Disulfonate hydrophobic association polymer oil-displacing agent with benzene ring structure and preparation method of disulfonate hydrophobic association polymer oil-displacing agent

Abstract

The invention relates to a bisulfonate hydrophobic association polymer oil-displacing agent with a benzene ring structure and a preparation method thereof. The polymer oil-displacing agent is formed by copolymerization of three monomers, namely acrylamide, sodium 2-allyl methylamino ethanesulfonate and long-chain alkyl disulfoethyl (4-vinyl benzyl) betaine which is a hydrophobic monomer with the benzene ring structure. The preparation method comprises the following steps: firstly adding distilled water, sequentially adding acrylamide, 2-allylmethylamino sodium ethanesulfonate and long-chain alkyl disulfoethyl (4-vinyl benzyl) betaine, adding water to adjust the total concentration, introducing N2 to remove oxygen, adding an initiator, and reacting at a certain temperature to obtain the terpolymer. The polymer oil-displacing agent prepared by the invention has good water solubility and good temperature resistance and shear resistance, shows good salt resistance in saline water with the degree of mineralization being greater than or equal to 30000 mg / L, shows a good oil-displacing effect in heterogeneous rock cores, and can improve the crude oil recovery rate by 10% or above.

Description

Technical Field

[0001] The present invention relates to an oil recovery auxiliary agent, in particular to a hydrophobically associating polymer oil-displacing agent containing a cyclic hydrophobic group, specifically a hydrophobically associating polymer oil-displacing agent with a benzene ring structure disulfonate. The present invention also relates to a preparation method of the hydrophobically associating polymer oil-displacing agent with a benzene ring structure disulfonate. Background Art

[0002] Polymer flooding technology is an important tertiary oil recovery technology. It uses polymer aqueous solution as a flooding agent to increase the viscosity of the injected water and improve its sweep efficiency, thereby achieving the purpose of increasing crude oil recovery. Since the 1990s, polymer flooding technology has been widely used in oil fields and has achieved significant water reduction and oil increase effects, playing an important role in stabilizing the production of old oil fields. Currently, polymer flooding mainly uses partially hydrolyzed polyacrylamide (HPAM). However, HPAM is very sensitive to salt, and the amide group on the molecular chain is easily hydrolyzed when the temperature is higher than 70°C, resulting in a significant decrease in its viscosity, making it unsuitable for high-temperature and high-salinity reservoirs. In order to improve the temperature and salt resistance of polymers, meet the conditions of high-temperature and high-salinity reservoirs, and carry out production-increasing measures such as polymer flooding, composite flooding, profile adjustment, and deep flow diversion technology, the research and development of temperature-resistant and salt-resistant polymers has been one of the topics that scholars at home and abroad have been competing to study in recent years, among which hydrophobic associating polymers are one of the products.

[0003] The study of hydrophobic associating polymers began in the 1950s. In 1987, Evani and Roes used maleic anhydride / styrene copolymers to partially esterify long-chain alkyl polyvinyl ethers to prepare hydrophobically modified aqueous solution polymers, and used the hydrophobic associating polymers in oil field exploitation and studied their temperature and salt resistance. The results showed that these copolymers all showed relatively obvious viscosity increase and salt resistance (Evani S, Rose G D. Water soluble hydrophobe association polymers [J]. Polymer Material Science Engineering, 1987, 57: 477-481). In the late 1990s in my country, many experts and scholars also studied hydrophobic associating polymers. Academician Luo Pingya of Southwest Petroleum Institute designed a hydrophobic associating water-soluble polymer for crude oil exploitation based on the actual needs of oil and gas exploitation engineering and combined the basic principles of polymer science and colloid chemistry (Zheng Yan. Synthesis and solution performance of associating polymers for oil and gas exploitation [D]. Doctoral dissertation of Southwest Petroleum Institute, 1999.6), and developed a series of products. At present, hydrophobic associative polymerization has been developed and applied in many offshore oil fields and has achieved good results.

[0004] Related patent literature: CN 103059217A discloses a heat-resistant and salt-resistant hydrophobic associating polymer and a preparation method thereof. The preparation scheme: the mass is in grams, the monomer mass percentage is, acrylamide AM 57.0-59.8%, sodium acrylate NaAA 39.3-40.0%, N-allylphenylacetamide NAPA 0.1-0.2%, N, N-dimethyl-N-allyl hexadecyl ammonium chloride AHAC 0.1-3.5%; the preparation method is to add NAPA, AHAC and an emulsifier into a reactor, add water to emulsify completely; then add NaAA and AM, adjust the pH to 7, then add an initiator, wash, crush and dry after the reaction to obtain a polymer product. CN102391418A discloses a water-soluble hydrophobic associating polymer oil-displacing agent for oil reservoir flooding to improve crude oil recovery and a synthesis method thereof. It is water-soluble, increases the viscosity of the solution, and exhibits good heat and salt resistance and shear resistance. Its technical scheme: The oil displacement agent is a ternary polymer composed of acrylamide, sodium acrylate, and N, N-diallyl oleyl imide; the mass percentages of the monomers used are: AM 53.5-59.9, NaAA 40-45, and DNDA 0.1-1.5. Its synthesis method: Add the prepared DNDA into a flask, then add OP-10 emulsifier and water, stir and emulsify, add AM, acrylic acid and NaOH, prepare a 10-25% solution, adjust the pH to 7.5-11, pass N2 for 20 minutes, then add an initiator and pass N2 for 10-20 minutes, react at 30-60°C for 4-12 hours; finally wash, crush, and dry to obtain an AM / NaAA / DNDA polymer. CN104152130A discloses a water-soluble EOR agent containing an imidazoline structure hydrophobic associating polymer oil displacement agent AM / NaAA / NIDA and its synthesis method. The technical scheme is as follows: a certain amount of NIDA, OP-10 and deionized water are put into a flask, stirred and emulsified, and then AM and AA are added to prepare an aqueous solution with a monomer concentration of 10-20wt%, the pH is adjusted, N2 is passed for 20 minutes and the temperature is raised to 40°C; an initiator (ammonium persulfate and sodium bisulfite molar ratio is 1:1) is added, and the amount of initiator added is 0.8wt% of the total weight of the monomer, N2 is continued to be passed and the reaction is carried out at a constant temperature (40°C) for 8-12 hours; white polymer powder is obtained by washing with ethanol, crushing and drying. The polymer has good heat resistance, shear resistance and salt resistance, and the recovery rate is increased by 13.52% in the indoor simulated core displacement experiment.

[0005] The hydrophobic associating polymer synthesized by the above technology has certain temperature and salt resistance, and has good viscosity increasing ability below the mineralization degree of 30000 mg / L, but its salt resistance is poor when the mineralization degree is ≥30000 mg / L. Summary of the invention

[0006] The purpose of the present invention is to provide a hydrophobically associating polymer oil-displacing agent with a benzene ring structure and a disulfonate, which has good performance, good viscosity increasing ability under high temperature and high salinity, and good shear resistance, can achieve a higher recovery rate, and can meet the technical requirements of a polymer oil-displacing agent with a wide range of uses on the market, thereby ensuring the smooth progress of oil production in high-temperature and high-salinity oil fields, and solving the problems that the existing hydrophobically associating polymer has poor temperature and salt resistance in brine with high salinity (mineralization ≥30000 mg / L), is easily hydrolyzed underground, and has a low crude oil recovery rate.

[0007] To this end, another object of the present invention is to provide a method for preparing a hydrophobically associating polymer oil-displacing agent of a disulfonate salt with a benzene ring structure.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0009] A (water-soluble) hydrophobic associating polymer oil-displacing agent with a benzene ring structure disulfonate, the technical scheme of which is that it is composed of acrylamide AM, 2-allylmethylaminoethylsulfonate sodium AMES-Na and a hydrophobic monomer with a benzene ring structure long-chain alkyl disulfoethyl (4-vinylbenzyl) betaine C n DSVBBA is copolymerized by three monomers, and the structural formula of the polymer oil displacement agent is as follows:

[0010]

[0011] In the above structural formula, x, y, and z are the molar percentage ranges of the structural units: x=69% to 84.7%, y=15% to 30%, z=0.3% to 1%, x+y+z=100%, wherein n=12, 14, 16, 18, 20.

[0012] The water-soluble disulfonate hydrophobically associated polymer oil-displacing agent with a benzene ring structure has the following molar fractions of each monomer (i.e., the oil-displacing agent is made of the following molar fractions of monomers): 69 to 84.7 parts of acrylamide AM, 15 to 30 parts of 2-allylmethylaminoethylsulfonic acid sodium AMES-Na, and a long-chain alkyl disulfoethyl (4-vinylbenzyl) betaine C having a benzene ring structure hydrophobic monomer. n DSVBBA 0.3~1 part.

[0013] The preparation method of the above-mentioned 2-allylmethylaminoethanesulfonic acid sodium AMES-Na comprises the following process steps: in a (500mL) three-necked flask equipped with a thermometer, a reflux condenser with a Soxhlet extractor and a magnetic rotor, adding an appropriate amount of anhydrous ethanol as a solvent, adding 65-95g of 2-chloroethylsulfonic acid sodium at room temperature (temperature is 23-25°C), then slowly adding 30-43g of N-methylallylamine under stirring, adding 0.15-0.21g of inhibitor methylhydroquinone, and charging 32-47g of an acid binding agent wrapped with filter paper into the Soxhlet extractor, raising the temperature to reflux, reacting at a constant temperature for 20-25 hours, and removing the solvent and excess N-methylallylamine by reduced pressure distillation using a rotary evaporator to obtain 2-allylmethylaminoethanesulfonic acid sodium AMES-Na.

[0014] The above hydrophobic monomer long-chain alkyl disulfoethyl (4-vinylbenzyl) betaine C with a benzene ring structure n The preparation method of DSVBBA comprises the following process steps: (1) adding an appropriate amount of anhydrous ethanol as a solvent to a three-necked flask (500 mL) equipped with a thermometer, a reflux condenser with a Soxhlet extractor and a magnetic rotor, adding 40 to 60 g of a long-chain alkylamine at room temperature (temperature of 23 to 25° C.), then slowly adding 60 to 80 g of sodium 2-chloroethylsulfonate under stirring, adding 28 to 39 g of an acid binding agent wrapped with filter paper to the Soxhlet extractor, raising the temperature to reflux, reacting at a constant temperature for 30 to 35 hours, removing the solvent by reduced pressure distillation using a rotary evaporator, and recrystallizing using anhydrous ethanol to obtain a long-chain alkyl disulfoethyl tertiary amine; (2) adding a reflux condenser with a thermometer, a Soxhlet extractor and a magnetic rotor, and then slowly adding 60 to 80 g of sodium 2-chloroethylsulfonate under stirring, and adding 28 to 39 g of an acid binding agent wrapped with filter paper to the Soxhlet extractor, raising the temperature to reflux, and reacting at a constant temperature for 30 to 35 hours, and then removing the solvent by reduced pressure distillation using a rotary evaporator, and recrystallizing using anhydrous ethanol to obtain a long-chain alkyl disulfoethyl tertiary amine; (3) A (500 mL) three-necked flask with a flow condenser and a magnetic rotor is added with an appropriate amount of anhydrous ethanol as a solvent, and 60 to 90 g of long-chain alkyl disulfoethyl tertiary amine is added at room temperature (temperature is 23 to 25° C.), and then 30 to 45 g of 4-vinylbenzyl chloride (i.e., 4-vinylbenzyl chloride) is slowly added under stirring, and 0.2 to 0.3 g of methyl hydroquinone as an inhibitor is added, and the temperature is raised to reflux. After constant temperature reaction for 10 to 12 hours, the solvent is removed by reduced pressure distillation using a rotary evaporator, and 4-vinylbenzyl chloride is separated by distilled water, and water is removed by reduced pressure distillation, and recrystallization is performed using acetone to obtain a hydrophobic monomer long-chain alkyl disulfoethyl (4-vinylbenzyl) betaine C with a benzene ring structure is obtained. n DSVBBA.

[0015] The preparation method of the hydrophobically associated polymer oil-displacing agent with a benzene ring structure disulfonate comprises the following process steps: firstly, 1000 to 1500 mole parts of distilled water are added into a reactor, and 69 to 84.7 mole parts of acrylamide AM, 15 to 30 mole parts of 2-allylmethylaminoethylsulfonate AMES-Na, long-chain alkyl disulfoethyl (4-vinylbenzyl) betaine C are added in sequence under stirring.n 0.3-1 molar portion of DSVBBA, and then distilled water are added to control the total mass percentage concentration of the reaction monomers to be between 15% and 30% (the total mass percentage concentration of the reaction monomers is the mass percentage concentration of the above three monomers combined, the same below), and after stirring evenly (stirring the solution until the solution is a nearly transparent homogeneous system), N2 is passed through for 30 minutes; then an initiator is added, and N2 is continued to be passed through, and the reaction is carried out for 4-10 hours under nitrogen protection at 30-60°C; after the reaction, the obtained gel product is washed with anhydrous ethanol, and the product is crushed and dried to obtain AM / AMES / C n DSVBBA terpolymer is a disulfonate hydrophobically associated polymer oil displacement agent with a benzene ring structure.

[0016] In the above technical scheme, the preferred technical scheme may be that the initiator is a composite initiator, including an oxidation-reduction system initiator and a water-soluble azo initiator; in the oxidation-reduction system initiator, the oxidant is potassium persulfate or ammonium persulfate, the reductant is sodium bisulfite, and the molar ratio of the oxidant to the reductant is 1:1 to 1.5; the water-soluble azo initiator is one or a combination of azobisisobutylamidine hydrochloride (V-50), azobisisobutylimidazoline hydrochloride (VA-044), and azobis(N-2-carboxyethyl-2-methylpropionamidine) hydrate (VA-057), and the ratio thereof is arbitrary when combined; in the composite initiator, the mass ratio of the oxidation-reduction system initiator to the water-soluble azo initiator is 1:1 to 2.

[0017] In the above technical solution, the preferred technical solution can also be that the hydrophobic monomer long-chain alkyl disulfoethyl (4-vinylbenzyl) betaine C with a benzene ring structure n In DSVBBA, the long-chain alkyl is octadecyl, the long-chain alkylamine in step (1) is octadecylamine (i.e., octadecylamine), and the final product in step (2) is a hydrophobic monomer having a benzene ring structure, octadecyl disulfoethyl (4-vinylbenzyl) betaine C 18 DSVBBA. See Example 1.

[0018] In the above technical solution, the preferred technical solution can also be that the hydrophobic monomer long-chain alkyl disulfoethyl (4-vinylbenzyl) betaine C with a benzene ring structure n In the DSVBBA monomer, the long-chain alkyl is hexadecyl, the long-chain alkylamine in step (1) is hexadecylamine, and the final product in step (2) is hexadecyl disulfoethyl (4-vinylbenzyl) betaine C having a benzene ring structure. 16 DSVBBA. See Example 2.

[0019] In the above technical solution, a preferred technical solution can also be that the acid binding agent can be potassium carbonate or sodium carbonate, etc.; the added amount of the initiator is 0.05% to 0.2% of the total mass of the reaction monomers, and the total mass of the reaction monomers is the total mass of the three monomers mentioned above.

[0020] Among the above technical solutions, a preferred technical solution may also be Embodiment 1 of the present invention.

[0021] The polymer oil displacement agent of the present invention is composed of acrylamide AM, 2-allylmethylaminoethylsulfonic acid sodium AMES-Na and a long-chain alkyl disulfoethyl (4-vinylbenzyl) betaine C with a benzene ring structure hydrophobic monomer. n Preparation method: Add an appropriate amount of distilled water into the reactor, add acrylamide AM, 2-allylmethylaminoethylsulfonate AMES-Na, long-chain alkyl disulfoethyl (4-vinylbenzyl) betaine C with a benzene ring structure hydrophobic monomer, and then add 1% d-butyl sulfonate. n DSVBBA, and then add distilled water to make the total concentration of the reaction monomer reach the design requirement. After stirring evenly, N2 is passed to deoxygenate, and then the initiator is added. At a certain temperature, the reaction is carried out to obtain AM / AMES / C n The DSVBBA terpolymer is the polymer oil-displacing agent. The present invention introduces a hydrophobic chain, a sulfonic acid group and a benzene ring structure into the polymer chain to improve the polymer's viscosity-increasing ability and salt resistance, and increases the rigidity of the molecular chain by introducing a ring structure, thereby improving the polymer's thermal stability and shear resistance. Sulfonic acid groups are introduced into the molecular chain to improve the water solubility and salt resistance of the polymer, meeting the actual construction needs of injection water with a mineralization of ≥30000 mg / L on site. The polymer oil-displacing agent prepared by the present invention has good water solubility, shows good temperature and salt resistance in salt water with a mineralization of ≥30000 mg / L, and shows good oil recovery effect in oil displacement experiments, which can increase crude oil recovery by more than 10%.

[0022] Compared with the prior art, the present invention has the following effects: (1) by introducing long hydrophobic chains and benzene rings, the rigidity of the polymer molecular chain is greatly enhanced and the hydrophobic association between copolymer molecules is increased, thereby greatly increasing the viscosity and rheological properties of the polymer and significantly improving the temperature resistance of the polymer; (2) by introducing sulfonic acid groups, the salt resistance of the polymer is improved; (3) the polymer exhibits good temperature resistance, salt resistance and shear thinning resistance, and can effectively improve the crude oil recovery rate.

[0023] Referring to the experimental (test) part of the present invention below, in summary, the present invention provides a (water-soluble) hydrophobically associating polymer oil-displacing agent with a benzene ring structure disulfonate, which has good performance, good viscosity increasing ability at high temperature and high salinity, and good shear resistance, can achieve a higher recovery rate, and can meet the technical requirements of polymer oil-displacing agents with a wide range of uses on the market, thereby ensuring the smooth progress of oil production in high-temperature and high-salinity oil fields, and solving the problems of poor temperature and salt resistance of existing hydrophobically associating polymers in brine with high salinity (mineralization ≥ 30000 mg / L), easy hydrolysis underground, and low crude oil recovery rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is the infrared spectrum of the copolymer (oil-displacing agent) synthesized (prepared) in Example 1 of the present invention.

[0025] Figure 2 Graph showing the relationship between the apparent viscosity of the copolymer (oil displacing agent) synthesized in Example 1 of the present invention and the change in concentration.

[0026] Figure 3 Graph showing the relationship between the apparent viscosity of the copolymer (oil displacing agent) synthesized in Example 1 of the present invention and the change in temperature.

[0027] Figure 4 The figure is a relationship diagram of the apparent viscosity of the copolymer (oil displacement agent) synthesized in Example 1 of the present invention as a function of the salinity.

[0028] Figure 5 Graph showing the relationship between the apparent viscosity of the copolymer (oil displacing agent) synthesized in Example 1 of the present invention and the shear rate.

[0029] Figure 6 This is a diagram showing the oil displacement effect of the copolymer (oil displacement agent) synthesized in Example 1 of the present invention. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described in conjunction with the embodiments below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. Based on this embodiment, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of the present invention.

[0031] Example 1: The hydrophobically associated polymer oil displacement agent with a benzene ring structure disulfonate according to the present invention is prepared from the following monomers in molar fractions (copolymerized from three monomers): 79.15 parts of acrylamide AM, 20.48 parts of 2-allylmethylaminoethylsulfonate AMES-Na, and 10.5 parts of a hydrophobic monomer with a benzene ring structure, long-chain alkyl disulfoethyl (4-vinylbenzyl) betaine C n DSVBBA 0.37 parts. The structural formula of the polymer oil displacement agent is as follows:

[0032]

[0033] In the above structural formula, x, y, and z are the molar percentage ranges of the structural units: x=79.15%, y=20.48%, z=0.37%, x+y+z=100%, wherein n=12, 14, 16, 18, 20. In this embodiment, n=16.

[0034] The above-mentioned hydrophobic monomer long-chain alkyl disulfoethyl (4-vinylbenzyl) betaine C with a benzene ring structure n In DSVBBA, the long-chain alkyl is octadecyl, the long-chain alkylamine in the following step (1) is octadecylamine, and the final product in the following step (2) is octadecyl disulfoethyl (4-vinylbenzyl) betaine C having a hydrophobic monomer having a benzene ring structure. 18 DSVBBA.

[0035] The preparation method of the above-mentioned 2-allylmethylaminoethanesulfonic acid sodium AMES-Na comprises the following process steps: in a 500mL three-necked flask equipped with a thermometer, a reflux condenser with a Soxhlet extractor and a magnetic rotor, 180mL of anhydrous ethanol is added as a solvent, 70g of sodium 2-chloroethylsulfonate is added at a temperature of 25°C, and then 32g of N-methylallylamine is slowly added under stirring, 0.16g of methylhydroquinone as an inhibitor is added, 35g of potassium carbonate (acid binding agent) wrapped with filter paper is loaded into the Soxhlet extractor, the temperature is raised to reflux, and after isothermal reaction for 23 hours, the solvent and excess N-methylallylamine are removed by reduced pressure distillation using a rotary evaporator to obtain 2-allylmethylaminoethanesulfonic acid sodium AMES-Na.

[0036] The hydrophobic monomer octadecyl disulfoethyl (4-vinylbenzyl) betaine C having a benzene ring structure 18The preparation method of DSVBBA comprises the following process steps: (1) adding 180 mL of anhydrous ethanol as a solvent to a 500 mL three-necked flask equipped with a thermometer, a reflux condenser with a Soxhlet extractor and a magnetic rotor, adding 54 g of octadecylamine at a temperature of 25° C., and then slowly adding 63 g of sodium 2-chloroethylsulfonate under stirring, adding 31 g of potassium carbonate (acid binding agent) wrapped with filter paper to the Soxhlet extractor, raising the temperature to reflux, reacting at a constant temperature for 33 hours, removing the solvent by reduced pressure distillation using a rotary evaporator, and recrystallizing using anhydrous ethanol to obtain octadecyl disulfoethyl tertiary amine; (2) In a 500mL three-necked flask equipped with a thermometer, a reflux condenser and a magnetic rotor, 200mL of anhydrous ethanol is added as a solvent, 90g of octadecyl disulfoethyl tertiary amine is added at a temperature of 25°C, and then 40g of 4-vinylbenzyl chloride is slowly added under stirring, and 0.25g of methyl hydroquinone as an inhibitor is added, and the temperature is raised to reflux. After constant temperature reaction for 12 hours, the solvent is removed by vacuum distillation using a rotary evaporator, and 4-vinylbenzyl chloride is separated by distilled water. Water is removed by vacuum distillation, and recrystallization is performed using acetone to obtain a hydrophobic monomer octadecyl disulfoethyl (4-vinylbenzyl) betaine C having a benzene ring structure. 18 DSVBBA.

[0037] The preparation method of the hydrophobically associated polymer oil-displacing agent with a benzene ring structure disulfonate comprises the following process steps: firstly, 1000 mole parts of distilled water are added into a reactor, and then 79.15 mole parts of acrylamide AM, 0.48 mole parts of 2-allylmethylaminoethylsulfonate AMES-Na and octadecyl disulfoethyl (4-vinylbenzyl) betaine C having a benzene ring structure hydrophobic monomer are added in sequence under stirring. 18 0.37 molar parts of DSVBBA, and then distilled water was added to control the total mass percentage concentration of the reaction monomers to 25%, and after stirring evenly, N2 was passed for 30 minutes; then 0.09% of the initiator of the total mass of the reaction monomers was added (the total mass of the reaction monomers was the total mass of the three monomers mentioned above), and N2 was continued to be passed, and the reaction was carried out under nitrogen protection at 45°C for 8 hours; after the reaction was completed, the obtained gel product was washed with anhydrous ethanol, and the product was crushed and dried to obtain AM / AMES / C n DSVBBA terpolymer, the terpolymer is a disulfonate hydrophobically associated polymer oil-displacing agent with a benzene ring structure (that is, the polymer oil-displacing agent of the present invention).

[0038] The above-mentioned initiator is a composite initiator, including an oxidation-reduction system initiator and a water-soluble azo initiator. In the above-mentioned oxidation-reduction system initiator, the oxidant is potassium persulfate, the reductant is sodium bisulfite, and the molar ratio of the oxidant to the reductant is 1:1. The above-mentioned water-soluble azo initiator is a combination of azobisisobutylimidazoline hydrochloride (VA-044) and azobisisobutylamidine hydrochloride (V-50), and the mass ratio of VA-044 to V-50 is 2:1. In the composite initiator, the mass ratio of the oxidation-reduction system initiator to the water-soluble azo initiator is 1:1.6.

[0039] Preparation Comparative Example: For the convenience of the experimental part of the present invention, AM / AMES / C 18 The DSVBBA terpolymer is abbreviated as PAAC (ie, the polymer oil displacement agent of the present invention). Under the same conditions, acrylamide AM and acrylic acid AA are used to synthesize partially hydrolyzed polyacrylamide HPAM (comparative example).

[0040] Example 2: The hydrophobically associated polymer oil displacement agent with a benzene ring structure disulfonate of the present invention is prepared from the following monomers in molar fractions (copolymerized from three monomers): 80.32 parts of acrylamide AM, 19.21 parts of 2-allylmethylaminoethylsulfonate AMES-Na, and 19.21 parts of a hydrophobic monomer with a benzene ring structure long-chain alkyl disulfoethyl (4-vinylbenzyl) betaine C n DSVBBA 0.47 parts. The structural formula of the polymer oil-displacing agent is the same as that of Example 1.

[0041] In the above structural formula, x, y, and z are the molar percentage ranges of the structural units: x=80.32%, y=19.21%, z=0.47%, x+y+z=100%, wherein n=12, 14, 16, 18, 20. In this embodiment, n=14.

[0042] The above-mentioned hydrophobic monomer long-chain alkyl disulfoethyl (4-vinylbenzyl) betaine C with a benzene ring structure n In the DSVBBA monomer, the long-chain alkyl is hexadecyl, the long-chain alkylamine in the following step (1) is hexadecylamine, and the final product in the following step (2) is a hydrophobic monomer hexadecyl disulfoethyl (4-vinylbenzyl) betaine C having a benzene ring structure. 16 DSVBBA.

[0043] The preparation method of the above-mentioned 2-allylmethylaminoethanesulfonic acid sodium AMES-Na comprises the following process steps: in a 500mL three-necked flask equipped with a thermometer, a reflux condenser with a Soxhlet extractor and a magnetic rotor, 180mL of anhydrous ethanol is added as a solvent, 77g of sodium 2-chloroethylsulfonate is added at a temperature of 25°C, and then 35g of N-methylallylamine is slowly added under stirring, 0.17g of methylhydroquinone as an inhibitor is added, 38g of potassium carbonate (acid binding agent) wrapped with filter paper is loaded into the Soxhlet extractor, the temperature is increased to reflux, and after constant temperature reaction for 24 hours, the solvent and excess N-methylallylamine are removed by reduced pressure distillation using a rotary evaporator to obtain 2-allylmethylaminoethanesulfonic acid sodium AMES-Na.

[0044] The hydrophobic monomer hexadecyl disulfoethyl (4-vinylbenzyl) betaine C having a benzene ring structure 16 The preparation method of DSVBBA comprises the following process steps: (1) adding 180 mL of anhydrous ethanol as a solvent to a 500 mL three-necked flask equipped with a thermometer, a reflux condenser with a Soxhlet extractor and a magnetic rotor, adding 44 g of hexadecylamine at a temperature of 25° C., and then slowly adding 60 g of sodium 2-chloroethylsulfonate under stirring, adding 29 g of potassium carbonate (acid binding agent) wrapped with filter paper to the Soxhlet extractor, raising the temperature to reflux, reacting at a constant temperature for 35 hours, removing the solvent by reduced pressure distillation using a rotary evaporator, and recrystallizing using anhydrous ethanol to obtain hexadecyl disulfoethyl tertiary amine; (2) In a 500mL three-necked flask equipped with a thermometer, a reflux condenser and a magnetic rotor, 180mL of anhydrous ethanol was added as a solvent, 85g of hexadecyl disulfoethyl tertiary amine was added at a temperature of 25°C, and then 41g of 4-vinylbenzyl chloride was slowly added under stirring, and 0.23g of methyl hydroquinone as an inhibitor was added, and the temperature was raised to reflux. After constant temperature reaction for 11 hours, the solvent was removed by vacuum distillation using a rotary evaporator, and then 4-vinylbenzyl chloride was separated by distilled water, water was removed by vacuum distillation, and recrystallization was performed using acetone to obtain a hydrophobic monomer hexadecyl disulfoethyl (4-vinylbenzyl) betaine C having a benzene ring structure. 16 DSVBBA.

[0045] The preparation method of the hydrophobically associated polymer oil-displacing agent with a benzene ring structure disulfonate comprises the following process steps: firstly, 1200 mole parts of distilled water are added into a reactor, and then 0.32 mole parts of acrylamide AM8, 19.21 mole parts of sodium 2-allylmethylaminoethanesulfonate and hexadecyl disulfoethyl (4-vinylbenzyl) betaine C with a benzene ring structure hydrophobic monomer are added in sequence under stirring. 160.47 molar parts of DSVBBA, and then distilled water was added to control the total mass percentage concentration of the reaction monomers to 20%, and after stirring evenly, N2 was passed for 30 minutes; then 0.1% of the initiator of the total mass of the reaction monomers was added (the total mass of the reaction monomers was the total mass of the three monomers mentioned above), and N2 was continued to be passed, and the reaction was carried out under nitrogen protection at 50°C for 7 hours; after the reaction was completed, the obtained gel product was washed with anhydrous ethanol, and the product was crushed and dried to obtain AM / AMES / C 16 DSVBBA terpolymer, the terpolymer is a disulfonate hydrophobically associated polymer oil-displacing agent with a benzene ring structure (that is, the polymer oil-displacing agent of the present invention).

[0046] The above-mentioned initiator is a composite initiator, including an oxidation-reduction system initiator and a water-soluble azo initiator. In the above-mentioned oxidation-reduction system initiator, the oxidant is ammonium persulfate, the reductant is sodium bisulfite, and the molar ratio of the oxidant to the reductant is 1:1.2. The above-mentioned water-soluble azo initiator is azobisisobutylamidine hydrochloride (V-50). In the composite initiator, the mass ratio of the oxidation-reduction system initiator to the water-soluble azo initiator is 1:1.2.

[0047] The following is the experimental (test) part of the present invention:

[0048] For the convenience of expression in the following experimental part of the present invention, AM / AMES / C 18 The DSVBBA terpolymer is abbreviated as PAAC (ie, the polymer oil displacement agent of the present invention). Under the same conditions, acrylamide AM and acrylic acid AA are used to synthesize partially hydrolyzed polyacrylamide HPAM (comparative example).

[0049] Experiment 1: AM / AMES / C 18 Structural characterization of the DSVBBA terpolymer oil-displacing agent (ie, the polymer oil-displacing agent of the present invention).

[0050] The structure of the polymer PAAC (i.e., the polymer oil displacement agent of the present invention) prepared in Example 1 was analyzed as follows: The FTIR spectrum of the polymer is as follows: Figure 1 Shown: 3335cm -1 -NH (antisymmetric) stretching vibration absorption peak; 3197cm -1 is the stretching vibration absorption peak of -NH (symmetric); 2929cm -1 and 2855cm -1 They are the asymmetric and symmetric stretching vibration absorption peaks of methylene respectively; 1652cm -1 It is -C=O stretching vibration absorption peak; 1604cm -1 Benzene ring skeleton vibration absorption peak; 1453cm -1The absorption peaks are the in-plane bending vibration absorption peaks of methylene and the vibration absorption peaks of benzene skeleton; 1415cm -1 is the absorption peak of amide CN stretching vibration; 1341cm -1 The stretching vibration absorption peak of tertiary amine and quaternary ammonium salt CN is at 1182cm -1 and 1039cm -1 -SO3 characteristic absorption peak; 840cm -1 It is the absorption peak of the out-of-plane bending vibration of the benzene ring. The infrared spectrum confirms that the product contains structures such as -CONH2, -SO3, -CH2-, -CH3, -C6H4-, tertiary amine, and quaternary ammonium salt. From the infrared spectrum data, it can be proved that the target product is AM / AMES / C 18 DSVBBA terpolymer.

[0051] Experiment 2: AM / AMES / C 18 Viscosity test experiment of DSVBBA terpolymer oil-displacing agent (i.e., polymer oil-displacing agent of the present invention).

[0052] At room temperature (25±1°C), the apparent viscosities of the polymer PAAC (i.e., the polymer oil displacement agent of the present invention) and HPAM solution (prepared with distilled water) prepared in Example 1 with different concentrations were measured using a NDJ-5S digital rotational viscometer to investigate the changes in the apparent viscosities of the two solutions with the polymer concentration. Figure 2 .Depend on Figure 2 It can be seen that at 1000 mg / L, the two polymers PAAC and HPAM can reach 40.2 mPa·s and 28.1 mPa·s respectively, 2000 mg / L can reach 210.7 mPa·s and 103.6 mPa·s respectively, and 4000 mg / L can reach 1110 mPa·s and 237.6 mPa·s respectively. The results show that compared with HPAM, when the concentration exceeds 1000 mg / L, the synthesized terpolymer exhibits better viscosity-increasing ability.

[0053] Experiment 3: AM / AMES / C 18 Experimental test on the heat resistance of the DSVBBA terpolymer oil-displacing agent (i.e., the polymer oil-displacing agent of the present invention).

[0054] The polymer PAAC (i.e., the polymer oil-displacing agent of the present invention) and HPAM prepared in Example 1 were prepared into 2000 mg / L aqueous solution with distilled water, and the apparent viscosity of the PAAC and HPAM solutions was measured at 25°C to 90°C as a function of temperature. Figure 3 .Depend on Figure 3It can be seen that the apparent viscosity of the two polymer solutions gradually decreases with the increase of temperature, and PAAC exhibits better temperature resistance. When the temperature reaches 90°C, the apparent viscosities of PAAC and HPAM solutions are 102.5mPa·s and 33.9mPa·s, respectively. Compared with the viscosity at 25°C, the viscosity retention rates of the two polymers are 48.65% and 32.72%, respectively; the results show that compared with HPAM, the synthesized terpolymer (i.e., the polymer oil displacement agent of the present invention) exhibits better temperature resistance.

[0055] Experiment 4: AM / AMES / C 18 Experimental test on salt resistance of DSVBBA terpolymer oil-displacing agent (i.e., polymer oil-displacing agent of the present invention).

[0056] The PAAC and HPAM prepared in Example 1 were prepared into 2000 mg / L aqueous solutions using mixed brine of different concentrations (the ratio of various salts in the mixed brine was NaCl: KCl: CaCl2: MgCl2 = 7:2:0.6:0.4, mass ratio). The apparent viscosities of the two polymer solutions were measured at 25°C. Figure 4 .Depend on Figure 4 It can be seen that when the mineralization of the brine increases, the apparent viscosity of the two polymers increases first and then decreases. PAAC exhibits better salt resistance, showing salt thickening below a mineralization of 7000 mg / L, while HPAM shows salt thickening below a mineralization of 1000 mg / L. When the brine content increases to 50000 mg / L, the apparent viscosities of the PAAC and HPAM solutions are 90.9 mPa·s and 13.1 mPa·s, respectively, and their viscosity retention rates are 43.14% and 12.64%, respectively; the results show that compared with HPAM, the synthesized terpolymer (i.e., the polymer oil displacement agent of the present invention) exhibits better salt resistance.

[0057] Experiment 5: AM / AMES / C 18 Shear resistance test experiment of DSVBBA terpolymer (i.e., polymer oil displacement agent of the present invention).

[0058] The polymer PAAC (i.e., the polymer oil-displacing agent of the present invention) prepared in Example 1 was prepared into a target solution of 2000 mg / L using distilled water and 10000 mg / L composite brine, and the HPAM was prepared into a target solution of 2000 mg / L using distilled water. The polymer solutions were sheared at speeds of 3500 r / min, 7000 r / min, 11500 r / min, 14500 r / min, and 17000 r / min, respectively. The shear resistance of the two polymer solutions was investigated. Figure 5 .Depend on Figure 5It can be seen that the apparent viscosity of the two polymer solutions decreases with the increase of shear rate. When the shear speed is 3500r / min, the apparent viscosity of polymer PAAC in distilled water and salt water is 174.5mPa·s and 106.3mPa·s, respectively, and the apparent viscosity of HPAM is 65.6mPa·s; the viscosity retention rate of PAAC in the two water qualities is 82.82% and 52.16%, respectively, and the viscosity retention rate of HPAM is 63.32%; when the speed reaches 17000r / min, the apparent viscosity of polymer PAAC in distilled water and salt water is 82.1mPa·s and 51.7mPa·s, respectively, and the apparent viscosity of HPAM is 14.1mPa·s; the viscosity retention rate of PAAC in the two water qualities is 38.97% and 25.37%, respectively, and the viscosity retention rate of HPAM is 13.61%. The results show that compared with HPAM, the synthesized terpolymer (ie, the polymer oil-displacing agent of the present invention) exhibits better shear resistance.

[0059] Experiment 6: AM / AMES / C 18 Indoor core flooding experiment of DSVBBA terpolymer (i.e., polymer oil-displacing agent of the present invention).

[0060] The polymer PAAC prepared in Example 1 (i.e., the polymer oil-displacing agent of the present invention) was prepared into a 2000 mg / L aqueous solution using a mixed brine with a salinity of 30000 mg / L (the ratio of various salts in the mixed brine was NaCl: KCl: CaCl2: MgCl2 = 7:2:0.6:0.4, mass ratio), a simulated reservoir temperature of 70°C, a simulated oil viscosity of 82.3 mPa·s, and a three-layer heterogeneous core of 4.5×4.5×30.0 cm, with an average permeability of about 1254×10 -3 μm 2 . The core saturated with simulated oil is displaced with brine at an injection rate of 1 mL / min. When the instantaneous water content exceeds 70%, polymer flooding is carried out with an injection volume of 0.3 PV, followed by subsequent water flooding until the instantaneous water content reaches 95% three times. The final recovery is calculated. The same method is used for water flooding until the instantaneous water content reaches 95% three times. The experimental results show that the final recovery rate using water flooding is 30.52%, and after using polymer flooding, the final recovery rate reaches 42.69%. Through indoor oil recovery experiments, it is calculated that the polymer can increase the recovery rate by 12.17%. The terpolymer (i.e., the polymer oil-displacing agent of the present invention) has a good oil recovery effect under high temperature and high mineralization.

[0061] In summary, the polymer oil-displacing agent prepared by the above embodiments of the present invention has good viscosity, temperature resistance and shear resistance; it shows good salt resistance in mixed brine with a salinity of ≥30000 mg / L; the indoor oil displacement experiment shows good oil displacement effect, and the crude oil recovery rate is increased by more than 10%. The present invention provides a (water-soluble) hydrophobic associating polymer oil-displacing agent with a benzene ring structure disulfonate, which has good performance, good viscosity-increasing ability at high temperature and high salinity, and good shear resistance, achieving a high recovery rate, and meeting the technical requirements of the polymer oil-displacing agent with a wide range of use in the market, thereby ensuring the smooth progress of oil exploitation in high-temperature and high-salinity oil fields, and solving the problems of poor temperature and salt resistance of existing hydrophobic associating polymers in brine with high salinity (mineralization ≥30000 mg / L), easy hydrolysis underground, and low crude oil recovery rate.

Claims

1. A hydrophobically associated polymer oil displacement agent with a benzene ring structure disulfonate, characterized in that It is composed of acrylamide AM, 2-allylmethylaminoethylsulfonate AMES-Na and a long-chain alkyl disulfoethyl (4-vinylbenzyl) betaine C with a benzene ring structure hydrophobic monomer n DSVBBA is copolymerized by three monomers, and the structural formula of the polymer oil displacement agent is as follows: In the above structural formula, x, y, and z are the molar percentage ranges of the structural units: x=69% to 84.7%, y=15% to 30%, z=0.3% to 1%, x+y+z=100%, wherein n=12, 14, 16, 18, 20.

2. The oil-displacing agent of the disulfonate hydrophobically associating polymer with a benzene ring structure according to claim 1, characterized in that The molar fractions of each monomer are as follows: 69-84.7 parts of acrylamide AM, 15-30 parts of 2-allylmethylaminoethylsulfonate AMES-Na, and long-chain alkyl disulfoethyl (4-vinylbenzyl) betaine C, a hydrophobic monomer with a benzene ring structure. n DSVBBA 0.3~1 part.

3. The oil-displacing agent of the disulfonate hydrophobically associating polymer with a benzene ring structure according to claim 1 or 2, characterized in that The preparation method of 2-allylmethylaminoethanesulfonic acid sodium AMES-Na comprises the following process steps: adding an appropriate amount of anhydrous ethanol as a solvent to a three-necked flask equipped with a thermometer, a reflux condenser with a Soxhlet extractor and a magnetic rotor, adding 65-95 g of sodium 2-chloroethylsulfonate at room temperature, then slowly adding 30-43 g of N-methylallylamine under stirring, adding 0.15-0.21 g of methylhydroquinone as an inhibitor, and charging 32-47 g of an acid binding agent wrapped with filter paper into the Soxhlet extractor, raising the temperature to reflux, reacting at a constant temperature for 20-25 hours, and removing the solvent and excess N-methylallylamine by reduced pressure distillation using a rotary evaporator to obtain 2-allylmethylaminoethanesulfonic acid sodium AMES-Na.

4. The oil-displacing agent of the disulfonate hydrophobically associating polymer with a benzene ring structure according to claim 1 or 2, characterized in that The above hydrophobic monomer long-chain alkyl disulfoethyl (4-vinylbenzyl) betaine C with a benzene ring structure n The preparation method of DSVBBA comprises the following process steps: (1) adding an appropriate amount of anhydrous ethanol as a solvent to a three-necked flask equipped with a thermometer, a reflux condenser with a Soxhlet extractor and a magnetic rotor, adding 40-60 g of a long-chain alkylamine at room temperature, and then slowly adding 60-80 g of sodium 2-chloroethylsulfonate under stirring, adding 28-39 g of an acid binding agent wrapped with filter paper to the Soxhlet extractor, raising the temperature to reflux, reacting at a constant temperature for 30-35 hours, removing the solvent by reduced pressure distillation using a rotary evaporator, and recrystallizing using anhydrous ethanol to obtain a long-chain alkyl disulfoethyl tertiary amine; (2) adding a reflux condenser with a thermometer and a Soxhlet extractor to a reflux condenser. A 500mL three-necked flask with a reflux condenser and a magnetic rotor is added with an appropriate amount of anhydrous ethanol as a solvent, 60-90g of long-chain alkyl disulfoethyl tertiary amine is added at room temperature, and then 30-45g of 4-vinylbenzyl chloride is slowly added under stirring, and 0.2-0.3g of methyl hydroquinone as an inhibitor is added. The temperature is raised to reflux, and after constant temperature reaction for 10-12 hours, the solvent is removed by vacuum distillation using a rotary evaporator, and 4-vinylbenzyl chloride is separated by distilled water. The water is removed by vacuum distillation, and recrystallization is performed using acetone to obtain a hydrophobic monomer long-chain alkyl disulfoethyl (4-vinylbenzyl) betaine C with a benzene ring structure is obtained. n DSVBBA.

5. The oil-displacing agent of the disulfonate hydrophobically associating polymer with a benzene ring structure according to claim 1, characterized in that The preparation method comprises the following process steps: firstly, 1000-1500 mole parts of distilled water are added into a reactor, and then 69-84.7 mole parts of acrylamide AM, 15-30 mole parts of 2-allylmethylaminoethylsulfonic acid sodium AMES-Na, long-chain alkyl disulfoethyl (4-vinylbenzyl) betaine C are added in sequence under stirring. n DSVBBA 0.3-1 molar part, and then distilled water is added to control the total mass percentage concentration of the reaction monomers between 15% and 30%, and after stirring evenly, N2 is passed for 30 minutes; then an initiator is added, and N2 is continued to be passed, and the reaction is carried out under nitrogen protection at 30-60°C for 4-10 hours; after the reaction, the obtained gel product is washed with anhydrous ethanol, and the product is crushed and dried to obtain AM / AMES / C n DSVBBA terpolymer is a disulfonate hydrophobically associated polymer oil displacement agent with a benzene ring structure.

6. The oil-displacing agent of the disulfonate hydrophobically associating polymer with a benzene ring structure according to claim 5, characterized in that The above-mentioned initiator is a composite initiator, including an oxidation-reduction system initiator and a water-soluble azo initiator; in the oxidation-reduction system initiator, the oxidant is potassium persulfate or ammonium persulfate, the reductant is sodium bisulfite, and the molar ratio of the oxidant to the reductant is 1:1 to 1.5; the water-soluble azo initiator is one or a combination of azobisisobutylamidine hydrochloride V-50, azobisisobutylimidazoline hydrochloride VA-044, and azobis(N-2-carboxyethyl-2-methylpropionamidine) hydrate VA-057, and the ratio when combined is arbitrary; in the composite initiator, the mass ratio of the oxidation-reduction system initiator to the water-soluble azo initiator is 1:1 to 2.

7. The oil-displacing agent of the disulfonate hydrophobically associating polymer with a benzene ring structure according to claim 3 or 4, characterized in that The above acid binding agent is potassium carbonate or sodium carbonate.

8. The oil-displacing agent of the disulfonate hydrophobically associating polymer with a benzene ring structure according to claim 4, characterized in that The above-mentioned hydrophobic monomer long-chain alkyl disulfoethyl (4-vinylbenzyl) betaine C with a benzene ring structure n In DSVBBA, the long-chain alkyl is octadecyl, the long-chain alkylamine in step (1) is octadecylamine, and the final product in step (2) is octadecyl disulfoethyl (4-vinylbenzyl) betaine C having a benzene ring structure and a hydrophobic monomer. 18 DSVBBA; or, The above-mentioned hydrophobic monomer long-chain alkyl disulfoethyl (4-vinylbenzyl) betaine C with a benzene ring structure n In the DSVBBA monomer, the long-chain alkyl group is hexadecyl, the long-chain alkylamine in step (1) is hexadecylamine, and the final product in step (2) is hexadecyl disulfoethyl (4-vinylbenzyl) betaine C having a benzene ring structure. 16 DSVBBA.

9. The oil-displacing agent of the disulfonate hydrophobically associating polymer with a benzene ring structure according to claim 5, characterized in that The added amount of the initiator is 0.05% to 0.2% of the total mass of the reaction monomers, and the total mass of the reaction monomers is the total mass of the three monomers mentioned above.

10. A method for preparing the oil-displacing agent of the disulfonate hydrophobically associating polymer with a benzene ring structure according to claim 1, characterized in that The method comprises the following process steps: firstly, 1000-1500 mole parts of distilled water are added into a reactor, and then 69-84.7 mole parts of acrylamide AM, 15-30 mole parts of 2-allylmethylaminoethylsulfonic acid sodium AMES-Na, long-chain alkyl disulfoethyl (4-vinylbenzyl) betaine C are added in sequence under stirring. n DSVBBA 0.3-1 molar part, and then distilled water is added to control the total mass percentage concentration of the reaction monomers between 15% and 30%, and after stirring evenly, N2 is passed for 30 minutes; then an initiator is added, and N2 is continued to be passed, and the reaction is carried out under nitrogen protection at 30-60°C for 4-10 hours; after the reaction, the obtained gel product is washed with anhydrous ethanol, and the product is crushed and dried to obtain AM / AMES / C n DSVBBA terpolymer is a disulfonate hydrophobically associated polymer oil displacement agent with a benzene ring structure.

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