Amphiphobic core-shell structure unblocking composition and preparation method thereof

Abstract

The invention relates to the field of oil field blockage, in particular to an amphiphobic core-shell structure blockage removal composition and a preparation method and application thereof. The blocking removal composition comprises a surfactant dispersant, an oxidant, a cosurfactant, a cosolvent, an organic solvent, an ion regulator, a surface performance regulator, a complexing agent and the balance of water, the blocking removal composition is an oil-in-water emulsion system with an amphiphobic core-shell structure, which is formed by carrying out oxidation reaction and addition reaction on an organic solvent, a surface active agent dispersing agent and an oxidizing agent. Meanwhile, the formed emulsion unblocking system with the amphiphobic core-shell structure also has a dispersing function, dissolved metal ions can be shielded in a dispersing manner, secondary precipitation is eliminated, and the unblocking effect on blockage formed by a heavy oil reservoir is greatly enhanced.

Description

Technical Field

[0001] The present application relates to the field of oilfield blockage, and in particular to a biphobic core-shell structure blockage-removing composition and a preparation method and application thereof. Background Art

[0002] The blockage in heavy oil reservoirs mainly comes from the deposition of colloid asphalt surface materials. At present, if inorganic acid-based unblocking agents are used to remove blockage pollution, it will lead to fast reaction speed, small treatment radius, secondary damage, etc., which will greatly affect the unblocking effect. At the same time, there is also the possibility of acid slag in heavy oil acidification. Therefore, there is currently no way to protect and remove the water lock damage caused by foreign liquids to the reservoir during the transformation process while unblocking. At the same time, this phenomenon will cause serious damage to low-permeability or ultra-low-permeability reservoirs. In addition, inorganic acid-based unblocking agents have no effect on removing oil-soluble blockages in the reservoir, which will also affect the effect of acidification and unblocking in oil wells. Therefore, reducing the reaction speed of the acid unblocking agent, increasing the treatment radius, and improving the ability to remove oil-soluble blockages are the key points to improve the unblocking effect of the unblocking agent.

[0003] At present, the methods for removing blockages include: (1) in an efficient and environmentally friendly water-based heavy oil organic scale dispersion and blockage removal system, the organic scale dispersion and blockage removal system is only suitable for removing blockages caused by colloid, asphaltene, dead oil and other substances in the near-wellbore area and wellbore, and still cannot solve the problems of fast reaction speed, small treatment radius, secondary damage, residue and water lock in the process of heavy oil blockage removal; (2) in an efficient and environmentally friendly heavy oil organic scale dispersion and blockage removal system and its preparation method, a heavy oil blockage removal technology has emerged, but this technology only achieves high efficiency and environmental protection, and still cannot solve the problems of fast reaction speed, small treatment radius, secondary damage, residue and water lock in the process of heavy oil blockage removal; (3) in the method for removing blockage and increasing injection in deep sandstone heavy oil reservoirs, a deep heavy oil reservoir water injection well removal and injection technology has emerged, but this technology mainly achieves removal and injection by variable displacement pulse injection and inorganic acid, and this technology is only applicable to deep heavy oil reservoir water injection wells, and cannot discharge the acid residue generated after acidization.

[0004] Therefore, how to provide a biphobic core-shell structured plugging-removing composition and a preparation method thereof to eliminate secondary precipitation while improving the plugging-removing effect of heavy oil reservoir blockage is a technical problem that urgently needs to be solved. Summary of the invention

[0005] The present application provides a biphobic core-shell structure plugging removal composition and a preparation method thereof, so as to solve the technical problems of secondary precipitation and low plugging removal effect of heavy oil reservoir blockage in the inorganic acid plugging removal system in the prior art.

[0006] In the first aspect, the present application provides a biphobic core-shell structured anti-blocking composition, which includes, by mass fraction: a surfactant dispersant: 15% to 20%, an oxidant: 10% to 15%, a co-surfactant: 5% to 6%, a co-solvent: 10% to 15%, an organic solvent: 18% to 20%, an ion regulator: 0% to 2%, a surface property regulator: 0.1% to 0.5%, a complexing agent: 0.3% to 1%, and the rest is water.

[0007] Optionally, the surfactant dispersant includes a nonionic surfactant and an anionic surfactant, the nonionic surfactant includes alkylphenol polyoxyethylene ether and / or fatty alcohol polyoxyethylene ether, and the anionic surfactant includes at least one of fatty alcohol polyoxyethylene ether sulfates, phosphates, sulfonates and carboxylates.

[0008] Optionally, the surfactant dispersant includes at least one of nonylphenol polyoxyethylene ether-10, fatty alcohol polyoxyethylene ether, sodium α-olefin sulfonate and nonylphenol polyoxyethylene ether phosphate.

[0009] Optionally, the oxidant comprises at least one of oxalic acid, aminosulfonic acid, formic acid, acetic acid, citric acid and phosphorus pentoxide; and / or,

[0010] The co-surfactant is a betaine zwitterionic surfactant; and / or,

[0011] The co-solvent comprises at least one of ethylene glycol butyl ether, diethylene glycol propyl ether and ethylene glycol dibutyl ether; and / or,

[0012] The organic solvent comprises at least one of solvent oil, rosin alcohol and unsaturated aromatic hydrocarbons; and / or,

[0013] The ion regulator is a monovalent metal salt; and / or,

[0014] The surface property regulator is a non-ionic fluorine-containing surfactant; and / or,

[0015] The complexing agent includes EDTA and / or ascorbic acid.

[0016] In a second aspect, the present application provides a method for preparing the plugging-removing composition according to the first aspect, the method comprising:

[0017] Mixing the surfactant dispersant, the water and the co-solvent to obtain a first mixed solution;

[0018] Preheating the first mixed solution, adding the oxidant, and stirring to dissolve, to obtain a second mixed solution;

[0019] The second mixed solution is kept warm to complete the oxidation reaction, thereby obtaining a third mixed solution;

[0020] The third mixed solution is kept warm, and the organic solvent, the ion regulator and the complexing agent are added, followed by stirring to obtain a fourth mixed solution;

[0021] The fourth mixed liquid is kept warm, and the surface property regulator is added, followed by stirring to obtain a plugging-removing composition.

[0022] Optionally, the end point temperature of the preheating is 60°C to 65°C.

[0023] Optionally, the oxidation reaction time is 2h to 4h.

[0024] Optionally, the volume ratio of the surfactant dispersant, water and co-solvent in the first mixed liquid is 1:5-15:1-5.

[0025] Optionally, the mass ratio of oxidant, oxidant and water in the second mixed liquid is 8-12:2-5:40-50.

[0026] Optionally, the mass ratio of the organic solvent, the ion regulator, water and the complexing agent in the fourth mixed liquid is 1:0.1-1:1-5:0.1-1.

[0027] Optionally, the mass ratio of water to the surface property regulator in the plugging-removing composition is 0.5 to 1:0.05.

[0028] In a third aspect, the present application provides an application of a biphobic core-shell structured plugging-removing composition, wherein the plugging-removing composition described in the first aspect is used in the preparation of an aqueous solution of a plugging-removing agent for a blockage in a heavy oil reservoir.

[0029] Optionally, the mass concentration of the blocking-removing composition in the blocking-removing agent aqueous solution satisfies:

[0030] When the viscosity of crude oil in the heavy oil reservoir is less than 5000 mPa.s, the mass concentration of the plugging-removing composition is 0.1%;

[0031] When 5000Pa.s≤the viscosity of crude oil in the heavy oil reservoir≤10000mPa.s, the mass concentration of the plugging-removing composition is 0.2%;

[0032] When the viscosity of crude oil in the heavy oil reservoir is greater than 10000 mPa.s, the mass concentration of the plugging-removing composition is 0.0.3% to 0.5%.

[0033] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0034] The embodiment of the present application provides a double-phobic core-shell structure blockage-removing composition, which utilizes oxidation reaction and nucleophilic addition reaction to generate an emulsion system of core-shell structure. Compared with other acidic blockage-removing agents, the formed core-shell structure is more stable and pollution-free by modifying the surfactant-type dispersant. At the same time, the present application adopts efficient organic solvents and co-solvents as non-polar solvents, which can be combined with the surfactant-type dispersant through non-chemical bonds, making the double-phobic core-shell structure blockage-removing system more stable. At the same time, the added co-surfactant and chelating agent have the ability to dissolve organic matter, and can remove organic blockage in the pores during the blockage-removing process. Finally, a surface property regulator is added, which has the characteristics of stable performance and good compatibility. Therefore, it can be used for oil layer unblocking and heavy oil viscosity reduction. At the same time, it also has good solubilizing ability, water lock removal ability, large unblocking radius and fast flowback. Moreover, due to the use of a double-phobic core-shell structure unblocking system, it has dual-phase wetting ability, and by reducing surface tension, changing rock wettability, reducing or eliminating water lock, reducing residual water saturation, and at the same time, the dissolved metal ions can be masked in a dispersed form to eliminate secondary precipitation, thereby increasing the relative permeability of the oil phase, and greatly enhancing the unblocking effect of the blockage formed in the heavy oil reservoir. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0036] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0037] Figure 1 A schematic diagram of the process for preparing a plugging-removing composition provided in an embodiment of the present application. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0039] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0040] The creative thinking of this application is:

[0041] The double-repellent core-shell structure plugging removal system is a plugging removal system formed by oxidation reaction and / or addition reaction of oxidant with organic solvent, imbibition agent and dispersant. In the system, organic solvent, imbibition agent, dispersant and oxidant undergo oxidation and / or addition reaction, and form non-chemical bonds between molecules and combine to form a double electric layer. In the double electric layer, the molecules are arranged in a regular manner to form a molecular layer with different polarities, so that organic solvent, imbibition agent, surfactant dispersant and co-solvent can form a stable homogeneous system. At present, different organic solvents are included in the double-repellent core-shell structure plugging removal system, and the whole system forms a new stable emulsion system. The oxidants used in the double-repellent core-shell structure plugging removal system include aminosulfonic acid, acetic acid, oxalic acid, formic acid, diphosphorus oxide, etc., so that the double-repellent core-shell structure plugging removal system is weakly acidic with a pH value of 3-4. The oxidants contained in the double-repellent core-shell structure plugging removal system can remove inorganic blockage in the formation, and can also partially dissolve the soluble mineral components in the reservoir, which plays a role in increasing porosity and permeability.

[0042] The ampholytic core-shell structure plugging removal system generally has a nanometer-scale particle size, so it can enter into tiny pores and microcracks to act. At the same time, the ampholytic core-shell structure plugging removal system also has low surface tension and interfacial tension, and has the function of bidirectional wetting. During the plugging removal process, it can penetrate into the pores and release water locks. It can also remove blockages caused by organic matter deposition through dispersion and emulsification, and will not cause secondary precipitation damage. Therefore, it has special advantages in the plugging removal of heavy oil reservoirs.

[0043] The embodiment of the present application provides a biphobic core-shell structure anti-blocking composition, which includes, by mass fraction, 15% to 20% surfactant dispersant, 10% to 15% oxidant, 5% to 6% co-surfactant, 10% to 15% co-solvent, 18% to 20% organic solvent, 0% to 2% ion regulator, 0.1% to 0.5% surface property regulator, 0.3% to 1% complexing agent, and the rest is water.

[0044] In the embodiments of the present application, by controlling the specific mass fraction of the surfactant dispersant, the water solubility, foaming ability, salt resistance and temperature resistance of the plugging-removing composition can be improved through subsequent modification, and the formed core-shell structure can be made more stable and pollution-free.

[0045] By controlling the specific mass fraction of the oxidant, the pH of the deblocking composition can be adjusted by the oxidant, while providing sufficient free radicals in the oxidation reaction stage to promote the formation of a core-shell structured emulsion system through oxidation reaction and nucleophilic addition reaction.

[0046] By controlling the specific mass fraction of the co-surfactant, the solubility of the surfactant dispersant can be improved through the co-surfactant. At the same time, the co-surfactant can improve the surface activity and hydrophilic-lipophilic balance of the plugging-removing composition, participate in the formation of micelles, thereby improving the polarity of the water-soluble components and oily components in the plugging-removing composition to form an emulsion system.

[0047] By controlling the specific mass fraction of the co-solvent, the co-solvent can be used to promote the full dissolution of each component in the plugging-removing composition, and at the same time, the water-soluble components and the oily components can be fully mixed to form a uniformly dispersed emulsion system.

[0048] By controlling the specific mass fraction of the organic solvent, the organic solvent can be combined with the surfactant dispersant and the co-surfactant through non-chemical bonds, making the amphiphilic core-shell structure deblocking system more stable.

[0049] By controlling the specific mass fraction of the ion regulator, the ion concentration in the plugging-removing composition can be adjusted by the ion regulator, while increasing the hydrolysis reaction rate, thereby prompting the plugging-removing composition to form an emulsion system.

[0050] By controlling the specific mass fraction of the surface property regulator, since the surface property regulator has the characteristics of stable performance and good compatibility, the surface property regulator can be used to improve the stability of the plugging removal composition, thereby obtaining a stable emulsion system.

[0051] By controlling the specific mass fraction of the complexing agent, the complexing agent can chelate most of the metal ions to form complex ion compounds, thereby improving the solubilization ability and water-locking ability of the plugging-removing composition.

[0052] In some optional embodiments, the surfactant dispersant includes a nonionic surfactant and an anionic surfactant, the nonionic surfactant includes alkylphenol polyoxyethylene ether and / or fatty alcohol polyoxyethylene ether, and the anionic surfactant includes at least one of fatty alcohol polyoxyethylene ether sulfates, phosphates, sulfonates and carboxylates.

[0053] In the embodiments of the present application, the specific type of surfactant dispersant is controlled, which can not only further improve the water solubility, foaming ability, salt resistance and temperature resistance of the plugging-removing composition in the subsequent modification, but also make the formed core-shell structure more stable and pollution-free.

[0054] In some optional embodiments, the surfactant dispersant includes at least one of nonylphenol polyoxyethylene ether-10, fatty alcohol polyoxyethylene ether, sodium α-olefin sulfonate and nonylphenol polyoxyethylene ether phosphate.

[0055] In the embodiments of the present application, further controlling the specific type of surfactant dispersant can further improve the water solubility, foaming ability, salt resistance and temperature resistance of the plugging-removing composition, making the formed core-shell structure more stable and pollution-free.

[0056] In some optional embodiments, the oxidant comprises at least one of sulfamic acid, formic acid, acetic acid, oxalic acid, citric acid and phosphorus pentoxide; and / or,

[0057] The co-surfactant is a betaine zwitterionic surfactant; and / or,

[0058] The co-solvent comprises at least one of ethylene glycol butyl ether, diethylene glycol propyl ether and ethylene glycol dibutyl ether; and / or,

[0059] The organic solvent comprises at least one of solvent oil, rosin alcohol and unsaturated aromatic hydrocarbons; and / or,

[0060] The ion regulator is a monovalent metal salt; and / or,

[0061] The surface property regulator is a non-ionic fluorine-containing surfactant; and / or,

[0062] The complexing agent comprises EDTA and / or ascorbic acid; and / or,

[0063] In the embodiments of the present application, by controlling the specific types of oxidants, co-surfactants, co-solvents, organic solvents, ion regulators, surface property regulators and complexing agents, a thermodynamically stable emulsion system can be further obtained, and at the same time, the solubilization ability is stronger, and it has super strong water-locking ability, a large plugging removal radius, and fast backflow. The plugging removal composition has a slow reaction speed and a long effective action distance in the formation. The plugging removal composition also has a two-phase wetting ability, and can reduce or eliminate water locks, reduce residual water saturation, and increase the relative permeability of the oil phase by reducing surface tension and changing rock wettability, thereby achieving the effect of plugging removal and increased production.

[0064] like Figure 1 As shown, based on a general inventive concept, the present embodiment provides a method for preparing the declogging composition, the method comprising:

[0065] S1. Mixing the surfactant dispersant, the water and the cosolvent to obtain a first mixed solution;

[0066] S2. preheating the first mixed solution, adding the oxidant, and stirring to dissolve to obtain a second mixed solution;

[0067] S3. The second mixed solution is kept warm to complete the oxidation reaction to obtain a third mixed solution;

[0068] S4. The third mixed solution is kept warm, and the organic solvent, the ion regulator and the complexing agent are added, and then stirred to obtain a fourth mixed solution;

[0069] S5. The fourth mixed liquid is kept warm, and the surface property regulator is added, followed by stirring to obtain a plugging-removing composition.

[0070] In the embodiments of the present application, a surfactant dispersant and a co-solvent are first mixed to fully mix the surfactant dispersant and water, and then an oxidant and an oxidant are added to carry out an oxidation reaction, and then an organic solvent, an ion regulator and a complexing agent are added, and finally a surface property regulator is added, so that a nucleophilic addition reaction occurs in the third mixed liquid after the oxidation reaction to form an emulsion system with a core-shell structure.

[0071] This method is a method for preparing the above-mentioned unblocking composition. The specific composition of the unblocking composition can refer to the above-mentioned embodiment. Since this method adopts part or all of the technical solutions of the above-mentioned embodiment, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiment, which will not be repeated here one by one.

[0072] In some optional embodiments, the end point temperature of the preheating is 60°C to 65°C.

[0073] In the embodiments of the present application, the specific endpoint temperature of the preheating is controlled so that the oxidation reaction and the nucleophilic addition reaction can be respectively carried out within a suitable temperature range, thereby obtaining a stable deblocking composition system.

[0074] In some optional embodiments, the oxidation reaction time is 2h to 4h.

[0075] In the embodiments of the present application, the specific time of the oxidation reaction is controlled to facilitate the sufficient oxidation reaction between the surfactant dispersant, the oxidant and the oxidant, so that a core-shell structured emulsion system can be subsequently generated through a nucleophilic addition reaction.

[0076] In some optional embodiments, the volume ratio of the surfactant dispersant, water and co-solvent in the first mixed liquid is 1:5-15:1-5.

[0077] In some optional embodiments, the mass ratio of the oxidant, the oxidant and the water in the second mixed liquid is 8-12:2-5:40-50.

[0078] In some optional embodiments, the mass ratio of the organic solvent, the ion regulator, water and the complexing agent in the fourth mixed liquid is 1:0.1-1:1-5:0.1-1.

[0079] In some optional embodiments, the mass ratio of water to the surface property regulator in the plugging-removing composition is 0.5 to 1:0.05.

[0080] In the embodiments of the present application, by controlling the specific composition and volume or mass ratio of the first mixed liquid, the second mixed liquid, the fourth mixed liquid and the final product, the oxidation reaction and the nucleophilic addition reaction can be fully reacted to obtain an emulsion system with a stable core-shell structure.

[0081] Based on a general inventive concept, an embodiment of the present application provides an application of a biphobic core-shell structured plugging-removing composition, wherein the plugging-removing composition is used in the preparation of an aqueous solution of a plugging-removing agent for a blockage in a heavy oil reservoir.

[0082] This application is realized based on the above-mentioned unblocking composition. The specific composition of the unblocking composition can refer to the above-mentioned embodiment. Since this application adopts part or all of the technical solutions of the above-mentioned embodiment, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiment, which will not be described one by one here.

[0083] In some optional embodiments, the mass concentration of the blocking-removing composition in the blocking-removing agent aqueous solution satisfies:

[0084] When the viscosity of crude oil in the heavy oil reservoir is less than 5000 mPa.s, the mass concentration of the plugging-removing composition is 0.1%;

[0085] When 5000Pa.s≤the viscosity of crude oil in the heavy oil reservoir≤10000mPa.s, the mass concentration of the plugging-removing composition is 0.2%;

[0086] When the viscosity of crude oil in the heavy oil reservoir is greater than 10000 mPa.s, the mass concentration of the plugging-removing composition is 0.0.3% to 0.5%.

[0087] In the embodiments of the present application, the mass concentration of the plugging-releasing composition is determined by referring to the viscosity of crude oil in the heavy oil reservoir. The plugging-releasing composition can be used to reduce or eliminate water lock, lower the residual water saturation, and increase the relative permeability of the oil phase, thereby achieving the effect of plugging relief and increased production.

[0088] The subsequent use process is: inject the prepared double-phobic core-shell structure plugging removal system liquid into the target layer to be unblocked, shut down the well for 12 hours, and then open the well for normal production.

[0089] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0090] Example 1

[0091] Take 70mL of water and add it to a 250mL beaker, put it in a water bath, add the surfactant dispersant and co-solvent to the beaker and stir evenly, wherein the surfactant dispersant added is AEO-9, the co-solvent is ethylene glycol butyl ether and diethylene glycol propyl ether in a volume ratio of 1:1, and the added amount is 15mL; the volume ratio of surfactant dispersant: water: co-solvent is 2:15:2;

[0092] Heat the liquid obtained above to 60℃~65℃, then add the ion regulator, stir and dissolve into a uniform liquid. The ion regulator is sodium chloride, the addition amount is 0.4g, and the mass ratio of ion regulator to water is 1:20;

[0093] The liquid obtained above was heated to 65°C, and 23g of nonionic surfactant and 18g of oxidant were added. The nonionic surfactant added was nonylphenol polyoxyethylene ether-10; and the oxidant added was aminosulfonic acid.

[0094] The above liquid was reacted at 60°C to 65°C for 2h to 3h.

[0095] The temperature of the above liquid was controlled at 60°C to 65°C, and an organic solvent and a co-surfactant were added. The organic solvent was rosin alcohol, and the amount added was 20 mL; the co-surfactant was alkyl glycoside, and the amount added was 15 mL. Stir for 1 hour.

[0096] The obtained liquid was heated continuously to maintain at 60°C to 65°C, and a surface property regulator was added, wherein the surface regulator was a 12-carbon perfluoro surfactant, and the amount added was 3 mL, and the mixture was stirred for 1 hour.

[0097] The mixture was heated and stirred for another 1 h to obtain a brown homogeneous liquid.

[0098] It is prepared into a 0.3% aqueous solution with a surface tension of 23.97 mN / m, an interfacial tension of 0.8 mN / m, a wetting angle of 30.4°, a pH value of 4, and a particle size of particles of the amphiphilic core-shell structure deblocking system in the aqueous solution of 10 nm to 22 nm.

[0099] Example 2

[0100] Comparing Example 2 with Example 1, the difference between Example 2 and Example 1 is:

[0101] Take 65mL of water and add it to a 250mL beaker, put it in a water bath, add the surfactant dispersant and cosolvent to the beaker and stir evenly. The surfactant dispersant added is AEC (fatty alcohol polyoxyethylene ether carboxylate), the amount added is 15mL; the cosolvent is isopropanol and diethylene glycol propyl ether, the amount added is 15mL; the volume ratio of surfactant dispersant: water: cosolvent is 1:8:1;

[0102] Heat the liquid obtained above to 60℃~65℃, add ion regulator, stir and dissolve into a uniform liquid. The ion regulator is ammonium chloride, the addition amount is 4g, and the mass ratio of ion regulator to water is 1:10;

[0103] The liquid obtained above was heated to 70°C, and 23g of nonionic surfactant and 15g of oxidant were added. The nonionic surfactant added was nonylphenol polyoxyethylene ether-10; and the oxidant added was formic acid.

[0104] The above liquid was reacted at 65°C for 2h to 3h.

[0105] Adjust the temperature of the above liquid to 60℃~65℃, add organic solvent and co-surfactant, wherein the plant-based organic solvent is pine alcohol, the addition amount is 20mL; the co-surfactant is octadecyl hydroxyethyl sulfonyl betaine and 30mL of amine oxide. The ratio of octadecyl hydroxyethyl sulfonyl betaine to amine oxide is 2.2:1. Stir for 1h.

[0106] The obtained liquid was heated to maintain at 60℃~65℃, and a surface property regulator was added, the surface regulator was a 12 carbon perfluoro surfactant and a 10 carbon perfluoro surfactant, the ratio of the two was 1:2. The amount added was 5 mL, and stirred for 1 hour.

[0107] The mixture was heated and stirred for another 1 h to obtain a brown homogeneous liquid (emulsion).

[0108] It is prepared into a 0.3% aqueous solution with a surface tension of 22.4 mN / m, an interfacial tension of 0.5 mN / m, a wetting angle of 21.3°, a pH value of 3, and a particle size of 14 nm to 34 nm of the amphiphilic core-shell structure deblocking system in the aqueous solution.

[0109] Example 3

[0110] Comparing Example 3 with Example 1, the difference between Example 3 and Example 1 is:

[0111] Take 70mL of water and add it to a 250mL beaker, put it in a water bath, add the surfactant dispersant and co-solvent to the beaker and stir evenly. The surfactant dispersant added is AEO-7, the amount added is 20mL; the co-solvent is isopropanol and diethylene glycol propyl ether, the amount added is 20mL; the volume ratio of surfactant dispersant: water: co-solvent is 1:6:1;

[0112] Heat the liquid obtained above to 60℃~65℃, add ion regulator, stir and dissolve into a uniform liquid. The ion regulator is ammonium chloride, the addition amount is 4g, and the mass ratio of ion regulator to water is 1:10;

[0113] The liquid obtained above was heated to 70°C, and 25g of nonionic surfactant and 18g of oxidant were added. The nonionic surfactant added was nonylphenol polyoxyethylene ether-10; and the oxidant added was citric acid.

[0114] The above liquid was reacted at 65°C for 2h to 3h.

[0115] Adjust the temperature of the above liquid to 60℃~65℃, add organic solvent and co-surfactant, wherein the plant-based organic solvent is pine alcohol, the addition amount is 22mL; the co-surfactant is hexadecyl sulfobetaine and 30mL of amine oxide. The ratio of hexadecyl sulfobetaine to amine oxide is 2.2:1. Stir for 1h.

[0116] The obtained liquid was heated to maintain at 60℃~65℃, and a surface property regulator was added, the surface regulator was a 12 carbon perfluoro surfactant and a 10 carbon perfluoro surfactant, the ratio of the two was 1:2. The amount added was 6 mL, and stirred for 1 hour.

[0117] The mixture was heated and stirred for another 1 h to obtain a brown homogeneous liquid (emulsion).

[0118] It is prepared into a 0.3% aqueous solution with a surface tension of 23.1 mN / m, an interfacial tension of 0.6 mN / m, a wetting angle of 25.3°, a pH value of 3, and a particle size of 9 nm to 21 nm of the amphiphilic core-shell structure deblocking system in the aqueous solution.

[0119] Comparative Example 1

[0120] Comparative Example 1 and Example 1 are compared. The difference between Comparative Example 1 and Example 1 is:

[0121] The water-based unblocking agent system is used. The previous water-based unblocking agent system is mainly for inorganic scale or precipitation, mainly containing inorganic strong acid. Its unblocking principle is to remove scale and precipitation through acid dissolution; in addition to acid, it also includes corrosion inhibitor. However, this system is prone to secondary precipitation pollution, which greatly reduces the unblocking effect.

[0122] Comparative Example 2

[0123] Comparative Example 2 and Example 1 are compared. The difference between Comparative Example 2 and Example 1 is:

[0124] Organic solvent plugging removers are usually used to remove organic blockages, but simply injecting organic solvents is very dangerous. For safe construction, organic solvents are usually mixed with surfactant aqueous solutions to form emulsions, which is the initial form of microemulsions. However, such emulsions cannot form tiny emulsion droplets, and are thermodynamically unstable and will stratify, causing the performance of the emulsion to disappear, and are also unsafe.

[0125] In summary, the biphobic core-shell structure deblocking system provided in the embodiment of the present application contains both a surfactant system and an organic solvent. Moreover, a microemulsion is formed, and its particle size distribution is 10nm to 50nm, and at 1mm 2 There can be up to 5 million microemulsion droplets on an area of ​​1000 square meters. Therefore, it has the advantages of small size and large number. These advantages make the biphobic core-shell structure blockage remover not only remove organic blockage, but also remove inorganic blockage without negative effects. At the same time, it can also enter the deep formation for deep blockage removal.

[0126] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0127] (1) The present application provides an amphiphobic core-shell structure plugging-removing composition, which is an oil-in-water amphiphobic core-shell structure emulsion system formed by oxidation reaction and addition reaction of an organic solvent, a surfactant dispersant and an oxidant. At the same time, the amphiphobic core-shell structure emulsion plugging-removing system formed also has a dispersion function, which can mask the dissolved metal ions in a dispersed form, eliminate secondary precipitation, and greatly enhance the plugging-removing effect on the blockage formed by the heavy oil reservoir.

[0128] (2) The embodiment of the present application provides a biphobic core-shell structure plugging removal composition, which is a water-in-oil biphobic core-shell structure emulsion system. Therefore, a water-oil homogeneous plugging removal system can be formed during the plugging removal process. Compared with the single phase of traditional water-based or oil-based plugging removal systems, it can cope with more complex reservoir plugging treatment environments.

[0129] (3) The present application provides a biphobic core-shell structured anti-blocking composition, which is a uniform transparent liquid that will not stratify after being left for a long time and has a pH value of 3 to 4.

[0130] (4) The biphobic core-shell structured declogging composition provided in the embodiments of the present application has no pollution to the environment because the organic solvent and surfactant dispersant used in the declogging composition are both environmentally friendly.

[0131] (5) An embodiment of the present application provides a biphobic core-shell structured anti-blocking composition, which has low surface tension and interfacial tension. At a concentration of 0.3%, the surface tension can reach 20mN / m to 23mN / m, and the interfacial tension is less than 1mN / m.

[0132] (6) The embodiment of the present application provides a double-repellent core-shell structure plugging-releasing composition, which has a strong water-locking ability. By adding 0.3% of the double-repellent core-shell structure plugging-releasing system to the fluid in the injection well, the permeability of the sandstone formation can be restored to more than 70%.

[0133] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0134] In the present application, in the absence of any contrary description, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the present specification, the terms "including", "comprising", etc. refer to "including but not limited to". In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of the associated objects, indicating that there may be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist at the same time, and B exists alone. Wherein A, B can be singular or plural. In this article, "at least one" refers to one or more, and "plural" refers to two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, "at least one of a, b, or c", or "at least one of a, b and c", can both mean: a, b, c, ab (i.e. a and b), ac, bc or abc, where a, b, c can be single or plural, respectively.

[0135] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A biphobic core-shell structure plugging-removing composition, characterized in that: The declogging composition comprises, by mass fraction, 15% to 20% surfactant dispersant, 10% to 15% oxidant, 5% to 6% cosurfactant, 10% to 15% cosolvent, 18% to 20% organic solvent, 0% to 2% ion regulator, 0.1% to 0.5% surface property regulator, 0.3% to 1% complexing agent, and the rest is water.

2. The plugging-removing composition according to claim 1, characterized in that: The surfactant dispersant includes a nonionic surfactant and an anionic surfactant. The nonionic surfactant includes alkylphenol polyoxyethylene ether and / or fatty alcohol polyoxyethylene ether. The anionic surfactant includes at least one of fatty alcohol polyoxyethylene ether sulfate, phosphate, sulfonate and carboxylate.

3. The plugging-removing composition according to claim 2, characterized in that: The surfactant dispersant includes at least one of nonylphenol polyoxyethylene ether-10, fatty alcohol polyoxyethylene ether, sodium α-olefin sulfonate and nonylphenol polyoxyethylene ether phosphate.

4. The plugging-removing composition according to claim 1, characterized in that: The oxidant comprises at least one of oxalic acid, aminosulfonic acid, formic acid, acetic acid, citric acid and phosphorus pentoxide; and / or, The co-surfactant is a betaine zwitterionic surfactant; and / or, The co-solvent comprises at least one of ethylene glycol butyl ether, diethylene glycol propyl ether and ethylene glycol dibutyl ether; and / or, The organic solvent comprises at least one of solvent oil, rosin alcohol and unsaturated aromatic hydrocarbons; and / or, The ion regulator is a monovalent metal salt; and / or, The surface property regulator is a non-ionic fluorine-containing surfactant; and / or, The complexing agent includes EDTA and / or ascorbic acid.

5. A method for preparing the blocking-removing composition according to any one of claims 1 to 4, characterized in that: The method comprises: Mixing the surfactant dispersant, the water and the co-solvent to obtain a first mixed solution; Preheating the first mixed solution, adding the oxidant, and stirring to dissolve, to obtain a second mixed solution; The second mixed solution is kept warm to complete the oxidation reaction, thereby obtaining a third mixed solution; The third mixed solution is kept warm, and the organic solvent, the ion regulator and the complexing agent are added, followed by stirring to obtain a fourth mixed solution; The fourth mixed liquid is kept warm, and the surface property regulator is added, followed by stirring to obtain a plugging-removing composition.

6. The method according to claim 5, characterized in that The end point temperature of the preheating is 60°C to 65°C.

7. The method according to claim 5, characterized in that The oxidation reaction time is 2h to 4h.

8. The method according to claim 5, characterized in that The volume ratio of the surfactant dispersant, water and co-solvent in the first mixed liquid is 1:5-15:1-5.

9. The method according to claim 5, characterized in that The mass ratio of the oxidant, the oxidant and the water in the second mixed solution is 8-12:2-5:40-50.

10. The method according to claim 5, characterized in that The mass ratio of the organic solvent, the ion regulator, water and the complexing agent in the fourth mixed liquid is 1:0.1-1:1-5:0.1-1.

11. The method according to claim 5, characterized in that The mass ratio of water to the surface property regulator in the plugging-removing composition is 0.5 to 1:0.

05.

12. An application of a biphobic core-shell structure plugging-removing composition, characterized in that: The plugging-removing composition as claimed in any one of claims 1 to 4 is used in the preparation of a plugging-removing agent aqueous solution for a blockage in a heavy oil reservoir.

13. The use according to claim 12, characterized in that: The mass concentration of the blocking-removing composition in the blocking-removing agent aqueous solution satisfies: When the viscosity of crude oil in the heavy oil reservoir is less than 5000 mPa.s, the mass concentration of the plugging-removing composition is 0.1%; When 5000Pa.s≤the viscosity of crude oil in the heavy oil reservoir≤10000mPa.s, the mass concentration of the plugging-removing composition is 0.2%; When the viscosity of crude oil in the heavy oil reservoir is greater than 10000 mPa.s, the mass concentration of the plugging-removing composition is 0.0.3% to 0.5%.

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