Delay crosslinking water shutoff profile control agent for oil extraction and preparation method of delayed crosslinking water shutoff profile control agent

Abstract

The invention relates to the technical field of water shutoff and profile control agents, in particular to a delayed crosslinking water shutoff and profile control agent for oil extraction and a preparation method thereof.The delayed crosslinking water shutoff and profile control agent is prepared from, by weight, 25-30 parts of modified polyacrylamide, 12-15 parts of composite crosslinking agent, 8-10 parts of stabilizer and 2-3 parts of deoxidant; by taking Na-montmorillonite as a carrier, loading a zirconium phytate organic cross-linking agent and introducing a Schiff base structure, the composite cross-linking agent has good slow-release delayed cross-linking performance through the slow-release effect of a nano material, and the problem that the blocking effect is reduced due to the fact that an existing water shutoff profile control agent is cross-linked in advance is solved; and modified polyacrylamide with a telechelic structure is synthesized, so that the plugging performance of the water plugging and profile control agent is further enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of water plugging and profile controlling agents, and in particular to a delayed cross-linking water plugging and profile controlling agent for oil production and a preparation method thereof. Background Art

[0002] During the oil field exploitation process, the presence of cracks aggravates the lateral and longitudinal heterogeneity of the reservoir, and also causes the rapid channeling of the displacement medium along the cracks, reducing the sweep efficiency, thereby affecting the oil field recovery efficiency. Therefore, it is necessary to perform water plugging and profile control. The most widely used profile control agent system is the polymer cross-linking system. However, due to the excessively fast cross-linking reaction rate of the traditional profile control agent, such as the patent CN116589637A, a profile control and water plugging agent and its preparation method and application, the profile control and water plugging agent has a unique double network structure of hydrogel material, good stability, and still maintains good strength under high temperature and high salt conditions. However, the water plugging and profile control agent will not reach the deep layer of the heterogeneous oil reservoir, that is, the fracture-pore composite formation, and cross-linking and gelation will occur, resulting in the risk of near-well blockage, resulting in the inability of the water plugging and profile control agent to migrate to the deep formation, affecting the plugging effect and failing to meet market demand. Summary of the invention

[0003] The object of the present invention is to provide a delayed cross-linking water plugging and profile control agent for oil production and a preparation method thereof. By using sodium montmorillonite as a carrier, loading a zirconium phytate organic cross-linking agent, and introducing a Schiff base structure, the composite cross-linking agent has good slow-release delayed cross-linking performance through the sustained-release effect of nanomaterials, thereby solving the problem that the existing water plugging and profile control agents are cross-linked in advance, resulting in a decrease in the plugging effect. By synthesizing a modified polyacrylamide with a telechelic structure, the plugging performance of the water plugging and profile control agent is further enhanced.

[0004] The object of the present invention can be achieved by the following technical scheme: a method for preparing a delayed cross-linking water plugging and profile control agent for oil production, comprising the following steps: weighing the following raw materials in parts by weight: 25-30 parts of modified polyacrylamide, 12-15 parts of a composite cross-linking agent, 8-10 parts of a stabilizer and 2-3 parts of a deoxidizer, mixing the modified polyacrylamide, the composite cross-linking agent, the stabilizer and the deoxidizer to prepare a delayed cross-linking water plugging and profile control agent for oil production; The deoxidizer is Gabel XH21 deoxidizer; The stabilizer is Lingchuang NW-1 stabilizer; The modified polyacrylamide is prepared by the following steps: Step A1: mixing hydroquinone and dichloromethane, stirring at a rate of 180-240 rpm and a temperature of 0-5°C, stirring and adding 2-bromoisobutyryl bromide, stirring for 30 minutes, heating to room temperature, reacting for 10-12 hours, then adding triethylamine, continuing to stir for 10-15 minutes, then adding deionized water, extracting and collecting the dichloromethane phase, drying over anhydrous magnesium sulfate, filtering, rotary evaporation, and drying to obtain a double-head initiator; mixing the double-head initiator, sodium ascorbate, acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, N,N-dimethylformamide and deionized water, stirring at a rate of 180-240 rpm and a temperature of 35-40°C, adding cuprous bromide, reacting for 24 hours, rotary evaporation, recrystallization, filtering, and drying to obtain a macromolecular initiator; The dosage ratio of hydroquinone, dichloromethane, 2-bromoisobutyryl bromide, triethylamine and deionized water is 2-2.1g:45-50mL:5.8-5.9mL:0.8-1mL:45-50mL; the dosage ratio of double-head initiator, sodium ascorbate, acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, N,N-dimethylformamide, deionized water and cuprous bromide is 0.24-0.25g:0.01g:3.5-3.6g:2-2.1g:10-15mL:20-25mL:0.01-0.02g; During the reaction, the hydroxyl group in p-diphenol first reacts with the acyl bromide group in 2-bromoisobutyryl bromide to obtain a double-head initiator, and then an atom transfer radical polymerization method is used to obtain a macromolecular initiator using the double-head initiator as an initiator, sodium ascorbate and cuprous bromide as catalysts, and acrylamide and 2-acrylamide-2-methylpropanesulfonic acid as monomers;

[0005] Step A2: Mix dehydroabietic acid and dichloromethane, stir and add oxalyl chloride and N,N-dimethylformamide under nitrogen protection, stirring rate of 140-180 rpm, temperature of 0-5°C, react for 3-4 hours, and rotary evaporate to obtain intermediate 1; mix intermediate 1 and dichloromethane, stir and add triethylamine and hydroxyethyl methacrylate under nitrogen protection, stirring rate of 140-180 rpm, temperature of 0-5°C, and react for 48 hours, wash with sodium bicarbonate solution until neutral, dry, and rotary evaporate to obtain intermediate 2; The dosage ratio of dehydroabietic acid, dichloromethane, oxalyl chloride and N,N-dimethylformamide is 28-30g: 160-180mL: 25-26g: 0.8-1mL; the mass fraction of sodium bicarbonate solution is 5%, and the dosage ratio of intermediate 1, dichloromethane, triethylamine and hydroxyethyl methacrylate is 24-26g: 160-180mL: 14.5-14.8g: 14.4-14.5g; During the reaction, the carboxyl group in dehydroabietic acid reacts with oxalyl chloride to form an acyl chloride group to obtain intermediate 1. Then, under the action of triethylamine, the acyl chloride group in intermediate 1 reacts with the hydroxyl group in hydroxyethyl methacrylate to form an ester group and introduce a double bond to obtain intermediate 2.

[0006] Step A3: Mix the macromolecular initiator, sodium ascorbate, intermediate 2, N,N-dimethylformamide and deionized water, stir and add cuprous bromide under argon protection, stirring at a rate of 180-200 rpm and a temperature of 30-35° C., react for 10-12 hours, rotary evaporate, recrystallize, filter and dry to obtain modified polyacrylamide; The ratio of macromolecular initiator, sodium ascorbate, intermediate 2, N,N-dimethylformamide, deionized water and cuprous bromide is 4.2-4.5 g: 0.03-0.05 g: 0.8-0.9 g: 10-12 mL: 15-18 mL: 0.02-0.03 g; During the reaction, the double bond in the intermediate 2 reacts with the middle end of the macromolecular initiator by atom transfer radical polymerization with sodium ascorbate and cuprous bromide as catalysts, thereby forming a telechelic block structure of a terminal dehydroabietic acid segment to obtain a modified polyacrylamide.

[0007] The composite cross-linking agent is prepared by the following steps: Step B1: Sodium phytate, zirconium dichloride octahydrate and deionized water are mixed, stirred and hydrochloric acid solution is added, the pH value is adjusted to 4, the reaction is carried out for 1 hour at a stirring rate of 180-240 rpm and a temperature of 80-90°C, centrifuged, washed, filtered, and ground to obtain a zirconium phytate complex; sodium montmorillonite and deionized water are mixed and ultrasonically dispersed for 10-15 minutes, stirred and the zirconium phytate complex and N,N-dimethylformamide are added at a stirring rate of 180-240 rpm and a temperature of 50-55°C, stirred for 24 hours, centrifuged, washed, and dried to obtain an intercalated montmorillonite; The mass fraction of the hydrochloric acid solution is 30%, the dosage ratio of sodium phytate, zirconium dichloride octahydrate and deionized water is 9.5-9.7g:9.2-9.3g:60-70mL; the dosage ratio of sodium montmorillonite, deionized water, zirconium phytate complex and N,N-dimethylformamide is 0.2-0.24g:8-10mL:1.8-1.9g:15-20mL; The sodium montmorillonite is 200 mesh sodium montmorillonite; During the reaction, a phytate zirconium complex is prepared by direct precipitation method through the complexation between the phosphate bond in the phytate and the zirconium ion, and then the phytate zirconium complex is intercalated between the montmorillonite layers to prepare the intercalated montmorillonite; Step B2: Mix dextran and deionized water, stir and add sodium periodate under the condition of avoiding light, stirring at a rate of 140-180 rpm, room temperature, react for 3-4 hours, then add ethylene glycol, continue to react for 30-40 minutes, dialyze with pure water, dry, and obtain oxidized dextran; mix trishydroxymethylaminomethane and hydrochloric acid solution, stir and add intercalated montmorillonite and deionized water under the condition of stirring at a rate of 140-180 rpm, temperature of 60-62°C, react for 3-4 hours, then cool to room temperature, add oxidized dextran, and continue to react for 12 hours to obtain a composite cross-linking agent; The dosage ratio of dextran, deionized water, sodium periodate and ethylene glycol is 1.1-1.2 g: 8-10 mL: 0.13-0.14 g: 0.34-0.35 mL; the molar concentration of the hydrochloric acid solution is 0.375 mol / L, and the dosage ratio of tris(hydroxymethyl)aminomethane, hydrochloric acid solution, intercalated montmorillonite, deionized water and oxidized dextran is 2.15-2.2 g: 300-350 mL: 14-15 g: 300-350 mL: 1.8-2 g; The glucan is source leaf glucan T-1; During the reaction, under the action of sodium periodate, the o-dialdehyde structure in dextran is oxidized to form an aldehyde group, thereby obtaining oxidized dextran. The intercalated montmorillonite is modified with trihydroxymethylaminomethane, and amino groups are introduced on its surface. The amino groups react with the aldehyde groups in the oxidized dextran to form a Schiff base structure, thereby obtaining a composite cross-linking agent.

[0008] Beneficial effects of the invention: The invention discloses a delayed cross-linking water plugging and profile control agent for oil production and a preparation method thereof. By using sodium montmorillonite as a carrier, loading a zirconium phytate organic cross-linking agent, and introducing a Schiff base structure, the composite cross-linking agent has good slow-release delayed cross-linking performance through the slow-release effect of nanomaterials, thereby solving the problem that the existing water plugging and profile control agent is cross-linked in advance, resulting in a decrease in the plugging effect. By synthesizing a modified polyacrylamide with a telechelic structure, the plugging performance of the water plugging and profile control agent is further enhanced. Since the surface of the composite cross-linking agent is modified with trishydroxymethylaminomethane and reacts with oxidized dextran, a A Schiff base structure is formed, and a large number of hydroxyl groups are introduced. Through the coordination effect between the Schiff base structure and the zirconium phytate structure released by the composite cross-linking agent, and the hydrogen bonding effect between the large number of hydroxyl groups and the modified polyacrylamide, the gel network formed by it has good gel strength under high temperature conditions. Since the modified polyacrylamide is a telechelic block polymer terminated with intermediate 2, the hydrophobic groups are located at both ends of the molecular chain, and the association effect between the hydrophobic groups is less affected by the bending shielding of the molecular chain. Therefore, its hydrophobic association effect is more obvious, thereby further improving its gel strength under high temperature conditions, thereby reflecting a better blocking effect. DETAILED DESCRIPTION

[0009] 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.

[0010] Example 1 A method for preparing a delayed cross-linking water plugging and profile control agent for oil production, comprising the following steps: weighing the following raw materials in parts by weight: 25 parts of modified polyacrylamide, 12 parts of a composite cross-linking agent, 8 parts of a stabilizer and 2 parts of a deoxidizer, mixing the modified polyacrylamide, the composite cross-linking agent, the stabilizer and the deoxidizer to prepare a delayed cross-linking water plugging and profile control agent for oil production; The deoxidizer is Gabel XH21 deoxidizer; The stabilizer is Lingchuang NW-1 stabilizer; The modified polyacrylamide is prepared by the following steps: Step A1: mixing hydroquinone and dichloromethane, stirring at a rate of 180 rpm and a temperature of 0°C under argon protection, stirring and adding 2-bromoisobutyryl bromide, stirring for 30 minutes, heating to room temperature, reacting for 10 hours, then adding triethylamine, continuing to stir for 10 minutes, then adding deionized water, extracting and collecting the dichloromethane phase, drying over anhydrous magnesium sulfate, filtering, rotary evaporation, and drying to obtain a double-head initiator; mixing the double-head initiator, sodium ascorbate, acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, N,N-dimethylformamide and deionized water, stirring at a rate of 180 rpm and a temperature of 35°C under nitrogen protection, stirring and adding cuprous bromide, reacting for 24 hours, rotary evaporation, recrystallization, filtering, and drying to obtain a macromolecular initiator; The dosage ratio of hydroquinone, dichloromethane, 2-bromoisobutyryl bromide, triethylamine and deionized water is 2g:45mL:5.8mL:0.8mL:45mL; the dosage ratio of double-head initiator, sodium ascorbate, acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, N,N-dimethylformamide, deionized water and cuprous bromide is 0.24g:0.01g:3.5g:2g:10mL:20mL:0.01g; Step A2: Dehydroabietic acid and dichloromethane are mixed, and under nitrogen protection, the stirring rate is 140 rpm, and the temperature is 0°C, oxalyl chloride and N,N-dimethylformamide are added with stirring, and the reaction is carried out for 3 hours, and the mixture is rotary evaporated to obtain intermediate 1. Intermediate 1 is mixed with dichloromethane, and under nitrogen protection, the stirring rate is 140 rpm, and the temperature is 0°C, triethylamine and hydroxyethyl methacrylate are added with stirring, and the reaction is carried out for 48 hours, and the mixture is washed with sodium bicarbonate solution until neutral, dried, and rotary evaporated to obtain intermediate 2; The amount ratio of dehydroabietic acid, dichloromethane, oxalyl chloride and N,N-dimethylformamide is 28g:160mL:25g:0.8mL; the mass fraction of sodium bicarbonate solution is 5%, and the amount ratio of intermediate 1, dichloromethane, triethylamine and hydroxyethyl methacrylate is 24g:160mL:14.5g:14.4g; Step A3: Mix the macromolecular initiator, sodium ascorbate, intermediate 2, N,N-dimethylformamide and deionized water, stir and add cuprous bromide under argon protection, stirring at a rate of 180 rpm and a temperature of 30° C., react for 10 h, rotary evaporate, recrystallize, filter and dry to obtain modified polyacrylamide; The ratio of macromolecular initiator, sodium ascorbate, intermediate 2, N,N-dimethylformamide, deionized water and cuprous bromide is 4.2 g: 0.03 g: 0.8 g: 10 mL: 15 mL: 0.02 g; The composite cross-linking agent is prepared by the following steps: Step B1: Sodium phytate, zirconium dichloride octahydrate and deionized water are mixed, stirred and hydrochloric acid solution is added, the pH value is adjusted to 4, the reaction is carried out at a stirring rate of 240 rpm and a temperature of 80°C for 1 hour, centrifuged, washed, filtered, and ground to obtain a phytic acid zirconium complex; sodium montmorillonite and deionized water are mixed and ultrasonically dispersed for 15 minutes, stirred and the phytic acid zirconium complex and N,N-dimethylformamide are added at a stirring rate of 180 rpm and a temperature of 55°C, stirred for 24 hours, centrifuged, washed, and dried to obtain an intercalated montmorillonite; The mass fraction of hydrochloric acid solution is 30%, the dosage ratio of sodium phytate, zirconium oxychloride octahydrate and deionized water is 9.5g:9.3g:60mL; the dosage ratio of sodium montmorillonite, deionized water, zirconium phytate complex and N,N-dimethylformamide is 0.2g:10mL:1.8g:20mL; The sodium montmorillonite is 200 mesh sodium montmorillonite; Step B2: Mix dextran and deionized water, stir and add sodium periodate in a dark environment at a stirring rate of 140 rpm and room temperature, react for 3 hours, then add ethylene glycol, continue to react for 40 minutes, dialyze with pure water, and dry to obtain oxidized dextran; mix tris(hydroxymethylaminomethane) and hydrochloric acid solution, stir and add intercalated montmorillonite and deionized water at a stirring rate of 140 rpm and a temperature of 60°C, react for 4 hours, then cool to room temperature, add oxidized dextran, and continue to react for 12 hours to obtain a composite cross-linking agent; The dosage ratio of dextran, deionized water, sodium periodate and ethylene glycol is 1.1 g: 10 mL: 0.13 g: 0.34 mL; the molar concentration of the hydrochloric acid solution is 0.375 mol / L, and the dosage ratio of tris(hydroxymethyl)aminomethane, hydrochloric acid solution, intercalated montmorillonite, deionized water and oxidized dextran is 2.2 g: 300 mL: 15 g: 300 mL: 1.8 g; The glucan is source leaf glucan T-1.

[0011] Example 2 A method for preparing a delayed cross-linking water plugging and profile control agent for oil production, comprising the following steps: weighing the following raw materials in parts by weight: 30 parts of modified polyacrylamide, 12 parts of a composite cross-linking agent, 10 parts of a stabilizer and 3 parts of a deoxidizer, mixing the modified polyacrylamide, the composite cross-linking agent, the stabilizer and the deoxidizer to prepare a delayed cross-linking water plugging and profile control agent for oil production; The deoxidizer is Gabel XH21 deoxidizer; The stabilizer is Lingchuang NW-1 stabilizer; The modified polyacrylamide is prepared by the following steps: Step A1: mixing hydroquinone and dichloromethane, stirring at a rate of 180 rpm and a temperature of 5°C under argon protection, stirring and adding 2-bromoisobutyryl bromide, stirring for 30 minutes, heating to room temperature, reacting for 12 hours, then adding triethylamine, continuing to stir for 15 minutes, then adding deionized water, extracting and collecting the dichloromethane phase, drying over anhydrous magnesium sulfate, filtering, rotary evaporation, and drying to obtain a double-head initiator; mixing the double-head initiator, sodium ascorbate, acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, N,N-dimethylformamide and deionized water, stirring and adding cuprous bromide under nitrogen protection, stirring at a rate of 180 rpm and a temperature of 40°C, reacting for 24 hours, rotary evaporation, recrystallization, filtering, and drying to obtain a macromolecular initiator; The dosage ratio of hydroquinone, dichloromethane, 2-bromoisobutyryl bromide, triethylamine and deionized water is 2g:50mL:5.8mL:1mL:45mL; the dosage ratio of double-head initiator, sodium ascorbate, acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, N,N-dimethylformamide, deionized water and cuprous bromide is 0.24g:0.01g:3.5g:2.1g:10mL:25mL:0.01g; Step A2: Dehydroabietic acid and dichloromethane are mixed, and under nitrogen protection, the stirring rate is 180 rpm, the temperature is 0°C, oxalyl chloride and N,N-dimethylformamide are added with stirring, and the reaction is carried out for 4 hours, and rotary evaporation is performed to obtain intermediate 1. Intermediate 1 is mixed with dichloromethane, and under nitrogen protection, the stirring rate is 140 rpm, the temperature is 5°C, triethylamine and hydroxyethyl methacrylate are added with stirring, and the reaction is carried out for 48 hours, and sodium bicarbonate solution is washed until neutral, dried, and rotary evaporation is performed to obtain intermediate 2; The amount ratio of dehydroabietic acid, dichloromethane, oxalyl chloride and N,N-dimethylformamide is 28-30g:160mL:26g:0.8mL; the mass fraction of sodium bicarbonate solution is 5%, and the amount ratio of intermediate 1, dichloromethane, triethylamine and hydroxyethyl methacrylate is 26g:160mL:14.5g:14.5g; Step A3: Mix the macromolecular initiator, sodium ascorbate, intermediate 2, N,N-dimethylformamide and deionized water, stir and add cuprous bromide under argon protection, stirring at a rate of 200 rpm and a temperature of 30° C., react for 10 h, rotary evaporate, recrystallize, filter and dry to obtain modified polyacrylamide; The ratio of macromolecular initiator, sodium ascorbate, intermediate 2, N,N-dimethylformamide, deionized water and cuprous bromide is 4.5 g: 0.03 g: 0.9 g: 10 mL: 18 mL: 0.02 g; The composite cross-linking agent is prepared by the following steps: Step B1: Sodium phytate, zirconium dichloride octahydrate and deionized water are mixed, stirred and hydrochloric acid solution is added, the pH value is adjusted to 4, the reaction is carried out at a stirring rate of 180 rpm and a temperature of 80°C for 1 hour, centrifuged, washed, filtered, and ground to obtain a phytic acid zirconium complex; sodium montmorillonite and deionized water are mixed and ultrasonically dispersed for 10 minutes, stirred and the phytic acid zirconium complex and N,N-dimethylformamide are added at a stirring rate of 180 rpm and a temperature of 50°C, stirred for 24 hours, centrifuged, washed, and dried to obtain an intercalated montmorillonite; The mass fraction of hydrochloric acid solution is 30%, the dosage ratio of sodium phytate, zirconium chloride octahydrate and deionized water is 9.5g:9.2g:60mL; the dosage ratio of sodium montmorillonite, deionized water, zirconium phytate complex and N,N-dimethylformamide is 0.2g:8mL:1.8g:15mL; The sodium montmorillonite is 200 mesh sodium montmorillonite; Step B2: Mix dextran and deionized water, stir and add sodium periodate in a dark environment at a stirring rate of 140 rpm and room temperature, react for 3 hours, then add ethylene glycol, continue to react for 30 minutes, dialyze with pure water, and dry to obtain oxidized dextran; mix trishydroxymethylaminomethane and hydrochloric acid solution, stir and add intercalated montmorillonite and deionized water at a stirring rate of 140 rpm and a temperature of 60°C, react for 3 hours, then cool to room temperature, add oxidized dextran, and continue to react for 12 hours to obtain a composite cross-linking agent; The dosage ratio of dextran, deionized water, sodium periodate and ethylene glycol is 1.1 g: 8 mL: 0.13 g: 0.34 mL; the molar concentration of the hydrochloric acid solution is 0.375 mol / L, and the dosage ratio of tris(hydroxymethyl)aminomethane, hydrochloric acid solution, intercalated montmorillonite, deionized water and oxidized dextran is 2.15 g: 300 mL: 14 g: 300 mL: 1.8 g; The glucan is source leaf glucan T-1.

[0012] Example 3 A method for preparing a delayed cross-linking water plugging and profile control agent for oil production, comprising the following steps: weighing the following raw materials in parts by weight: 30 parts of modified polyacrylamide, 15 parts of a composite cross-linking agent, 10 parts of a stabilizer and 3 parts of a deoxidizer, mixing the modified polyacrylamide, the composite cross-linking agent, the stabilizer and the deoxidizer to prepare a delayed cross-linking water plugging and profile control agent for oil production; The deoxidizer is Gabel XH21 deoxidizer; The stabilizer is Lingchuang NW-1 stabilizer; The modified polyacrylamide is prepared by the following steps: Step A1: mixing hydroquinone and dichloromethane, stirring at a rate of 240 rpm and a temperature of 5°C under argon protection, stirring and adding 2-bromoisobutyryl bromide, stirring for 30 minutes, heating to room temperature, reacting for 12 hours, then adding triethylamine, continuing stirring for 15 minutes, then adding deionized water, extracting and collecting the dichloromethane phase, drying over anhydrous magnesium sulfate, filtering, rotary evaporation, and drying to obtain a double-head initiator; mixing the double-head initiator, sodium ascorbate, acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, N,N-dimethylformamide and deionized water, stirring at a rate of 240 rpm and a temperature of 40°C under nitrogen protection, stirring and adding cuprous bromide, reacting for 24 hours, rotary evaporation, recrystallization, filtering, and drying to obtain a macromolecular initiator; The dosage ratio of hydroquinone, dichloromethane, 2-bromoisobutyryl bromide, triethylamine and deionized water is 2.1g:50mL:5.9mL:1mL:50mL; the dosage ratio of double-head initiator, sodium ascorbate, acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, N,N-dimethylformamide, deionized water and cuprous bromide is 0.25g:0.01g:3.6g:2.1g:15mL:25mL:0.02g; Step A2: Dehydroabietic acid and dichloromethane are mixed, and under nitrogen protection, the stirring rate is 180 rpm, and the temperature is 5°C, oxalyl chloride and N,N-dimethylformamide are added with stirring, and the reaction is carried out for 4 hours, and the mixture is rotary evaporated to obtain intermediate 1. Intermediate 1 is mixed with dichloromethane, and under nitrogen protection, the stirring rate is 180 rpm, and the temperature is 5°C, triethylamine and hydroxyethyl methacrylate are added with stirring, and the reaction is carried out for 48 hours, and the mixture is washed with sodium bicarbonate solution until neutral, dried, and rotary evaporated to obtain intermediate 2; The amount ratio of dehydroabietic acid, dichloromethane, oxalyl chloride and N,N-dimethylformamide is 30g:180mL:26g:1mL; the mass fraction of sodium bicarbonate solution is 5%, and the amount ratio of intermediate 1, dichloromethane, triethylamine and hydroxyethyl methacrylate is 26g:180mL:14.8g:14.5g; Step A3: Mix the macromolecular initiator, sodium ascorbate, intermediate 2, N,N-dimethylformamide and deionized water, stir and add cuprous bromide under argon protection, stirring at a rate of 200 rpm and a temperature of 35° C., react for 12 h, rotary evaporate, recrystallize, filter and dry to obtain modified polyacrylamide; The ratio of macromolecular initiator, sodium ascorbate, intermediate 2, N,N-dimethylformamide, deionized water and cuprous bromide is 4.5 g: 0.05 g: 0.9 g: 12 mL: 18 mL: 0.03 g; The composite cross-linking agent is prepared by the following steps: Step B1: Sodium phytate, zirconium dichloride octahydrate and deionized water are mixed, stirred and hydrochloric acid solution is added, the pH value is adjusted to 4, the reaction is carried out at a stirring rate of 240 rpm and a temperature of 90°C for 1 hour, centrifuged, washed, filtered, and ground to obtain a phytic acid zirconium complex; sodium montmorillonite and deionized water are mixed and ultrasonically dispersed for 15 minutes, stirred and the phytic acid zirconium complex and N,N-dimethylformamide are added at a stirring rate of 240 rpm and a temperature of 55°C, stirred for 24 hours, centrifuged, washed, and dried to obtain an intercalated montmorillonite; The mass fraction of hydrochloric acid solution is 30%, the dosage ratio of sodium phytate, zirconium chloride octahydrate and deionized water is 9.7g:9.3g:70mL; the dosage ratio of sodium montmorillonite, deionized water, zirconium phytate complex and N,N-dimethylformamide is 0.24g:10mL:1.9g:20mL; The sodium montmorillonite is 200 mesh sodium montmorillonite; Step B2: Mix dextran and deionized water, stir and add sodium periodate in a dark environment at a stirring rate of 180 rpm and room temperature, react for 4 hours, then add ethylene glycol, continue to react for 40 minutes, dialyze with pure water, and dry to obtain oxidized dextran; mix tris(hydroxymethylaminomethane) and hydrochloric acid solution, stir and add intercalated montmorillonite and deionized water at a stirring rate of 180 rpm and a temperature of 62°C, react for 4 hours, then cool to room temperature, add oxidized dextran, and continue to react for 12 hours to obtain a composite cross-linking agent; The dosage ratio of dextran, deionized water, sodium periodate and ethylene glycol is 1.2 g: 10 mL: 0.14 g: 0.35 mL; the molar concentration of the hydrochloric acid solution is 0.375 mol / L, and the dosage ratio of tris(hydroxymethyl)aminomethane, hydrochloric acid solution, intercalated montmorillonite, deionized water and oxidized dextran is 2.2 g: 350 mL: 15 g: 350 mL: 2 g; The glucan is source leaf glucan T-1.

[0013] Comparative Example 1 Compared with Example 3, this comparative example is different in that the composite cross-linking agent in the preparation process of the delayed cross-linking water plugging and profile control agent in Example 3 is replaced by the intercalated montmorillonite in Example 3, and the other steps are the same.

[0014] Comparative Example 2 Compared with Example 3, this comparative example removes the intermediate 2 in the preparation process of modified polyacrylamide in Example 3, and the other steps are the same.

[0015] Take the delayed cross-linking water plugging and profile control agent for oil production prepared in Example 1, Example 2, Example 3, Comparative Example 1 and Comparative Example 2, mix 6.5g of the delayed cross-linking water plugging and profile control agent with 1000mL of injection water, the injection water salinity is 6000mg / L, the pH is 6.5, and the gelation time and gelation strength are measured at a temperature of 65°C. Under the condition of a shear rate of 40rad / s, shear for 24h, stand for 30min, and then measure the gelation strength. Calculate the gelation strength retention rate after shearing. The length is 6cm, the diameter is 2.5cm, the porosity is 28.80%, and the permeability is 756×10 -3 μm -2 The plugging rate and residual resistance coefficient of the artificial core were measured at a flow rate of 0.5 mL / min and a temperature of 50°C. The test results are shown in Table 1. Table 1 Test results Test items Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Gelation time (h) 75.5 75.4 75.6 79.4 75.4 Gel strength (mPa·s) 17277 17354 17580 15253 17074 Gel strength retention rate after shearing (%) 94.21 94.19 94.52 91.04 94.28 Blockage rate (%) 97.04 97.18 97.63 92.32 96.87 Residual resistance coefficient 42.41 42.62 42.97 38.31 41.90 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 and Comparative Example 2, Comparative Example 1 replaces the composite cross-linking agent in the preparation process of the delayed cross-linking water plugging and profile control agent in Example 3 with the intercalated montmorillonite in Example 3. Due to the lack of Schiff base structure and hydroxyl group, its strength after gelation decreases. Comparative Example 2 removes the intermediate 2 in the preparation process of the modified polyacrylamide in Example 3. Due to the lack of telechelic block structure, its strength after gelation decreases.

[0016] 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.

[0017] 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, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing a delayed cross-linking water plugging and profile control agent for oil production, characterized in that: The method comprises the following steps: weighing the following raw materials by weight: 25-30 parts of modified polyacrylamide, 12-15 parts of composite crosslinking agent, 8-10 parts of stabilizer and 2-3 parts of deoxidizer, mixing the modified polyacrylamide, composite crosslinking agent, stabilizer and deoxidizer to prepare a delayed crosslinking water plugging and profile control agent for oil production; The composite cross-linking agent is prepared by the following steps: Step B1: Sodium phytate, zirconium dichloride octahydrate and deionized water are mixed, stirred and hydrochloric acid solution is added, the pH value is adjusted to 4, the reaction is carried out for 1 hour at a stirring rate of 180-240 rpm and a temperature of 80-90°C, centrifuged, washed, filtered, and ground to obtain a zirconium phytate complex; sodium montmorillonite and deionized water are mixed and ultrasonically dispersed for 10-15 minutes, stirred and the zirconium phytate complex and N,N-dimethylformamide are added at a stirring rate of 180-240 rpm and a temperature of 50-55°C, stirred for 24 hours, centrifuged, washed, and dried to obtain an intercalated montmorillonite; Step B2: Mix dextran and deionized water, stir and add sodium periodate under the condition of avoiding light, stirring at a rate of 140-180 rpm, room temperature, react for 3-4 hours, then add ethylene glycol, continue to react for 30-40 minutes, dialyze with pure water, dry, and obtain oxidized dextran; mix trihydroxymethylaminomethane and hydrochloric acid solution, stir and add intercalated montmorillonite and deionized water under the condition of stirring at a rate of 140-180 rpm, temperature of 60-62°C, react for 3-4 hours, then cool to room temperature, add oxidized dextran, and continue to react for 12 hours to obtain a composite cross-linking agent.

2. The method for preparing a delayed cross-linking water plugging and profile control agent for oil production according to claim 1, characterized in that: In step B1: the mass fraction of the hydrochloric acid solution is 30%, the amount ratio of sodium phytate, zirconium dichloride octahydrate and deionized water is 9.5-9.7g:9.2-9.3g:60-70mL; the amount ratio of sodium montmorillonite, deionized water, zirconium phytate complex and N,N-dimethylformamide is 0.2-0.24g:8-10mL:1.8-1.9g:15-20mL.

3. The method for preparing a delayed cross-linking water plugging and profile control agent for oil production according to claim 1, characterized in that: In step B2, the dosage ratio of dextran, deionized water, sodium periodate and ethylene glycol is 1.1-1.2 g: 8-10 mL: 0.13-0.14 g: 0.34-0.35 mL; the molar concentration of the hydrochloric acid solution is 0.375 mol / L, and the dosage ratio of tris(hydroxymethyl)aminomethane, hydrochloric acid solution, intercalated montmorillonite, deionized water and oxidized dextran is 2.15-2.2 g: 300-350 mL: 14-15 g: 300-350 mL: 1.8-2 g.

4. The method for preparing a delayed cross-linking water plugging and profile control agent for oil production according to claim 1, characterized in that: The modified polyacrylamide is prepared by the following steps: Step A1: mixing hydroquinone and dichloromethane, stirring at a rate of 180-240 rpm and a temperature of 0-5°C, stirring and adding 2-bromoisobutyryl bromide, stirring for 30 minutes, heating to room temperature, reacting for 10-12 hours, then adding triethylamine, continuing to stir for 10-15 minutes, then adding deionized water, extracting and collecting the dichloromethane phase, drying over anhydrous magnesium sulfate, filtering, rotary evaporation, and drying to obtain a double-head initiator; mixing the double-head initiator, sodium ascorbate, acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, N,N-dimethylformamide and deionized water, stirring at a rate of 180-240 rpm and a temperature of 35-40°C, adding cuprous bromide, reacting for 24 hours, rotary evaporation, recrystallization, filtering, and drying to obtain a macromolecular initiator; Step A2: Mix dehydroabietic acid and dichloromethane, stir and add oxalyl chloride and N,N-dimethylformamide under nitrogen protection, stirring rate of 140-180 rpm, temperature of 0-5°C, react for 3-4 hours, and rotary evaporate to obtain intermediate 1; mix intermediate 1 and dichloromethane, stir and add triethylamine and hydroxyethyl methacrylate under nitrogen protection, stirring rate of 140-180 rpm, temperature of 0-5°C, and react for 48 hours, wash with sodium bicarbonate solution until neutral, dry, and rotary evaporate to obtain intermediate 2; Step A3: Mix the macromolecular initiator, sodium ascorbate, intermediate 2, N,N-dimethylformamide and deionized water, stir and add cuprous bromide under argon protection, stirring rate of 180-200 rpm, temperature of 30-35°C, react for 10-12h, rotary evaporate, recrystallize, filter and dry to obtain modified polyacrylamide.

5. The method for preparing a delayed cross-linking water plugging and profile control agent for oil production according to claim 4, characterized in that: In step A1: the amount ratio of hydroquinone, dichloromethane, 2-bromoisobutyryl bromide, triethylamine and deionized water is 2-2.1g:45-50mL:5.8-5.9mL:0.8-1mL:45-50mL; the amount ratio of double-head initiator, sodium ascorbate, acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, N,N-dimethylformamide, deionized water and cuprous bromide is 0.24-0.25g:0.01g:3.5-3.6g:2-2.1g:10-15mL:20-25mL:0.01-0.02g.

6. The method for preparing a delayed cross-linking water plugging and profile control agent for oil production according to claim 4, characterized in that: In step A2, the amount ratio of dehydroabietic acid, dichloromethane, oxalyl chloride and N,N-dimethylformamide is 28-30 g: 160-180 mL: 25-26 g: 0.8-1 mL; the mass fraction of the sodium bicarbonate solution is 5%, and the amount ratio of the intermediate 1, dichloromethane, triethylamine and hydroxyethyl methacrylate is 24-26 g: 160-180 mL: 14.5-14.8 g: 14.4-14.5 g.

7. The method for preparing a delayed cross-linking water plugging and profile control agent for oil production according to claim 4, characterized in that: In step A3: the ratio of macromolecular initiator, sodium ascorbate, intermediate 2, N,N-dimethylformamide, deionized water and cuprous bromide is 4.2-4.5g: 0.03-0.05g: 0.8-0.9g: 10-12mL: 15-18mL: 0.02-0.03g.

8. A delayed cross-linking water plugging and profile control agent for oil production, characterized in that: Prepared according to any one of claims 1 to 7.

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