A degradable oil-soluble temporary plugging agent and preparation method thereof

Abstract

The invention relates to the field of oil-soluble temporary plugging agents, and in particular to a degradable oil-soluble temporary plugging agent and a preparation method thereof. The oil-soluble temporary plugging agent comprises the following raw materials in weight percentage: 10-12% of a modified oil-soluble resin, 0.8-1% of a composite auxiliary agent and 0.1-0.12% of a cross-linking agent, and the balance is water. The oil-soluble resin is modified and the composite auxiliary agent is added, thereby solving the problems of low water plugging success rate, low strength and poor selectivity of the existing oil-soluble temporary plugging agent, and improving the degradation performance of the oil-soluble temporary plugging agent, so as to improve the environmental protection of the oil-soluble temporary plugging.

Description

Technical Field

[0001] The invention relates to the field of oil-soluble temporary plugging agents, and in particular to a degradable oil-soluble temporary plugging agent and a preparation method thereof. Background Art

[0002] Reservoir protection is one of the key technologies in the drilling and completion process. Temporary plugging agents directly affect the quality of the shielding temporary plugging zone and the reservoir permeability recovery value. Currently, most of the commonly used temporary plugging agents are oil-soluble temporary plugging agents. However, with the deepening of mining, the commonly used oil-soluble temporary plugging agents have gradually failed to meet the technical needs. They have the problems of low water plugging success rate, low strength, poor selectivity and poor environmental protection. Summary of the invention

[0003] The purpose of the present invention is to provide a degradable oil-soluble temporary plugging agent and a preparation method thereof. By modifying the oil-soluble resin and adding a composite auxiliary agent, the problems of low water plugging success rate, low strength and poor selectivity of the existing oil-soluble temporary plugging agent are solved, and the degradation performance of the oil-soluble temporary plugging agent is improved to improve the environmental friendliness of the oil-soluble temporary plugging.

[0004] The purpose of the present invention can be achieved by the following technical scheme: A method for preparing a degradable oil-soluble temporary plugging agent, comprising the following steps: Step S1: weighing the following raw materials in weight percentage: 10-12% of a modified oil-soluble resin, 0.8-1% of a composite auxiliary agent, and 0.1-0.12% of a cross-linking agent, with the remainder being water;

[0005] Step S2: mixing a composite auxiliary agent, a cross-linking agent and water, adding the pulverized modified oil-soluble resin, and stirring for 15-20 minutes to prepare a degradable oil-soluble temporary plugging agent;

[0006] The modified oil-soluble resin is prepared by the following steps:

[0007] Step A1: isosorbide, p-fluoronitrobenzene and 18-crown ether-6 are mixed, and potassium carbonate is added under nitrogen protection at a stirring rate of 200-240 rpm and a temperature of 145° C., and the mixture is reacted for 3-4 hours to obtain intermediate 1; intermediate 1, palladium carbon catalyst and anhydrous ethanol are mixed, and hydrazine hydrate is added under nitrogen protection at a stirring rate of 100-120 rpm and a temperature of 80° C., and the mixture is reacted for 6-8 hours to obtain intermediate 2;

[0008] The dosage ratio of isosorbide, p-fluoronitrobenzene, 18-crown ether-6 and potassium carbonate is 0.05-0.06 mol: 0.1-0.11 mol: 1.3-1.4 g: 14-15 g, the mass fraction of hydrazine hydrate is 80%, and the dosage ratio of intermediate 1, palladium carbon catalyst and hydrazine hydrate is 0.03-0.04 mol: 0.6-0.7 g: 18-20 mL;

[0009] During the reaction, under the action of 18-crown ether-6 and potassium carbonate, the hydroxyl group in isosorbide and the fluorine in p-fluoronitrobenzene undergo a substitution reaction to introduce a nitro group to obtain intermediate 1. Under the action of a palladium-carbon catalyst and hydrazine hydrate, the nitro group in intermediate 1 is reduced to an amino group to obtain intermediate 2.

[0010] Step A2: side chain epoxy silicone oil, adamantane-2-carboxylic acid and toluene are mixed, and under nitrogen protection, the stirring rate is 100-120rpm, the temperature is 110°C, and triethylamine is added for reaction for 6-7h to obtain modified silicone oil; polyformaldehyde, N-methylpyrrolidone and deionized water are mixed, and the stirring rate is 80-100rpm, the temperature is 80°C, and the stirring is carried out for 30min, and then the intermediate 2 and the modified silicone oil are added, and the reaction is continued for 1h, centrifuged, and dried to obtain a modified oil-soluble resin;

[0011] The amount of side chain epoxy silicone oil, adamantane-2-carboxylic acid and triethylamine is 5-6g: 0.01-0.012mol: 0.08-0.1g, and the amount of polyformaldehyde, intermediate 2 and modified silicone oil is 1.8-2g: 0.02-0.024mol: 2.5-3g;

[0012] During the reaction, under the action of triethylamine, the epoxy group in the side chain epoxy silicone oil reacts with the carboxyl group in adamantane-2-carboxylic acid to generate a hydroxyl group to obtain a modified silicone oil, and the polyformaldehyde is first depolymerized into formaldehyde, and then the formaldehyde reacts with the amino group in the intermediate 2 and the hydroxyl group in the modified silicone oil to obtain a modified oil-soluble resin;

[0013] The composite auxiliary agent is prepared by the following steps:

[0014] Step B1: 2-propyn-1-ol, triethylamine and dichloromethane are mixed, and 2-bromo-2-methylpropionyl bromide is added under nitrogen protection and stirring at a rate of 80-100 rpm at room temperature, and the mixture is reacted for 24 hours to obtain intermediate a; intermediate a, methacryloyloxyethyl trimethylammonium chloride, ethyl methacrylate and isopropanol are mixed, and tri[2-(dimethylamino)ethyl]amine and copper chloride are added under stirring at a rate of 80-100 rpm and a temperature of 50° C., and the mixture is reacted for 10-12 hours to obtain a terminal acetylenic polymer;

[0015] The amount ratio of 2-propyn-1-ol, triethylamine and 2-bromo-2-methylpropionyl bromide is 0.04-0.042 mol: 5-5.2 g: 0.05-0.052 mol, and the amount ratio of intermediate a, methacryloyloxyethyl trimethylammonium chloride, ethyl methacrylate, tri[2-(dimethylamino)ethyl]amine and cupric chloride is 0.04-0.042 mol: 0.01-0.011 mol: 0.02 mol: 0.8-1 mL: 0.1-0.12 g;

[0016] During the reaction, under the action of triethylamine, the hydroxyl group in 2-propyn-1-ol reacts with the acyl bromide group in 2-bromo-2-methylpropionyl bromide to form an ester group to obtain an intermediate a, and then under the conditions of tri[2-(dimethylamino)ethyl]amine and copper chloride as catalysts, with the intermediate a as a small molecule initiator, methacryloyloxyethyl trimethylammonium chloride and ethyl methacrylate as monomers, atom transfer free radical polymerization occurs to obtain a terminal acetylenic polymer;

[0017] Step B2: Mono-6-O-(p-toluenesulfonyl)-β-cyclodextrin, sodium azide and deionized water are mixed, and the mixture is reacted for 12 hours at a stirring rate of 200-240 rpm and a temperature of 80°C to obtain azidized cyclodextrin. The azidized cyclodextrin, terminal acetylenic polymer, pentamethyldiethylenetriamine and N,N-dimethylformamide are mixed, and the mixture is stirred at a stirring rate of 120-140 rpm and a temperature of 75°C under nitrogen protection, and cuprous bromide is added, and the mixture is reacted for 24 hours to obtain a composite polymer.

[0018] The dosage ratio of mono-6-O-(p-toluenesulfonyl)-β-cyclodextrin, sodium azide and deionized water is 5-5.4 g: 1.2-1.3 g: 50-60 mL, and the dosage ratio of azidated cyclodextrin, terminal acetylenic polymer, pentamethyldiethylenetriamine and cuprous bromide is 3-3.2 g: 2.5-2.7 g: 3-4 mL: 0.25-0.3 g;

[0019] During the reaction, under the action of sodium azide, the sulfonic acid group in mono-6-O-(p-toluenesulfonyl)-β-cyclodextrin is broken and azidated to obtain azidated cyclodextrin. Then, under the action of pentamethyldiethylenetriamine and cuprous bromide, the azide group in the azidated cyclodextrin reacts with the alkyne group in the terminal alkyne polymer to form a triazole structure to obtain a composite polymer.

[0020] Step B3: Mix the composite polymer, dicyclohexylcarbodiimide, 4-dimethylaminopyridine and dichloromethane, stir at a rate of 120-140 rpm and room temperature, add lipoic acid, and react for 24 hours to obtain a composite auxiliary agent;

[0021] The ratio of the composite polymer, dicyclohexylcarbodiimide, 4-dimethylaminopyridine and lipoic acid is 2.8-3.2 g: 0.24-0.26 g: 0.12-0.13 g: 0.008-0.01 mol;

[0022] During the reaction, under the action of dicyclohexylcarbodiimide and 4-dimethylaminopyridine, the hydroxyl group in the cyclodextrin structure of the composite polymer reacts with the carboxyl group in lipoic acid to form an ester group, thereby obtaining a composite auxiliary agent;

[0023] Beneficial effects of the invention: The invention discloses a degradable oil-soluble temporary plugging agent and a preparation method thereof, which solves the problems of low water plugging success rate, low strength and poor selectivity of the existing oil-soluble temporary plugging agent by modifying the oil-soluble resin and adding a composite auxiliary agent, and at the same time improves the degradation performance of the oil-soluble temporary plugging agent to improve the environmental friendliness of the oil-soluble temporary plugging agent;

[0024] The modified oil-soluble resin contains a large amount of isosorbide structure, and the adamantane structure is introduced into the epoxy side chain silicone oil. In the preparation process of the modified oil-soluble resin, due to the presence of the silicone oil segment, the adamantane structure is guided to migrate to the surface of the modified oil-soluble resin, thereby exposing the adamantane structure on the surface of the modified oil-soluble resin. At the same time, due to the presence of the isosorbide structure, the modified oil-soluble resin is endowed with better degradation performance. In addition, since the modified oil-soluble resin is prepared by the reaction of formaldehyde with the intermediate 2 and the modified silicone oil, It also has good oil solubility. Intermediate a is used as a small molecule initiator, methacryloyloxyethyl trimethyl ammonium chloride and ethyl methacrylate are used as monomers to prepare a terminal acetylenic polymer, which is then reacted with azidated cyclodextrin to prepare a composite auxiliary agent. During the use of the degradable oil-soluble temporary plugging agent, as the temperature and pressure rise, the adamantane structure on the surface of the modified oil-soluble resin and the cyclodextrin structure in the composite auxiliary agent undergo host-guest inclusion complexation, thereby gradually forming a gel structure on the surface of the modified oil-soluble resin, thereby playing a temporary plugging role;

[0025] At the same time, due to the presence of a large number of lipoic acid structures in the composite additive, it undergoes self-crosslinking behavior, thereby forming a crosslinking network during the temporary plugging process, thereby improving its temporary plugging strength and exerting better temporary plugging performance. In addition, since it contains a quaternary ammonium structure, it not only improves the temporary plugging effect, but can also combine with the silicone oil segment in the modified oil-soluble resin, so that the oil-soluble temporary plugging agent can effectively remove the plugging after the fracturing operation without causing damage to the formation. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Example 1 A method for preparing a degradable oil-soluble temporary plugging agent comprises the following steps: Step S1: weighing the following raw materials in weight percentage: 10% of modified oil-soluble resin, 0.8% of composite auxiliary agent and 0.1% of commercially available JL-6 cross-linking agent, and the balance is water;

[0028] Step S2: mixing a composite auxiliary agent, a cross-linking agent and water, adding the pulverized modified oil-soluble resin, and stirring for 15 minutes to prepare a degradable oil-soluble temporary plugging agent;

[0029] The modified oil-soluble resin is prepared by the following steps:

[0030] Step A1: isosorbide, p-fluoronitrobenzene and 18-crown ether-6 are mixed, and potassium carbonate is added under nitrogen protection at a stirring rate of 200 rpm and a temperature of 145°C, and the mixture is stirred for 3 hours to obtain intermediate 1; intermediate 1, palladium carbon catalyst and anhydrous ethanol are mixed, and hydrazine hydrate is added under nitrogen protection at a stirring rate of 100 rpm and a temperature of 80°C, and the mixture is stirred for 6 hours to obtain intermediate 2;

[0031] The dosage ratio of isosorbide, p-fluoronitrobenzene, 18-crown ether-6 and potassium carbonate is 0.05 mol: 0.1 mol: 1.3 g: 14 g, the mass fraction of hydrazine hydrate is 80%, and the dosage ratio of intermediate 1, palladium carbon catalyst and hydrazine hydrate is 0.03 mol: 0.6 g: 18 mL;

[0032] Step A2: Mix commercially available BSM204 side chain epoxy silicone oil, adamantane-2-carboxylic acid and toluene, stir and add triethylamine under nitrogen protection, stirring at a rate of 100 rpm and a temperature of 110°C, and react for 6 hours to obtain modified silicone oil; mix commercially available Haizhiqi polyformaldehyde, N-methylpyrrolidone and deionized water, stir at a rate of 80 rpm and a temperature of 80°C for 30 minutes, then add intermediate 2 and modified silicone oil, continue to react for 1 hour, centrifuge and dry to obtain a modified oil-soluble resin;

[0033] The amount of side chain epoxy silicone oil, adamantane-2-carboxylic acid and triethylamine used is 5g:0.01mol:0.08g, and the amount ratio of polyformaldehyde, intermediate 2 and modified silicone oil used is 1.8g:0.02mol:2.5g;

[0034] The composite auxiliary agent is prepared by the following steps:

[0035] Step B1: 2-propyn-1-ol, triethylamine and dichloromethane were mixed, and 2-bromo-2-methylpropionyl bromide was added under nitrogen protection and stirring at a rate of 80 rpm at room temperature, and the mixture was reacted for 24 hours to obtain intermediate a. Intermediate a, methacryloyloxyethyl trimethylammonium chloride, ethyl methacrylate and isopropanol were mixed, and tri[2-(dimethylamino)ethyl]amine and copper chloride were added under stirring at a rate of 80 rpm and a temperature of 50°C, and the mixture was reacted for 10 hours to obtain a terminal acetylenic polymer;

[0036] The amount ratio of 2-propyn-1-ol, triethylamine and 2-bromo-2-methylpropionyl bromide is 0.04 mol: 5 g: 0.05 mol, and the amount ratio of intermediate a, methacryloyloxyethyl trimethylammonium chloride, ethyl methacrylate, tri[2-(dimethylamino)ethyl]amine and cupric chloride is 0.04 mol: 0.01 mol: 0.02 mol: 0.8 mL: 0.1 g;

[0037] Step B2: Mono-6-O-(p-toluenesulfonyl)-β-cyclodextrin, sodium azide and deionized water are mixed, and the mixture is reacted for 12 hours at a stirring rate of 200 rpm and a temperature of 80°C to obtain azidized cyclodextrin. The azidized cyclodextrin, terminal acetylenic polymer, pentamethyldiethylenetriamine and N,N-dimethylformamide are mixed, and the mixture is stirred at a stirring rate of 120 rpm and a temperature of 75°C under nitrogen protection, and cuprous bromide is added, and the mixture is reacted for 24 hours to obtain a composite polymer.

[0038] The amount ratio of mono-6-O-(p-toluenesulfonyl)-β-cyclodextrin, sodium azide and deionized water is 5g:1.2g:50mL, and the amount ratio of azidated cyclodextrin, terminal acetylenic polymer, pentamethyldiethylenetriamine and cuprous bromide is 3g:2.5g:3mL:0.25g;

[0039] Step B3: Mix the composite polymer, dicyclohexylcarbodiimide, 4-dimethylaminopyridine and dichloromethane, stir at a stirring rate of 120 rpm and room temperature, add lipoic acid, and react for 24 hours to obtain a composite auxiliary agent;

[0040] The usage ratio of the composite polymer, dicyclohexylcarbodiimide, 4-dimethylaminopyridine and lipoic acid is 2.8 g: 0.24 g: 0.12 g: 0.008 mol.

[0041] Example 2 A method for preparing a degradable oil-soluble temporary plugging agent comprises the following steps: Step S1: weighing the following raw materials in weight percentage: 12% of modified oil-soluble resin, 0.8% of composite auxiliary agent and 0.12% of commercially available JL-6 cross-linking agent, and the balance is water;

[0042] Step S2: mixing a composite auxiliary agent, a cross-linking agent and water, adding the pulverized modified oil-soluble resin, and stirring for 20 minutes to prepare a degradable oil-soluble temporary plugging agent;

[0043] The modified oil-soluble resin is prepared by the following steps:

[0044] Step A1: isosorbide, p-fluoronitrobenzene and 18-crown ether-6 are mixed, and potassium carbonate is added under nitrogen protection, stirring at a rate of 200 rpm and a temperature of 145°C, and the mixture is reacted for 4 hours to obtain intermediate 1; intermediate 1, palladium carbon catalyst and anhydrous ethanol are mixed, and hydrazine hydrate is added under nitrogen protection, stirring at a rate of 100 rpm and a temperature of 80°C, and the mixture is reacted for 8 hours to obtain intermediate 2;

[0045] The dosage ratio of isosorbide, p-fluoronitrobenzene, 18-crown ether-6 and potassium carbonate is 0.05 mol: 0.11 mol: 1.3 g: 15 g, the mass fraction of hydrazine hydrate is 80%, and the dosage ratio of intermediate 1, palladium carbon catalyst and hydrazine hydrate is 0.03 mol: 0.7 g: 18 mL;

[0046] Step A2: Mix commercially available BSM204 side chain epoxy silicone oil, adamantane-2-carboxylic acid and toluene, stir and add triethylamine under nitrogen protection, stirring at a rate of 120 rpm and a temperature of 110°C, and react for 6 hours to obtain modified silicone oil; mix commercially available Haizhiqi polyformaldehyde, N-methylpyrrolidone and deionized water, stir at a rate of 80 rpm and a temperature of 80°C for 30 minutes, then add intermediate 2 and modified silicone oil, continue to react for 1 hour, centrifuge and dry to obtain a modified oil-soluble resin;

[0047] The amount of side chain epoxy silicone oil, adamantane-2-carboxylic acid and triethylamine used is 6g:0.01mol:0.1g, and the amount ratio of polyformaldehyde, intermediate 2 and modified silicone oil used is 1.8g:0.024mol:3g;

[0048] The composite auxiliary agent is prepared by the following steps:

[0049] Step B1: 2-propyn-1-ol, triethylamine and dichloromethane were mixed, and 2-bromo-2-methylpropionyl bromide was added under nitrogen protection and stirring at a rate of 100 rpm at room temperature, and the mixture was reacted for 24 hours to obtain intermediate a. Intermediate a, methacryloyloxyethyl trimethylammonium chloride, ethyl methacrylate and isopropanol were mixed, and tri[2-(dimethylamino)ethyl]amine and copper chloride were added under stirring at a rate of 80 rpm and a temperature of 50°C, and the mixture was reacted for 10 hours to obtain a terminal acetylenic polymer;

[0050] The amount ratio of 2-propyn-1-ol, triethylamine and 2-bromo-2-methylpropionyl bromide is 0.042 mol: 5.2 g: 0.05 mol, and the amount ratio of intermediate a, methacryloyloxyethyl trimethylammonium chloride, ethyl methacrylate, tri[2-(dimethylamino)ethyl]amine and cupric chloride is 0.04 mol: 0.011 mol: 0.02 mol: 1 mL: 0.12 g;

[0051] Step B2: Mono-6-O-(p-toluenesulfonyl)-β-cyclodextrin, sodium azide and deionized water are mixed, and the mixture is reacted for 12 hours at a stirring rate of 200 rpm and a temperature of 80°C to obtain azidized cyclodextrin. The azidized cyclodextrin, terminal acetylenic polymer, pentamethyldiethylenetriamine and N,N-dimethylformamide are mixed, and the mixture is stirred at a stirring rate of 140 rpm and a temperature of 75°C under nitrogen protection, and cuprous bromide is added, and the mixture is reacted for 24 hours to obtain a composite polymer.

[0052] The amount ratio of mono-6-O-(p-toluenesulfonyl)-β-cyclodextrin, sodium azide and deionized water is 5g:1.3g:50mL, and the amount ratio of azidated cyclodextrin, terminal acetylenic polymer, pentamethyldiethylenetriamine and cuprous bromide is 3.2g:2.5g:4mL:0.25g;

[0053] Step B3: Mix the composite polymer, dicyclohexylcarbodiimide, 4-dimethylaminopyridine and dichloromethane, stir at a stirring rate of 140 rpm and room temperature, add lipoic acid, and react for 24 hours to obtain a composite auxiliary agent;

[0054] The usage ratio of the composite polymer, dicyclohexylcarbodiimide, 4-dimethylaminopyridine and lipoic acid is 3.2 g: 0.24 g: 0.12 g: 0.01 mol.

[0055] Example 3 A method for preparing a degradable oil-soluble temporary plugging agent comprises the following steps: Step S1: weighing the following raw materials in weight percentage: 12% of modified oil-soluble resin, 1% of composite auxiliary agent and 0.12% of commercially available JL-6 cross-linking agent, and the balance is water;

[0056] Step S2: mixing a composite auxiliary agent, a cross-linking agent and water, adding the pulverized modified oil-soluble resin, and stirring for 20 minutes to prepare a degradable oil-soluble temporary plugging agent;

[0057] The modified oil-soluble resin is prepared by the following steps:

[0058] Step A1: isosorbide, p-fluoronitrobenzene and 18-crown ether-6 are mixed, and potassium carbonate is added under nitrogen protection at a stirring rate of 240 rpm and a temperature of 145°C, and the mixture is reacted for 4 hours to obtain intermediate 1; intermediate 1, palladium carbon catalyst and anhydrous ethanol are mixed, and hydrazine hydrate is added under nitrogen protection at a stirring rate of 120 rpm and a temperature of 80°C, and the mixture is reacted for 8 hours to obtain intermediate 2;

[0059] The dosage ratio of isosorbide, p-fluoronitrobenzene, 18-crown ether-6 and potassium carbonate is 0.06 mol: 0.11 mol: 1.4 g: 15 g, the mass fraction of hydrazine hydrate is 80%, and the dosage ratio of intermediate 1, palladium carbon catalyst and hydrazine hydrate is 0.04 mol: 0.7 g: 20 mL;

[0060] Step A2: Mix commercially available BSM204 side chain epoxy silicone oil, adamantane-2-carboxylic acid and toluene, stir and add triethylamine under nitrogen protection, stirring at a rate of 120 rpm and a temperature of 110°C, and react for 7 hours to obtain modified silicone oil; mix commercially available Haizhiqi polyformaldehyde, N-methylpyrrolidone and deionized water, stir at a rate of 100 rpm and a temperature of 80°C for 30 minutes, then add intermediate 2 and modified silicone oil, continue to react for 1 hour, centrifuge and dry to obtain a modified oil-soluble resin;

[0061] The amount of side chain epoxy silicone oil, adamantane-2-carboxylic acid and triethylamine used is 6g:0.012mol:0.1g, and the amount ratio of polyformaldehyde, intermediate 2 and modified silicone oil used is 2g:0.024mol:3g;

[0062] The composite auxiliary agent is prepared by the following steps:

[0063] Step B1: 2-propyn-1-ol, triethylamine and dichloromethane were mixed, and 2-bromo-2-methylpropionyl bromide was added under nitrogen protection and stirring at a rate of 100 rpm at room temperature, and the mixture was reacted for 24 hours to obtain intermediate a. Intermediate a, methacryloyloxyethyl trimethylammonium chloride, ethyl methacrylate and isopropanol were mixed, and tri[2-(dimethylamino)ethyl]amine and copper chloride were added under stirring at a rate of 100 rpm and a temperature of 50° C., and the mixture was reacted for 12 hours to obtain a terminal acetylenic polymer;

[0064] The amount ratio of 2-propyn-1-ol, triethylamine and 2-bromo-2-methylpropionyl bromide is 0.042 mol: 5.2 g: 0.052 mol, and the amount ratio of intermediate a, methacryloyloxyethyl trimethylammonium chloride, ethyl methacrylate, tri[2-(dimethylamino)ethyl]amine and cupric chloride is 0.042 mol: 0.011 mol: 0.02 mol: 1 mL: 0.12 g;

[0065] Step B2: Mono-6-O-(p-toluenesulfonyl)-β-cyclodextrin, sodium azide and deionized water were mixed, and the mixture was reacted for 12 hours at a stirring rate of 240 rpm and a temperature of 80°C to obtain azidized cyclodextrin. The azidized cyclodextrin, terminal acetylenic polymer, pentamethyldiethylenetriamine and N,N-dimethylformamide were mixed, and the mixture was stirred at a stirring rate of 140 rpm and a temperature of 75°C under nitrogen protection, and cuprous bromide was added, and the mixture was reacted for 24 hours to obtain a composite polymer.

[0066] The amount ratio of mono-6-O-(p-toluenesulfonyl)-β-cyclodextrin, sodium azide and deionized water is 5.4 g:1.3 g:60 mL, and the amount ratio of azidated cyclodextrin, terminal acetylenic polymer, pentamethyldiethylenetriamine and cuprous bromide is 3.2 g:2.7 g:4 mL:0.3 g;

[0067] Step B3: Mix the composite polymer, dicyclohexylcarbodiimide, 4-dimethylaminopyridine and dichloromethane, stir at a stirring rate of 140 rpm and room temperature, add lipoic acid, and react for 24 hours to obtain a composite auxiliary agent;

[0068] The usage ratio of the composite polymer, dicyclohexylcarbodiimide, 4-dimethylaminopyridine and lipoic acid is 3.2 g: 0.26 g: 0.13 g: 0.01 mol.

[0069] Comparative Example 1 Compared with Example 3, this comparative example is different in that the intermediate 2 in the preparation process of the modified oil-soluble resin in Example 3 is replaced by p-phenylenediamine, and the other steps are the same.

[0070] Comparative Example 2 Compared with Example 3, this comparative example is different in that adamantane-2-carboxylic acid in the preparation process of the modified oil-soluble resin in Example 3 is replaced by propionic acid, and the other steps are the same.

[0071] Comparative Example 3 Compared with Example 3, this comparative example is different in that methacryloyloxyethyltrimethylammonium chloride in the preparation process of the composite auxiliary agent in Example 3 is replaced by butyl methacrylate, and the other steps are the same.

[0072] Comparative Example 4 Compared with Example 3, this comparative example is different in that the lipoic acid in the preparation process of the composite auxiliary agent in Example 3 is replaced by octanoic acid, and the other steps are the same.

[0073] Take the degradable oil-soluble temporary plugging agent prepared in Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4, add the modified oil-soluble resin into kerosene, heat at 80°C for 16 hours, filter, weigh, calculate the ratio of the mass difference of the modified oil-soluble resin before and after immersion to the original weight, and obtain the oil solubility. Dry the degradable oil-soluble temporary plugging agent and bury it in a plastic container filled with soil, the soil pH = 7, store it at 100°C in air for ninety days, and calculate the mass residual rate of the sample after ninety days. The permeability is selected as 5.02μm 2 , a core sample with a length of 10cm, injected with 10PV of degradable oil-soluble temporary plugging agent at a rate of 5mL / min, kept warm for 30min at a temperature of 90℃, and reversely water-driven the core at an injection rate of 2mL / min until the first drop of liquid flows down the core outlet and liquid continues to flow out, record the pressure at this time, and calculate the breakthrough pressure gradient. Under the condition of temperature of 90℃, the core displacement experiment was carried out using the DOZ-Ⅱ multifunctional core displacement device, and its plugging rate and unblocking rate were calculated. The test results are shown in Table 1:

[0074] Table 1 Test results

[0075] Test items Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Oil solubility (%) 98.58 98.62 98.70 95.15 98.67 97.61 98.03 Quality residual rate (%) 31.27 30.49 30.15 75.76 30.60 30.28 30.52 Breakthrough pressure gradient (MPa / m) 34.41 34.63 35.27 30.11 21.04 27.15 25.35 Blockage rate (%) 98.24 98.56 98.71 93.34 84.14 95.60 92.11 Blockage removal rate (%) 90.76 90.98 91.22 85.89 86.63 80.01 82.24

[0076] It can be seen from the test results in the table shown that when Example 1, Example 2 and Example 3 are compared with Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4, Comparative Example 1 replaces the intermediate 2 in the preparation process of the modified oil-soluble resin in Example 3 with p-phenylenediamine. Due to the lack of isosorbide structure, its degradation performance is reduced. In Comparative Example 2, the adamantane-2-carboxylic acid in the preparation process of the modified oil-soluble resin in Example 3 is replaced with propionic acid. Due to the lack of adamantane structure, it cannot be included to form a gel, resulting in a significant decrease in its breakthrough pressure gradient and plugging performance. In Comparative Example 3, methacryloyloxyethyltrimethylammonium chloride in the preparation process of the composite auxiliary agent in Example 3 is replaced with butyl methacrylate. Due to the lack of quaternary ammonium structure, its unblocking performance is reduced. In Comparative Example 4, thioctic acid in the preparation process of the composite auxiliary agent in Example 3 is replaced with octanoic acid. Due to the lack of thioctic acid, its breakthrough pressure gradient and plugging performance are reduced.

[0077] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0078] The above contents are merely examples and explanations of the concept of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A method for preparing a degradable oil-soluble temporary plugging agent, characterized in that: The method comprises the following steps: Step S1: weighing the following raw materials in weight percentage: 10-12% of modified oil-soluble resin, 0.8-1% of composite auxiliary agent and 0.1-0.12% of cross-linking agent, and the balance is water; Step S2: mixing a composite auxiliary agent, a cross-linking agent and water, adding the pulverized modified oil-soluble resin, and stirring for 15-20 minutes to prepare a degradable oil-soluble temporary plugging agent; The modified oil-soluble resin is prepared by the following steps: Step A1: isosorbide, p-fluoronitrobenzene and 18-crown ether-6 are mixed, and potassium carbonate is added under nitrogen protection at a stirring rate of 200-240 rpm and a temperature of 145° C., and the mixture is reacted for 3-4 hours to obtain intermediate 1; intermediate 1, palladium carbon catalyst and anhydrous ethanol are mixed, and hydrazine hydrate is added under nitrogen protection at a stirring rate of 100-120 rpm and a temperature of 80° C., and the mixture is reacted for 6-8 hours to obtain intermediate 2; Step A2: side chain epoxy silicone oil, adamantane-2-carboxylic acid and toluene are mixed, and under nitrogen protection, the stirring rate is 100-120rpm, the temperature is 110°C, and triethylamine is added for reaction for 6-7h to obtain modified silicone oil; polyformaldehyde, N-methylpyrrolidone and deionized water are mixed, and the stirring rate is 80-100rpm, the temperature is 80°C, and the stirring is carried out for 30min, and then the intermediate 2 and the modified silicone oil are added, and the reaction is continued for 1h, centrifuged, and dried to obtain a modified oil-soluble resin; In step A1: the dosage ratio of isosorbide, p-fluoronitrobenzene, 18-crown ether-6 and potassium carbonate is 0.05-0.06 mol: 0.1-0.11 mol: 1.3-1.4 g: 14-15 g, the mass fraction of hydrazine hydrate is 80%, and the dosage ratio of intermediate 1, palladium carbon catalyst and hydrazine hydrate is 0.03-0.04 mol: 0.6-0.7 g: 18-20 mL; In step A2: the amount of side chain epoxy silicone oil, adamantane-2-carboxylic acid and triethylamine is 5-6 g: 0.01-0.012mol:0.08-0.1g, the usage ratio of paraformaldehyde, intermediate 2 and modified silicone oil is 1.8-2g:0.02-0.024mol:2.5-3g; The composite auxiliary agent is prepared by the following steps: Step B1: 2-propyn-1-ol, triethylamine and dichloromethane are mixed, and 2-bromo-2-methylpropionyl bromide is added under nitrogen protection and stirring at a rate of 80-100 rpm at room temperature, and the mixture is reacted for 24 hours to obtain intermediate a; intermediate a, methacryloyloxyethyl trimethylammonium chloride, ethyl methacrylate and isopropanol are mixed, and tri[2-(dimethylamino)ethyl]amine and copper chloride are added under stirring at a rate of 80-100 rpm and a temperature of 50° C., and the mixture is reacted for 10-12 hours to obtain a terminal acetylenic polymer; Step B2: Mono-6-O-(p-toluenesulfonyl)-β-cyclodextrin, sodium azide and deionized water are mixed, and the mixture is reacted for 12 hours at a stirring rate of 200-240 rpm and a temperature of 80°C to obtain azidized cyclodextrin. The azidized cyclodextrin, terminal acetylenic polymer, pentamethyldiethylenetriamine and N,N-dimethylformamide are mixed, and the mixture is stirred at a stirring rate of 120-140 rpm and a temperature of 75°C under nitrogen protection, and cuprous bromide is added, and the mixture is reacted for 24 hours to obtain a composite polymer. Step B3: Mix the composite polymer, dicyclohexylcarbodiimide, 4-dimethylaminopyridine and dichloromethane, stir at a rate of 120-140 rpm and room temperature, add lipoic acid, and react for 24 hours to obtain a composite auxiliary agent; In step B1: the ratio of 2-propyn-1-ol, triethylamine and 2-bromo-2-methylpropionyl bromide is 0.04-0.042 mol: 5-5.2 g: 0.05-0.052 mol, and the ratio of intermediate a, methacryloyloxyethyltrimethylammonium chloride, ethyl methacrylate, tri[2-(dimethylamino)ethyl]amine and cupric chloride is 0.04-0.042 mol: 0.01-0.011 mol: 0.02 mol: 0.8-1 mL: 0.1-0.12 g; In step B2: the ratio of mono-6-O-(p-toluenesulfonyl)-β-cyclodextrin, sodium azide and deionized water is 5-5.4 g: 1.2-1.3 g: 50-60 mL, and the ratio of azidated cyclodextrin, terminal acetylenic polymer, pentamethyldiethylenetriamine and cuprous bromide is 3-3.2 g: 2.5-2.7 g: 3-4 mL: 0.25-0.3 g; In step B3, the ratio of the composite polymer, dicyclohexylcarbodiimide, 4-dimethylaminopyridine and lipoic acid is 2.8-3.2 g: 0.24-0.26 g: 0.12-0.13 g: 0.008-0.01 mol.

2. A degradable oil-soluble temporary plugging agent, characterized in that: Prepared according to the preparation method of claim 1.