Oil-in-water type paraffin remover as well as preparation method and application thereof

Abstract

The invention provides an oil-in-water type paraffin remover as well as a preparation method and application thereof, and belongs to the technical field of paraffin removers. According to the invention, after the sodium dodecyl sulfate, the fatty alcohol-polyoxyethylene ether and the alkyl polyglucoside are compounded, a synergistic effect can be generated, the oil-water interfacial tension is greatly reduced, the viscosity of crude oil is effectively reduced, and the fluidity of the crude oil is improved, so that the wax crystal adhesion probability is further reduced; the mutual solvent, the alkali component, the emulsifier and the dispersing agent can promote uniform mixing of all the components, so that a uniform and stable oil-in-water system is formed; the raw materials adopted by the invention are low in toxicity and have a very good environment-friendly effect. Results of the embodiment show that the wax dissolving rate of the oil-in-water type paraffin remover at the temperature of 45 DEG C is larger than or equal to 40 mg / min and is far higher than the requirement that the wax dissolving rate is 0.016 g / min in the industrial standard, and meanwhile the stabilization time of the oil-in-water type paraffin remover reaches 48 h or above.

Description

Technical Field

[0001] This invention relates to the field of wax removal agents, and in particular to an oil-in-water wax removal agent, its preparation method, and its application. Background Technology

[0002] Crude oil produced in oilfields often contains a significant amount of waxy crude oil, ranging from 15% to 37%. This waxy crude oil is characterized by high pour point, high viscosity, complex rheological properties, and poor low-temperature fluidity. While waxy crude oil exhibits good fluidity under high temperature and pressure conditions in the reservoir, as the oil is extracted, the temperature and pressure gradually decrease. During this process, wax and asphaltenes in the crude oil precipitate, causing varying degrees of wax deposition in the wells. The wax deposits adsorbed on the tubing reduce the effective inner diameter of the tubing, increasing transport friction and significantly reducing oil and gas production. In severe cases, this can lead to tubing blockage and production shutdown, increasing the difficulty and risk of producing waxy crude oil. Furthermore, the wax deposition problem persists throughout the entire gathering and transportation process, resulting in substantial economic losses annually due to pump jamming accidents caused by wax deposition.

[0003] Currently, the main methods for solving the wax buildup problem are physical, biological, and chemical wax removal. Physical wax removal primarily relies on mechanical methods such as hot nitrogen washing and coiled tubing washing, but these methods are not very effective. Biological wax removal mainly uses microorganisms; however, microorganisms require suitable temperature, pressure, salinity (mineralization), and nutrients to survive and function. Drastic changes in the oil well environment affect the activity of microorganisms, leading to inconsistent effectiveness of biological wax removal. Furthermore, microorganisms need time to grow, reproduce, and metabolize wax, resulting in a slow wax removal effect and limited ability to remove already hardened wax plugs. Chemical wax removal, on the other hand, has advantages such as rapid action, thorough wax removal, and no impact on normal oil well production, and is therefore widely used. However, with the deepening exploitation of crude oil resources, the problem of wax blockage in high-wax and microcrystalline wax oil and gas resources is becoming increasingly serious. Conventional chemical wax removers have low flash points (<45℃), poor low-temperature wax dissolving effect (poor room-temperature wax dissolving effect), poor dissolving effect on microcrystalline wax, and contain easily corrosive elements such as sulfur and chlorine. As a result, conventional agents have poor wax dissolving effect on high-wax oil and gas resources, and there are safety risks in the process of use.

[0004] Meanwhile, the wax-removing agents used in chemical wax removal are mainly water-based and oil-based. Oil-based wax removers have the advantages of strong adaptability to crude oil, fast wax melting speed, and quick effect after being added to oil wells. Furthermore, their high freezing point makes them convenient for use in winter. However, oil-based wax removers have the disadvantage of low relative density, making them unsuitable for oil wells with high water content, and their low flash point makes them prone to ignition, posing a safety hazard. Water-based wax removers have the advantages of higher relative density, making them more effective in oil wells with high water content, and they are safe to use with no fire hazard. However, due to the poor miscibility between water-based wax removers and oil, their effect after being added to oil wells is slow.

[0005] Therefore, providing a high-efficiency, safe, and suitable dewaxing agent for oil well unclogging under various complex working conditions has become a pressing technical problem to be solved in this field. Summary of the Invention

[0006] The purpose of this invention is to provide an oil-in-water wax remover, its preparation method, and its application. The oil-in-water wax remover provided by this invention has a fast wax dissolution rate, high wax removal efficiency, and good stability. At the same time, the raw materials used are basically non-toxic or low-toxic materials, making it highly safe to use and capable of unclogging oil wells under different complex working conditions.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides an oil-in-water wax remover, comprising the following components by mass percentage: 15-50% organic solvent, 5-35% surfactant, 1-10% miscible solvent, 0.3-2% alkali component, 2-6% emulsifier, 0.5-10% dispersant, and the balance being water; The organic solvent is vegetable oil and xylene, with a volume ratio of vegetable oil to xylene of 1:(0.5~3). The surfactant comprises sodium dodecyl sulfonate, fatty alcohol polyoxyethylene ether, and alkyl polysaccharide; the mass ratio of sodium dodecyl sulfonate, fatty alcohol polyoxyethylene ether, and alkyl polysaccharide is 1:(0.1~0.2):(0.4~0.5).

[0008] Preferably, the vegetable oil is palm oil or pine oil.

[0009] Preferably, the fatty alcohol polyoxyethylene ether is AEO-9; and the alkyl polysaccharide is hexadecyl glucoside.

[0010] Preferably, the mutual solvent is any one or more of ethanol, isopropanol, ethylene glycol butyl ether, and diethylene glycol monobutyl ether.

[0011] Preferably, the alkaline component is sodium hydroxide or potassium hydroxide.

[0012] Preferably, the emulsifier is a Tween series or a Span series.

[0013] Preferably, the emulsifier is Tween-60 or Span-80.

[0014] Preferably, the dispersant is an ethylene oxide-propylene oxide block copolymer.

[0015] This invention provides a method for preparing the water-in-oil type wax remover described in the above technical solution, comprising the following steps: (1) Mix the organic solvent and the miscible solvent to obtain a mixed solvent; (2) Mix water, dispersant and alkaline components to obtain alkaline water; (3) Mix the mixed solvent obtained in step (1) and the alkaline water obtained in step (2), then add surfactant and emulsifier and mix evenly to obtain an oil-in-water wax remover; The preparation of steps (1) and (2) is not in any particular order.

[0016] This invention provides the application of the oil-in-water wax remover described in the above technical solution or the oil-in-water wax remover prepared by the preparation method described in the above technical solution in oilfield wax removal.

[0017] This invention provides an oil-in-water wax remover, comprising the following components by mass percentage: 15-50% organic solvent, 5-35% surfactant, 1-10% miscible solvent, 0.3-2% alkali component, 2-6% emulsifier, 0.5-10% dispersant, and the balance being water; wherein the organic solvent is vegetable oil and xylene, and the volume ratio of vegetable oil to xylene is 1:(0.5-3); wherein the surfactant includes sodium dodecyl sulfonate, fatty alcohol polyoxyethylene ether, and alkyl polysaccharide; and the mass ratio of sodium dodecyl sulfonate, fatty alcohol polyoxyethylene ether, and alkyl polysaccharide is 1:(0.1-0.2):(0.4-0.5). This invention utilizes vegetable oil and xylene as organic solvents. Vegetable oil, as the oil phase base, can dissolve and carry other effective components, and acts as a mild solvent for wax, enabling its slow dissolution. Xylene, on the other hand, has strong dissolving power, directly and quickly destroying and dissolving the wax crystal structure. This invention combines vegetable oil and xylene. Xylene can remove heavy wax and effectively remove hard, thick wax blockages. Meanwhile, vegetable oil can eliminate residual wax, providing comprehensive wax removal. Furthermore, vegetable oil is highly nutritious; the vegetable oil residue on the inner wall of the oil pipe can provide nutrients for microbial growth, which in turn can decompose wax, reducing the probability of wax formation. This invention utilizes vegetable oil, which is not only inexpensive but also safe, environmentally friendly, low-toxic, renewable, and has a high flash point (high safety) with no risk of explosion. The sodium dodecyl sulfonate and fatty alcohol polyoxyethylene ether in the surfactant can adsorb onto the surface of oil pipes and formation rocks, changing them from oleophilic to hydrophilic. This makes it difficult for wax crystals to adhere, and any existing wax is more easily stripped away by water flow, thus preventing direct wax adhesion and achieving a wax-preventing effect. Simultaneously, it can adsorb onto the surface of tiny wax crystals, forming electrostatic repulsion or steric hindrance, preventing them from agglomerating into large deposits, allowing the wax to be discharged with the liquid flow, thus playing an auxiliary role in wax prevention and removal. Furthermore, it can significantly reduce the oil-water interfacial tension, aiding in the removal of existing wax and improving the contact between the wax remover (especially water-based ones) and crude oil. The process involves contact, which improves wax removal efficiency and disperses the wax-containing oil phase into the aqueous phase, forming an oil-in-water emulsion that facilitates the removal of wax from the wellbore. Alkyl polysaccharides have strong lipophilicity and enhanced emulsification and solubilization capabilities for oily substances. They also exhibit high structural similarity and affinity to waxes, making them more likely to adsorb or insert into wax crystals and distort their growth. This makes them suitable for preventing and dispersing heavy waxes and high-wax crude oils. The combination of sodium dodecyl sulfonate, fatty alcohol polyoxyethylene ether, and alkyl polysaccharides produces a synergistic effect, significantly reducing the interfacial tension between oil and water, effectively lowering crude oil viscosity, and improving its fluidity, thereby further reducing the likelihood of wax crystal adhesion. Mutual solvents, alkaline components, emulsifiers, and dispersants promote uniform mixing of the components, resulting in a homogeneous and stable oil-in-water system.The results of the examples show that the water-in-oil wax remover provided by the present invention has a wax dissolution rate of ≥40mg / min at 45℃, which is far higher than the industry standard requirement of 0.016g / min for wax dissolution rate. At the same time, the stability time of the water-in-oil wax remover reaches more than 48h. Detailed Implementation

[0018] This invention provides an oil-in-water wax remover, comprising the following components by mass percentage: 15-50% organic solvent, 5-35% surfactant, 1-10% miscible solvent, 0.3-2% alkali component, 2-6% emulsifier, 0.5-10% dispersant, and the balance being water; The organic solvent is vegetable oil and xylene, with a volume ratio of vegetable oil to xylene of 1:(0.5~3). The surfactant comprises sodium dodecyl sulfonate, fatty alcohol polyoxyethylene ether, and alkyl polysaccharide; the mass ratio of sodium dodecyl sulfonate, fatty alcohol polyoxyethylene ether, and alkyl polysaccharide is 1:(0.1~0.2):(0.4~0.5).

[0019] In this invention, unless otherwise specified, all raw materials used are commercially available products well known to those skilled in the art or products prepared by known methods.

[0020] The oil-in-water wax remover provided by this invention comprises 15-50% organic solvent by weight percentage. In one embodiment of this invention, the weight percentage of the organic solvent can be 20%, 25%, 30%, 35%, 40%, or 45%. By controlling the amount of organic solvent, this invention can give the oil-in-water wax remover excellent flowability.

[0021] In this invention, the organic solvent is vegetable oil and xylene; the vegetable oil is preferably palm oil or pine oil; the volume ratio of the vegetable oil to xylene is 1:(0.5~3). As one embodiment of this invention, the volume ratio of the vegetable oil to xylene can be 1:0.8, 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, 1:2.2, 1:2.5, or 1:2.8. This invention utilizes vegetable oil and xylene as organic solvents. Vegetable oil, as the oil phase base, can dissolve and carry other effective components, and acts as a mild solvent for wax, enabling its slow dissolution. Xylene, with its strong dissolving power, can directly and rapidly destroy and dissolve the wax crystal structure. The combination of vegetable oil and xylene allows xylene to remove heavy wax and effectively remove hardened, thick wax blockages, while the vegetable oil eliminates residual wax, providing comprehensive wax removal. Furthermore, vegetable oil is highly nutritious; the residue left on the inner wall of the oil pipe provides nutrients for microbial growth, which in turn decomposes wax, reducing the probability of wax formation. The vegetable oil used in this invention is not only inexpensive but also safe, environmentally friendly, low in toxicity, renewable, has a high flash point (high safety), and poses no risk of explosion.

[0022] The oil-in-water dewaxing agent provided by this invention comprises 5-35% surfactant by weight percentage. In this invention, the mass percentage of the surfactant can be 10%, 15%, 20%, 25%, or 30%. By controlling the amount of surfactant, this invention can avoid excessively high costs for the oil-in-water dewaxing agent while still ensuring it has excellent dewaxing ability.

[0023] In this invention, the surfactant comprises sodium dodecyl sulfonate, fatty alcohol polyoxyethylene ether (AEO), and alkyl polysaccharide (APG); the fatty alcohol polyoxyethylene ether is preferably AEO-9; the alkyl polysaccharide is preferably hexadecyl glucoside; the hexadecyl polysaccharide is preferably hexadecyl glucoside (hexadecyl-D-glucoside, C...) produced by Shanghai Fakai Chemical Co., Ltd. 22 H 44 O6); the mass ratio of sodium dodecyl sulfonate, fatty alcohol polyoxyethylene ether and alkyl polysaccharide is 1:(0.1~0.2):(0.4~0.5).

[0024] In this invention, sodium dodecyl sulfonate and fatty alcohol polyoxyethylene ether can be adsorbed onto the surface of tubing and formation rocks, changing them from oleophilic to hydrophilic. This makes it difficult for wax crystals to adhere, and the already adhered wax is more easily stripped away by the water flow, thus preventing direct adhesion of wax crystals and achieving a wax-proof effect. At the same time, they can also be adsorbed onto the surface of tiny wax crystals, forming electrostatic repulsion or steric hindrance, preventing them from agglomerating into large deposits, allowing the wax to be discharged with the liquid flow, playing an auxiliary role in wax prevention and removal. In addition, they can significantly reduce the oil-water interfacial tension, which helps to peel off the already adhered wax and improve the contact between the wax remover (especially the water-based one) and crude oil, improving the wax removal efficiency. They can also disperse the oil phase containing wax into the aqueous phase, forming an oil-in-water emulsion, which facilitates the removal of wax from the wellbore. Alkyl polysaccharides have strong oleophilicity and stronger emulsification and solubilization capabilities for oily substances. At the same time, they have high structural similarity with waxes and strong affinity, making it easier to adsorb or insert into wax crystals and distort wax crystal growth. They are suitable for wax prevention and dispersion of heavy wax and high-wax crude oil. In this invention, the combination of sodium dodecyl sulfonate, fatty alcohol polyoxyethylene ether, and alkyl polysaccharide can produce a synergistic effect, greatly reducing the interfacial tension between oil and water, effectively reducing the viscosity of crude oil, improving its fluidity, and thus further reducing the probability of wax crystal adhesion.

[0025] The oil-in-water wax remover provided by this invention comprises 1-10% by weight; the mutual solvent is preferably any one or more of ethanol, isopropanol, ethylene glycol butyl ether, and diethylene glycol monobutyl ether. As one embodiment of this invention, the weight percentage of the mutual solvent can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, or 9%. By adding a mutual solvent, this invention helps to improve the miscibility of vegetable oils in water.

[0026] The oil-in-water wax remover provided by this invention comprises 0.3-2% alkaline component by mass percentage; the alkaline component is preferably sodium hydroxide or potassium hydroxide. As one embodiment of this invention, the mass percentage of the alkaline component can be 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.5%, 1.6%, or 1.8%. By adding the alkaline component, this invention creates an alkaline environment in the system, which is beneficial for the dispersion of the components.

[0027] The oil-in-water wax remover provided by this invention comprises 2-6% emulsifier by weight percentage; the emulsifier is preferably a Tween series or a Span series, more preferably Tween-60 or Span-80. In one embodiment of this invention, the weight percentage of the emulsifier can be 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, or 5.5%. By adding an emulsifier, this invention improves the emulsifying properties of the wax remover, thereby promoting the formation of an oil-in-water system.

[0028] The oil-in-water wax remover provided by this invention comprises 0.5-10% dispersant by weight percentage; the dispersant is preferably an ethylene oxide-propylene oxide block copolymer, more preferably Pluronic produced by BASF (Germany). As one embodiment of this invention, the weight percentage of the dispersant can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, or 9%. In this invention, alkyl polysaccharides have poor solubility and dispersibility in water. By adding an ethylene oxide-propylene oxide block copolymer as a dispersant, which has a PEO-PPO-PEO triblock structure, with a hydrophobic polypropylene oxide (PPO) in the middle and hydrophilic polyethylene oxide (PEO) at both ends, the alkyl polysaccharides can be uniformly dispersed in water, thereby facilitating the formation of an oil-in-water system.

[0029] The water-in-oil wax remover provided by the present invention comprises the remainder water by weight percentage; the water is preferably deionized water or distilled water.

[0030] This invention utilizes vegetable oil and xylene as organic solvents. Vegetable oil, as the oil phase base, can dissolve and carry other effective components, and acts as a mild solvent for wax, enabling its slow dissolution. Xylene, on the other hand, has strong dissolving power, directly and quickly destroying and dissolving the wax crystal structure. This invention combines vegetable oil and xylene. Xylene can remove heavy wax and effectively remove hard, thick wax blockages. Meanwhile, vegetable oil can eliminate residual wax, providing comprehensive wax removal. Furthermore, vegetable oil is highly nutritious; the vegetable oil residue on the inner wall of the oil pipe can provide nutrients for microbial growth, which in turn can decompose wax, reducing the probability of wax formation. This invention utilizes vegetable oil, which is not only inexpensive but also safe, environmentally friendly, low-toxic, renewable, and has a high flash point (high safety) with no risk of explosion. The sodium dodecyl sulfonate and fatty alcohol polyoxyethylene ether in the surfactant can adsorb onto the surface of oil pipes and formation rocks, changing them from oleophilic to hydrophilic. This makes it difficult for wax crystals to adhere, and any existing wax is more easily stripped away by water flow, thus preventing direct adhesion of wax crystals and achieving a wax-resistant effect. Simultaneously, it can adsorb onto the surface of tiny wax crystals, forming electrostatic repulsion or steric hindrance, preventing them from agglomerating into large deposits, allowing the wax to be discharged with the liquid flow. This compound plays an auxiliary role in preventing and removing wax, and also significantly reduces the oil-water interfacial tension, which helps to peel off the attached wax and improves the contact between the wax remover (especially the water-based one) and the crude oil, thus increasing the wax removal efficiency. It can also disperse the wax-containing oil phase into the aqueous phase, forming an oil-in-water emulsion, which facilitates the removal of wax from the wellbore. Alkyl polysaccharides have strong lipophilicity and stronger emulsifying and solubilizing abilities for oily substances. They also have high structural similarity to waxes, strong affinity, and are more likely to adsorb or insert into wax crystals, distorting wax crystal growth. This makes them suitable for preventing and dispersing heavy waxes and high-wax crude oils. In this invention, the combination of sodium dodecyl sulfonate, fatty alcohol polyoxyethylene ether, and alkyl polysaccharide produces a synergistic effect, greatly reducing the oil-water interfacial tension, effectively reducing crude oil viscosity, and improving its fluidity, thereby further reducing the probability of wax crystal adhesion. The mutual solvent, alkaline component, emulsifier, and dispersant can promote uniform mixing of the components, thus forming a homogeneous and stable oil-in-water system.

[0031] This invention also provides a method for preparing the water-in-oil type wax remover described in the above technical solution, comprising the following steps: (1) Mix the organic solvent and the miscible solvent to obtain a mixed solvent; (2) Mix water, dispersant and alkaline components to obtain alkaline water; (3) Mix the mixed solvent obtained in step (1) and the alkaline water obtained in step (2), then add surfactant and emulsifier and mix evenly to obtain an oil-in-water wax remover; The preparation of steps (1) and (2) is not in any particular order.

[0032] This invention mixes organic solvents and mutual solvents to obtain a mixed solvent.

[0033] This invention does not impose any particular limitation on the specific method of mixing the organic solvent and the miscible solvent, as long as they are mixed uniformly. As one embodiment of this invention, the mixing method may be stirring.

[0034] This invention mixes water, a dispersant, and an alkaline component to obtain alkaline water.

[0035] This invention does not impose any particular limitation on the specific method of mixing the water, dispersant, and alkali components, as long as they are mixed uniformly. As one embodiment of this invention, the mixing method may be stirring.

[0036] After obtaining the mixed solvent and alkaline water, the present invention mixes the mixed solvent and alkaline water, and then adds surfactant and emulsifier and mixes evenly to obtain an oil-in-water type wax remover.

[0037] In this invention, the mixing method of the mixed solvent and alkaline water is preferably stirring; the mixing temperature is preferably 30~50℃, more preferably 40℃; the mixing time is preferably 1~3h, more preferably 1~2h. This invention does not impose any special limitation on the stirring rate; it can be determined based on the technical knowledge of those skilled in the art, as long as it avoids solution splashing.

[0038] In this invention, the temperature at which the surfactant and emulsifier are added and mixed uniformly is preferably 30-50°C, more preferably 40°C; the uniform mixing is preferably carried out under stirring conditions. This invention does not impose any special limitations on the stirring rate and time for uniform mixing, as long as it achieves uniform mixing.

[0039] The preparation method provided by this invention is simple, requires little equipment, and is inexpensive, which is conducive to large-scale industrial application.

[0040] The present invention also provides the application of the water-in-oil wax remover described in the above technical solution or the water-in-oil wax remover prepared by the preparation method described in the above technical solution in oilfield wax removal.

[0041] The present invention does not impose any special limitation on the specific application method, and any application method known to those skilled in the art can be used.

[0042] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0043] Example 1 An oil-in-water wax remover comprises, by weight percentage: 40% organic solvent, 15% surfactant, 2% mutual solvent, 0.5% alkaline component, 3% emulsifier, 1% dispersant, and the balance being water; The organic solvent is vegetable oil and xylene; the vegetable oil is palm oil; the volume ratio of the vegetable oil to xylene is 1:0.5. The surfactant is sodium dodecyl sulfonate, fatty alcohol polyoxyethylene ether, and alkyl polysaccharide; the fatty alcohol polyoxyethylene ether is AEO-9; the alkyl polysaccharide is hexadecyl glucoside produced by Shanghai Fakai Chemical Co., Ltd.; the mass ratio of sodium dodecyl sulfonate, fatty alcohol polyoxyethylene ether, and alkyl polysaccharide is 1:0.1:0.4. The mutual solvent is diethylene glycol monobutyl ether; the alkaline component is sodium hydroxide; the emulsifier is Tween-60; the dispersant is Pluronic produced by BASF (Germany); and the water is distilled water. The preparation method of the water-in-oil type wax remover includes the following steps: (1) Mix the organic solvent and the mutual solvent to obtain a mixed solvent; (2) Mix water, dispersant and alkali components to obtain alkaline water; (3) The mixed solvent obtained in step (1) and the alkaline water obtained in step (2) are mixed at 40°C for 2 hours, and then a surfactant and an emulsifier are added and mixed evenly to obtain an oil-in-water wax remover.

[0044] Example 2 The volume ratio of the vegetable oil to xylene was 1:1; other conditions were the same as in Example 1.

[0045] Example 3 The volume ratio of the vegetable oil to xylene was 1:2; other conditions were the same as in Example 1.

[0046] Example 4 The volume ratio of the vegetable oil to xylene was 1:3; other conditions were the same as in Example 1.

[0047] Comparative Example 1 The organic solvent is vegetable oil; other conditions are the same as in Example 1.

[0048] According to the evaluation method of industry standard SY / T63000-2009 "Technical Conditions for Wax Removers and Inhibitors in Oil Production", the wax dissolution rate of the oil-in-water wax removers obtained in Examples 1-4 and Comparative Example 1 was tested at 45℃. Specifically, 15mL of sample and approximately 1g of paraffin (medical high-efficiency slice paraffin with a melting point of 56-58℃) were added to a stopper, and the wax dissolution rate of the wax remover was measured. The results are shown in Table 1. Table 1 shows the wax dissolving rates of the oil-in-water wax removers obtained in Examples 1-4 and Comparative Example 1.

[0049] As shown in Table 1, the wax dissolution rate of the oil-in-water wax removers prepared in Examples 1-4 of this invention is ≥40 mg / min, which is far higher than the industry standard requirement of 0.016 g / min. A comparison between Examples 1-4 and Comparative Example 1 shows that the wax dissolution rate of the oil-in-water wax removers increases with the increase in the proportion of xylene. This is because xylene has a higher wax dissolution rate than vegetable oil. However, when vegetable oil is used alone as a solvent, the wax dissolution rate decreases significantly.

[0050] The stability of the oil-in-water dewaxing agents obtained in Examples 1-4 and Comparative Example 1 was tested according to the petrochemical industry standard SH / T 0579-1994 "Determination of Emulsion Stability". The results are shown in Table 2. Table 2 shows the stability of the oil-in-water wax removers obtained in Examples 1-4 and Comparative Example 1.

[0051] As can be seen from Table 2, the stability of water-in-oil wax removers decreased slightly after the type of organic solvent was changed.

[0052] Example 5 An oil-in-water wax remover comprises, by weight percentage: 40% organic solvent, 17% surfactant, 2% mutual solvent, 0.5% alkaline component, 3% emulsifier, 1% dispersant, and the balance being water; The organic solvent is vegetable oil and xylene; the vegetable oil is palm oil; the volume ratio of the vegetable oil to xylene is 1:1. The surfactant is sodium dodecyl sulfonate, fatty alcohol polyoxyethylene ether, and alkyl polysaccharide; the fatty alcohol polyoxyethylene ether is AEO-9; the alkyl polysaccharide is hexadecyl glucoside produced by Shanghai Fakai Chemical Co., Ltd.; the mass ratio of sodium dodecyl sulfonate, fatty alcohol polyoxyethylene ether, and alkyl polysaccharide is 1:0.2:0.5. The mutual solvent is diethylene glycol monobutyl ether; the alkaline component is sodium hydroxide; the emulsifier is Tween-60; the dispersant is Pluronic produced by BASF (Germany); and the water is distilled water. The preparation method of the water-in-oil type wax remover includes the following steps: (1) Mix the organic solvent and the mutual solvent to obtain a mixed solvent; (2) Mix water, dispersant and alkali components to obtain alkaline water; (3) The mixed solvent obtained in step (1) and the alkaline water obtained in step (2) are mixed at 42°C for 2 hours, and then a surfactant and an emulsifier are added and mixed evenly to obtain an oil-in-water wax remover.

[0053] Comparative Example 2 The surfactant is sodium dodecyl sulfonate and fatty alcohol polyoxyethylene ether; the mass ratio of sodium dodecyl sulfonate to fatty alcohol polyoxyethylene ether is 1:0.7; other conditions are the same as in Example 5.

[0054] Comparative Example 3 The surfactant is sodium dodecyl sulfonate and alkyl polysaccharide; the mass ratio of sodium dodecyl sulfonate to alkyl polysaccharide is 1:0.7; other conditions are the same as in Example 5.

[0055] Comparative Example 4 The surfactant is a fatty alcohol polyoxyethylene ether and an alkyl polysaccharide glycoside; the mass ratio of the fatty alcohol polyoxyethylene ether to the alkyl polysaccharide glycoside is 0.2:0.5; other conditions are the same as in Example 5.

[0056] According to the evaluation method of industry standard SY / T63000-2009 "Technical Conditions for Wax Removers and Inhibitors in Oil Production", the wax dissolution rate of the oil-in-water wax removers obtained in Example 5 and Comparative Examples 2-4 was tested at 45℃. Specifically, 15mL of sample and approximately 1g of paraffin wax (medical high-efficiency slice paraffin with a melting point of 56-58℃) were added to a stopper, and the wax dissolution rate of the wax remover was measured. The results are shown in Table 3. Table 3 shows the wax dissolution rates of the oil-in-water wax removers obtained in Example 5 and Comparative Examples 2-4.

[0057] As shown in Table 3, the wax-dissolving rate of the oil-in-water wax remover prepared in Example 5 of this invention is ≥40 mg / min, which is far higher than the industry standard requirement of 0.016 g / min. A comparison between Example 5 and Comparative Examples 2-4 shows that, with the total amount of surfactant remaining constant, omitting any one of sodium dodecyl sulfonate, fatty alcohol polyoxyethylene ether, and alkyl polysaccharide glycoside significantly reduces the wax-dissolving rate of the resulting oil-in-water wax remover. This indicates that the present invention, by using three different surfactants in combination, has a good synergistic effect and can further improve the wax-dissolving rate of the oil-in-water wax remover.

[0058] The stability of the oil-in-water dewaxing agents obtained in Example 5 and Comparative Examples 2-4 was tested according to the petrochemical industry standard SH / T 0579-1994 "Determination of Emulsion Stability". The results are shown in Table 4. Table 4 shows the stability of the oil-in-water wax removers obtained in Example 5 and Comparative Examples 2-4.

[0059] As can be seen from Table 4, the change in surfactant type does not affect the stability of water-in-oil wax remover.

[0060] Comparative Example 5 The mutual solvents are omitted, and other conditions are the same as in Example 5.

[0061] Comparative Example 6 The alkali component is omitted, and other conditions are the same as in Example 5.

[0062] Comparative Example 7 The emulsifier was omitted, and other conditions were the same as in Example 5.

[0063] Comparative Example 8 The dispersant was omitted, and other conditions were the same as in Example 5.

[0064] According to the evaluation method of industry standard SY / T63000-2009 "Technical Conditions for Wax Removers and Inhibitors in Oil Production", the wax dissolution rate of the oil-in-water wax removers obtained in Example 5 and Comparative Examples 5-8 was tested at 45℃. Specifically, 15mL of sample and approximately 1g of paraffin wax (medical high-efficiency slice paraffin with a melting point of 56-58℃) were added to a stopper, and the wax dissolution rate of the wax remover was measured. The results are shown in Table 5. Table 5 shows the wax dissolving rates of the oil-in-water wax removers obtained in Example 5 and Comparative Examples 5-8.

[0065] As can be seen from Table 5, by comparing Example 5 and Comparative Examples 5-6, it can be seen that when any one of the mutual solvent, alkali component, emulsifier and dispersant is omitted, the wax dissolution rate of the obtained oil-in-water wax remover will be greatly reduced under the condition that other conditions remain unchanged. This shows that the present invention can further improve the wax dissolution rate of the oil-in-water wax remover by adding additives.

[0066] The stability of the oil-in-water dewaxing agents obtained in Example 5 and Comparative Examples 5-8 was tested according to the petrochemical industry standard SH / T 0579-1994 "Determination of Emulsion Stability". The results are shown in Table 6. Table 6 shows the stability of the oil-in-water wax removers obtained in Example 5 and Comparative Examples 5-8.

[0067] As can be seen from Table 6, the stability of water-in-oil wax removers decreases significantly when any one of the mutual solvents, alkaline components, emulsifiers, and dispersants is omitted.

[0068] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A water-in-oil type wax remover, characterized in that, By mass percentage, it comprises the following components: 15-50% organic solvent, 5-35% surfactant, 1-10% miscible solvent, 0.3-2% alkali component, 2-6% emulsifier, 0.5-10% dispersant, and the balance being water; The organic solvent is vegetable oil and xylene, with a volume ratio of vegetable oil to xylene of 1:(0.5~3). The surfactant comprises sodium dodecyl sulfonate, fatty alcohol polyoxyethylene ether, and alkyl polysaccharide; the mass ratio of sodium dodecyl sulfonate, fatty alcohol polyoxyethylene ether, and alkyl polysaccharide is 1:(0.1~0.2):(0.4~0.5).

2. The water-in-oil type wax remover according to claim 1, characterized in that, The vegetable oil is palm oil or pine oil.

3. The water-in-oil type wax remover according to claim 1, characterized in that, The fatty alcohol polyoxyethylene ether is AEO-9; the alkyl polysaccharide is hexadecyl glucoside.

4. The water-in-oil type wax remover according to claim 1, characterized in that, The mutual solvents are any one or more of ethanol, isopropanol, ethylene glycol butyl ether, and diethylene glycol monobutyl ether.

5. The water-in-oil type wax remover according to claim 1, characterized in that, The alkaline component is sodium hydroxide or potassium hydroxide.

6. The water-in-oil type wax remover according to claim 1, characterized in that, The emulsifier is either from the Tween series or the Span series.

7. The water-in-oil type wax remover according to claim 6, characterized in that, The emulsifier is Tween-60 or Span-80.

8. The water-in-oil type wax remover according to claim 1, characterized in that, The dispersant is an ethylene oxide-propylene oxide block copolymer.

9. A method for preparing the oil-in-water wax remover according to any one of claims 1 to 8, characterized in that, Includes the following steps: (1) Mix the organic solvent and the miscible solvent to obtain a mixed solvent; (2) Mix water, dispersant and alkaline components to obtain alkaline water; (3) Mix the mixed solvent obtained in step (1) and the alkaline water obtained in step (2), then add surfactant and emulsifier and mix evenly to obtain an oil-in-water wax remover; The preparation of steps (1) and (2) is not in any particular order.

10. The application of the oil-in-water dewaxing agent according to any one of claims 1 to 8 or the oil-in-water dewaxing agent prepared by the preparation method according to claim 9 in oilfield dewaxing.

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