Polymer composition and profile control agent comprising the same, and preparation method and application thereof

Abstract

The present application relates to the technical field of oil reservoir development, discloses a polymer composition, a profile control and displacement agent containing the same, and a preparation method and application thereof.The polymer composition comprises a sulfonic acid type copolymer and a cross-linkable polymer; the sulfonic acid type copolymer comprises structural unit A and structural unit B shown in formula I; the structural unit B comprises structural unit B1 shown in formula II and / or structural unit B2 shown in formula III; the cross-linkable polymer is selected from one or more of acrylamide polymers; the hydrolysis degree of the acrylamide polymers is not more than 10%.The polymer composition of the present application can react with a cross-linking agent to form a chain ball-shaped three-dimensional network gel structure with a certain strength under the oil reservoir environment, can realize gradual viscosity increase, and can make the profile control and displacement agent maintain a certain viscosity and strength, realize deep profile control and displacement, flow channel adjustment and long-acting plugging.

Description

Technical Field

[0001] This invention relates to the field of reservoir development technology, and more specifically, to polymer compositions, flood control agents containing the same, their preparation methods, and applications. Background Technology

[0002] Carbonate reservoirs are highly heterogeneous and prone to water channeling during water injection development. Modulation-driven oil recovery (MWR) technology is crucial for improving the recovery rate of carbonate reservoirs, including flow regulation using high-viscosity fluids and plugging using high-strength plugging agents. Currently, commonly used flow regulators and plugging agents are mostly polymer gels, obtained by reacting polymers with crosslinking agents to produce high-viscosity fluids or high-strength plugging agents. However, carbonate reservoirs operate in harsh environments, with temperatures mostly exceeding 110℃ and salinity ≥20×10⁻⁶. 4 mg / L, calcium and magnesium ion content ≥1×10 4 mg / L.

[0003] The applicable temperature and upper limit of salinity of existing gels are far below the application environment of carbonate reservoirs. They fail due to rapid dehydration in carbonate reservoir environments, resulting in reduced flow regulation or plugging effects.

[0004] Therefore, there is an urgent need to develop new polymer and gel-based flow control systems that are resistant to temperature, salt, and high calcium and magnesium ions to meet the flow control and plugging requirements of carbonate reservoirs. Summary of the Invention

[0005] The purpose of this invention is to overcome the problem that existing polymer gels cannot perform flow regulation and blockage control for extended periods in high-mineralization, high-calcium-magnesium environments. This invention provides a polymer composition, a flow regulation agent containing the composition, its preparation method, and its application. This polymer composition can be used to prepare a flow regulation agent that can effectively perform flow regulation and blockage control for extended periods in environments with temperatures of 90-150°C, mineralization up to 300 g / L, and calcium and magnesium ions up to 10 g / L.

[0006] To achieve the above objectives, a first aspect of the present invention provides a polymer composition comprising a sulfonic acid copolymer and a crosslinkable polymer; wherein the sulfonic acid copolymer comprises structural unit A and structural unit B of Formula I; structural unit B comprises structural unit B1 of Formula II and / or structural unit B2 of Formula III; the crosslinkable polymer is selected from one or more acrylamide polymers; the degree of hydrolysis of the acrylamide polymer is not greater than 10%; and the acrylamide polymer can be hydrolyzed at temperatures above 90°C to produce carboxyl groups;

[0007]

[0008] R1, R7, and R8 are each independently H or C1-C6 alkyl groups;

[0009] R2, R9 and R 10 Each is independently an H or C1-C6 alkyl group;

[0010] R3 and R4 are each independently C1-C6 alkyl groups;

[0011] R5 is a C1-C6 alkylene group;

[0012] R6 represents H or an alkali metal element.

[0013] A second aspect of the present invention provides a modulating agent comprising the polymer composition described in the first aspect.

[0014] A third aspect of the present invention provides a method for preparing a modulator, the method comprising: mixing the polymer composition described in the first aspect with a crosslinking agent and a solvent to form a polymer solution containing swollen particles and a crosslinking agent.

[0015] The fourth aspect of the present invention provides the use of the polymer composition as described in the first aspect above, or the modulating agent as described in the second aspect above, or the modulating agent prepared by the preparation method described in the third aspect above, in oil displacement.

[0016] The beneficial technical effects achieved by the present invention through the above technical solution are as follows:

[0017] (1) The polymer composition of the present invention includes a sulfonic acid copolymer and a crosslinkable polymer; the sulfonic acid copolymer contains an olefin skeleton and sulfonic acid groups, amide groups and / or amino acyl groups bonded to the olefin skeleton, and has good solubility in high-salt, high-mineralization, and high-calcium-magnesium reservoir environments; the crosslinkable polymer is not easily dissolved in reservoir environments, only the surface molecules undergo solvation and swelling, and after swelling, it can be stably dispersed in the polymer solution to form a heterogeneous polymer solution.

[0018] (2) The polymer composition of the present invention can be used to prepare a modulating agent. The crosslinking sites released by the hydrolysis of the salt sulfonic acid resistant copolymer in the reservoir environment can combine with the crosslinking agent to form a modulating agent. After the surface of the crosslinkable polymer is solvated, it contains amide groups, which can be hydrolyzed at high temperature to release carboxyl groups, react with the crosslinking agent, and together with the salt sulfonic acid resistant copolymer, form a chain-spherical three-dimensional network gel structure with a certain strength. This achieves low viscosity and good injectability before injection into the reservoir. After injection, the crosslinking groups are continuously released through slow hydrolysis during the migration process, which gradually increases viscosity and keeps the modulating agent at a certain viscosity and strength, thereby achieving deep modulating and driving, and realizing flow channel adjustment and long-term blockage control.

[0019] (2a) The sulfonic acid type copolymer and the crosslinkable polymer microspheres that can be hydrolyzed to release carboxyl groups of the present invention can form a high viscosity regulating agent system by forming coordination bonds with metal crosslinking agents. This regulating agent system still has a high viscosity after aging at 90-130℃ for 30-120 days under the conditions of mineralization ≤300000mg / L and calcium and magnesium ion content ≤10000mg / L. It can be used as a flow regulating agent for carbonate reservoirs to achieve flow channel adjustment.

[0020] (2b) The sulfonic acid copolymer of the present invention can react with surface-solventized crosslinkable polymer microspheres containing amide groups to form a high-strength modulator system with phenolic and aldehyde crosslinking agents. This modulator system can be stable for 30-60 days at a high temperature of 130-150℃ under conditions of mineralization ≤300000mg / L and calcium and magnesium ion content ≤10000mg / L, maintaining good colloidal strength and plugging rate. It can be used as a modulator for carbonate reservoirs to achieve long-term modulator. Detailed Implementation

[0021] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0022] A first aspect of the present invention provides a polymer composition comprising a sulfonic acid copolymer and a crosslinkable polymer; wherein the sulfonic acid copolymer comprises structural unit A and structural unit B of Formula I; structural unit B comprises structural unit B1 of Formula II and / or structural unit B2 of Formula III; the crosslinkable polymer is selected from one or more acrylamide polymers; the degree of hydrolysis of the acrylamide polymer is not greater than 10%; the acrylamide polymer can be hydrolyzed at temperatures above 90°C to produce carboxyl groups;

[0023]

[0024] R1, R7, and R8 are each independently H or C1-C6 alkyl groups;

[0025] R2, R9 and R 10 Each is independently an H or C1-C6 alkyl group;

[0026] R3 and R4 are each independently C1-C6 alkyl groups;

[0027] R5 is a C1-C6 alkylene group;

[0028] R6 represents H or an alkali metal element.

[0029] According to the present invention, the crosslinkable polymer can be hydrolyzed at high temperatures to produce carboxyl groups, especially at temperatures above 90°C.

[0030] According to this invention, the polymer composition comprises a sulfonic acid copolymer and a crosslinkable polymer insoluble in high-saltage brine. The sulfonic acid copolymer contains an olefin backbone and sulfonic acid groups, amide groups, and / or aminoacyl groups bonded to the olefin backbone. It exhibits good solubility in high-salt, high-saltage, and high-calcium-magnesium reservoir environments and does not precipitate. The crosslinkable polymer insoluble in high-saltage brine is difficult for water molecules to solubilize all molecular chains in reservoir environments; only the molecular chains on the particle surface are solubilized, resulting in swelling and poor dissolution. After swelling, it can be stably dispersed in the polymer solution, forming a heterogeneous polymer solution. The sulfonic acid groups in the sulfonic acid copolymer can control the slow hydrolysis of amide and / or aminoacyl groups in reservoir environments to generate carboxyl and / or amino groups. Then, the carboxyl and / or amino groups can react with a crosslinking agent to form a high-viscosity fluid. This invention, through the synergistic effect of structural unit A and structural unit B, can increase the stability of the polymer composition under high salt conditions, while the resulting heterogeneous solution remains stable and does not separate into layers.

[0031] According to the present invention, the C1-C6 alkyl groups include, but are not limited to: methyl, ethyl, propyl, butyl, pentyl, and hexyl.

[0032] According to the present invention, the degree of hydrolysis of the acrylamide polymer is not greater than 10%, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, and any value within any range of any two values, preferably not greater than 5%.

[0033] According to the present invention, the method for determining the degree of hydrolysis is as follows: in accordance with GB / T 12005.6-1989 "Determination of the Degree of Hydrolysis of Partially Hydrolyzed Polyacrylamide" (the titration endpoint is pH=3).

[0034] According to a preferred embodiment of the present invention, R1, R7 and R8 are each independently H or methyl.

[0035] According to a preferred embodiment of the present invention, R2 and R9 are each independently H.

[0036] According to a preferred embodiment of the present invention, R3 and R4 are each independently methyl.

[0037] According to a preferred embodiment of the present invention, R5 is methylene; R6 is H or Na.

[0038] According to a preferred embodiment of the present invention, R 10 It is H or methyl.

[0039] According to the present invention, based on the total weight of the sulfonic acid copolymer, the weight content of sulfonic acid groups is not less than 21% by weight, for example, 21% by weight, 22% by weight, 23% by weight, 24% by weight, 25% by weight, 26% by weight, 27% by weight, 28% by weight, 29% by weight, 30% by weight, 31% by weight, 32% by weight, 33% by weight, 34% by weight, 35% by weight, and any two of the above values ​​within the range, preferably 23-30% by weight.

[0040] According to the present invention, by controlling the content of sulfonic acid groups in the sulfonic acid copolymer within the above-mentioned range, it can be completely dissolved in brine with a mineralization of up to 300 g / L and a calcium and magnesium ion concentration of up to 10 g / L, and will not precipitate after long-term storage at a temperature of up to 130°C. The sulfonic acid copolymer is a high-salt sulfonic acid copolymer.

[0041] According to the present invention, the viscosity-average molecular weight of the sulfonic acid copolymer is 4 million to 18 million, for example, it can be 4 million, 5 million, 6 million, 7 million, 8 million, 9 million, 10 million, 11 million, 11.6 million, 12 million, 13 million, 14.5 million, 15 million, 16 million, 17 million, 18 million, or any two of the above values, or values ​​within the range; preferably 5 million to 17 million.

[0042] In this invention, the unit of viscosity-average molecular weight is g / mol.

[0043] According to a preferred embodiment of the present invention, based on the total weight of the sulfonic acid copolymer, the content of structural unit A is not less than 60% by weight, for example, 60% by weight, 65% by weight, 70% by weight, 75% by weight, 80% by weight, 84% by weight, 85% by weight, 88% by weight, 90% by weight, and any range formed by any two of the above values ​​and values ​​within that range.

[0044] According to a preferred embodiment of the present invention, based on the total weight of the sulfonic acid copolymer, the content of structural unit A is 65-90% by weight, for example, 65% by weight, 70% by weight, 75% by weight, 80% by weight, 84% by weight, 85% by weight, 88% by weight, 90% by weight, and any range formed by any two of the above values, preferably 70-85% by weight; the content of structural unit B is 10-35% by weight, for example, 10% by weight, 15% by weight, 16% by weight, 18% by weight, 20% by weight, 25% by weight, 30% by weight, 35% by weight, and any range formed by any two of the above values, preferably 16-32% by weight.

[0045] According to a preferred embodiment of the present invention, the structural unit B includes structural unit B1 shown in Formula II and structural unit B2 shown in Formula III, and the weight ratio of the two is 1:0.01-3, for example, 1:0.01, 1:0.05, 1:0.1, 1:0.2, 1:0.5, 1:1, 1:2, 1:3, and any value in the range of any two values, preferably 1:0.05-1.

[0046] According to a preferred embodiment of the present invention, the crosslinkable polymer is insoluble in brine with a mineralization of ≥50000 mg / L.

[0047] According to a preferred embodiment of the present invention, the weight ratio of the sulfonic acid copolymer to the crosslinkable polymer is 1-15:1, for example, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, and any value within the range of any two values, preferably 4-10:1.

[0048] According to a preferred embodiment of the present invention, the content of acrylamide structural units in the crosslinkable polymer is not less than 80 wt%, for example, 80 wt%, 85 wt%, 90 wt%, 95 wt%, 100 wt%, and any value within the range of any two values, preferably 85-100 wt%.

[0049] According to the present invention, the content of each structural unit in the copolymer can be tested using conventional methods in the prior art, such as infrared spectroscopy and nuclear magnetic resonance. Alternatively, the content of each structural unit in the copolymer can be determined by the monomer feed rate. Specifically, the feed ratio of each monomer actually participating in polymerization is determined by testing the content of unreacted monomers, thereby determining the content of each structural unit in the copolymer. Furthermore, in the present invention, when the content of each unreacted monomer in the copolymer is tested to be less than 0.02% by weight of its own content, it indicates that all monomers have essentially participated in the polymerization reaction. Specifically, the content of the residual monomers can be determined by liquid chromatography.

[0050] According to a preferred embodiment of the present invention, the particle size of the crosslinkable polymer is 75 μm-250 μm.

[0051] Preferably, the crosslinkable polymer has a particle size of 100μm-180μm.

[0052] According to a preferred embodiment of the present invention, the residue of the crosslinkable polymer is 20% or less, preferably 10% or less.

[0053] According to the present invention, the sieve residue refers to the percentage of the weight of the residue remaining on the sieve after the sample passes through a sieve with a certain aperture size, relative to the total weight of the sample.

[0054] According to the present invention, the crosslinkable polymer has a particle size of 75μm-250μm and a sieve residue of less than 10%, that is, based on the total weight of the crosslinkable polymer, the content of particles with a particle size less than 75μm and greater than 250μm is less than 10% by weight.

[0055] According to the present invention, the fine powder of the crosslinkable polymer can swell after the surface molecules are solvated in brine with a salinity ≥50000 mg / L. At high temperatures in oil reservoirs, the amide groups in the solvated molecules hydrolyze to generate carboxyl groups, which can then crosslink with a metal crosslinking agent. The fine powder of the crosslinkable polymer can be an acrylamide polymer or its pre-crosslinked gel particles (PPG). The acrylamide polymer can be an acrylamide homopolymer or copolymer. The pre-crosslinked gel particles are obtained by those skilled in the art using conventional methods, typically branched viscoelastic particles obtained by acrylamide and / or sodium acrylate monomers and / or sodium 2-acrylamido-2-methylpropanesulfonate and / or methyl methacrylate and a crosslinking agent under the action of a redox initiator.

[0056] According to a preferred embodiment of the present invention, the acrylamide polymer is selected from one or more of polyacrylamide, acrylamide / N-vinylpyrrolidone copolymer, acrylamide / sodium 2-acrylamido-2-methylpropanesulfonic acid (AMPS) copolymer, acrylamide / N-vinylformamide copolymer, acrylamide / N-vinylacetamide copolymer, acrylamide / acrylonitrile copolymer, acrylamide / sodium acrylate / N-vinylpyrrolidone copolymer, acrylamide / sodium acrylate / AMPS copolymer, and acrylamide / sodium acrylate / acrylonitrile copolymer.

[0057] According to a preferred embodiment of the present invention, the acrylamide polymer is selected from acrylamide pre-crosslinked gel particles; the acrylamide pre-crosslinked gel particles are branched viscoelastic particles obtained by reacting acrylamide and optional polymeric monomers with a crosslinking agent; wherein, the polymeric monomer is selected from one or more of acrylic acid, sodium acrylate, sodium 2-acrylamido-2-methylpropanesulfonate and methyl methacrylate; the crosslinking agent is selected from one or more of bisacrylamides; preferably N,N-methylenebisacrylamide.

[0058] According to a preferred embodiment of the present invention, the acrylamide structural unit content in the acrylamide pre-crosslinked gel particles is ≥80% by weight, and the sodium acrylate content is ≤10% by weight.

[0059] This invention does not impose any particular limitation on the above-mentioned reaction, as long as it enables acrylamide and optional polymeric monomers to react with the crosslinking agent, and commonly used polymerization reactions and conditions in the art can be employed. For example, the acrylamide-based pre-crosslinked gel particles are branched viscoelastic particles obtained by reacting acrylamide and optional polymeric monomers with a crosslinking agent under the action of a redox initiator.

[0060] A second aspect of the present invention provides a modulating agent comprising the polymer composition described in the first aspect.

[0061] According to the present invention, the polymer composition includes sulfonic acid copolymers and crosslinkable polymers, as detailed in the preceding description, and will not be repeated here.

[0062] According to a preferred embodiment of the present invention, based on the total weight of the modulator, the content of the sulfonic acid copolymer is 0.3-1.5 wt%, for example, 0.3 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, 1.2 wt%, 1.5 wt%, and any two of the above values ​​within the range, more preferably 0.5-1.2 wt%.

[0063] In this invention, based on the total weight of the modulator, the content of the crosslinkable polymer is preferably 0.1-0.4 wt%, for example, 0.1 wt%, 0.15 wt%, 0.2 wt%, 0.25 wt%, 0.3 wt%, 0.4 wt%, and any two of the above values ​​within the range, more preferably 0.15-0.3 wt%.

[0064] According to some embodiments of the present invention, the modulator further includes a crosslinking agent.

[0065] In this invention, the crosslinking agent can be selected from substances commonly found in the art that can crosslink the sulfonic acid copolymer.

[0066] According to a preferred embodiment of the present invention, the crosslinking agent is selected from one or more of organometallic crosslinking agents, phenolic crosslinking agents, and aldehyde crosslinking agents.

[0067] According to a preferred embodiment of the present invention, the organometallic crosslinking agent is a crosslinking agent formed by metal ions and organic ligand compounds; wherein the metal ions are selected from one or more of aluminum, chromium, zirconium, iron and titanium; and the organic ligand compounds are selected from one or more of organic acids and organic amines, preferably at least one of citric acid, oxalic acid, acetic acid, lactic acid, polyene polyamine and triethanolamine.

[0068] According to a preferred embodiment of the present invention, the organometallic crosslinking agent is selected from at least one of chromium citrate, chromium oxalate, chromium lactate, zirconium citrate, zirconium lactate, n-propanezirconate, aluminum citrate, and aluminum lactate.

[0069] According to a preferred embodiment of the present invention, the phenolic crosslinking agent is selected from one or more of phenol, cresol, hydroquinone, catechol and resorcinol.

[0070] According to a preferred embodiment of the present invention, the aldehyde-type crosslinking agent is selected from one or more of formaldehyde, acetaldehyde, paraformaldehyde, hexamethylenetetramine, and furfural.

[0071] According to a preferred embodiment of the present invention, based on the total weight of the modulator, the content of the crosslinking agent is 0.01-2 wt%, for example, 0.01 wt%, 0.02 wt%, 0.05 wt%, 0.1 wt%, 0.5 wt%, 1 wt%, 1.2 wt%, 1.5 wt%, 1.8 wt%, 2 wt%, and any two of the above values ​​within a range, preferably 0.02-1.5 wt%.

[0072] According to the present invention, the modulator further includes an optional stabilizer and an optional oxygen scavenger.

[0073] According to the present invention, the flow modifier contains a crosslinking agent and, as described above, a sulfonic acid copolymer, crosslinkable polymer powder, and a stabilizer. This flow modifier is particularly suitable for flow regulation and plugging in carbonate reservoirs.

[0074] The crosslinking sites released by the hydrolysis of the salt sulfonic acid resistant copolymer in the reservoir environment can combine with the crosslinking agent to form a regulating agent system. The amide groups in the solvable molecules on the surface of the crosslinkable polymer and the carboxyl groups hydrolyzed at high temperature can react with the crosslinking agent and form a chain-spherical three-dimensional network gel structure with a certain strength together with the salt sulfonic acid resistant copolymer. This achieves low viscosity and good injectability before injection into the reservoir. After injection, the crosslinking groups are continuously released through slow hydrolysis during the migration process, which gradually increases viscosity and maintains a certain viscosity and strength of the regulating agent system, realizing deep regulation and driving, and achieving flow channel adjustment and long-term blockage control.

[0075] A third aspect of the present invention provides a method for preparing a modulator, the method comprising: mixing the polymer composition described in the first aspect with a crosslinking agent and a solvent to form a polymer solution containing swollen particles and a crosslinking agent.

[0076] Specifically, the preparation method includes the following steps:

[0077] (1) The polymer composition described in the first aspect above is mixed with a solvent and stirred to fully dissolve the salt sulfonic acid resistant copolymer in the polymer composition to obtain a polymer solution containing swollen particles;

[0078] (2) The polymer solution containing the swollen particles is mixed with a crosslinking agent to obtain a polymer solution containing the swollen particles and the crosslinking agent, which is the modulator of the present invention.

[0079] According to this invention, the copolymer in the copolymer solution originates from the sulfonic acid copolymer in the polymer composition; the swollen particles originate from the crosslinkable polymer in the polymer composition. The polymer composition and crosslinking agent are mixed in a solvent to form a polymer solution containing swollen particles and a crosslinking agent. The swollen particles can be uniformly dispersed in the polymer solution and remain stable without stratification over long periods. At high temperatures, the amide groups on the surface of the crosslinkable polymer swollen particles and the carboxyl groups released from their hydrolysis can react with the crosslinking agent, simultaneously forming a chain-like three-dimensional network gel structure with a certain strength together with the salt-sulfonic acid resistant copolymer. This achieves low viscosity and good injectability before injection into the reservoir. After injection, during migration, the crosslinking groups are continuously released through slow hydrolysis, gradually increasing viscosity and maintaining a certain viscosity and strength in the modifier system, enabling deep modifier operation, channel adjustment, and long-term plugging control.

[0080] According to a preferred embodiment of the present invention, the method for preparing the sulfonic acid copolymer includes: under solution polymerization conditions, in the presence of an initiator, causing an alkenyl monomer to undergo a polymerization reaction; wherein the alkenyl monomer includes monomer a and monomer b as shown in Formula 1, and monomer b includes monomer b1 as shown in Formula 2 and / or monomer b2 as shown in Formula 3;

[0081]

[0082] R1, R7, and R8 are each independently H or C1-C6 alkyl groups;

[0083] R2, R9 and R 10 Each is independently an H or C1-C6 alkyl group;

[0084] R3 and R4 are each independently C1-C6 alkyl groups;

[0085] R5 is a C1-C6 alkylene group;

[0086] R6 represents H or an alkali metal element.

[0087] According to the present invention, the definitions of the above substituents are the same as those in the first aspect, and will not be repeated here.

[0088] According to a preferred embodiment of the present invention, based on the total weight of the alkenyl monomers, the content of monomer a is 65-90% by weight, for example, 65% by weight, 70% by weight, 75% by weight, 80% by weight, 84% by weight, 85% by weight, 88% by weight, 90% by weight, and any range formed by any two of the above values, preferably 70-85% by weight; the content of monomer b is 10-35% by weight, for example, 10% by weight, 15% by weight, 16% by weight, 18% by weight, 20% by weight, 25% by weight, 30% by weight, 35% by weight, and any range formed by any two of the above values, preferably 16-32% by weight;

[0089] According to a preferred embodiment of the present invention, the monomer b includes monomer b1 as shown in Formula 2 and / or monomer b2 as shown in Formula 3; the weight ratio of the two is 1:0.01-3, for example, 1:0.0.01, 1:0.05, 1:0.1, 1:0.2, 1:0.5, 1:0.8, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, and any value within the range of any two values, preferably 1:0.05-1.

[0090] According to the present invention, the initiator may be selected from various initiators commonly used in the art, for example, the initiator may be selected from azo initiators and / or redox initiators.

[0091] According to the present invention, the azo initiator is preferably a water-soluble azo initiator. The redox initiator comprises an oxidant and a reductant, wherein the reductant is an inorganic reductant and / or an organic reductant, and the weight ratio of the oxidant to the reductant is 0.1-1:1.

[0092] Preferably, the water-soluble azo initiator is selected from at least one of 2,2'-azobis(2-amidinylpropane) dihydrochloride, 2,2'-azobis(2-imidazolinepropane) dihydrochloride, and 4,4'-azobis(4-cyanopentanoic acid). Preferably, the oxidant is selected from at least one of benzoyl peroxide, hydrogen peroxide, tert-butyl hydroperoxide, 2,5-dimethyl-2,5-bis(hydrogen peroxide)hexane, ammonium persulfate, sodium persulfate, and potassium persulfate. Preferably, the inorganic reducing agent is selected from at least one of ferrous sulfate, ferrous ammonium sulfate, cuprous chloride, potassium sulfite, sodium sulfite, ammonium bisulfite, potassium bisulfite, sodium thiosulfate, potassium thiosulfate, sodium formaldehyde sulfoxylate (sodium formaldehyde sulfoxylate), and sodium bisulfite. Preferably, the organic reducing agent is selected from at least one of N,N-dimethylethanolamine, N,N'-dimethylpiperazine, N,N,N',N'-tetramethylurea and N,N,N',N'-tetramethylethylenediamine.

[0093] According to the present invention, the amount of the initiator can be 0.0003-0.05% by weight of the alkenyl monomer. Preferably, the amount of the azo initiator is 0.0001-0.1% by weight of the alkenyl monomer. Preferably, the amount of the redox initiator is 0.0002-0.3% by weight of the alkenyl monomer.

[0094] According to the present invention, the solution polymerization conditions enable the resulting copolymer to have the viscosity-average molecular weight as described above. Preferably, the solution polymerization conditions include: an initial polymerization temperature of -10°C to 30°C, a time of 2-12 hours, and a pH of 4-8. Preferably, the initial polymerization temperature is -5°C to 10°C, the time is 3-10 hours, and the pH is 5-7.

[0095] In this invention, alkali metal hydroxides (such as sodium hydroxide or potassium hydroxide) can be used to adjust the pH value of the polymerization reaction. It is understood that by adjusting the pH value using alkali metal hydroxides, R6 in structural unit A (monomer a) can be converted from H to an alkali metal element (such as Na). Furthermore, by controlling the amount of alkali metal hydroxide used, structural unit A in the copolymer of this invention can simultaneously possess structural units containing both H and alkali metal elements.

[0096] According to the present invention, at the start of the solution polymerization reaction, the ratio between the total weight of the alkenyl monomer and the total weight of the solvent and the alkenyl monomer is 0.3-0.55:1, preferably 0.35-0.5:1.

[0097] According to the present invention, in order to better control the induction period and reduce the polymerization inhibition effect of dissolved oxygen, the polymerization reaction is preferably carried out in an inert atmosphere, which may be provided by nitrogen and / or an inert gas.

[0098] According to the present invention, the preparation method may further include: granulating, drying, pulverizing and sieving the copolymer colloid obtained by the polymerization reaction to obtain the copolymer product.

[0099] According to the present invention, the drying conditions include a temperature of 40-70°C, preferably 45-65°C. In this invention, the drying time is not specifically limited; drying can be carried out until the solid content reaches 85-95% by weight, preferably 88-90% by weight. Generally, the drying time is 2-24 hours.

[0100] According to a preferred embodiment of the present invention, the organometallic crosslinking agent is a crosslinking agent formed by metal ions and organic ligand compounds; wherein the metal ions are selected from one or more of aluminum, chromium, zirconium, iron and titanium; and the organic ligand compounds are selected from one or more of organic acids and organic amines, preferably at least one of citric acid, oxalic acid, acetic acid, lactic acid, polyene polyamine and triethanolamine.

[0101] According to a preferred embodiment of the present invention, the organometallic crosslinking agent is selected from at least one of chromium citrate, chromium oxalate, chromium lactate, zirconium citrate, zirconium lactate, n-propanezirconate, aluminum citrate, and aluminum lactate.

[0102] According to a preferred embodiment of the present invention, the phenolic crosslinking agent is selected from one or more of phenol, cresol, hydroquinone, catechol and resorcinol.

[0103] According to a preferred embodiment of the present invention, the aldehyde-type crosslinking agent is selected from one or more of formaldehyde, acetaldehyde, paraformaldehyde, hexamethylenetetramine, and furfural.

[0104] The polymer composition of the present invention can form a flow regulating agent system with organometallic crosslinking agents and / or phenolic and aldehyde crosslinking agents. This flow regulating agent system can be used as a flow regulating agent or plugging agent in water with a salinity ≤300000 mg / L and a calcium and magnesium ion content ≤10000 mg / L. After aging at 90-150℃ for 30-120 days, it still has good viscosity and strength and excellent stability. It can be used to regulate flow channels or plug in carbonate reservoirs.

[0105] According to a preferred embodiment of the present invention, the mass ratio of the polymer composition to the crosslinking agent is 1:0.05-1.5, for example, 1:0.05, 1:0.1, 1:0.5, 1:1, 1:1.2, 1:1.5, and any value within the range of any two values.

[0106] According to a preferred embodiment of the present invention, the mass ratio of the polymer composition to the solvent is 1:0.007-0.015, for example, 1:0.007, 1:0.008, 1:0.009, 1:0.01, 1:0.011, 1:0.012, 1:0.013, 1:0.014, 1:0.015, and any value within the range of any two values.

[0107] According to a preferred embodiment of the present invention, the solvent is selected from one or more of water, seawater, and brine with a mineralization of ≤300g / L.

[0108] In this invention, the solvent is preferably water.

[0109] In this invention, water serves as both the solvent and the reaction medium in the modulator / reactive agent system, and there are no particular limitations on its selection. The water can be natural water or artificially produced water. Natural water can be river water, lake water, atmospheric water, seawater, or groundwater, etc., while artificially produced water can be tap water, distilled water, deionized water, or heavy water.

[0110] Generally, in practical applications, the water used is typically local water from the oilfield or its corresponding simulated brine. Preferably, the water's salinity is below 300,000 mg / L.

[0111] It should be understood that, depending on the salinity of the water, the composition of the displacement modifier may contain impurities from water; however, in the calculation, these impurities are treated as a whole with the water. A fourth aspect of the present invention provides the application of the polymer composition as described in the first aspect, or the displacement modifier as described in the second aspect, or the displacement modifier prepared by the method described in the third aspect, in oil displacement.

[0112] According to the present invention, the above-mentioned polymer composition or modifier is used in oil reservoir development, especially in the sealing of high-permeability channels in high-temperature and high-salinity oil reservoirs, and even more particularly in the application of flow regulation or plugging in carbonate oil reservoirs.

[0113] The present invention also provides a method for oil reservoir development, the method comprising: injecting the aforementioned modulator into the formation, thereby causing the modulator to crosslink in situ in the formation to form a gel.

[0114] According to the present invention, the repellent agent can form a sealant at a high temperature of ≤150°C after gelation, and maintain this sealant at this temperature for 30-120 days.

[0115] The present invention will be described in detail below through embodiments.

[0116] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0117] In the following examples, simulated brine was prepared according to the applicable reservoir environment. The salinity of the simulated brine was ≤300,000 mg / L and the calcium and magnesium ion content was ≤10,000 mg / L (it should be understood that its salinity is an approximate value).

[0118] The testing method is as follows:

[0119] 1) Viscosity-average molecular weight: The German Lauda Proline PVS2.59 was used, and the test was conducted according to the method specified in GB / T 12005.10-92 "Determination of molecular weight of polyacrylamide by viscosity method".

[0120] 2) Aging viscosity: The copolymer formed by the polymer composition and the metal crosslinking agent is gelled into a liquid and placed in a sealed stainless steel reactor. It is then placed in a constant temperature chamber at a certain temperature (e.g., 130°C) for reaction. After a set time (e.g., 60 days), it is taken out of the constant temperature chamber and the viscosity is measured.

[0121] 3) Viscosity increase rate: The viscosity at a shear rate of 7.34 s⁻¹ was measured using a Brookfield R / S Rheometer at 30 °C. The formula for calculating the viscosity increase rate is: Viscosity increase rate = (viscosity after aging - initial viscosity) / initial viscosity × 100%.

[0122] 4) Storage modulus: The gel strength of the modulator is reflected by measuring the storage modulus of the system using a rheological method. The measurement method is in accordance with SY / T6296-1997 "Determination of Strength of Polymer Gel for Oil Production - Rheological Parameter Method". The test instrument is a HAAKERS6000 rheometer.

[0123] 5) The specific test methods for sealing performance are as follows:

[0124] A simulated core (core diameter d = 25 mm, length L = 200 mm) was prepared. After vacuuming, water was injected into the core at a flow rate of 2 ml / min (injection rate Q), and the permeability (k0) before plugging was measured. Then, 1.0-1.5 PV of modulator was injected into the core model, and both ends of the core were plugged with wire. The core was placed in a constant temperature chamber at a certain temperature and left to stand for a certain period of time. Water was injected again until the pressure stabilized, and the permeability (k') after plugging was obtained, thereby calculating the plugging rate.

[0125] The plugging rate (η) is used as a parameter to characterize the plugging performance of the plugging agent, and the calculation formula is as follows:

[0126]

[0127] Preparation Example 1

[0128] Dissolve 80.5g of sodium 2-acrylamido-2-methylpropanesulfonate and 28g of acrylamide in 191.5g of deionized water. Adjust the pH to 6 using sodium hydroxide solution and control the initial temperature to 8℃. Purge the system with nitrogen for 20min to remove oxygen. Then add 0.9g of 0.25 wt% aqueous solution of 2,2-azobis(2-amidinepropane) dihydrochloride, 1.8g of 0.2 wt% aqueous solution of ammonium persulfate, and 1.3g of 0.3 wt% aqueous solution of sodium bisulfite to initiate polymerization. After the system temperature rises by 0.5℃, stop purging with nitrogen and continue the reaction until the maximum polymerization temperature is reached, then stop the reaction to obtain a blocky colloid. Take out the colloid, granulate it, dry it at 50℃ until the solid content reaches 89 wt%, pulverize it, and sieve it through a 20-80 mesh sieve to obtain a 20-80 mesh salt-resistant sulfonic acid copolymer dry powder product.

[0129] The viscosity-average molecular weight of the dry powder product was determined to be 16.6 million.

[0130] Furthermore, based on calculations of the feed amount, the prepared sulfonic acid copolymer contains:

[0131] Structural unit A (as shown in Formula I, where R1 and R2 are both H, R3 and R4 are both methyl, R5 is methylene, and R6 is Na); structural unit B (as shown in Formula II, where R7 is H);

[0132] Based on the total weight of the salt-resistant sulfonic acid copolymer, the content of structural unit A is 74.2% by weight, the content of sulfonic acid groups is 25.9% by weight, and the content of structural unit B is 25.8% by weight.

[0133] Preparation Example 2

[0134] Take 75g of sodium 2-acrylamido-2-methylpropanesulfonate, 26g of monomer b1 and 5g of monomer b2 (monomer b1 is acrylamide, and the structural formula of monomer b2 is shown in Formula 3, where R8, R9, R... 10 All (H) were dissolved in 194g of deionized water, and the pH was adjusted to 6 using sodium hydroxide solution. The initial temperature was controlled at 8℃, and nitrogen gas was bubbled into the system for 20min to remove oxygen. Then, 1.25g of 0.25wt% 2,2-azobis(2-amidinepropane) dihydrochloride aqueous solution, 1.8g of 0.2wt% ammonium persulfate aqueous solution, and 1.25g of 0.3wt% sodium bisulfite aqueous solution were added to the system to initiate polymerization. After the system temperature rose by 0.5℃, the nitrogen bubbling was stopped, and the reaction continued until the maximum polymerization temperature was reached, at which point the reaction was stopped to obtain a blocky colloid. The colloid was removed, granulated, dried at 50℃ until the solid content reached 89wt%, pulverized, and sieved through a 20-80 mesh sieve to obtain a salt-resistant sulfonic acid copolymer dry powder product.

[0135] The viscosity-average molecular weight of the dry powder product was determined to be 13.9 million.

[0136] Furthermore, based on calculations of the feed amount, the prepared sulfonic acid copolymer contains:

[0137] Structural unit A (as shown in Formula I, where R1 and R2 are both H, R3 and R4 are both methyl, R5 is methylene, and R6 is Na); structural unit B1 (as shown in Formula II, where R7 is H); structural unit B2 (as shown in Formula III, where R8, R9, and R6 are Na); 10 All are H);

[0138] Based on the total weight of the salt-resistant sulfonic acid copolymer, the content of structural unit A is 70.8% by weight, the content of sulfonic acid groups is 24.7% by weight, the content of structural unit B1 is 24.5% by weight, and the content of structural unit B2 is 4.7% by weight.

[0139] Preparation Example 3

[0140] Take 90g of sodium 2-acrylamido-2-methylpropanesulfonate, 20g of monomer b1 and 2.2g of monomer b2 (monomer b1 is acrylamide, and the structural formula of monomer b2 is shown in Formula 3, where R8 and R9 are H, R 10 The methyl group was dissolved in 190g of deionized water, and the pH was adjusted to 6 using sodium hydroxide solution. The initial temperature was controlled at 8℃, and nitrogen gas was bubbled into the system for 20min to remove oxygen. Then, 1.25g of 0.25wt% aqueous solution of 2,2-azobis(2-amidinepropane) dihydrochloride, 1.8g of 0.2wt% aqueous solution of ammonium persulfate, and 1.25g of 0.3wt% aqueous solution of sodium bisulfite were added to the system to initiate polymerization. After the system temperature rose by 0.5℃, the nitrogen bubbling was stopped, and the reaction continued until the maximum polymerization temperature was reached, at which point the reaction was stopped to obtain a blocky colloid. The colloid was removed, granulated, dried at 50℃ until the solid content reached 89wt%, pulverized, and sieved through a 20-80 mesh sieve to obtain a salt-resistant sulfonic acid copolymer dry powder product.

[0141] The viscosity-average molecular weight of the dry powder product was determined to be 11.2 million.

[0142] Furthermore, based on calculations of the feed amount, the prepared sulfonic acid copolymer contains:

[0143] Structural unit A (as shown in Formula I, where R1 and R2 are both H, R3 and R4 are both methyl, R5 is methylene, and R6 is Na); structural unit B1 (as shown in Formula II, where R7 is H); structural unit B2 (as shown in Formula III, where R8 and R9 are H, R... 10 (methyl)

[0144] Based on the total weight of the salt-resistant sulfonic acid copolymer, the content of structural unit A is 80.2% by weight, the content of sulfonic acid groups is 28.0% by weight, the content of structural unit B1 is 17.8% by weight, and the content of structural unit B2 is 2.0% by weight.

[0145] Preparation Example 4

[0146] Take 75g of sodium 2-acrylamido-2-methylpropanesulfonate, 15g of monomer b1 and 8g of monomer b2 (monomer b1 is acrylamide, and the structural formula of monomer b2 is shown in Formula 3, where R8, R9, and R... 10All (H) were dissolved in 207g of deionized water, and the pH was adjusted to 6 using sodium hydroxide solution. The initial temperature was controlled at 8℃, and nitrogen gas was bubbled into the system for 20min to remove oxygen. Then, 1.25g of 0.25 wt% 2,2-azobis(2-amidinepropane) dihydrochloride aqueous solution, 1.8g of 0.2 wt% ammonium persulfate aqueous solution, and 1.25g of 0.3 wt% sodium bisulfite aqueous solution were added to the system to initiate polymerization. After the system temperature rose by 0.5℃, the nitrogen bubbling was stopped, and the reaction continued until the maximum polymerization temperature was reached, at which point the reaction was stopped to obtain a blocky colloid. The colloid was removed, granulated, dried at 50℃ until the solid content reached 89 wt%, pulverized, and sieved through a 20-80 mesh sieve to obtain a salt-resistant sulfonic acid copolymer dry powder product.

[0147] The viscosity-average molecular weight of the dry powder product was determined to be 9.4 million.

[0148] Furthermore, based on calculations of the feed amount, the prepared sulfonic acid copolymer contains:

[0149] Structural unit A (as shown in Formula I, where R1 and R2 are both H, R3 and R4 are both methyl, R5 is methylene, and R6 is Na); structural unit B1 (as shown in Formula II, where R7 is H); structural unit B2 (as shown in Formula III, where R8, R9, and R6 are Na); 10 All are H);

[0150] Based on the total weight of the salt-resistant sulfonic acid copolymer, the content of structural unit A is 75.3% by weight, the content of sulfonic acid groups is 26.3% by weight, the content of structural unit B1 is 16.1% by weight, and the content of structural unit B2 is 8.6% by weight.

[0151] Preparation Example 5

[0152] Take 66.5g of sodium 2-acrylamido-2-methylpropanesulfonate, 17g of monomer b1 and 15g of monomer b2 (the structural formula of monomer b1 is shown in Formula 2, where R7 is methyl, and the structural formula of monomer b2 is shown in Formula 3, where R8, R9, and R...). 10All (H) were dissolved in 201.5g of deionized water, and the pH was adjusted to 6 using sodium hydroxide solution. The initial temperature was controlled at 8℃, and nitrogen gas was bubbled into the system for 20min to remove oxygen. Then, 1.8g of 0.25 wt% 2,2-azobis(2-amidinepropane) dihydrochloride aqueous solution, 2.0g of 0.2 wt% ammonium persulfate aqueous solution, and 1.5g of 0.3 wt% sodium bisulfite aqueous solution were added to the system to initiate polymerization. After the system temperature rose by 0.5℃, the nitrogen bubbling was stopped, and the reaction continued until the maximum polymerization temperature was reached, at which point the reaction was stopped to obtain a blocky colloid. The colloid was removed, granulated, dried at 50℃ until the solid content reached 89 wt%, pulverized, and sieved through a 20-80 mesh sieve to obtain a salt-resistant sulfonic acid copolymer dry powder product.

[0153] The viscosity-average molecular weight of the dry powder product was determined to be 8.1 million.

[0154] Furthermore, based on calculations of the feed amount, the prepared sulfonic acid copolymer contains:

[0155] Structural unit A (as shown in Formula I, where R1 and R2 are both H, R3 and R4 are both methyl, R5 is methylene, and R6 is Na); structural unit B1 (as shown in Formula II, where R7 is methyl); structural unit B2 (as shown in Formula III, where R8, R9, and R6 are methyl); 10 All are H);

[0156] Based on the total weight of the salt-resistant sulfonic acid copolymer, the content of structural unit A is 67.5% by weight, the content of sulfonic acid groups is 23.6% by weight, the content of structural unit B1 is 17.3% by weight, and the content of structural unit B2 is 15.2% by weight.

[0157] Example 1

[0158] 7.8 g of the sulfonic acid copolymer prepared in Preparation Example 1 and 1.5 g of crosslinkable polymer powder (acrylamide homopolymer, degree of hydrolysis 0%, average particle size 125-150 μm, with the content of particles smaller than 125 μm and larger than 150 μm less than 10% by weight, based on the total weight of the crosslinkable polymer powder) were added to 900 g of simulated brine (mineralization 300,000 mg / L, calcium and magnesium ion content 10,000 mg / L). After stirring for 1 h, 0.3 g of chromium oxalate (Cr) was added. 3+ 0.8g chromium lactate (Cr content 4%) 3+ The mixture (containing 3% sodium bisulfite) and 0.8g sodium bisulfite were added to a total weight of 1kg with simulated brine (mineralization of 300,000mg / L and calcium and magnesium ion content of 10,000mg / L). The mixture was stirred evenly to obtain flow modifier A1, which can be used as a flow modifier for channel adjustment.

[0159] The initial viscosity of the modulator A1, the aging viscosity and the viscosity increase rate after being placed at 90-130℃ for 30-120 days were measured. The results are shown in Table 1.

[0160] Example 2

[0161] 7.5 g of the sulfonic acid copolymer prepared in Preparation Example 2 and 1 g of crosslinkable polymer powder (acrylamide / sodium 2-acrylamido-2-methylpropanesulfonate copolymer, in which the content of acrylamide structural units is 85%, the degree of hydrolysis is 0%, the average particle size is 150-180 μm, and the content of particles with a particle size less than 125 μm and greater than 150 μm is less than 10% by weight based on the total weight of the crosslinkable polymer powder) were added to 900 g of simulated brine (mineralization of 300,000 mg / L, calcium and magnesium ion content of 10,000 mg / L). After stirring for 1 h, 1 g of chromium lactate (Cr) was added. 3+ The mixture (containing 3% sodium bisulfite) and 0.8g sodium bisulfite were added to a total weight of 1kg with simulated brine (mineralization of 300,000mg / L and calcium and magnesium ion content of 10,000mg / L). The mixture was stirred evenly to obtain flow modifier A2, which can be used as a flow modifier for channel adjustment.

[0162] The initial viscosity of the modulator A2 was measured, and the aging viscosity and viscosity increase rate after being placed at 130℃ for 30 days were also measured. The results are shown in Table 1.

[0163] Example 3

[0164] 8.5 g of the sulfonic acid copolymer prepared in Preparation Example 3 and 0.9 g of crosslinkable polymer powder (acrylamide / sodium 2-acrylamido-2-methylpropanesulfonate / N-vinylpyrrolidone copolymer, in which the content of acrylamide structural units is 85%, the degree of hydrolysis is 0%, the average particle size is 180-212 μm, and the content of particles smaller than 180 μm and larger than 212 μm is less than 10% by weight based on the total weight of the crosslinkable polymer powder) were added to 900 g of simulated brine (mineralization of 300,000 mg / L, calcium and magnesium ion content of 10,000 mg / L). After stirring for 1 h, 1.5 g of chromium lactate (Cr) was added. 3+ The mixture (containing 3% sodium bisulfite) and 0.8g sodium bisulfite were added to a total weight of 1kg with simulated brine (mineralization of 300,000mg / L and calcium and magnesium ion content of 10,000mg / L). The mixture was stirred evenly to obtain flow modifier A3, which can be used as a flow modifier for channel adjustment.

[0165] The initial viscosity of the modulator A3, the aging viscosity and the viscosity increase rate after being placed at 130℃ for 30 days were measured. The results are shown in Table 1.

[0166] Example 4

[0167] Nine g of the sulfonic acid copolymer prepared in Preparation Example 4 and 0.8 g of pre-crosslinked gel particles (purchased from Puyang Xinyuan Environmental Protection Technology Co., Ltd., with an acrylamide structural unit content of 100% by weight, an average particle size of 180-212 μm, and based on the total weight of the pre-crosslinked gel particles, the content of particles smaller than 180 μm and larger than 212 μm was less than 15% by weight) were added to 900 g of simulated brine (mineralization of 300,000 mg / L, calcium and magnesium ion content of 10,000 mg / L). After stirring for 1 h, 0.8 g of chromium lactate (Cr) was added. 3+ The mixture (containing 3% sodium bisulfite) and 0.8g sodium bisulfite were added to a total weight of 1kg with simulated brine (mineralization of 300,000mg / L and calcium and magnesium ion content of 10,000mg / L). The mixture was stirred evenly to obtain a chain-like spherical flow modifier A4. This flow modifier A4 can be used as a flow modifier for channel adjustment.

[0168] The initial viscosity of the modulator A4, the aging viscosity and the viscosity increase rate after being placed at 130℃ for 30 days were measured. The results are shown in Table 1.

[0169] Example 5

[0170] 7.5 g of the sulfonic acid copolymer prepared in Preparation Example 5 and 2 g of crosslinkable polymer powder (acrylamide / sodium acrylate / sodium 2-acrylamido-2-methylpropanesulfonate copolymer, in which the content of acrylamide structural units is 88%, the degree of hydrolysis is 5%, the average particle size is 150-180 μm, and the content of particles with a particle size less than 125 μm and greater than 150 μm is less than 10% by weight based on the total weight of the crosslinkable polymer powder) were added to 900 g of simulated brine (mineralization of 300,000 mg / L, calcium and magnesium ion content of 10,000 mg / L). After stirring for 1 h, 1 g of chromium lactate (Cr) was added. 3+ A mixture of 3% sodium bisulfite and 0.8g sodium bisulfite was added to a total weight of 1kg with simulated brine (mineralization of 300,000mg / L and calcium and magnesium ion content of 10,000mg / L). The mixture was stirred until homogeneous to obtain flow modifier A5. Flow modifier A5 can be used as a flow modifier for channel adjustment. The initial viscosity, aging viscosity, and viscosity increase rate of flow modifier A5 after 30 days at 130℃ were measured. The results are shown in Table 1.

[0171] Example 6

[0172] 7.7g of the sulfonic acid copolymer prepared in Preparation Example 1 and 1.5g of crosslinkable polymer powder (acrylamide homopolymer, degree of hydrolysis 0%, average particle size 125-150μm, with the content of particles smaller than 125μm and larger than 150μm less than 10% by weight, based on the total weight of the crosslinkable polymer powder) were added to 900g of simulated brine (mineralization 300000mg / L, calcium and magnesium ion content 10000mg / L). After stirring for 1h, 4.5g of hydroquinone, 5.5g of hexamethylenetetramine and 0.8g of sodium bisulfite were added, and the total weight was made up to 1kg with simulated brine (mineralization 300000mg / L, calcium and magnesium ion content 10000mg / L). The mixture was stirred evenly to obtain chain-spherical reversing agent B1. This reversing agent B1 can be used as a plugging agent for macropore sealing.

[0173] The colloidal strength of the modulator B1 after gelation and the blocking rate after being placed at 130-150℃ for 30-60 days were measured. The results are shown in Table 2.

[0174] Example 7

[0175] 8g of the sulfonic acid copolymer prepared in Preparation Example 2 and 1g of crosslinkable polymer powder (acrylamide / sodium 2-acrylamido-2-methylpropanesulfonate copolymer, wherein the content of acrylamide structural units in the copolymer is 90%, the degree of hydrolysis is 0%, the average particle size is 125-150μm, and the content of particles smaller than 125μm and larger than 150μm is less than 10% by weight based on the total weight of the crosslinkable polymer powder) were added to 900g of simulated brine ( In a solution with a mineralization of 300,000 mg / L and a calcium and magnesium ion content of 10,000 mg / L, after stirring for 1 hour, 5 g of hydroquinone, 6 g of hexamethylenetetramine, and 0.8 g of sodium bisulfite were added. The solution was then made up to a total weight of 1 kg with simulated brine (mineralization of 300,000 mg / L and calcium and magnesium ion content of 10,000 mg / L). The solution was stirred until homogeneous to obtain a chain-like spherical reversing agent B2. This reversing agent B2 can be used as a plugging agent for large-pore sealing.

[0176] The colloidal strength of the modulator B2 after gelation and the blocking rate after being placed at 150℃ for 30 days were measured. The results are shown in Table 2.

[0177] Example 8

[0178] 8.5g of the sulfonic acid copolymer prepared in Preparation Example 3 and 1g of crosslinkable polymer powder (acrylamide homopolymer, degree of hydrolysis 0%, average particle size 125-150μm, with the content of particles smaller than 125μm and larger than 150μm less than 10% by weight, based on the total weight of the crosslinkable polymer powder) were added to 900g of simulated brine (mineralization 300000mg / L, calcium and magnesium ion content 10000mg / L). After stirring for 1h, 5.5g of hydroquinone, 5g of hexamethylenetetramine and 0.8g of sodium bisulfite were added, and the total weight was made up to 1kg with simulated brine (mineralization 300000mg / L, calcium and magnesium ion content 10000mg / L). The mixture was stirred evenly to obtain the reversing agent B3, which can be used as a plugging agent for macropore sealing.

[0179] The colloidal strength of the modulator B3 after gelation and the blocking rate after being placed at 150℃ for 30 days were measured. The results are shown in Table 2.

[0180] Example 9

[0181] 8.5g of the sulfonic acid copolymer prepared in Preparation Example 4 and 0.8g of pre-crosslinked gel particles (purchased from Puyang Xinyuan Environmental Protection Technology Co., Ltd., with an acrylamide structural unit weight content of 100% by weight, an average particle size of 180-212μm, and based on the total weight of the pre-crosslinked gel particles, the content of particles with a particle size less than 180μm and greater than 212μm is less than 15% by weight) were added to 900g of simulated brine (mineralization of 300000mg / L, calcium and magnesium ion content of 10000mg / L). After stirring for 1h, 4.5g of hydroquinone, 4.5g of hexamethylenetetramine and 0.8g of sodium bisulfite were added, and the total weight was made up to 1kg with simulated brine (mineralization of 300000mg / L, calcium and magnesium ion content of 10000mg / L). The mixture was stirred evenly to obtain chain-spherical flow modifier B4, which can be used as a flow modifier for channel adjustment.

[0182] The colloidal strength of the modulator B4 after gelation and the blocking rate after being placed at 150℃ for 30 days were measured. The results are shown in Table 2.

[0183] Example 10

[0184] 8g of the sulfonic acid copolymer prepared in Preparation Example 7 and 2g of crosslinkable polymer powder (acrylamide / sodium acrylate / sodium 2-acrylamido-2-methylpropanesulfonate copolymer, in which the content of acrylamide structural units is 88%, the degree of hydrolysis is 5%, the average particle size is 150-180μm, and the content of particles with a particle size less than 125μm and greater than 150μm is less than 10% by weight based on the total weight of the crosslinkable polymer powder) were added to 900g of simulated salt. In water (mineralization of 300,000 mg / L, calcium and magnesium ion content of 10,000 mg / L), after stirring for 1 hour, 5 g hydroquinone, 6 g hexamethylenetetramine, and 0.8 g sodium bisulfite were added. Simulated brine (mineralization of 300,000 mg / L, calcium and magnesium ion content of 10,000 mg / L) was added to bring the total weight to 1 kg. The mixture was stirred evenly to obtain chain-spherical revelocity modifier B5. This revelocity modifier B5 can be used as a plugging agent for large-pore sealing.

[0185] The colloidal strength of the modulator B5 after gelation and the blocking rate after being placed at 150℃ for 30 days were measured. The results are shown in Table 2.

[0186] Comparative Example 1

[0187] Following the method of Example 3, except that 0.9 g of crosslinkable polymer powder was not added, the revelocity modulator DA1 was obtained. The viscosity of the obtained revelocity modulator DA1 after standing at 130°C for 30 days is shown in Table 1.

[0188] Comparative Example 2

[0189] Following the method of Example 3, except that 0.9 g of the crosslinkable polymer powder was replaced with 0.9 g of the sulfonic acid copolymer prepared in Example 3 to obtain the revelocity modulator DA2. The aging viscosity and thickening rate of the obtained revelocity modulator DA2 after standing at 130°C for 30 days are shown in Table 1.

[0190] Comparative Example 3

[0191] Following the method of Example 4, except that 0.8g of pre-crosslinked gel particles were not added, the revelocity modulator DA3 was obtained. The aging viscosity and thickening rate of the obtained revelocity modulator DA3 after standing at 130°C for 30 days are shown in Table 1.

[0192] Comparative Example 4

[0193] Following the method of Example 4, except that the sulfonic acid copolymer was replaced with an equal mass of partially hydrolyzed polyacrylamide (relative molecular mass of 25 million, degree of hydrolysis of 25.6%), a stable heterogeneous solution with swollen particles could not be obtained. Precipitation appeared after standing at 130°C for 3 days, and the tested solution viscosity was <10 mPa·s.

[0194] Comparative Example 5

[0195] Following the method of Example 4, except that the sulfonic acid copolymer was replaced with an equal mass of acrylamide / sodium acrylate / sodium 2-acrylamido-2-methylpropanesulfonate copolymer (relative molecular mass of 29.13 million, degree of hydrolysis of 21.6%, and sodium 2-acrylamido-2-methylpropanesulfonate content of 10% by weight), a stable heterogeneous solution with swollen particles could not be obtained. After standing at 130°C for 3 days, precipitation occurred, and the tested solution viscosity was <10 mPa·s.

[0196] Comparative Example 6

[0197] Following the method of Example 8, except that 1g of crosslinkable polymer powder was not added, the reversing agent DB6 was obtained. The gel strength and blocking rate of the obtained reversing agent DB6 after standing at 150°C for 30 days are shown in Table 2.

[0198] Comparative Example 7

[0199] Following the method of Example 8, except that 1g of the crosslinkable polymer powder was replaced with 1g of the sulfonic acid copolymer prepared in Preparation Example 3 to obtain the reversing agent DB7. The gel strength and blocking rate of the obtained reversing agent DB7 after standing at 150°C for 30 days are shown in Table 2.

[0200] Comparative Example 8

[0201] Following the method of Example 9, except that 0.8 g of pre-crosslinked gel particles were not added, the reversing agent DB8 was obtained. The gel strength and blocking rate of the obtained reversing agent DB8 after standing at 150°C for 30 days are shown in Table 2.

[0202] Comparative Example 9

[0203] Following the method of Example 9, except that the sulfonic acid copolymer was replaced with an equal mass of partially hydrolyzed polyacrylamide (relative molecular mass of 25 million, degree of hydrolysis of 25.6%), a stable heterogeneous solution with swollen particles could not be obtained, and a three-dimensional network structure gel could not be formed when the solution was left to stand at 150°C.

[0204] Comparative Example 10

[0205] Following the method of Example 9, except that the sulfonic acid copolymer was replaced with an equal mass of acrylamide / sodium acrylate / sodium 2-acrylamido-2-methylpropanesulfonate copolymer (relative molecular mass of 29.13 million, degree of hydrolysis of 21.6%, and sodium 2-acrylamido-2-methylpropanesulfonate content of 10% by weight), a stable heterogeneous solution with swollen particles could not be obtained, and a three-dimensional network structure gel could not be formed when the solution was left to stand at 150°C.

[0206] Table 1

[0207]

[0208] As can be seen from the results in Table 1, compared with Comparative Examples 1-5, the modulators prepared in Examples 1-5 of the present invention have higher viscosity and viscosity growth rate after aging at 90-130℃.

[0209] Table 2

[0210]

[0211] As can be seen from the results in Table 2, compared with Comparative Examples 6-10, the plugging agent prepared in Examples 6-10 of the present invention can remain stable at 130-150℃ for 30-60 days, and has higher gel strength and plugging rate, showing significantly better effect on plugging large channels in carbonate reservoirs.

[0212] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A polymer composition, characterized in that, The polymer composition comprises a sulfonic acid copolymer and a crosslinkable polymer; wherein the sulfonic acid copolymer comprises structural unit A and structural unit B as shown in Formula I; structural unit B comprises structural unit B1 as shown in Formula II and / or structural unit B2 as shown in Formula III; the crosslinkable polymer is selected from one or more acrylamide polymers; the degree of hydrolysis of the acrylamide polymer is not greater than 10%; the acrylamide polymer can be hydrolyzed to produce carboxyl groups at temperatures above 90°C; R1, R7, and R8 are each independently H or C1-C6 alkyl groups; R2, R9 and R 10 Each is independently an H or C1-C6 alkyl group; R3 and R4 are each independently C1-C6 alkyl groups; R5 is a C1-C6 alkylene group; R6 represents H or an alkali metal element.

2. The polymer composition according to claim 1, wherein, R1, R7, and R8 are each independently H or methyl; And / or, R2 and R9 are each independently H; And / or, R3 and R4 are each independently methyl; And / or, R5 is methylene; R6 is H or Na; And / or, R 10 It is H or methyl.

3. The polymer composition according to claim 1 or 2, wherein, Based on the total weight of the sulfonic acid copolymer, the weight content of sulfonic acid groups is not less than 21% by weight; preferably 23-30% by weight. And / or, the viscosity-average molecular weight of the sulfonic acid copolymer is 4 million to 18 million; preferably 5 million to 17 million.

4. The polymer composition according to any one of claims 1-3, wherein, Based on the total weight of the sulfonic acid copolymer, the content of structural unit A is not less than 60% by weight; Preferably, based on the total weight of the sulfonic acid copolymer, the content of structural unit A is 65-90% by weight, preferably 70-85% by weight; and the content of structural unit B is 10-35% by weight, preferably 16-32% by weight.

5. The polymer composition according to any one of claims 1-4, wherein, The structural unit B includes structural unit B1 shown in Formula II and structural unit B2 shown in Formula III, with a weight ratio of 1:0.01-3, preferably 1:0.05-1.

6. The polymer composition according to any one of claims 1-5, wherein, The crosslinkable polymer is insoluble in brine with a mineralization of ≥50000 mg / L; And / or, the weight ratio of the sulfonic acid copolymer to the crosslinkable polymer is 1-15:1, preferably 4-10:1; And / or, the content of acrylamide structural units in the crosslinkable polymer is not less than 80% by weight, preferably 85-100% by weight; And / or, the crosslinkable polymer has a particle size of 75 μm-250 μm, preferably 100 μm-180 μm; And / or, the residue of the crosslinkable polymer on the sieve is less than 20%, preferably less than 10%.

7. The polymer composition according to any one of claims 1-6, wherein, The acrylamide polymers are selected from one or more of the following: polyacrylamide, acrylamide / N-vinylpyrrolidone copolymer, acrylamide / 2-acrylamido-2-methylpropanesulfonic acid (sodium) copolymer, acrylamide / N-vinylformamide copolymer, acrylamide / N-vinylacetamide copolymer, acrylamide / acrylonitrile copolymer, acrylamide / sodium acrylate / N-vinylpyrrolidone copolymer, acrylamide / sodium acrylate / 2-acrylamido-2-methylpropanesulfonic acid (sodium) copolymer, and acrylamide / sodium acrylate / acrylonitrile copolymer; And / or, the acrylamide polymer is selected from acrylamide pre-crosslinked gel particles; the acrylamide pre-crosslinked gel particles are branched viscoelastic particles obtained by reacting acrylamide and optional polymeric monomers with a crosslinking agent; wherein, the polymeric monomer is selected from one or more of acrylic acid, sodium acrylate, sodium 2-acrylamido-2-methylpropanesulfonate and methyl methacrylate; the crosslinking agent is selected from one or more of bisacrylamides; preferably, the weight content of acrylamide structural units in the acrylamide pre-crosslinked gel particles is ≥80% by weight, and the weight content of sodium acrylate is ≤10% by weight.

8. A modulator, characterized in that, The modulator comprises the polymer composition according to any one of claims 1-7.

9. The modulator according to claim 8, wherein, Based on the total weight of the driving agent, the content of the sulfonic acid copolymer is 0.3-1.5% by weight, preferably 0.5-1.2% by weight; And / or, based on the total weight of the modulator, the content of the crosslinkable polymer is 0.1-0.4% by weight, preferably 0.15-0.3% by weight.

10. The modulator according to claim 8 or 9, wherein, The modulator further includes a crosslinking agent, which is selected from one or more of organometallic crosslinking agents, phenolic crosslinking agents, and aldehyde crosslinking agents; Preferably, the organometallic crosslinking agent is a crosslinking agent formed by metal ions and organic ligand compounds; wherein the metal ions are selected from one or more of aluminum, chromium, zirconium, iron, and titanium; and the organic ligand compounds are selected from one or more of organic acids and organic amines; more preferably, the organometallic crosslinking agent is selected from at least one of chromium citrate, chromium oxalate, chromium lactate, zirconium citrate, zirconium lactate, zirconium propionate, aluminum citrate, and aluminum lactate; Preferably, the phenolic crosslinking agent is selected from one or more of phenol, cresol, hydroquinone, catechol, and resorcinol; Preferably, the aldehyde-type crosslinking agent is selected from one or more of formaldehyde, acetaldehyde, paraformaldehyde, hexamethylenetetramine, and furfural; preferably, based on the total weight of the modulator, the content of the crosslinking agent is 0.01-2% by weight, preferably 0.02-1.5% by weight.

11. A method for preparing a modulator / redirector, characterized in that, The preparation method includes: mixing the polymer composition according to any one of claims 1-7 with a crosslinking agent and a solvent to form a polymer solution containing swollen particles and a crosslinking agent.

12. The preparation method according to claim 11, wherein, The method for preparing the sulfonic acid copolymer includes: under solution polymerization conditions, in the presence of an initiator, causing an alkenyl monomer to undergo a polymerization reaction; wherein the alkenyl monomer includes monomer a and monomer b as shown in Formula 1, and monomer b includes monomer b1 as shown in Formula 2 and / or monomer b2 as shown in Formula 3; R1, R7, and R8 are each independently H or C1-C6 alkyl groups; R2, R9 and R 10 Each is independently an H or C1-C6 alkyl group; R3 and R4 are each independently C1-C6 alkyl groups; R5 is a C1-C6 alkylene group; R6 represents H or an alkali metal element.

13. The preparation method according to claim 12, wherein, Based on the total weight of the alkenyl monomers, the content of monomer a is 65-90% by weight, preferably 70-85% by weight; the content of monomer b is 10-35% by weight, preferably 16-32% by weight. Preferably, the monomer b includes monomer b1 shown in Formula 2 and / or monomer b2 shown in Formula 3; the weight ratio of the two is 1:0.01-3, preferably 1:0.05-1.

14. The preparation method according to any one of claims 11-13, wherein, The crosslinking agent is selected from one or more of organometallic crosslinking agents, phenolic crosslinking agents, and aldehyde crosslinking agents; Preferably, the organometallic crosslinking agent is a crosslinking agent formed by metal ions and organic ligand compounds; wherein the metal ions are selected from one or more of aluminum, chromium, zirconium, iron, and titanium; and the organic ligand compounds are selected from one or more of organic acids and organic amines; more preferably, the organometallic crosslinking agent is selected from at least one of chromium citrate, chromium oxalate, chromium lactate, zirconium citrate, zirconium lactate, zirconium propionate, aluminum citrate, and aluminum lactate; Preferably, the phenolic crosslinking agent is selected from one or more of phenol, cresol, hydroquinone, catechol, and resorcinol; Preferably, the aldehyde-type crosslinking agent is selected from one or more of formaldehyde, acetaldehyde, paraformaldehyde, hexamethylenetetramine, and furfural.

15. The preparation method according to any one of claims 11-14, wherein, The mass ratio of the polymer composition to the crosslinking agent is 1:0.05-1.5; And / or, the mass ratio of the polymer composition to the solvent is 1:0.007-0.015; And / or, the solvent is selected from one or more of water, seawater, and brine with a mineralization of ≤300 g / L.

16. The use of the polymer composition according to any one of claims 1-7, or the modulating agent according to any one of claims 8-10, or the modulating agent prepared by the preparation method according to any one of claims 11-15 in oil displacement.

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