Pore wall surface responsive coating oil-water selective profile control and plugging agent as well as use method and application thereof

Abstract

The invention relates to a pore wall surface responsive coating oil-water selective plugging agent and a use method and application thereof, and relates to the technical field of oilfield chemical reagents, the pore wall surface responsive coating oil-water selective plugging agent comprises a wall surface anchoring agent and an oil-water response brush agent according to a weight ratio of (0.05-0.2): (0.4-2.0). The oil-water selective plugging agent with the pore wall surface responsiveness coating can form the oil-water responsiveness coating on the pore wall surface of rock, the coating expands when a water phase flows through, the effective seepage diameter of pores is reduced, additional seepage resistance is caused to prevent the water phase from passing through, the coating shrinks when an oil phase flows through, and thus the oil-water selective plugging agent with the pore wall surface responsiveness coating is formed. The effective seepage diameter of the pores is enlarged, and the oil phase seepage resistance is reduced, so that the water-proof and oil-permeable selective plugging effect is realized, and the application prospect is wide.

Description

Technical Field

[0001] The present invention relates to the technical field of oilfield chemical reagents, and in particular to a pore wall responsive coating oil-water selective plugging agent and a use method and application thereof. Background Art

[0002] In the middle and late stages of oilfield development, oil reservoirs generally enter a high water-cut stage. The heterogeneity of the formation leads to ineffective water circulation, which has become a key issue restricting further improvements in recovery rates. Flooding operations, as an effective way to address water channeling problems, are widely used in oilfield production. During the process of profile adjustment and water blocking, the plugging agent is required to enter the high permeability layer as much as possible to effectively block the water-producing layer, while for the medium and low permeability layers rich in residual oil, no damage or minimal damage is required. Commonly used pore wall responsive coating oil-water selective plugging agents are mainly polymer gels, polymer microspheres, and pre-crosslinked expanded particles. However, conventional pore wall responsive coating oil-water selective plugging agents generally have the problem of poor oil-water selectivity. While blocking high permeability water channeling channels, they often invade oil-bearing pore throats, resulting in a sharp drop in oil phase permeability. In severe cases, they even completely block the oil-producing layer, resulting in the negative effect of controlling water without increasing oil. Summary of the Invention

[0003] To solve the above problems, the present invention provides a pore wall responsive coating oil-water selective plugging agent and a use method and application thereof.

[0004] In a first aspect, the present invention provides a pore wall responsive coating oil-water selective plugging agent, the pore wall responsive coating oil-water selective plugging agent comprising a wall anchoring agent and an oil-water responsive brushing agent in a weight ratio of (0.05-0.2): (0.4-2.0); The preparation of the wall anchoring agent includes the following steps: The intermediate CD-N is obtained by reacting ethylenediamine with citric acid in the first reaction; Alternatingly reacting the intermediate CD-N with methyl methacrylate and ethylenediamine in sequence, repeating the alternating reaction at least twice to obtain the wall anchoring agent; The oil-water responsive brush agent is obtained by a second reaction of a polyether compound and acryloyl chloride; wherein the chemical structure characteristics of the polyether compound are as follows: ; The value of m is 54~90, and the value of n is 10~40.

[0005] Furthermore, the weight ratio of the wall anchoring agent to the oil-water responsive brushing agent is (0.08-0.15): (1.0-1.5).

[0006] Furthermore, the step of reacting ethylenediamine with citric acid to obtain the intermediate CD-N comprises the following process: The ethylenediamine and the citric acid are mixed in a weight ratio of (1-2):1, and then the first reaction is carried out at a temperature of 175-185° C. for 5.5-6.5 hours to obtain the intermediate CD-N.

[0007] Furthermore, the intermediate CD-N is subjected to an alternating reaction with methyl methacrylate and ethylenediamine in sequence, and the alternating reaction is repeated at least twice to obtain the wall anchoring agent, which comprises the following process: The intermediate CD-N and the methyl methacrylate are added to an alcohol solvent in a weight ratio of 1:(3-4) and mixed, and then a third reaction is carried out at room temperature for 22-26 hours to obtain the intermediate CD-MN-0.5; The intermediate CD-MN-0.5 and the ethylenediamine are added to an alcohol solvent in a weight ratio of 1:(2-3) and mixed, and then a fourth reaction is carried out at room temperature for 22-26 hours to obtain the intermediate CD-MN-1.0; The intermediate CD-MN-1.0 and the methyl methacrylate are added to an alcohol solvent in a weight ratio of 1:(3-4) and mixed, and then a fifth reaction is carried out at room temperature for 22-26 hours to obtain the intermediate CD-MN-1.5; The intermediate CD-MN-1.5 and the ethylenediamine are added to an alcohol solvent in a weight ratio of 1:(2-3) and mixed, and then a sixth reaction is carried out at room temperature for 22-26 hours to obtain the intermediate CD-MN-2.0; The intermediate CD-MN-2.0 and the methyl methacrylate are added to an alcohol solvent in a weight ratio of 1:(3-4) and mixed, and then a seventh reaction is carried out at room temperature for 22-26 hours to obtain the intermediate CD-MN-2.5; The intermediate CD-MN-2.5 and the ethylenediamine are added to an alcohol solvent in a weight ratio of 1:(2-3) and mixed, and then an eighth reaction is carried out at room temperature for 22-26 hours to obtain the wall anchoring agent.

[0008] Furthermore, the preparation of the oil-water responsive brush agent includes the following process: dissolving a polyether compound and a basic catalyst in an organic solvent to obtain a mixture; Under ice-water bath conditions, adding a 2.5-4.0% mass concentration of acryloyl chloride solution to the mixture, after the addition is complete, and then performing the second reaction at room temperature for 22-26 hours to obtain the oil-water responsive brush agent; Wherein, the molar ratio of the polyether compound, the alkaline catalyst and the acryloyl chloride is 1:(2.2-3):(1-1.05).

[0009] Furthermore, the polyether compound is an amphiphilic block copolymer, the hydrophilic block in the amphiphilic block copolymer is a polyoxyethylene ether structure, and the hydrophobic block in the amphiphilic block copolymer is a polyoxypropylene ether structure; and the alkaline catalyst includes triethylamine.

[0010] Furthermore, the value of m is 60, and the value of n is 40.

[0011] In a second aspect, based on the same inventive concept, the present invention provides a method for using the pore wall responsive coating oil-water selective plugging agent according to any one of the first aspects, the method comprising the following steps: dissolving the wall anchoring agent in a solvent to obtain a wall anchoring agent dispersion; dissolving the oil-water responsive brush agent in a solvent to obtain an oil-water responsive brush agent dispersion; The wall anchoring agent dispersion is injected into the oil reservoir, and then pure water is continuously injected into the oil reservoir, and finally the oil-water responsive brush agent dispersion is continuously injected into the oil reservoir.

[0012] Furthermore, the solvent includes at least one of water and sodium chloride aqueous solution, the mass percentage of the wall anchor agent in the wall anchor agent dispersion is 0.05~0.2%, the mass percentage of the oil-water responsive brush agent in the oil-water responsive brush agent dispersion is 0.4~2.0%, and the weight ratio of the wall anchor agent dispersion, the oil-water responsive brush agent dispersion and the pure water is 1:1:(2.5~3.5).

[0013] In a third aspect, based on the same inventive concept, the present invention provides an application of the pore wall responsive coating oil-water selective plugging agent described in any one of the first aspects in oil field exploitation.

[0014] The above technical solution provided by the embodiment of the present invention has at least the following advantages compared with the prior art: The embodiments of the present invention provide a pore wall responsive coating oil-water selective plugging agent and its use method and application. The pore wall responsive coating oil-water selective plugging agent provided by the present invention can form an oil-water responsive coating on the rock pore wall. When the water phase flows through, the coating expands, reducing the effective seepage diameter of the pore and causing additional seepage resistance to hinder the passage of the water phase. When the oil phase flows through, the coating shrinks, expanding the effective seepage diameter of the pore and reducing the oil phase seepage resistance, thereby achieving a "water-proof and oil-permeable" selective plugging effect, and has broad application prospects. Specifically: 1) The wall anchoring agent in the pore wall responsive coating oil-water selective plugging agent provided by the present invention has an extremely small particle size (<10nm) and a surface hyperbranched structure, and there are a large number of amino groups on the surface. After being injected into the formation, the surface energy generated by its small particle size and the surface amino groups are gradually adsorbed and retained on the surface of the formation rock. When the oil-water responsive brush agent is injected into the formation in a subsequent plug, it will contact the wall anchoring agent adsorbed on the rock surface in the formation. The oil-water responsive brush agent will be grafted to the surface of the wall anchoring agent adsorbed on the rock through the Michael addition reaction. As the oil-water responsive brush agent continues to enrich on the surface of the wall anchoring agent, hydrophobic physical cross-linking points will gradually form between the brushing agents and gelation will occur, and then the wall anchoring agent will be used to form a physical hydrogel layer cross-linked by hydrophobic action on the rock wall, i.e., an oil-water responsive coating. When the subsequent liquid flow is water phase, the oil-water responsive coating can absorb water and swell and maintain a three-dimensional network structure, shrinking or blocking the pores to hinder the passage of the water phase; when the subsequent liquid flow is oil phase, the hydrophobic physical cross-linking points in the oil-water responsive coating will be destroyed and the hydrophilic blocks of the oil-water responsive brush agent will shrink. The three-dimensional network structure of the oil-water responsive coating will be destroyed and the volume will shrink. The effective seepage diameter of the pores will expand and the seepage resistance of the oil phase will be reduced, thereby achieving selective blocking of oil and water.

[0015] 2) The components of the pore wall responsive coating oil-water selective plugging agent provided by the present invention have small particle size / molecular size, good reservoir injectivity, and a wide range of applicable reservoir physical properties.

[0016] 3) The pore wall responsive coating oil-water selective plugging agent provided by the present invention has sensitive oil-water identification performance and stronger oil-water selective plugging ability than conventional pore wall responsive coating oil-water selective plugging agents.

[0017] 4) The pore wall responsive coating oil-water selective plugging agent provided by the present invention has good erosion resistance and a long effective period after construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0020] Figure 1 This is a flow chart for preparing the wall anchoring agent in the pore wall responsive coating oil-water selective plugging agent provided in an embodiment of the present invention.

[0021] Figure 2 This is a microscopic morphology of the wall anchoring agent in the pore wall responsive coating oil-water selective plugging agent provided in an embodiment of the present invention.

[0022] Figure 3 This is an infrared characterization image of the wall anchoring agent in the pore wall responsive coating oil-water selective plugging agent provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts are within the scope of protection of the present invention.

[0024] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0025] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are intended to illustrate the present invention only and are not intended to limit the scope of the invention. The experimental methods in the following examples where specific conditions are not specified are generally measured in accordance with national standards. If there are no corresponding national standards, then the methods are carried out in accordance with general international standards, conventional conditions, or the conditions recommended by the manufacturer.

[0026] The main information of the polyether compounds involved in the following examples and comparative examples is as follows: PPO 60 -PEO 40 -PPO 60 The chemical structure characteristics are as follows: m is 60, n is 40 purchased from BASF, product model is Pluronic ® L-44, CAS number 9003-11-6, molecular weight 2200Da.

[0027] PPO 54 -PEO 10 -PPO 54 The chemical structure characteristics are as follows: m is 54, n is 10, purchased from BASF, product model is Pluronic ® L-61, CAS number 9003-11-6, molecular weight 2000Da.

[0028] PPO90 -PEO 10 -PPO 90 The chemical structure characteristics are as follows: m is 90, n is 10, purchased from BASF, product model is Pluronic ® L-121, CAS number 9003-11-6, molecular weight 4400Da.

[0029] PPO 54 -PEO 24 -PPO 54 The chemical structure characteristics are as follows: ; m is 54, n is 24, purchased from BASF, product model is Pluronic ® 10R5, CAS number is 9003-11-6, and molecular weight is 4000Da.

[0030] PPO 20 -PEO 80 -PPO 20 The chemical structure characteristics are as follows: m is 20, n is 80, purchased from BASF, product model is Pluronic ® F-108, CAS number 9003-11-6, molecular weight 14600Da.

[0031] Example 1 This example provides a pore wall responsive coating oil-water selective plugging agent, which comprises a wall anchoring agent and an oil-water responsive brushing agent in a weight ratio of 0.1:1.2; The preparation process of the wall anchor is as follows Figure 1 As shown, the following process is included: (1) 6 g of ethylenediamine and 4 g of citric acid were added to a 250 mL three-necked flask and mixed. The mixture was then heated to 180 °C for 6 h under stirring at 200 r / min. The mixture was then cooled to room temperature. The reaction product was dissolved in 150 mL of excess anhydrous ethanol and centrifuged at 12,000 rpm for 10 min. The upper layer of the centrifuged liquid was distilled under reduced pressure to remove ethanol to obtain a crude product. The crude product was dissolved in 50 mL of deionized water and dialyzed with a 1 kDa dialysis membrane for 24 h. The intermediate CD-N was then freeze-dried. (2) Disperse 5 g of intermediate CD-N in 50 mL of methanol, then add 17.5 g of methyl methacrylate, react at room temperature for 24 h under stirring conditions of 200 r / min, centrifuge for 10 minutes, filter and dry to obtain intermediate CD-MN-0.5; (3) Disperse 10 g of the intermediate CD-MN-0.5 in 50 mL of methanol, then add 25 g of ethylenediamine, react at room temperature for 24 h under stirring conditions of 200 rpm, centrifuge for 10 minutes, filter and dry to obtain the intermediate CD-MN-1.0; (4) Repeat steps (2) and (3) twice to obtain the wall anchor product CD-MN-3.0 (i.e., wall anchor); The preparation of the oil-water responsive brush agent comprises the following process: (1) 5g of polyether (BAB type amphiphilic block copolymer, PPO 60 -PEO 40 -PPO 60 ) was dissolved in 55 g of dichloromethane and 0.575 g of triethylamine was added, and then 6.56 g of dichloromethane solution containing acryloyl chloride (the mass concentration of acryloyl chloride was 3.2%) was slowly added dropwise in an ice-water bath. After the addition was completed, the temperature of the reaction system was raised to room temperature, and the reaction was continued for 24 hours; (2) The mixture after the reaction in step (1) was filtered to remove triethylamine hydrochloride, the obtained filtrate was precipitated in 400 mL of ether, and the precipitated white solid was vacuum dried at 30° C. for 48 h to obtain an oil-water responsive brush agent.

[0032] The above-mentioned pore wall responsive coating oil-water selective plugging agent, when used, includes the following process: Dissolving the wall anchoring agent in water to obtain a wall anchoring agent dispersion with a mass percentage of 0.1%; The oil-water responsive brush agent is dissolved in water to obtain a 1.5% by mass oil-water responsive brush agent dispersion; The wall anchoring agent dispersion is injected into the oil reservoir, and then pure water is continuously injected into the oil reservoir (i.e., a water injection slug is used as an isolation slug in the middle), and finally the oil-water responsive brush agent dispersion is continuously injected into the oil reservoir; wherein the weight ratio of the wall anchoring agent dispersion, the oil-water responsive brush agent dispersion and the pure water is 1:1:3.

[0033] Example 2 This example provides a pore wall responsive coating oil-water selective plugging agent, which comprises a wall anchoring agent and an oil-water responsive brushing agent in a weight ratio of 0.1:1.2; The preparation of the wall anchoring agent includes the following steps: (1) 6 g of ethylenediamine and 3 g of citric acid were added to a 250 mL three-necked flask and mixed. The mixture was then heated to 180 °C for 6 h under stirring at 200 r / min. The mixture was then cooled to room temperature. The reaction product was dissolved in 150 mL of excess anhydrous ethanol and centrifuged at 12,000 rpm for 10 min. The upper layer of the centrifuged liquid was distilled under reduced pressure to remove ethanol to obtain a crude product. The crude product was dissolved in 50 mL of deionized water and dialyzed using a 1 kDa dialysis membrane for 24 h. The intermediate CD-N was then freeze-dried. (2) Disperse 5 g of intermediate CD-N in 50 mL of methanol, then add 20 g of methyl methacrylate, react at room temperature for 24 h under stirring conditions of 200 r / min, centrifuge for 10 minutes, filter and dry to obtain intermediate CD-MN-0.5; (3) Disperse 10 g of the intermediate CD-MN-0.5 in 50 mL of methanol, then add 30 g of ethylenediamine, and react at room temperature for 24 h under stirring conditions of 200 rpm. Centrifuge for 10 minutes, filter, and dry to obtain the intermediate CD-MN-1.0. (4) Repeat steps (2) and (3) twice to obtain the wall anchor product CD-MN-3.0 (i.e., wall anchor); The preparation of the oil-water responsive brush agent comprises the following process: (1) 5g of polyether (BAB type amphiphilic block copolymer, PPO 60 -PEO 40 -PPO 60 ) was dissolved in 55 g of dichloromethane and 0.575 g of triethylamine was added, and then 6.56 g of dichloromethane solution containing acryloyl chloride (the mass concentration of acryloyl chloride was 3.2%) was slowly added dropwise in an ice-water bath. After the addition was completed, the temperature of the reaction system was raised to room temperature, and the reaction was continued for 24 hours; (2) The mixture after the reaction in step (1) was filtered to remove triethylamine hydrochloride, the obtained filtrate was precipitated in 400 mL of ether, and the precipitated white solid was vacuum dried at 30° C. for 48 h to obtain an oil-water responsive brush agent.

[0034] The above-mentioned pore wall responsive coating oil-water selective plugging agent, when used, includes the following process: Dissolving the wall anchoring agent in water to obtain a wall anchoring agent dispersion with a mass percentage of 0.1%; The oil-water responsive brush agent is dissolved in water to obtain a 1.5% by mass oil-water responsive brush agent dispersion; The wall anchoring agent dispersion is injected into the oil reservoir, and then pure water is continuously injected into the oil reservoir (i.e., a water injection slug is used as an isolation slug in the middle), and finally the oil-water responsive brush agent dispersion is continuously injected into the oil reservoir; wherein the weight ratio of the wall anchoring agent dispersion, the oil-water responsive brush agent dispersion and the pure water is 1:1:3.

[0035] Example 3 This example provides a pore wall responsive coating oil-water selective plugging agent, which comprises a wall anchoring agent and an oil-water responsive brushing agent in a weight ratio of 0.1:1.2; The preparation of the wall anchoring agent includes the following steps: (1) 6 g of ethylenediamine and 4 g of citric acid were added to a 250 mL three-necked flask and mixed. The mixture was then heated to 180 °C for 6 h under stirring at 200 r / min. The mixture was then cooled to room temperature. The reaction product was dissolved in 150 mL of excess anhydrous ethanol and centrifuged at 12,000 rpm for 10 min. The upper layer of the centrifuged liquid was distilled under reduced pressure to remove ethanol to obtain a crude product. The crude product was dissolved in 50 mL of deionized water and dialyzed with a 1 kDa dialysis membrane for 24 h. The intermediate CD-N was then freeze-dried. (2) Disperse 5 g of intermediate CD-N in 50 mL of methanol, then add 17.5 g of methyl methacrylate, react at room temperature for 24 h under stirring conditions of 200 r / min, centrifuge for 10 minutes, filter and dry to obtain intermediate CD-MN-0.5; (3) Disperse 10 g of the intermediate CD-MN-0.5 in 50 mL of methanol, then add 25 g of ethylenediamine, react at room temperature for 24 h under stirring conditions of 200 rpm, centrifuge for 10 minutes, filter and dry to obtain the intermediate CD-MN-1.0; (4) Repeat steps (2) and (3) twice to obtain the wall anchor product CD-MN-3.0 (i.e., wall anchor); The preparation of the oil-water responsive brush agent comprises the following process: (1) 5g of polyether (BAB type amphiphilic block copolymer, PPO 90 -PEO 10 -PPO 90 ) was dissolved in 55 g of dichloromethane and 0.288 g of triethylamine was added, and then 3.28 g of a dichloromethane solution containing acryloyl chloride (the mass concentration of acryloyl chloride was 3.2%) was slowly added dropwise in an ice-water bath. After the addition was completed, the temperature of the reaction system was raised to room temperature, and the reaction was continued for 24 hours; (2) The mixture after the reaction in step (1) was filtered to remove triethylamine hydrochloride, the obtained filtrate was precipitated in 400 mL of ether, and the precipitated white solid was vacuum dried at 30° C. for 48 h to obtain an oil-water responsive brush agent.

[0036] The above-mentioned pore wall responsive coating oil-water selective plugging agent, when used, includes the following process: Dissolving the wall anchoring agent in water to obtain a wall anchoring agent dispersion with a mass percentage of 0.1%; The oil-water responsive brush agent is dissolved in water to obtain a 1.5% by mass oil-water responsive brush agent dispersion; The wall anchoring agent dispersion is injected into the oil reservoir, and then pure water is continuously injected into the oil reservoir (i.e., a water injection slug is used as an isolation slug in the middle), and finally the oil-water responsive brush agent dispersion is continuously injected into the oil reservoir; wherein the weight ratio of the wall anchoring agent dispersion, the oil-water responsive brush agent dispersion and the pure water is 1:1:3.

[0037] Example 4 This example provides a pore wall responsive coating oil-water selective plugging agent, which comprises a wall anchoring agent and an oil-water responsive brushing agent in a weight ratio of 0.1:1.2; The preparation of the wall anchoring agent includes the following steps: (1) 6 g of ethylenediamine and 4 g of citric acid were added to a 250 mL three-necked flask and mixed. The mixture was then heated to 180 °C for 6 h under stirring at 200 r / min. The mixture was then cooled to room temperature. The reaction product was dissolved in 150 mL of excess anhydrous ethanol and centrifuged at 12,000 rpm for 10 min. The upper layer of the centrifuged liquid was distilled under reduced pressure to remove ethanol to obtain a crude product. The crude product was dissolved in 50 mL of deionized water and dialyzed with a 1 kDa dialysis membrane for 24 h. The intermediate CD-N was then freeze-dried. (2) Disperse 5 g of intermediate CD-N in 50 mL of methanol, then add 17.5 g of methyl methacrylate, react at room temperature for 24 h under stirring conditions of 200 r / min, centrifuge for 10 minutes, filter and dry to obtain intermediate CD-MN-0.5; (3) Disperse 10 g of the intermediate CD-MN-0.5 in 50 mL of methanol, then add 25 g of ethylenediamine, react at room temperature for 24 h under stirring conditions of 200 rpm, centrifuge for 10 minutes, filter and dry to obtain the intermediate CD-MN-1.0; (4) Repeat steps (2) and (3) twice to obtain the wall anchor product CD-MN-3.0 (i.e., wall anchor); The preparation of the oil-water responsive brush agent comprises the following process: (1) 5g of polyether (BAB type amphiphilic block copolymer, PPO 60 -PEO 40 -PPO 60 ) was dissolved in 55 g of dichloromethane and 0.575 g of triethylamine was added, and then 6.45 g of a dichloromethane solution containing acryloyl chloride (the mass concentration of acryloyl chloride was 3.1%) was slowly added dropwise in an ice-water bath. After the addition was completed, the temperature of the reaction system was raised to room temperature, and the reaction was continued for 24 hours; (2) The mixture after the reaction in step (1) was filtered to remove triethylamine hydrochloride, the obtained filtrate was precipitated in 400 mL of ether, and the precipitated white solid was vacuum dried at 30° C. for 48 h to obtain an oil-water responsive brush agent.

[0038] The above-mentioned pore wall responsive coating oil-water selective plugging agent, when used, includes the following process: Dissolving the wall anchoring agent in water to obtain a wall anchoring agent dispersion with a mass percentage of 0.1%; The oil-water responsive brush agent is dissolved in water to obtain a 1.5% by mass oil-water responsive brush agent dispersion; The wall anchoring agent dispersion is injected into the oil reservoir, and then pure water is continuously injected into the oil reservoir (i.e., a water injection slug is used as an isolation slug in the middle), and finally the oil-water responsive brush agent dispersion is continuously injected into the oil reservoir; wherein the weight ratio of the wall anchoring agent dispersion, the oil-water responsive brush agent dispersion and the pure water is 1:1:3.

[0039] Example 5 This example provides a pore wall responsive coating oil-water selective plugging agent, which comprises a wall anchoring agent and an oil-water responsive brushing agent in a weight ratio of 0.05:2; The preparation of the wall anchoring agent includes the following steps: (1) 6 g of ethylenediamine and 4 g of citric acid were added to a 250 mL three-necked flask and mixed. The mixture was then heated to 180 °C for 6 h under stirring at 200 r / min. The mixture was then cooled to room temperature. The reaction product was dissolved in 150 mL of excess anhydrous ethanol and centrifuged at 12,000 rpm for 10 min. The upper layer of the centrifuged liquid was distilled under reduced pressure to remove ethanol to obtain a crude product. The crude product was dissolved in 50 mL of deionized water and dialyzed with a 1 kDa dialysis membrane for 24 h. The intermediate CD-N was then freeze-dried. (2) Disperse 5 g of intermediate CD-N in 50 mL of methanol, then add 17.5 g of methyl methacrylate, react at room temperature for 24 h under stirring conditions of 200 r / min, centrifuge for 10 minutes, filter and dry to obtain intermediate CD-MN-0.5; (3) Disperse 10 g of the intermediate CD-MN-0.5 in 50 mL of methanol, then add 25 g of ethylenediamine, react at room temperature for 24 h under stirring conditions of 200 rpm, centrifuge for 10 minutes, filter and dry to obtain the intermediate CD-MN-1.0; (4) Repeat steps (2) and (3) twice to obtain the wall anchor product CD-MN-3.0 (i.e., wall anchor); The preparation of the oil-water responsive brush agent comprises the following process: (1) 5g of polyether (BAB type amphiphilic block copolymer, PPO 60 -PEO 40 -PPO 60 ) was dissolved in 55 g of dichloromethane and 0.575 g of triethylamine was added, and then 6.56 g of dichloromethane solution containing acryloyl chloride (the mass concentration of acryloyl chloride was 3.2%) was slowly added dropwise in an ice-water bath. After the addition was completed, the temperature of the reaction system was raised to room temperature, and the reaction was continued for 24 hours; (2) The mixture after the reaction in step (1) was filtered to remove triethylamine hydrochloride, the obtained filtrate was precipitated in 400 mL of ether, and the precipitated white solid was vacuum dried at 30° C. for 48 h to obtain an oil-water responsive brush agent.

[0040] The above-mentioned pore wall responsive coating oil-water selective plugging agent, when used, includes the following process: dissolving the wall anchoring agent in water to obtain a wall anchoring agent dispersion having a mass percentage of 0.05%; The oil-water responsive brush agent is dissolved in water to obtain a 2% by mass oil-water responsive brush agent dispersion; The wall anchoring agent dispersion is injected into the oil reservoir, and then pure water is continuously injected into the oil reservoir (i.e., a water injection slug is used as an isolation slug in the middle), and finally the oil-water responsive brush agent dispersion is continuously injected into the oil reservoir; wherein the weight ratio of the wall anchoring agent dispersion, the oil-water responsive brush agent dispersion and the pure water is 1:1:3.

[0041] Example 6 This example provides a pore wall responsive coating oil-water selective plugging agent, which comprises a wall anchoring agent and an oil-water responsive brushing agent in a weight ratio of 0.2:1.5; The preparation of the wall anchoring agent includes the following steps: (1) 6 g of ethylenediamine and 6 g of citric acid were added to a 250 mL three-necked flask and mixed. The mixture was then heated to 175 °C with stirring at 200 r / min for 6.5 h. The mixture was then cooled to room temperature. The reaction product was dissolved in 150 mL of excess anhydrous ethanol and centrifuged at 12,000 rpm for 10 min. The upper layer of the centrifuged liquid was distilled under reduced pressure to remove ethanol to obtain a crude product. The crude product was dissolved in 50 mL of deionized water and dialyzed with a 1 kDa dialysis membrane for 24 h. The intermediate CD-N was then freeze-dried. (2) Disperse 5 g of intermediate CD-N in 50 mL of methanol, then add 15 g of methyl methacrylate, react at room temperature for 22 h under stirring conditions of 200 r / min, centrifuge for 10 minutes, filter and dry to obtain intermediate CD-MN-0.5; (3) Disperse 10 g of the intermediate CD-MN-0.5 in 50 mL of methanol, then add 20 g of ethylenediamine, and react at room temperature for 22 h at a stirring rate of 200 rpm. Centrifuge for 10 minutes, filter, and dry to obtain the intermediate CD-MN-1.0. (4) Repeat steps (2) and (3) twice to obtain the wall anchor product CD-MN-3.0 (i.e., wall anchor); The preparation of the oil-water responsive brush agent comprises the following process: (1) 5g of polyether (BAB type amphiphilic block copolymer, PPO 54 -PEO 10 -PPO 54 ) was dissolved in 55 g of dichloromethane and 0.557 g of triethylamine was added, and then 5.94 g of a dichloromethane solution containing acryloyl chloride (the mass concentration of acryloyl chloride was 4.0%) was slowly added dropwise in an ice-water bath. After the addition was completed, the temperature of the reaction system was raised to room temperature, and the reaction was continued for 22 hours; (2) The mixture after the reaction in step (1) was filtered to remove triethylamine hydrochloride, the obtained filtrate was precipitated in 400 mL of ether, and the precipitated white solid was vacuum dried at 30° C. for 48 h to obtain an oil-water responsive brush agent.

[0042] The above-mentioned pore wall responsive coating oil-water selective plugging agent, when used, includes the following process: Dissolving the wall anchoring agent in water to obtain a wall anchoring agent dispersion with a mass percentage of 0.2%; The oil-water responsive brush agent is dissolved in water to obtain a 1.5% by mass oil-water responsive brush agent dispersion; The wall anchoring agent dispersion is injected into the oil reservoir, and then pure water is continuously injected into the oil reservoir (i.e., a water injection slug is used as an isolation slug in the middle), and finally the oil-water responsive brush agent dispersion is continuously injected into the oil reservoir; wherein the weight ratio of the wall anchoring agent dispersion, the oil-water responsive brush agent dispersion and the pure water is 1:1:2.5.

[0043] Example 7 This example provides a pore wall responsive coating oil-water selective plugging agent, which comprises a wall anchoring agent and an oil-water responsive brushing agent in a weight ratio of 0.08:0.4; The preparation of the wall anchoring agent includes the following steps: (1) 6 g of ethylenediamine and 3 g of citric acid were added to a 250 mL three-necked flask and mixed. The mixture was then heated to 185 °C with stirring at 200 r / min for 5.5 h. The mixture was then cooled to room temperature. The reaction product was dissolved in 150 mL of excess anhydrous ethanol and centrifuged at 12,000 rpm for 10 min. The upper layer of the centrifuged liquid was distilled under reduced pressure to remove ethanol to obtain a crude product. The crude product was dissolved in 50 mL of deionized water and dialyzed with a 1 kDa dialysis membrane for 24 h. The intermediate CD-N was then freeze-dried. (2) Disperse 5 g of intermediate CD-N in 50 mL of methanol, then add 20 g of methyl methacrylate, react at room temperature for 26 h under stirring conditions of 200 r / min, centrifuge for 10 minutes, filter and dry to obtain intermediate CD-MN-0.5; (3) Disperse 10 g of the intermediate CD-MN-0.5 in 50 mL of methanol, then add 30 g of ethylenediamine, react at room temperature for 26 h under stirring conditions of 200 rpm, centrifuge for 10 minutes, filter and dry to obtain the intermediate CD-MN-1.0; (4) Repeat steps (2) and (3) twice to obtain the wall anchor product CD-MN-3.0 (i.e., wall anchor); The preparation of the oil-water responsive brush agent comprises the following process: (1) 5g of polyether (BAB type amphiphilic block copolymer, PPO 54 -PEO 24 -PPO 54 ) was dissolved in 55 g of dichloromethane and 0.379 g of triethylamine was added, and then 4.52 g of a dichloromethane solution containing acryloyl chloride (the mass concentration of acryloyl chloride was 2.5%) was slowly added dropwise in an ice-water bath. After the addition was completed, the temperature of the reaction system was raised to room temperature, and the reaction was continued for 26 hours; (2) The mixture after the reaction in step (1) was filtered to remove triethylamine hydrochloride, the obtained filtrate was precipitated in 400 mL of ether, and the precipitated white solid was vacuum dried at 30° C. for 48 h to obtain an oil-water responsive brush agent.

[0044] The above-mentioned pore wall responsive coating oil-water selective plugging agent, when used, includes the following process: Dissolving the wall anchoring agent in water to obtain a wall anchoring agent dispersion with a mass percentage of 0.08%; The oil-water responsive brush agent is dissolved in water to obtain a 0.4% by mass oil-water responsive brush agent dispersion; The wall anchoring agent dispersion is injected into the oil reservoir, and then pure water is continuously injected into the oil reservoir (i.e., a water injection slug is used as an isolation slug in the middle), and finally the oil-water responsive brush agent dispersion is continuously injected into the oil reservoir; wherein the weight ratio of the wall anchoring agent dispersion, the oil-water responsive brush agent dispersion and the pure water is 1:1:3.5.

[0045] Comparative Example 1 This example provides a plugging agent, which differs from Example 1 only in that: (1) No wall anchoring agent was added (i.e., the plugging agent consisted only of the oil-water responsive brush agent in Example 1).

[0046] When the above-mentioned plugging agent is used, the following process is included: The oil-water responsive brush agent was dissolved in water to obtain a 1.2% by mass oil-water responsive brush agent dispersion.

[0047] Comparative Example 2 This example provides a plugging agent, which differs from Example 1 only in that: (1) The oil-water responsive brush agent is an unmodified polyether (ie, the oil-water responsive brush agent is the PPO in Example 1). 60 -PEO 40 -PPO 60 ).

[0048] The above-mentioned plugging agent is used in the same manner as in Example 1.

[0049] Comparative Example 3 This example provides a plugging agent, which differs from Example 1 only in that: (1) Preparation of PPO in oil-water responsive brush agent 60 -PEO 40 -PPO 60 Replaced by PPO 20 -PEO 80 -PPO 20 .

[0050] The above-mentioned plugging agent is used in the same manner as in Example 1.

[0051] Comparative Example 4 This example provides a plugging agent, which differs from Example 1 only in that: (1) The intermediate CD-MN-1.0 in Example 1 was used as a wall anchor.

[0052] The above-mentioned plugging agent is used in the same manner as in Example 1.

[0053] Test Example 1 In this example, the wall anchoring agent obtained in Example 1 above was characterized, and the test results are as follows: (1) Microscopic morphology of wall anchoring agent: The microstructure of the samples was observed using a Talos F200X G2 transmission electron microscope. The test results are shown in the figure below. Figure 2 As shown, the wall anchoring agent is in the form of spherical particles and is evenly distributed.

[0054] (2) Fourier transform infrared characterization of wall anchoring agent The samples were tested by ATR infrared spectroscopy using a Tensor II Fourier transform infrared spectrometer (Bruker, Germany) with a wavenumber range of 4000–700 cm -1 .

[0055] The test results are as follows Figure 3 As shown, at a wave number of 3429 cm -1 The broad absorption peak is the stretching vibration absorption peak of the NH bond on the amide group, at 2927 cm -1 and 2852cm -1 The absorption peaks at 1694 cm-1 belong to the stretching vibration of -CH2 and -CH3. -1 The absorption peak at 1406cm is the stretching vibration of the C=O bond. -1 The absorption peak at 1229cm belongs to the stretching vibration absorption peak of the CH bond. -1 The absorption peak at 1076cm is the stretching vibration absorption peak of the CN bond. -1 The absorption peak at is the stretching vibration absorption peak of CO bond.

[0056] Test Example 2 In this example, the plugging agents obtained in Examples 1 to 6 and Comparative Examples 1 to 4 were subjected to a core flooding test for erosion resistance to examine their respective erosion resistance performances.

[0057] The test method is as follows: 1. Using 5 g / L sodium chloride brine as the preparation solvent, the wall anchoring agent or oil-water responsive brushing agent contained in the plugging agents obtained in Examples 1 to 6 and Comparative Examples 1 to 4 were respectively prepared into 0.1 wt% wall anchoring agent dispersion and 0.1 wt% oil-water responsive brushing agent dispersion.

[0058] 2. The anti-scour performance of the plugging agent was evaluated in a sand-filled tube (2.5 cm in diameter, 20 cm in length, and 350 mD in permeability). The basic experimental steps are as follows: (1) Water flooding was performed at a displacement rate of 0.2 mL / min until the pressure stabilized; (2) Inject 0.1 times the pore volume (PV) of wall anchoring agent (the same volume of 5 g / L sodium chloride brine was used instead in Comparative Example 1) into the sand filling pipe at a displacement rate of 0.2 mL / min, and then inject 0.1 times the pore volume (PV) of oil-water response brushing agent; (3) Remove the core tube and place it in a 75°C constant temperature box for 48 hours; (4) Inject 30 times the pore volume (PV) of formation water into the sand filling pipe at a displacement rate of 0.2 mL / min.

[0059] The permeability change during the displacement process was calculated based on the experimental pressure data, and the plugging efficiency was calculated. The plugging efficiency was recalculated when 30 PV was injected to evaluate the erosion resistance of the plugging agent. The experimental results are shown in Table 1.

[0060] Table 1 Test samples Blockage rate (%) 30PV blocking rate (%) Example 1 94% 91% Example 2 92% 86% Example 3 65% 30% Example 4 86% 82% Example 5 64% 23% Example 6 73% 57% Example 7 68% 31% Comparative Example 1 3% 0% Comparative Example 2 12% 5% Comparative Example 3 5% 0% Comparative Example 4 43% 15% It can be seen from Table 1 that compared with Comparative Examples 1 to 4, the plugging agent provided by the embodiment of the present invention has better scour resistance. Specifically: Comparative Example 1 has no anchoring agent, and the brush agent is not fixed and cannot achieve blocking. Comparative Example 2 has unmodified polyether and can only rely on van der Waals adsorption, and will desorb under low shear force. The PEO chain of Comparative Example 3 is overly hydrophilic and quickly dissolves in water, making it impossible to achieve water blocking. Comparative Example 4 is iterated only once, and the branching degree of CD-MN-1.0 is low, and the cross-linking network has defects, resulting in a low degree of entanglement and fragmented coating, making it difficult to achieve effective blocking.

[0061] Test Example 3 In this example, an oil-water selective core flow test was conducted on the plugging agents obtained in Examples 1 to 6 and Comparative Examples 1 to 4 to examine their respective plugging performances.

[0062] The test method is as follows: 1. Using 5 g / L sodium chloride brine as the preparation solvent, the wall anchoring agent or oil-water responsive brushing agent contained in the plugging agents obtained in Examples 1 to 6 and Comparative Examples 1 to 4 were respectively prepared into 0.1 wt% wall anchoring agent dispersion and 0.1 wt% oil-water responsive brushing agent dispersion.

[0063] 2. Use artificial sandstone core with a core size of φ2.5cm×10cm, a porosity of about 26%, and a permeability of about 100mD. The basic experimental steps are as follows: (1) Water flooding was performed at a displacement rate of 0.1 mL / min until the pressure stabilized; (2) Inject 5 times the pore volume (PV) of formation water into the core at a displacement rate of 1 mL / min; (3) Inject kerosene (5 times the pore volume (PV)) into the core at a displacement rate of 1 mL / min; (4) Inject 0.1 times the pore volume (PV) of wall anchoring agent into the core at a displacement rate of 1 mL / min (the same volume of 5 g / L sodium chloride brine was used instead in Comparative Example 1), and then inject 0.1 times the pore volume (PV) of oil-water response brushing agent; (5) Remove the core tube and place it in a 75°C constant temperature box for 7 days; (6) Reverse water drive and then reverse oil drive at a displacement rate of 1 mL / min.

[0064] The permeability change during the displacement process was calculated based on the pressure data of the experiments at each stage, and the water drive plugging rate and oil drive plugging rate were calculated. The experimental results are shown in Table 2.

[0065] Table 2 Test samples Water flooding plugging rate (%) Oil flooding plugging rate (%) Example 1 85% 8% Example 2 90% 12% Example 3 65% 94% Example 4 80% 16% Example 5 55% 19% Example 6 75% 28% Example 7 58% 38% Comparative Example 1 2% 5% Comparative Example 2 15% 20% Comparative Example 3 12% 5% Comparative Example 4 40% 45% It can be seen from Table 2 that compared with comparative examples 1 to 4, the oil-water selectivity of the plugging agent provided by the embodiment of the present invention is more significant, and can effectively achieve the selective plugging effect of "water-proof and oil-permeable". Specifically: Comparative example 1 lacks an anchoring agent, and can neither block water nor oil. Comparative example 2 has an unmodified brush agent, which can only block some small pores and can only form loose micelles in the oil phase, slightly increasing the seepage resistance. The PEO chain of comparative example 3 is overly hydrophilic and quickly dissolves in water, and cannot block water. At the same time, the dissolved brush agent is flushed out by the oil drive and cannot play the role of oil blocking. Comparative example 4 has a small number of iterations, CD-MN-1.0 has a low degree of branching and few cross-linking sites, and the water blocking effect is insufficient. The weakly cross-linked coating is easy to fall off, resulting in oil absorption and blockage in the oil phase.

[0066] Various embodiments of the present invention may be presented in the form of a range; it should be understood that the description in a range format is only for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention; therefore, the range description should be considered to have specifically disclosed all possible subranges and single numerical values ​​within the range. For example, the description of a range from 1 to 6 should be considered to have specifically disclosed subranges 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, regardless of the range. In addition, whenever a numerical range is indicated herein, it is intended to include any cited numeral (fractional or integer) within the indicated range.

[0067] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but is intended to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A pore wall responsive coating oil-water selective plugging agent, characterized in that: The pore wall responsive coating oil-water selective plugging agent comprises a wall anchoring agent and an oil-water responsive brushing agent in a weight ratio of (0.05-0.2): (0.4-2.0); The preparation of the wall anchoring agent includes the following steps: The intermediate CD-N is obtained by reacting ethylenediamine with citric acid in the first reaction; Alternatingly reacting the intermediate CD-N with methyl methacrylate and ethylenediamine in sequence, repeating the alternating reaction at least twice to obtain the wall anchoring agent; The oil-water responsive brush agent is obtained by a second reaction of a polyether compound and acryloyl chloride; wherein the chemical structure characteristics of the polyether compound are as follows: ; The value of m is 54~90, and the value of n is 10~40.

2. The pore wall responsive coating oil-water selective plugging agent according to claim 1, characterized in that: The weight ratio of the wall anchoring agent to the oil-water responsive brushing agent is (0.08-0.15): (1.0-1.5).

3. The pore wall responsive coating oil-water selective plugging agent according to claim 1, characterized in that: The step of first reacting ethylenediamine with citric acid to obtain the intermediate CD-N comprises the following steps: The ethylenediamine and the citric acid are mixed in a weight ratio of (1-2):1, and then the first reaction is carried out at a temperature of 175-185° C. for 5.5-6.5 hours to obtain the intermediate CD-N.

4. The pore wall responsive coating oil-water selective plugging agent according to claim 1, characterized in that: The intermediate CD-N is reacted alternately with methyl methacrylate and ethylenediamine in sequence, and the alternating reaction is repeated at least twice to obtain the wall anchoring agent, which comprises the following process: The intermediate CD-N and the methyl methacrylate are added to an alcohol solvent in a weight ratio of 1:(3-4) and mixed, and then a third reaction is carried out at room temperature for 22-26 hours to obtain the intermediate CD-MN-0.5; The intermediate CD-MN-0.5 and the ethylenediamine are added to an alcohol solvent in a weight ratio of 1:(2-3) and mixed, and then a fourth reaction is carried out at room temperature for 22-26 hours to obtain the intermediate CD-MN-1.0; The intermediate CD-MN-1.0 and the methyl methacrylate are added to an alcohol solvent in a weight ratio of 1:(3-4) and mixed, and then a fifth reaction is carried out at room temperature for 22-26 hours to obtain the intermediate CD-MN-1.5; The intermediate CD-MN-1.5 and the ethylenediamine are added to an alcohol solvent in a weight ratio of 1:(2-3) and mixed, and then a sixth reaction is carried out at room temperature for 22-26 hours to obtain the intermediate CD-MN-2.0; The intermediate CD-MN-2.0 and the methyl methacrylate are added to an alcohol solvent in a weight ratio of 1:(3-4) and mixed, and then a seventh reaction is carried out at room temperature for 22-26 hours to obtain the intermediate CD-MN-2.5; The intermediate CD-MN-2.5 and the ethylenediamine are added to an alcohol solvent in a weight ratio of 1:(2-3) and mixed, and then an eighth reaction is carried out at room temperature for 22-26 hours to obtain the wall anchoring agent.

5. The pore wall responsive coating oil-water selective plugging agent according to claim 1, characterized in that: The preparation of the oil-water responsive brush agent comprises the following process: dissolving a polyether compound and a basic catalyst in an organic solvent to obtain a mixture; Under ice-water bath conditions, adding a 2.5-4.0% mass concentration of acryloyl chloride solution to the mixture, after the addition is complete, and then performing the second reaction at room temperature for 22-26 hours to obtain the oil-water responsive brush agent; Wherein, the molar ratio of the polyether compound, the alkaline catalyst and the acryloyl chloride is 1:(2.2-3):(1-1.05).

6. The pore wall responsive coating oil-water selective plugging agent according to claim 5, characterized in that: The polyether compound is an amphiphilic block copolymer, the hydrophilic block in the amphiphilic block copolymer is a polyoxyethylene ether structure, and the hydrophobic block in the amphiphilic block copolymer is a polyoxypropylene ether structure; and the alkaline catalyst includes triethylamine.

7. The pore wall responsive coating oil-water selective plugging agent according to claim 1, characterized in that: The value of m is 60, and the value of n is 40.

8. A method for using the pore wall responsive coating oil-water selective plugging agent according to any one of claims 1 to 7, characterized in that: The method for using the pore wall responsive coating oil-water selective plugging agent comprises the following steps: dissolving the wall anchoring agent in a solvent to obtain a wall anchoring agent dispersion; dissolving the oil-water responsive brush agent in a solvent to obtain an oil-water responsive brush agent dispersion; The wall anchoring agent dispersion is injected into the oil reservoir, and then pure water is continuously injected into the oil reservoir, and finally the oil-water responsive brush agent dispersion is continuously injected into the oil reservoir.

9. The method for using the pore wall responsive coating oil-water selective plugging agent according to claim 8, characterized in that: The solvent includes at least one of water and sodium chloride aqueous solution, the mass percentage of the wall anchor agent in the wall anchor agent dispersion is 0.05~0.2%, the mass percentage of the oil-water responsive brush agent in the oil-water responsive brush agent dispersion is 0.4~2.0%, and the weight ratio of the wall anchor agent dispersion, the oil-water responsive brush agent dispersion and the pure water is 1:1:(2.5~3.5).

10. Use of the pore wall responsive coating oil-water selective plugging agent according to any one of claims 1 to 7 in oilfield production.

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