanged, to obtain a deep well drilling cooling coating and a cured deep well drilling cooling coating.

[0098] Example 13

[0099] Compared with Example 1, the difference lies in that the stirring speed in the dropping process of "adding 75g of emulsion to the composite phase change core material at a dropping rate of 8.6mL / min and a stirring speed of 8000rpm" is reduced to 4500rpm, the amount of emulsion is increased to 139.5g, and the dropping ratio of composite phase change core material to emulsion is increased from 1g:8.6mL / min to 1g:15mL / min. Other reaction conditions and material composition remain unchanged, resulting in a deep well drilling cooling coating and a cured deep well drilling cooling coating.

[0100] Example 14

[0101] The preparation of the deep well drilling cooling coating was the same as in Example 1. The difference compared to Example 1 was that the spraying thickness of the cured deep well drilling cooling coating was increased to 100 μm, while other reaction conditions and material composition remained unchanged, resulting in the cured deep well drilling cooling coating.

[0102] Comparative Example 1

[0103] Compared with Example 1, the difference is that xylitol is omitted, while other reaction conditions and material composition remain unchanged, resulting in a deep well drilling cooling coating after curing.

[0104] Comparative Example 2

[0105] Compared with Example 1, the difference is that the preparation step of the composite phase change core material is omitted, and xylitol is used as the phase change material instead of the composite phase change core material. Other reaction conditions and material composition remain unchanged, resulting in a deep well drilling cooling coating and a cured deep well drilling cooling coating.

[0106] Comparative Example 3

[0107] Compared to Example 1, the difference lies in that no composite phase change core material is prepared, and no other phase change materials are added. Other reaction conditions and material composition remain unchanged, resulting in a deep well drilling cooling coating and a cured deep well drilling cooling coating.

[0108] Comparative Example 4

[0109] Compared with Example 1, the difference is that magnesium nitrate hexahydrate of equal mass is used instead of xylitol, while other reaction conditions and material composition remain unchanged, resulting in a deep well drilling cooling coating and a cured deep well drilling cooling coating.

[0110] Comparative Example 5

[0111] Compared with Example 1, the difference is that zirconium oxychloride is omitted, while other reaction conditions and material composition remain unchanged, resulting in a deep well drilling cooling coating and a cured deep well drilling cooling coating.

[0112] Comparative Example 6

[0113] Compared with Example 1, the difference is that step (2) is omitted. After adding the additives and regulators in step (3) for a second reaction, the mixture is directly reacted with the mixed solvent and amine substances. Other reaction conditions and material composition remain unchanged to obtain the deep well drilling cooling coating and the cured deep well drilling cooling coating.

[0114] Comparative Example 7

[0115] Compared with Example 1, the difference is that step (3) is omitted. In step (4), the composite phase change core material of step (1) is heated and melted, and then the material of step (2) is added drop by drop to react. Other reaction conditions and material composition remain unchanged, so as to obtain the deep well drilling cooling coating and the deep well drilling cooling coating after curing.

[0116] Comparative Example 8

[0117] Compared with Example 1, the difference is that the spraying thickness of the cooling coating is reduced to 1.5 μm, while other reaction conditions and material composition remain unchanged, resulting in a cured and shaped deep well drilling cooling coating.

[0118] Comparative Example 9

[0119] According to the method described in CN112096303A, the internal threaded joint and the external threaded joint are fixedly connected to the drill pipe body by friction welding. An annular space is reserved inside the drill pipe, and an injection channel is reserved on the drill pipe to connect the annular space. A tapered internal thread section is set inside the injection channel. After the closed-cell particles and phenolic resin are sintered at high temperature, they are immediately injected into the annular space inside the drill pipe through the channel. After curing, a thermal insulation layer is formed. After the thermal insulation layer is cured, the filler is screwed into the filler hole and fixed with a threaded lock to seal the thermal insulation layer between the drill pipes and prevent it from oxidizing and failing due to contact with air. Then, a polyfluorinated high-temperature resistant coating is sprayed onto the surface of the drill pipe and forms an outer coating after drying.

[0120] Comparative Example 10

[0121] According to the method described in CN102219878A, xylene, ethylene glycol ethyl ether acetate, and tert-carbon glycidyl ester are added to a reactor, and the temperature is raised to 155°C. Acrylic acid, methyl methacrylate, butyl acrylate, hydroxyethyl acrylate, perfluorobutyl ethyl acrylate, and di-tert-butyl peroxide are mixed evenly and added dropwise for 3.5 hours. The mixture is kept at this temperature for 1.5 hours, and then cooled to 40°C to discharge the material, thus obtaining a hydroxy acrylic resin with a molecular weight of 15,000. The viscosity of the obtained hydroxy acrylic resin is adjusted with xylene and used as a film-forming component. Titanium dioxide is used as a pigment and filler, and 80g of the film-forming substance is added. The mixture is stirred evenly with a disperser and then ground with a sand mill to a fineness of less than 20μm to obtain a hydroxy acrylic slurry. 100g of the above slurry is mixed with 20.5g of aliphatic isocyanate curing agent hexamethylene-1,6-diisocyanate trimer to obtain a hydroxy acrylic coating.

[0122] Test Example 1

[0123] The thermal properties of the deep well drilling cooling coatings in Examples 1-14 and Comparative Examples 1-10 were determined, and the specific results are shown in Table 1.

[0124] Table 1. Thermal properties of the deep well drilling cooling coatings prepared in the examples and comparative examples.

[0125]

[0126]

[0127] The mechanical properties of the deep well drilling cooling coatings in Examples 1-14 and Comparative Examples 1-10 were determined, and the specific results are shown in Table 2.

[0128] Table 2 Mechanical properties of deep well drilling cooling coatings prepared in the examples and comparative examples

[0129]

[0130] As can be seen from Tables 1 and 2, the deep well drilling cooling coating prepared by the method of this invention possesses excellent thermal and mechanical properties. The latent heat of phase change, adiabatic coefficient, and supercooling of the sample in Example 1 reached 223.6 J / g, 24.8 mW / (m·K), and 5.7 °C, respectively. After 20 cycles of continuous endothermic-exothermic cycles, the latent heat of phase change, adiabatic coefficient, and supercooling of the sample in Example 1 remained at 221.9 J / g, 26.5 mW / (m·K), and 6.3 °C, respectively. In contrast, the latent heat of phase change of the comparative examples was generally lower than 180 J / g, and the adiabatic coefficient was higher than 40 mW / (m·K). Figure 1 and Figure 2 The differential scanning calorimetry (DSC) curves and scanning electron microscope (SEM) images further illustrate that the example samples exhibit good recyclability and particle integrity. (SEM image of Example 1 sample folded and bent at 180°C) Figure 3 This indicates that the sample has good flexibility and bending resistance, while the scanning electron microscope image of the sample in Comparative Example 6 after being folded and bent at 180°C ( Figure 4 The presence of obvious cracks indicates that its bending resistance is insufficient.

[0131] Test Example 2

[0132] The temperature rise curves of the deep well cooling coatings in Example 1 and Comparative Example 1 during the drilling process were measured. Specific results are shown in [link to details]. Figure 5 The drilling site is the Jiangsha-330-2 shale gas well in Sichuan, with a depth of 7860.7m.

[0133] Depend on Figure 5 It is evident that the heating rate of the sample in Example 1 within 60 minutes was significantly lower than that of the sample in Comparative Example 1, indicating that the deep well cooling coating prepared according to the method of the present invention contains phase change temperature regulating components, which significantly improves the overheating phenomenon of drilling equipment caused by formation temperature rise during drilling.

Claims

1. A method for preparing a cooling coating for deep well drilling, comprising the following steps: (1) After mixing and melting sugar alcohols and esters, an initiator is added for heating and reaction, and then benzene compounds are added for continued reaction to obtain composite phase change core material; (2) The silicate ester, zirconium oxide, organic solvent, siloxane and water are reacted and then aged at low temperature; (3) After vacuum treatment, the ester diol is mixed with isocyanate and catalyst for the first reaction, then the auxiliary agent and regulator are added for the second reaction, and then the mixture is allowed to stand for reaction with the material obtained in step (2), mixed solvent and amine, and then polyetheramine and water are added to obtain an emulsion. (4) The composite phase change core material of step (1) is heated and melted, and then the emulsion of step (3) is added drop by drop to it to carry out the reaction, so as to obtain the deep well drilling cooling coating. In step (3), the auxiliary agent is selected from one or more of dimethylolpropionic acid, dimethylolbutyric acid and trimethylolpropionic acid; the regulator is selected from one or more of nonylphenol polyoxyethylene ether-6, diisopropyl ketone and 1-phenyl-2-pyrrolidone.

2. The preparation method according to claim 1, characterized in that, In step (1), the sugar alcohol is selected from any one or more of xylitol, erythritol, threitol and mannitol; And / or, in step (1), the ester is selected from one or more of sucrose fatty acid esters, 3-phenyl propyl acrylate and polyethylene glycol methacrylate; And / or, in step (1), the initiator is selected from benzoyl peroxide and / or sodium peroxide; And / or, in step (1), the benzene series is selected from one or more of toluene, ethylbenzene and xylene.

3. The preparation method according to claim 1, characterized in that, In step (1), the melting conditions are heating and stirring melting, with a temperature of 120℃~200℃, a stirring speed of 500rpm~800rpm, and a time of 30min~60min; And / or, in step (1), the reaction temperature of the heating reaction is 150℃~250℃ and the reaction time is 3h~6h.

4. The preparation method according to claim 1, characterized in that, In step (1), the mass ratio of the sugar alcohol, ester, initiator and benzene series is 1:(0.1~1):(0.005~0.05):(0.8~2.4).

5. The preparation method according to claim 1, characterized in that, In step (2), the silicate ester is selected from one or more of tetraethyl orthosilicate, tetramethyl orthosilicate and polyethyl orthosilicate; And / or, in step (2), the zirconium oxide is selected from one or more of zirconium oxychloride and zirconium oxalate; And / or, in step (2), the organic solvent is selected from one or more of anhydrous methanol, anhydrous ethanol and N,N-dimethylformamide (DMF); And / or, in step (2), the siloxane is selected from one or more of triethoxysilane, methyltrimethoxysilane and isooctyltriethoxysilane.

6. The preparation method according to claim 1, characterized in that, In step (2), the mass ratio of the silicate ester, zirconium oxide, organic solvent, siloxane and water is 1: (0.08-0.75): (1-10): (0.06-0.33): (3-14).

7. The preparation method according to claim 1, characterized in that, In step (2), the reaction temperature is 40℃~80℃, the stirring speed is 800rpm~1000rpm, and the time is 25min~40min; And / or, in step (2), the low-temperature aging is water bath low-temperature aging, wherein the temperature of the water bath is -7℃ to 12℃; the aging treatment temperature is 20℃ to 80℃, and the time is 5h to 16h.

8. The preparation method according to claim 1, characterized in that, In step (3), the ester diol is selected from polycaprolactone diol with an average molecular weight of 500 to 2000 and / or polycarbonate diol with an average molecular weight of 500 to 2000. And / or, in step (3), the isocyanate is selected from one or more of dicyclohexylmethane diisocyanate (HMDI), hexamethylene diisocyanate (HDI) and lysine diisocyanate (LDI); And / or, in step (3), the catalyst is selected from one or more of stannous isooctanoate, zinc isooctanoate and bismuth isooctanoate; And / or, in step (3), the mixed solvent is selected from any two of anhydrous methanol, acetonitrile, isobutanol and cyclohexane; And / or, in step (3), the amine is selected from one or more of triethanolamine, diethylamine and 1,4-butanediamine; And / or, in step (3), the polyetheramine is selected from one or more polyetheramines with an average molecular weight of 200 to 2000 of difunctionality.

9. The preparation method according to claim 1, characterized in that, In step (3), the vacuum treatment conditions are heating treatment, with a temperature of 80℃~130℃, a vacuum degree of 0.3atm~0.6atm, and a time of 30min~60min; And / or, in step (3), the reaction temperature of the first reaction is 40℃~120℃, and the reaction time is 5min~60min; And / or, in step (3), the reaction temperature of the second reaction is 40℃~120℃, and the reaction time is 5min~40min; And / or, in step (3), the settling reaction time is 10 min to 80 min.

10. The preparation method according to claim 1, characterized in that, In step (3), the mass ratio of the ester diol to the material aged in step (2) is 1:(0.05~0.75). And / or, in step (3), the mass ratio of the ester diol, isocyanate, catalyst, auxiliary agent, regulator, mixed solvent, amine, polyetheramine and water is 1: (0.9-2.4): (0.003-0.02): (0.008-0.16): (0.001-0.01): (0.73-4.45): (0.06-0.72): (0.01-0.23): (0.003-0.04).

11. The preparation method according to claim 1, characterized in that, In step (4), the composite phase change core material is heated and melted at a temperature of 120°C to 180°C for 15 min to 30 min. And / or, in step (4), the reaction is a dynamic reaction, wherein the temperature is 120℃~180℃, the stirring speed is 2000rpm~8000rpm, and the time is 25min~80min.

12. The preparation method according to claim 1, characterized in that, In step (4), the mass ratio of the composite phase change core material to the emulsion is 1:(0.86~2.79). And / or, in step (4), the ratio of the composite phase change core material to the emulsion is 1g composite phase change core material: (3mL / min~15mL / min) emulsion.

13. A deep well drilling cooling coating obtained by the preparation method according to any one of claims 1-12.

14. The application of the coating according to claim 13 in deep well drilling, characterized in that, The coating is sprayed onto the outer surface of deep well drilling equipment and devices, and then cured and formed.

15. The application according to claim 14, characterized in that, The spraying process involves adding the coating material to a polyurethane spraying equipment and spraying it onto the outer surface of the drilling equipment and components. The polyurethane spraying equipment has a raw material output of 100g / min to 1000g / min, a heating power of 7.5kW to 10kW, and an output pressure of 9MPa to 12MPa. And / or, the thickness of the spray coating is 5 μm to 100 μm; And / or, the curing temperature is 20℃~30℃, and the time is 0.5h~4h.

16. The application according to claim 14 or 15, characterized in that, The properties of the cured deep well drilling cooling coating are as follows: phase change temperature is 90℃~170℃, latent heat of phase change is 180J / g~240J / g, supercooling is 5℃~10℃, adiabatic coefficient is 21.5mW / (m·K)~33.9mW / (m·K), compressive strength is 3.5MPa~4.3MPa, tensile strength is 2.6MPa~3.5MPa, and there are no cracks when folded and bent at 180℃.

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