Sulfonic acid type copolymer, preparation method and profile control and flooding system

Abstract

The invention relates to the field of oil exploitation, and discloses a sulfonic acid type copolymer, a preparation method and a profile control and flooding system. According to the invention, a sulfonic acid group monomer is used as a main construction unit, and amide, alkylamine acyl and tertiary carbonate monomer structural units are introduced, so that the hydrolysis rate of amido and alkylamide can be controlled, and precipitation can be inhibited at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of oil extraction, and specifically, to a sulfonic acid copolymer, a preparation method thereof, and a profile control and displacement system. Background Art

[0002] Carbonate reservoirs are mainly fracture-vuggy. Due to extremely strong heterogeneity, water channeling and low recovery rate are likely to occur during water injection development of the reservoir. The fluid flow state in carbonate reservoirs is complex, with both seepage flow and pipe flow existing simultaneously. Water channeling and water flooding in preferential channels have long troubled oilfield production. Currently, the widely used profile control and displacement technologies include flow control and plugging. Among them, flow control is to inject a flow control agent into a water well, and the fluid to be injected should have low viscosity during injection and high viscosity after reaching the deep layer. Plugging is to inject a high-strength plugging agent into an oil well, and the fluid to be injected should be able to maintain high strength for a long time after reaching the deep part. Currently, the commonly used flow control agents and plugging agents are mostly polymer gels. However, the carbonate reservoir environment is harsh. In domestic carbonate reservoirs in China, the general temperature is 110 - 160 °C, the salinity ≥ 20 × 10 4 mg / L, and the calcium and magnesium ion content ≥ 1 × 10 4 mg / L. Taking Abu Dhabi in the Middle East as an example for foreign carbonate reservoirs, the reservoir temperature is 115 - 139 °C, and the salinity is 15 × 10 4 -20 × 10 4 mg / L. Existing gels usually use acrylamide monomers as the main building units. In the reservoir environment, a large amount of rapid hydrolysis of the amide groups in the polymer leads to the formation of precipitates when encountering high calcium and magnesium ions, resulting in a sharp drop in viscosity, making it difficult to achieve high viscosity in the deep layer, or because a large amount of amide groups are reduced, it is difficult to form a high-strength gel, resulting in rapid dehydration and failure of the gel, and the profile control or plugging effect deteriorates.

[0003] Currently, the upper limits of temperature and salinity applicable to gels for profile control or plugging are much lower than the application environment of carbonate reservoirs. Therefore, there is an urgent need to develop new polymers and gel profile control and displacement systems with temperature resistance, salt resistance, and high calcium and magnesium ion resistance to meet the requirements of flow control and plugging in carbonate reservoirs. Summary of the Invention

[0004] The purpose of the present invention is to overcome the problems existing in the prior art, and provide a sulfonic acid copolymer, a preparation method thereof, and a profile control and displacement system.

[0005] To achieve the above purpose, the first aspect of the present invention provides a sulfonic acid copolymer.

[0006] The second aspect of the present invention provides a method for preparing a sulfonic acid copolymer.

[0007] The third aspect of the present invention provides a sulfonic acid copolymer obtained by the aforementioned preparation method.

[0008] The fourth aspect of the present invention provides a profile control system prepared from the sulfonic acid copolymer as described above.

[0009] Through the above technical solutions, the present invention uses monomers containing long-chain branched sulfonic acid groups as the main building units, and introduces amide, alkylamine acyl, and tertiary carbonate structural units, which can control the hydrolysis rate of amide groups and alkylamides, and avoid precipitation at the same time. It has strong hydrolysis resistance and a stable backbone structure. The copolymer of the present invention releases crosslinking sites through the hydrolysis of amide groups and alkylamine acyl groups at high temperatures, and can form a flow regulator with a certain viscosity and adjustable viscosity by coordinating with a metal crosslinking agent. This flow regulator still has a high viscosity after 60 days in a reservoir environment with a temperature of 60-130°C, a salinity ≤ 300000 mg / L, and a calcium and magnesium ion content ≤ 10000 mg / L, thus realizing flow path adjustment.

[0010] At the same time, the amino groups generated by the hydrolysis of amide groups and alkylamine acyl groups in the copolymer of the present invention can react with phenolic and aldehyde crosslinking agents to form a profile control system with high strength. In a reservoir environment with a temperature of 140-160°C, a salinity ≤ 300000 mg / L, and a calcium and magnesium ion content ≤ 10000 mg / L, it can be stable for at least 90 days, maintain good viscoelasticity, have a low dehydration rate, and achieve long-term profile control and plugging. Detailed implementation mode

[0011] In the ranges disclosed herein, the endpoints and any values are not limited to the exact 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 each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0012] The first aspect of the present invention provides a sulfonic acid copolymer, characterized in that the copolymer comprises structural unit A, structural unit B, structural unit C, and structural unit D; the structural unit A is The structural unit B is The structural unit C is The structural unit D is

[0013] Among them, R 1 is H or an alkali metal element, R 2 is H or methyl, R 3 is H or methyl, R 4 and R 5 are each independently an alkyl group with 1-6 carbon atoms, and when R 4 and R 5 are each independently an alkyl group with 2-6 carbon atoms, R 4 and R5 The total carbon number is 6 - 8.

[0014] Based on the total weight of the copolymer, the content of structural unit A is 65 - 90% by weight, preferably 70 - 84% by weight, more preferably 71 - 81% by weight.

[0015] Based on the total weight of the copolymer, the content of structural unit B is 5 - 30% by weight, preferably 12 - 25% by weight.

[0016] Based on the total weight of the copolymer, the content of structural unit C is 1 - 8% by weight, preferably 3 - 6% by weight.

[0017] Based on the total weight of the copolymer, the content of structural unit D is 0.1 - 2% by weight, preferably 0.2 - 1% by weight.

[0018] According to the present invention, the weight ratio of structural unit A, structural unit B, structural unit C, and structural unit D is 1:(0.01 - 1):(0.01 - 0.2):(0.0005 - 0.06), preferably 1:(0.08 - 0.6):(0.02 - 0.15):(0.0008 - 0.04).

[0019] According to the present invention, the viscosity - average molecular weight of the sulfonic acid - type copolymer is 5 million - 18 million. For example, it can be 5 million, 8 million, 10 million, 11 million, 11.6 million, 12 million, 13 million, 14.5 million, 15 million, 16 million, 17 million, 18 million, and values within the range formed by any two of the above values and within the range.

[0020] According to a preferred embodiment of the present invention, R 1 is H or Na.

[0021] According to a preferred embodiment of the present invention, R 2 is H.

[0022] According to a preferred embodiment of the present invention, R 3 is H or methyl.

[0023] According to a preferred embodiment of the present invention, R 4 is methyl and R 5 is methyl; or R 4 is methyl and R 5 is n - pentyl; or R 4 is methyl and R 5 is n - hexyl.

[0024] The second aspect of the present invention provides a method for preparing a sulfonic acid copolymer, which is characterized in that the method comprises: under solution polymerization reaction conditions, in the presence of an initiator, subjecting vinyl monomers to a polymerization reaction; wherein, the vinyl monomers include monomer A', monomer B', monomer C' and monomer D'; the monomer A' is The monomer B' is The monomer C' is The monomer D' is

[0025] Wherein, R 1 , R 2 , R 3 , R 4 and R 5 are as described above.

[0026] Based on the total weight of the vinyl monomers, the content of the monomer A' is 65-90% by weight, preferably 70-84% by weight, more preferably 71-81% by weight.

[0027] Based on the total weight of the vinyl monomers, the content of the monomer B' is 5-30% by weight, preferably 12-25% by weight.

[0028] Based on the total weight of the vinyl monomers, the content of the monomer C' is 1-8% by weight, preferably 3-6% by weight.

[0029] Based on the total weight of the vinyl monomers, the content of the monomer D' is 0.1-2% by weight, preferably 0.2-1% by weight.

[0030] (2) Granulating, drying, pulverizing and screening the copolymer colloid to obtain the copolymer.

[0031] According to the present invention, the weight ratio of the monomer A', the monomer B', the monomer C' and the monomer D' is 1:(0.01-1):(0.01-0.2):(0.0005-0.06), preferably 1:(0.08-0.6):(0.02-0.15):(0.0008-0.04).

[0032] According to the present invention, at the start of the solution polymerization reaction, the ratio of the total weight of the vinyl monomers to the sum of the solvent and the total weight of the vinyl monomers is (0.3-0.55):1, preferably (0.35-0.5):1.

[0033] According to the present invention, the solution polymerization reaction conditions can make the viscosity-average molecular weight of the obtained polymer as described above. Preferably, the solution polymerization reaction conditions include: the initial temperature of the polymerization reaction is -10°C to 30°C, the time is 2 to 12 hours, and the pH value is 4 to 8. Preferably, the initial temperature of the polymerization reaction is -5°C to 10°C, the time is 3 to 10 hours, and the pH value is 5 to 7. In the present invention, one or more of alkali metal hydroxides (such as sodium hydroxide, potassium hydroxide) and 2-acrylamido-2-methylpropanesulfonic acid can be used to adjust the pH value of the polymerization reaction. It can be understood that by using an alkali metal hydroxide (such as sodium hydroxide) to adjust the pH value, R in the structural unit A (monomer A') can be converted from H to an alkali metal element (such as Na). Moreover, by controlling the amount of the alkali metal hydroxide used, the polymer of the present invention can also have structural units in which R is H and R is an alkali metal element at the same time. 1 is converted from H to an alkali metal element (such as Na), and moreover, by controlling the amount of the alkali metal hydroxide used, the polymer of the present invention can also have R 1 being H and R 1 being an alkali metal element at the same time.

[0034] According to the present invention, the initiator can be selected from various common initiators in the art. For example, the initiator can be selected from azo initiators and / or redox initiators. The amount of the initiator can be 0.0003 to 0.05% by weight of the weight of the vinyl monomer. Preferably, the amount of the azo initiator is 0.0001 to 0.1% by weight of the weight of the vinyl monomer. Preferably, the amount of the redox initiator is 0.0002 to 0.3% by weight of the weight of the vinyl monomer.

[0035] According to the present invention, the azo initiator is preferably a water-soluble azo initiator. The redox initiator includes an oxidizing agent and a reducing agent. The reducing agent is an inorganic reducing agent and / or an organic reducing agent, and the weight ratio of the oxidizing agent to the reducing agent is (0.1 - 1):1.

[0036] Preferably, the water-soluble azo initiator is selected from at least one of 2,2'-azobis(2-amidinopropane) dihydrochloride, 2,2'-azobis(2-imidazolinopropane) dihydrochloride, and 4,4'-azobis(4-cyanovaleric acid). Preferably, the oxidant is selected from at least one of benzoyl peroxide, hydrogen peroxide, tert-butyl hydroperoxide, 2,5-dimethyl-2,5-bis(hydroperoxy)hexane, ammonium persulfate, sodium persulfate, and potassium persulfate. Preferably, the inorganic reducing agent is selected from at least one of ferrous sulfate, ammonium ferrous sulfate, cuprous chloride, potassium sulfite, sodium sulfite, ammonium bisulfite, potassium bisulfite, sodium thiosulfate, potassium thiosulfate, sodium formaldehyde sulfoxylate (rongalite), 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.

[0037] According to the present invention, in order to better control the induction period and reduce the inhibition effect of dissolved oxygen, the polymerization reaction is preferably carried out in an inert atmosphere, and the inert atmosphere can be provided by nitrogen and / or inert gas.

[0038] According to the present invention, preferably, the preparation method further contains an emulsifier, and the emulsifier can better disperse monomer D and play a role in solubilizing monomer D. The emulsifier includes one or more of Tween 60, Tween 80, sodium dodecyl sulfate, and sodium dodecylbenzenesulfonate, and the weight dosage of the emulsifier is 5-30 times the weight dosage of monomer D, based on the weight of the added D monomer.

[0039] According to the present invention, in order to control the foam in the reaction system, the polymerization reaction is carried out in the presence of an antifoaming agent. The dosage of the antifoaming agent can be 0.05-1% by weight of the amount of the vinyl monomer. The antifoaming agent can be selected from various common antifoaming agents in the art.

[0040] According to the present invention, the method may further include: granulating, drying, pulverizing, and screening the polymer colloid to obtain a polymer product.

[0041] According to the present invention, the conditions for drying include: the temperature is 40-70°C, preferably 45-65°C. In the present invention, the drying time is not specifically limited, and it can be dried until the solid content reaches 85-95% by weight, preferably 88-90% by weight. Generally, the drying time is 2-24 hours.

[0042] The third aspect of the present invention provides a sulfonic acid copolymer prepared by the aforementioned preparation method.

[0043] In the present invention, conventional methods in the prior art can be used to test the contents of various structural units in the polymer, such as infrared spectroscopy, nuclear magnetic resonance, and the feeding amounts of monomers during the polymerization process, etc. Preferably, the feeding amounts of monomers are used to determine the contents of various structural units in the polymer. Specifically, the feeding ratios of the monomers actually participating in the polymerization are determined by testing the contents of unreacted monomers, and then the contents of various structural units in the polymer are determined. Further, in the present invention, the contents of various unreacted monomers in the polymer are all tested to be below 0.02% by weight, indicating that all monomers basically participate in the polymerization reaction. Specifically, the content of the residual monomers can be determined by liquid chromatography.

[0044] In the fourth aspect of the present invention, a profile control and displacement system is provided, which is characterized in that the profile control and displacement system contains a crosslinking agent and the sulfonic acid copolymer as described above. The profile control and displacement system of the present invention is particularly suitable for flow regulation and plugging in carbonate reservoirs.

[0045] According to the present invention, the profile control and displacement system may further contain a solvent, and the solvent is water. The content of the solvent may be 97 - 99.6% by weight, preferably 98.3 - 99.1% by weight.

[0046] In the present invention, based on the total weight of the profile control and displacement system, the content of the sulfonic acid copolymer is preferably 0.3 - 1.5% by weight, more preferably 0.5 - 1.2% by weight.

[0047] In the present invention, based on the total weight of the profile control and displacement system, the content of the crosslinking agent is preferably 0.01 - 2% by weight, more preferably 0.02 - 1.5% by weight.

[0048] In the present invention, the crosslinking agent can be selected from substances commonly used in the art that can crosslink the sulfonic acid copolymer. For example, it can be at least one of organometallic crosslinking agents, phenolic crosslinking agents, and aldehyde crosslinking agents.

[0049] According to a more preferred embodiment of the present invention, the organometallic crosslinking agent is a crosslinking agent formed by a metal ion and an organic ligand compound. Preferably, the metal ion is selected from at least one of aluminum, chromium, zirconium, and titanium. Preferably, the organic ligand compound is selected from at least one of organic acids and / or organic amines, more preferably selected from at least one of citric acid, oxalic acid, acetic acid, lactic acid, polyenepolyamine, and triethanolamine. The profile control agent formed by the copolymer of the present invention and the organometallic crosslinking agent still has good viscosity and excellent stability after aging for 60 days at 60 - 130 °C in water with a salinity ≤ 300000 mg / L and a calcium and magnesium ion content ≤ 10000 mg / L, and can be used for adjusting the flow channels in carbonate reservoirs.

[0050] According to the present invention, the phenolic crosslinking agent and the aldehyde crosslinking agent can be provided by the same substance, such as at least one of water-soluble phenolic resin and sulfonated phenolic resin, preferably sulfonated phenolic resin.

[0051] According to a more preferred embodiment of the present invention, the phenolic crosslinking agent is at least one of phenol, cresol (such as o-cresol, m-cresol, p-cresol), hydroquinone, catechol, and resorcinol, and more preferably hydroquinone.

[0052] According to a more preferred embodiment of the present invention, the aldehyde crosslinking agent is at least one of formaldehyde, acetaldehyde, paraformaldehyde, hexamethylenetetramine (releasing formaldehyde upon heating), and furfural, and more preferably hexamethylenetetramine. The copolymer of the present invention can form a profile control and displacement agent with phenolic and aldehyde crosslinking agents. In an environment with a salinity ≤ 300000 mg / L and a calcium and magnesium ion content ≤ 10000 mg / L, after aging at a high temperature of 140 - 160 °C for 90 days, the dehydration rate is low, and it has a high storage modulus, indicating high strength and good thermal stability, and can be used as a profile control and displacement agent for ultra-deep wells in carbonate reservoirs.

[0053] In the present invention, the phenolic crosslinking agent and the aldehyde crosslinking agent can be provided by different substances. Further preferably, the weight ratio of the phenolic crosslinking agent to the aldehyde crosslinking agent is 1:(0.6 - 1.5).

[0054] In the present invention, the profile control and displacement system may further contain an oxygen scavenger. The content of the oxygen scavenger can be 0.005 - 0.3% by weight, preferably 0.02 - 0.25% by weight. The type and dosage of the oxygen scavenger can be selected with reference to the prior art. For the present invention, preferably, the oxygen scavenger is at least one of sodium thiosulfate, sodium sulfite, sodium bisulfite, sodium dithionite (insurance powder), isascorbic acid, and thiourea.

[0055] The fifth aspect of the present invention provides a method for preparing a profile control and displacement system, which includes: mixing a sulfonic acid copolymer with a crosslinking agent and an optional oxygen scavenger in the presence of a solvent, wherein the sulfonic acid copolymer is the aforementioned sulfonic acid copolymer. The specific selection and dosage of the solvent, copolymer, crosslinking agent, and oxygen scavenger are as described above and will not be elaborated here.

[0056] The sixth aspect of the present invention provides an application of the aforementioned profile control and displacement system as a flow regulator and / or profile control agent in oil reservoir exploitation.

[0057] According to the present invention, the oil reservoir is a high-temperature and high-salt oil reservoir, preferably a carbonate rock oil reservoir.

[0058] According to the present invention, preferably, the reservoir temperature of the reservoir is 60 - 160 °C, the salinity is ≤ 300,000 mg / L, and the calcium and magnesium ion concentration is ≤ 10,000 mg / L; more preferably, the reservoir temperature of the carbonate reservoir is 70 - 160 °C, the salinity is 1,000 - 300,000 mg / L, and the calcium and magnesium ion concentration is 100 - 10,000 mg / L.

[0059] In the present invention, water is used as the solvent and reaction medium in the sulfonic acid copolymer, and there is no particular limitation on its selection in the present invention. The water can be natural water and artificial water. Natural water can be river water, lake water, atmospheric water, seawater, groundwater, etc., and artificial water can be tap water, distilled water, deionized water or heavy water.

[0060] Generally speaking, in the actual application process, the water used is often the water at the oil field location (field water) or its corresponding simulated brine. Preferably, the salinity of the water is 1,000 - 300,000 mg / L, and the calcium and magnesium ion content is 100 - 10,000 mg / L.

[0061] The present invention will be described in detail below through examples. In the following examples and comparative examples:

[0062] 2 - acrylamido - 2 - methylpropanesulfonic acid and sodium 2 - acrylamido - 2 - methylpropanesulfonate in monomer A' are purchased from Shandong Weifang Jinshi Environmental Protection Technology Co., Ltd.

[0063] Acrylamide in monomer B' is purchased from Dongying Baomo Environmental Engineering Co., Ltd.

[0064] Monomer C' is purchased from Shanghai Macklin Biochemical Co., Ltd.

[0065] Monomer D' is purchased from Sigma - Aldrich.

[0066] Aluminum citrate, zirconium citrate, and zirconium lactate are purchased from Guangdong Wengjiang Chemical Reagent Co., Ltd.

[0067] Chromium citrate and chromium lactate are purchased from Shandong Shida Oilfield Technology Service Co., Ltd.

[0068] Unless otherwise specified, the reagents and materials used in the following examples can be obtained through commercial purchase. The defoamer used is an organosilicon defoamer, purchased from Jiangsu Haian Petrochemical Factory.

[0069] In the following examples, simulated brine is prepared according to the applicable reservoir environment. The salinity of the simulated brine is 100,000 - 300,000 mg / L, and the calcium and magnesium ion concentration is 5,000 - 10,000 mg / L (it should be understood that its salinity is an approximate value).

[0070] The test methods for copolymer or flooding system performance are as follows:

[0071] 1) The molecular weight test method is as follows:

[0072] The viscosity average molecular weight of the polymer is calculated according to the method specified in GB / T 12005.10-92 using the formula M=([η] / K) 1 / α To calculate, where K = 4.75 × 10 -3 , α = 0.8, [η] is the intrinsic viscosity; the intrinsic viscosity is determined according to the enterprise standard Q / SH1020 1572-2022 "Polyacrylamide for Oil Displacement" of Shengli Petroleum Administration Bureau of Sinopec Group.

[0073] 2) The content of cross-linked groups generated by hydrolysis = the content of carboxyl groups + the content of amine groups. The test method for the content of cross-linked groups (carboxyl groups and amine groups) is as follows: a) A certain mass of high-temperature aged polymer solution is measured according to the method of determining the degree of hydrolysis in accordance with the enterprise standard Q / SH1020 1572-2022 "Polyacrylamide for Oil Displacement" of Shengli Petroleum Administration Bureau of Sinopec Group to obtain the hydrochloric acid consumption V 1 (Total hydrochloric acid consumption of acrylate and formate (acetate) structural units); b) The same mass of high-temperature aged polymer solution is first purified by dialysis membrane (molecular weight cutoff: 3500, Solebow brand) to remove the sodium formate produced by hydrolysis, and then most of the water is removed by rotary evaporation, and the aged polymer powder sample is obtained by freeze-drying and crushing, and then the hydrolysis degree is determined by referring to the method of determining the hydrolysis degree of Sinopec Group Shengli Petroleum Administration Bureau Enterprise Standard Q / SH1020 1572-2022 "Polyacrylamide for Oil Displacement" to obtain the hydrochloric acid consumption V 2 (Hydrochloric acid consumption of acrylic acid radical), by V 2 Calculate the carboxyl content. c) Through V 3 =V 1 -V 2 Calculate the hydrochloric acid consumption of formate or acetate, and refer to the hydrolysis degree formula in Q / SH1020 1572-2022 "Polyacrylamide for Oil Displacement" to calculate the content of amine groups released by hydrolysis.

[0074] 3) The viscosity of the displacement system was measured using a Brookfield R / S Rheometer at 30°C for 7.34s -1 Viscosity at shear rate.

[0075] 4) The gel strength of the displacement system is measured by rheological method through the storage modulus of the system. The measurement method refers to the "Rheological parameter method for measuring the strength of polymer gel for oil production" (SY / T6296-1997). The testing instrument is HAAKE RS6000 rheometer. ​​​​​

[0076] 5) The thermal stability of the profile control system is reflected by the dehydration rate. The lower the dehydration rate, the stronger the stability. The test method for the dehydration rate is as follows: Place the gelled solution of the polymer gel formed by the polymer and the crosslinking agent in a closed stainless steel reactor, place it in a constant temperature oven at a temperature of 140 - 160 °C for reaction. Take it out of the constant temperature oven at fixed intervals (30 - 90 days), weigh the weight of the dehydrated water with a balance, and the ratio of this mass to the mass of the initial gelled solution is the dehydration rate.

[0077] Preparation Example 1

[0078] This preparation example is to illustrate the preparation of a sulfonic acid copolymer with a controllable hydrolysis rate by using the preparation method of the present invention.

[0079] (1) Take 86.5 g of monomer A′, 27.8 g of monomer B′ acrylamide, 5 g of monomer C′, and 0.6 g of monomer D′. Among them, the structural formula of monomer A′ is R 1 is Na, that is, 2-acrylamido-2-methylpropanesulfonic acid sodium; the structural formula of monomer C′ is R 3 is H; the structural formula of monomer D′ is Add 9 g of sodium dodecyl sulfate, dissolve it in 171.1 g of deionized water, adjust the pH value to 6 with sodium hydroxide solution, control the starting temperature at 2 °C, add 0.3 g of defoaming agent, purge nitrogen into the system for 20 min to remove oxygen, then add 1 g of 2,2-azobis(2-amidinopropane) dihydrochloride aqueous solution with a concentration of 0.25 wt%, 2 g of ammonium persulfate aqueous solution with a concentration of 0.2 wt%, and 1.5 g of sodium bisulfite aqueous solution with a concentration of 0.3 wt% to initiate polymerization. After the system temperature rises by 0.5 °C, stop purging nitrogen bubbles and continue the reaction for 4 hours;

[0080] (2) After the polymerization is completed, granulate the obtained colloid, dry it at 50 °C until the solid content reaches 89 wt%, crush and screen it to obtain a dry powder product of the sulfonic acid copolymer.

[0081] The viscosity-average molecular weight of the dry powder product is measured to be 14.8 million.

[0082] In addition, according to the calculated feeding amount, in the prepared sulfonic acid copolymer, the sulfonic acid copolymer contains:

[0083] Structural unit A( wherein, R 1 is Na);

[0084] Structural unit B( wherein, R 2 is H);

[0085] Structural unit C( Among them, R 3 is H);

[0086] structural unit D( );

[0087] Among them, based on the total weight of the sulfonic acid type copolymer, the content of the structural unit A is 72.1% by weight, the content of the structural unit B is 23.2% by weight, the content of the structural unit C is 4.2% by weight, and the content of the structural unit D is 0.5% by weight.

[0088] The content of the crosslinked groups generated after high temperature is measured after placing a 5000 mg / L polymer solution (prepared with deionized water) at 130 °C for 15 - 60 days, and the results are shown in Table 1.

[0089] Table 1 Content of crosslinked groups generated by the sulfonic acid type copolymers with controllable hydrolysis rate prepared in Preparation Examples 1 - 5 and the polymers obtained in Comparative Examples after high temperature aging at 130 °C for 15 - 60 days

[0090]

[0091] Preparation Example 2

[0092] This preparation example is to illustrate the preparation of a sulfonic acid type copolymer with controllable hydrolysis rate by using the preparation method of the present invention.

[0093] (1) Take 96.2 g of monomer A′, 24.6 g of monomer B′ acrylamide, 6.7 g of monomer C′, and 1.2 g of monomer D′. Among them, the structural formula of monomer A′ is R 1 is H, that is, 2 - acrylamido - 2 - methylpropanesulfonic acid; the structural formula of monomer C′ is R 3 is methyl; the structural formula of monomer D′ is; R 4 is methyl, R 5 is n - pentyl; 24 g of sodium dodecyl sulfate is dissolved in 147.4 g of deionized water, and the pH value is adjusted to 6 with sodium hydroxide solution, the starting temperature is controlled at 0 °C, 0.8 g of defoaming agent is added, nitrogen is bubbled into the system for 20 min for deoxygenation, then 1.4 g of a 2,2 - azobis(2 - amidinopropane) dihydrochloride aqueous solution with a concentration of 0.25% by weight, 2 g of an ammonium persulfate aqueous solution with a concentration of 0.2% by weight, and 1.7 g of a sodium bisulfite aqueous solution with a concentration of 0.3% by weight are added to initiate polymerization. After the temperature of the system rises by 0.5 °C, the nitrogen bubbling is stopped, and the reaction continues for 4 hours;

[0094] (2) After the polymerization is completed, the obtained colloid is granulated, dried at 50 °C until the solid content reaches 89% by weight, crushed and sieved to obtain a dry powder product of the sulfonic acid type copolymer.

[0095] The viscosity-average molecular weight of the dry powder product was determined to be 12.6 million.

[0096] In addition, as determined according to the feeding amount, in the sulfonic acid copolymer prepared, the sulfonic acid copolymer contains:

[0097] Structural unit A ( wherein R 1 is Na);

[0098] Structural unit B (the same as in Preparation Example 1);

[0099] Structural unit C ( wherein R 3 is methyl);

[0100] Structural unit D ( wherein R 4 is methyl and R 5 is n-pentyl);

[0101] Among them, based on the total weight of the sulfonic acid copolymer, the content of the structural unit A is 74.8% by weight, the content of the structural unit B is 19.1% by weight, the content of the structural unit C is 5.2% by weight, and the content of the structural unit D is 0.9% by weight.

[0102] The content of the cross-linked groups generated after high-temperature aging was measured after placing the 5000 mg / L polymer solution (prepared with deionized water) at 130 °C for 15 - 60 days, and the results are shown in Table 1.

[0103] Preparation Example 3

[0104] This preparation example is to illustrate the preparation of a sulfonic acid copolymer with a controllable hydrolysis rate by using the preparation method of the present invention.

[0105] (1) Take 84.7 g of monomer A′, 14.4 g of monomer B′ acrylamide, 6.1 g of monomer C′, and 0.3 g of monomer D′. Among them, monomer A′ and monomer B′ are the same as in Preparation Example 2; monomer C′ is the same as in Preparation Example 1; the structural formula of monomer D′ is; R 4 is methyl and R 5 is n-hexyl); 7.2 g of Tween 80 is dissolved in 187.3 g of deionized water, and the pH value is adjusted to 6 with sodium hydroxide solution. The initial temperature is controlled at 5 °C, 0.2 g of defoamer is added, nitrogen is bubbled into the system for 20 min for deoxygenation, and then 1 g of 2,2-azobis(2-amidinopropane) dihydrochloride aqueous solution with a concentration of 0.25 wt%, 2 g of ammonium persulfate aqueous solution with a concentration of 0.2 wt%, and 1.8 g of sodium bisulfite aqueous solution with a concentration of 0.3 wt% are added to initiate polymerization. After the temperature of the system rises by 0.5 °C, the nitrogen bubbling is stopped, and the reaction continues for 4 hours;

[0106] (2) After the polymerization is completed, the obtained colloid is granulated, dried at 50 °C until the solid content reaches 89% by weight, pulverized and sieved to obtain an acrylamide polymer dry powder product.

[0107] The viscosity-average molecular weight of the dry powder product is measured to be 14 million.

[0108] In addition, it is calculated and determined according to the feeding amount that in the sulfonic acid type copolymer prepared, the sulfonic acid type copolymer contains:

[0109] Structural unit A (the same as Preparation Example 2);

[0110] Structural unit B (the same as Preparation Example 2);

[0111] Structural unit C (the same as Preparation Example 1);

[0112] Structural unit D ( wherein, R 4 is methyl, and R 5 is n-hexyl);

[0113] Among them, based on the total weight of the sulfonic acid type copolymer, the content of the structural unit A is 80.3% by weight, the content of the structural unit B is 13.6% by weight, the content of the structural unit C is 5.8% by weight, and the content of the structural unit D is 0.3% by weight.

[0114] The content of the crosslinked groups generated after high-temperature aging is measured by placing a 5000 mg / L polymer solution (prepared with deionized water) at 130 °C for 15 - 60 days, and the results are shown in Table 1.

[0115] Preparation Example 4

[0116] This preparation example is to illustrate the preparation of a sulfonic acid type copolymer with a controllable hydrolysis rate by using the preparation method of the present invention.

[0117] (1) Take 84.9 g of monomer A' (the same as Preparation Example 1), 31.3 g of monomer B' (methyl-acrylamide), 2.4 g of monomer C' (the same as Preparation Example 1), 1.7 g of monomer D' (the same as Preparation Example 1), 17 g of sodium dodecyl sulfate, dissolve them in 162.7 g of deionized water, adjust the pH value to 6 with sodium hydroxide solution, control the starting temperature at 2 °C, add 0.5 g of defoamer, purge nitrogen into the system for 20 min to remove oxygen, then add 1.15 g of a 2,2-azobis(2-amidinopropane) dihydrochloride aqueous solution with a concentration of 0.25% by weight, 2 g of an ammonium persulfate aqueous solution with a concentration of 0.2% by weight, and 1.5 g of a sodium bisulfite aqueous solution with a concentration of 0.3% by weight to initiate polymerization. After the temperature of the system rises by 0.5 °C, stop purging nitrogen bubbles and continue the reaction for 4 hours;

[0118] (2) After the polymerization is completed, the obtained colloid is granulated, dried at 50 °C until the solid content reaches 89% by weight, pulverized and sieved to obtain an acrylamide polymer dry powder product.

[0119] The viscosity-average molecular weight of the dry powder product was measured to be 17 million.

[0120] In addition, according to the calculation based on the feeding amount, in the sulfonic acid copolymer prepared, the sulfonic acid copolymer contains:

[0121] Structural unit A (the same as Preparation Example 1);

[0122] Structural unit B ( wherein, R 2 is methyl);

[0123] Structural unit C (the same as Preparation Example 1);

[0124] Structural unit D (the same as Preparation Example 1);

[0125] Among them, based on the total weight of the sulfonic acid copolymer, the content of the structural unit A is 70.6% by weight, the content of the structural unit B is 26% by weight, the content of the structural unit C is 2% by weight, and the content of the structural unit D is 1.4% by weight.

[0126] The content of the cross-linked groups generated after high-temperature aging was measured after placing a 5000 mg / L polymer solution (prepared with deionized water) at 130 °C for 15 - 60 days, and the results are shown in Table 1.

[0127] Preparation Example 5

[0128] This preparation example is to illustrate the preparation of a sulfonic acid copolymer with a controllable hydrolysis rate by using the preparation method of the present invention.

[0129] (1) Take 100.1 g of monomer A' (the same as Preparation Example 1), 12 g of monomer B' (the same as Preparation Example 1), 7.8 g of monomer C' (the same as Preparation Example 1), 0.1 g of monomer D' (the same as Preparation Example 1), 1 g of sodium dodecyl sulfate, dissolve them in 179 g of deionized water, adjust the pH value to 6 with sodium hydroxide solution, control the starting temperature at 2 °C, add 0.15 g of defoaming agent, purge nitrogen gas into the system for 20 min to remove oxygen, then add 1.3 g of a 2,2-azobis(2-amidinopropane) dihydrochloride aqueous solution with a concentration of 0.25% by weight, 2.2 g of an ammonium persulfate aqueous solution with a concentration of 0.2% by weight, and 1.7 g of a sodium bisulfite aqueous solution with a concentration of 0.3% by weight to initiate polymerization. After the temperature of the system rises by 0.5 °C, stop purging nitrogen gas bubbles and continue the reaction for 4 hours;

[0130] (2) After the polymerization is completed, the obtained colloid is granulated, dried at 50 °C until the solid content reaches 89% by weight, pulverized and sieved to obtain a dry powder product of the sulfonic acid type copolymer.

[0131] The viscosity-average molecular weight of the dry powder product was measured to be 11.5 million.

[0132] In addition, according to the determined feed amount, in the sulfonic acid type copolymer prepared, the sulfonic acid type copolymer contains:

[0133] Structural unit A (same as Preparation Example 1);

[0134] Structural unit B (same as Preparation Example 1);

[0135] Structural unit C (same as Preparation Example 1);

[0136] Structural unit D (same as Preparation Example 1);

[0137] Among them, based on the total weight of the sulfonic acid type copolymer, the content of structural unit A is 83.4% by weight, the content of structural unit B is 10% by weight, the content of structural unit C is 6.5% by weight, and the content of structural unit D is 0.1% by weight.

[0138] The content of cross-linked groups generated after high-temperature aging was measured after placing a 5000 mg / L polymer solution (prepared with deionized water) at 130 °C for 15 - 60 days, and the results are shown in Table 1.

[0139] Example 1

[0140] This example is used to illustrate a polymer flooding and profile control system for carbonate rock reservoirs and its preparation method of the present invention.

[0141] 10 g of the polymer obtained in Preparation Example 1 was added to 900 g of simulated brine, stirred at 600 rpm / min until completely dissolved, then 0.5 g of chromium citrate and 0.8 g of chromium lactate were added and stirred until completely dissolved, and then 0.8 g of sodium thiosulfate was added. The total weight was made up to 1 kg with simulated brine and stirred evenly to obtain a polymer flooding and profile control system, which can be used as a flow path regulator for flow path adjustment.

[0142] Two kinds of salinity and calcium and magnesium ion contents were selected for the simulated brine. The salinity of the first kind of simulated brine was 300000 mg / L, and the calcium and magnesium ion content was 10000 mg / L. The salinity of the second kind of simulated brine was 100000 mg / L, and the calcium and magnesium ion content was 5000 mg / L.

[0143] The initial viscosity of the profile control system prepared with simulated brine with a salinity of 300,000 mg / L and a calcium and magnesium ion content of 10,000 mg / L is 680 mPa·s. The aged viscosities after being placed at 70 °C, 95 °C, and 130 °C for 60 days were measured respectively, and the results are shown in Table 2.

[0144] The initial viscosity of the profile control system prepared with simulated brine with a salinity of 100,000 mg / L and a calcium and magnesium ion content of 5,000 mg / L is 910 mPa·s. The aged viscosities after being placed at 70 °C, 95 °C, and 130 °C for 60 days were measured respectively, and the results are shown in Table 2.

[0145] Table 2 Viscosities of the profile control system obtained in Example 1 after aging for 60 days at different temperatures, different salinities and calcium and magnesium ion contents

[0146]

[0147] Example 2

[0148] This example is used to illustrate a sulfonic acid copolymer profile control system of the present invention and its preparation method.

[0149] 8 g of the polymer obtained in Preparation Example 2 was added to 900 g of simulated brine (300,000 mg / L, calcium and magnesium ion content of 10,000 mg / L). After stirring at 600 rpm / min until completely dissolved, 0.5 g of chromium citrate and 0.3 g of zirconium citrate were added. After stirring until completely dissolved, 0.4 g of thiourea was added, and the total weight was made up to 1 kg with simulated brine (300,000 mg / L, calcium and magnesium ion content of 10,000 mg / L). After stirring evenly, a sulfonic acid copolymer profile control system was obtained, and this profile control system can be used as a flow regulator for flow path adjustment.

[0150] The initial viscosity of the profile control system was measured, as well as the high-temperature aged viscosity after being placed at 130 °C for 60 days, and the results are shown in Table 3.

[0151] Table 3 Comparison of the initial viscosity and high-temperature aged viscosity of the profile control system

[0152]

[0153]

[0154] Example 3

[0155] This example is used to illustrate a polymer profile control system for carbonate rock reservoirs of the present invention and its preparation method.

[0156] Add 7 g of the acrylamide polymer prepared in Preparation Example 3 to 900 g of simulated brine (300,000 mg / L, calcium and magnesium ion content is 10,000 mg / L). After stirring for 1 h, add 0.3 g of aluminum citrate, 1 g of zirconium lactate, and 0.8 g of sodium bisulfite, and make up to a total weight of 1 kg with simulated brine (300,000 mg / L, calcium and magnesium ion content is 10,000 mg / L). Stir evenly to obtain a sulfonic acid copolymer profile control system, which can be used as a flow regulator to adjust the flow path.

[0157] Measure the initial viscosity of the said profile control system and the high-temperature aging viscosity after being placed at 130 °C for 60 days. The results are shown in Table 3.

[0158] Example 4

[0159] This example is used to illustrate a polymer profile control system for carbonate rock reservoirs and its preparation method of the present invention.

[0160] Add 7.5 g of the acrylamide polymer prepared in Preparation Example 4 to 900 g of simulated brine (300,000 mg / L, calcium and magnesium ion content is 10,000 mg / L). After stirring for 1 h, add 0.3 g of aluminum citrate, 0.5 g of chromium acetate, and 0.5 g of sodium thiosulfate, and make up to a total weight of 1 kg with simulated brine (300,000 mg / L, calcium and magnesium ion content is 10,000 mg / L). Stir evenly to obtain a sulfonic acid copolymer profile control system, which can be used as a flow regulator to adjust the flow path.

[0161] Measure the initial viscosity of the said profile control system and the high-temperature aging viscosity after being placed at 120 °C for 60 days. The results are shown in Table 3.

[0162] Example 5

[0163] This example is used to illustrate a polymer profile control system for carbonate rock reservoirs and its preparation method of the present invention.

[0164] Add 6.5 g of the polymer prepared in Preparation Example 5 to 900 g of simulated brine (300,000 mg / L, calcium and magnesium ion content is 10,000 mg / L). After stirring for 1 h, add 0.3 g of aluminum citrate, 0.6 g of chromium citrate, and 0.3 g of sodium thiosulfate, and make up to a total weight of 1 kg with simulated brine (300,000 mg / L, calcium and magnesium ion content is 10,000 mg / L). Stir evenly to obtain a sulfonic acid copolymer profile control system, which can be used as a flow regulator to adjust the flow path.

[0165] Measure the initial viscosity of the said profile control system and the high-temperature aging viscosity after being placed at 120 °C for 60 days. The results are shown in Table 3.

[0166] Example 6

[0167] This example is used to illustrate a polymer flooding and profile control system for carbonate reservoirs and its preparation method of the present invention.

[0168] 9 g of the polymer obtained in Preparation Example 1 was added to 900 g of simulated brine. After stirring at 600 rpm / min until completely dissolved, 4 g of hydroquinone and 5 g of hexamethylenetetramine were added and stirred until completely dissolved. Then, 0.8 g of sodium thiosulfate was added, and the total weight was made up to 1 kg with simulated brine. After stirring evenly, a polymer flooding and profile control system was obtained, and this flooding and profile control system can be used as a water plugging agent for water plugging.

[0169] Two kinds of salinity and calcium and magnesium ion contents were selected for the simulated brine. The salinity of the first kind of simulated brine was 300000 mg / L, and the calcium and magnesium ion content was 10000 mg / L. The salinity of the second kind of simulated brine was 100000 mg / L, and the calcium and magnesium ion content was 5000 mg / L.

[0170] The above-mentioned flooding and profile control system was prepared with the above two kinds of simulated brine respectively, and the storage modulus and dehydration rate of the flooding and profile control system after being placed at 140 - 160 °C for 90 days were measured. The results are shown in Table 4.

[0171] Table 4 Storage modulus and dehydration rate of the flooding and profile control system obtained in Example 6 after aging for 90 days at different temperatures, different salinities and calcium and magnesium ion contents

[0172]

[0173] Example 7

[0174] This example is used to illustrate a polymer flooding and profile control system for carbonate reservoirs and its preparation method of the present invention.

[0175] 12 g of the polymer obtained in Preparation Example 2 was added to 900 g of simulated brine (300000 mg / L, calcium and magnesium ion content was 10000 mg / L). After stirring at 600 rpm / min until completely dissolved, 5 g of catechol and 5 g of hexamethylenetetramine were added and stirred until completely dissolved. Then, 0.9 g of isoascorbic acid was added, and the total weight was made up to 1 kg with simulated brine (300000 mg / L, calcium and magnesium ion content was 10000 mg / L). After stirring evenly, a polymer flooding and profile control system was obtained, and this flooding and profile control system can be used as a water plugging agent for water plugging.

[0176] The storage modulus and dehydration rate of the flooding and profile control system were measured after being placed at 150 °C for 90 days. The results are shown in Table 5.

[0177] Example 8

[0178] This example is used to illustrate a polymer flooding and profile control system for carbonate reservoirs and its preparation method of the present invention.

[0179] 11 g of the polymer obtained in Preparation Example 3 was added to 900 g of simulated brine (300,000 mg / L, calcium and magnesium ion content of 10,000 mg / L). After stirring at 600 rpm / min until completely dissolved, 5 g of hydroquinone and 6 g of hexamethylenetetramine were added. After stirring until completely dissolved, 0.9 g of thiourea was added, and the total weight was made up to 1 kg with simulated brine (300,000 mg / L, calcium and magnesium ion content of 10,000 mg / L). After stirring evenly, a sulfonic acid copolymer plugging and profile control system was obtained. This profile control and displacement system can be used as a plugging agent for water plugging.

[0180] The storage modulus and dehydration rate of the profile control and displacement system were measured after being placed at 150 °C for 90 days. The results are shown in Table 5.

[0181] Example 9

[0182] This example is used to illustrate a polymer profile control and displacement system for carbonate rock reservoirs and its preparation method according to the present invention.

[0183] 8.5 g of the polymer obtained in Preparation Example 4 was added to 900 g of simulated brine (300,000 mg / L, calcium and magnesium ion content of 10,000 mg / L). After stirring at 600 rpm / min until completely dissolved, 5 g of resorcinol and 7 g of hexamethylenetetramine were added. After stirring until completely dissolved, 1 g of sodium bisulfite was added, and the total weight was made up to 1 kg with simulated brine (300,000 mg / L, calcium and magnesium ion content of 10,000 mg / L). After stirring evenly, a sulfonic acid copolymer plugging and profile control system was obtained. This profile control and displacement system can be used as a plugging agent for water plugging.

[0184] The storage modulus and dehydration rate of the profile control and displacement system were measured after being placed at 140 °C for 90 days. The results are shown in Table 5.

[0185] Example 10

[0186] This example is used to illustrate a polymer profile control and displacement system for carbonate rock reservoirs and its preparation method according to the present invention.

[0187] 9.5 g of the polymer obtained in Preparation Example 5 was added to 900 g of simulated brine (300,000 mg / L, calcium and magnesium ion content of 10,000 mg / L). After stirring at 600 rpm / min until completely dissolved, 6 g of hydroquinone and 6 g of hexamethylenetetramine were added. After stirring until completely dissolved, 0.9 g of sodium thiosulfate was added, and the total weight was made up to 1 kg with simulated brine (300,000 mg / L, calcium and magnesium ion content of 10,000 mg / L). After stirring evenly, a sulfonic acid copolymer plugging and profile control system was obtained. This profile control and displacement system can be used as a plugging agent for water plugging.

[0188] The energy storage modulus and dehydration rate of the described profile control and displacement system were measured after being placed at 140 °C for 90 days, and the results are shown in Table 5.

[0189] Comparative Example 1

[0190] This comparative example is used to illustrate the reference polymer profile control and displacement system, its preparation method and application.

[0191] The polymer was prepared according to the same method as in Preparation Example 1, except that: the addition amount of monomer A' was 27.8 g, and the addition amount of monomer B' was 86.5 g. Monomer C' and monomer D' were not added. The viscosity-average molecular weight of the polymer was 18.6 million.

[0192] In addition, as determined by calculating according to the feeding amount, in the polymer prepared, the polymer contains the same structural unit A and structural unit B as in Preparation Example 1; based on the total weight of the polymer, the content of structural unit A is 24.3% by weight, and the content of structural unit B is 75.7% by weight.

[0193] The content of crosslinked groups generated after high-temperature aging was measured for a 5000 mg / L polymer solution (prepared with deionized water) after being placed at 130 °C for 15 - 60 days, and the results are shown in Table 1.

[0194] The profile control fluid system was prepared according to the method described in Example 1, except that an equal amount of the above polymer was used to replace the polymer in Example 1. The simulated brine was selected to be 300000 mg / L, the calcium and magnesium ion content was 10000 mg / L, and the test results of the initial viscosity and high-temperature aging viscosity are shown in Table 3.

[0195] The profile control and plugging system was prepared according to the method described in Example 6, except that an equal amount of the above polymer was used to replace the polymer in Example 6. The dehydration rate of the profile control and plugging system after being placed at 150 °C for 30 days is shown in Table 5.

[0196] Comparative Example 2

[0197] This comparative example is used to illustrate the reference polymer profile control and displacement system, its preparation method and application.

[0198] The polymer was prepared according to the same method as in Preparation Example 1, except that: monomer C' and monomer D' were not added. The viscosity-average molecular weight of the polymer was 17.5 million.

[0199] In addition, as determined by calculating according to the feeding amount, in the polymer prepared, the polymer contains the same structural unit A and structural unit B as in Preparation Example 1; based on the total weight of the polymer, the content of structural unit A is 75.7% by weight, and the content of structural unit B is 24.3% by weight.

[0200] Prepare a flow control system according to the method described in Example 1, except that an equal amount of the above polymer is used to replace the polymer in Example 1. The simulated brine is selected to be 300000 mg / L with a calcium and magnesium ion content of 10000 mg / L. Measure the initial viscosity of the flow control system and the aged viscosity after 60 days at 130 °C, as shown in Table 3.

[0201] Prepare a profile control and plugging system according to the method described in Example 6, except that an equal amount of the above polymer is used to replace the polymer in Example 6. The storage modulus and dehydration rate of the profile control and plugging system after being placed at 150 °C for 90 days are shown in Table 5.

[0202] Comparative Example 3

[0203] This comparative example is used to illustrate a reference polymer flooding system, its preparation method and application.

[0204] Prepare a polymer according to the same method as Preparation Example 1, except that monomer C' is not added. The viscosity-average molecular weight of the polymer is 15.2 million.

[0205] In addition, it is calculated and determined according to the feeding amount that in the prepared polymer, the polymer contains the same structural units A, B, and D as in Preparation Example 1; based on the total weight of the polymer, the content of structural unit A is 75.3% by weight, the content of structural unit B is 24.2% by weight, and the content of structural unit D is 0.5% by weight.

[0206] Prepare a flow control system according to the method described in Example 1, except that an equal amount of the above polymer is used to replace the polymer in Example 1. The simulated brine is selected to be 300000 mg / L with a calcium and magnesium ion content of 10000 mg / L. Measure the initial viscosity of the flow control system and the aged viscosity after 60 days at 130 °C, and the results are shown in Table 3.

[0207] Prepare a profile control and plugging system according to the method described in Example 6, except that an equal amount of the above polymer is used to replace the polymer in Example 6. The storage modulus and dehydration rate of the profile control and plugging system after being placed at 150 °C for 90 days are shown in Table 5.

[0208] Comparative Example 4

[0209] This comparative example is used to illustrate a reference polymer flooding system, its preparation method and application.

[0210] Prepare a polymer according to the same method as Preparation Example 1, except that monomer D' is not added. The viscosity-average molecular weight of the polymer is 16 million.

[0211] In addition, it is determined according to the feeding amount that in the polymer prepared, the polymer contains the same structural units A, B, and C as in Preparation Example 1; based on the total weight of the polymer, the content of structural unit A is 72.5% by weight, the content of structural unit B is 23.3% by weight, and the content of structural unit C is 4.2% by weight.

[0212] Prepare a profile control and flow control system according to the method described in Example 1, except that an equal amount of the above polymer is used to replace the polymer in Example 1. The simulated brine is selected to be 300000 mg / L, and the calcium and magnesium ion content is 10000 mg / L. Measure the initial viscosity of the flow control system and the aged viscosity after standing at 130 °C for 60 days. The results are shown in Table 3.

[0213] Operate according to the method described in Example 6, except that an equal amount of the above polymer is used to replace the polymer in Example 6. Measure the storage modulus and dehydration rate of the profile control and flow control system after standing at 150 °C for 90 days. The results are shown in Table 5.

[0214] Comparative Example 5

[0215] This comparative example is used to illustrate a reference polymer flooding system and its preparation method and application.

[0216] Prepare a polymer according to the same method as in Preparation Example 1, except that the addition amount of monomer A' is 27.8 g and the addition amount of monomer B' is 86.5 g. The viscosity-average molecular weight of the polymer is 15.6 million.

[0217] In addition, it is determined according to the feeding amount that in the polymer prepared, the polymer contains the same structural units A, B, C, and D as in Preparation Example 1; based on the total weight of the polymer, the content of structural unit A is 23.2% by weight, the content of structural unit B is 72.1% by weight, the content of structural unit C is 4.2% by weight, and the content of structural unit D is 0.5% by weight.

[0218] Measure the content of crosslinked groups generated after high-temperature aging by placing a 5000 mg / L polymer solution (prepared with deionized water) at 130 °C for 15 - 60 days. The results are shown in Table 1.

[0219] Prepare a flow control system according to the method described in Example 1, except that an equal amount of the above polymer is used to replace the polymer in Example 1. The simulated brine is selected to be 300000 mg / L, and the calcium and magnesium ion content is 10000 mg / L. The results are shown in Table 3.

[0220] Prepare a profile control and water plugging system according to the method described in Example 6, except that an equal amount of the above polymer is used to replace the polymer in Example 6. Measure the dehydration rate of the profile control and water plugging system after being placed at 150 °C for 30 days. The results are shown in Table 5.

[0221] Comparative Example 6

[0222] This comparative example is used to illustrate a reference polymer flooding system and its preparation method and application.

[0223] Prepare a polymer according to the same method as in Preparation Example 1, except that: monomer D' is replaced with "vinyl acetate", and the structural formula is The viscosity-average molecular weight of the polymer is 15.4 million.

[0224] In addition, it is determined according to the feeding amount that in the prepared polymer, the polymer contains the same structural units A, B, C and structural unit Based on the total weight of the polymer, the content of structural unit A is 72.1% by weight, the content of structural unit B is 23.2% by weight, the content of structural unit C is 4.2% by weight, and the content of the structural unit is 0.5% by weight.

[0225] Prepare a flow control system according to the method described in Example 1, except that an equal amount of the above polymer is used to replace the polymer in Example 1. The simulated brine is selected to be 300000 mg / L, and the calcium and magnesium ion content is 10000 mg / L. Measure the initial viscosity of the flow control system and the aged viscosity after 60 days at 130 °C. The results are shown in Table 3.

[0226] Prepare a profile control and water plugging system according to the method described in Example 6, except that an equal amount of the above polymer is used to replace the polymer in Example 6. The simulated brine is selected to be 300000 mg / L, and the calcium and magnesium ion content is 10000 mg / L. Measure the storage modulus and dehydration rate of the profile control and water plugging system after being placed at 150 °C for 90 days. The results are shown in Table 5.

[0227] Table 5 Comparison of storage modulus and dehydration rate between the flooding systems obtained in Examples 7-10 and the flooding systems obtained in Comparative Examples 1-6

[0228] Number High temperature and aging time Storage modulus (Pa) Dehydration rate (%) Example 7 150℃ 35.7 3.1 Example 8 150℃ 32.5 2.6 Example 9 140℃ 21.6 8.2 Example 10 140℃ 22.1 8.8 Comparative Example 1 150℃(30d) - 69.9 Comparative Example 2 150℃ 16.4 20.8 Comparative Example 3 150℃ 20.2 14.9 Comparative Example 4 150℃ 23.2 13.4 Comparative Example 5 150℃(30d) - 35.7 Comparative Example 6 150℃ 24.0 13.2

[0229] As can be seen from the results in Table 1 above, compared with the comparative examples, the sulfonic acid copolymer prepared in Preparation Examples 1-5 of the present invention uses sulfonic acid groups containing long branched chains as the main building units, has strong hydrolysis resistance at a high temperature of 130 °C, and the hydrolysis rate is controllable.

[0230] As can be seen from the results of Table 2 and Table 3 above, compared with Comparative Examples 1-6, in Examples 1-5 of the present invention, by using the flow regulator formed by the sulfonic acid copolymer with controllable hydrolysis rate prepared in Preparation Examples 1-5 and a metal crosslinking agent, in water with a salinity ≤ 300000 mg / L and a calcium and magnesium ion content ≤ 10000 mg / L, after aging at 60-130 °C for 60 days, it still has good viscosity and excellent stability, and can be used for adjusting the flow path in carbonate reservoirs.

[0231] As can be seen from the results of Table 4 and Table 5, compared with Comparative Examples 1-6, in Examples 6-10 of the present invention, by using the polymer plugging agent obtained by reacting the sulfonic acid copolymer with controllable hydrolysis rate prepared in Preparation Examples 1-5 with phenolic and aldehyde crosslinking agents, in an environment with a salinity ≤ 300000 mg / L and a calcium and magnesium ion content ≤ 10000 mg / L, after aging at a high temperature of 140-160 °C for 90 days, the dehydration rate is low, and it has a high storage modulus, indicating high strength and good thermal stability, and can be used as a plugging agent for ultra-deep wells in carbonate reservoirs.

[0232] 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 technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A sulfonic acid copolymer, characterized in that: The copolymer comprises structural unit A, structural unit B, structural unit C and structural unit D; wherein the structural unit A is The structural unit B is The structural unit C is The structural unit D is Wherein, R1 is H or an alkali metal element, R2 is H or a methyl group, R3 is H or a methyl group, R4 and R5 are each independently a C1-C6 alkyl group, and when R4 and R5 are each independently a C2-C6 alkyl group, the total number of carbon atoms of R4 and R5 is 6-8; the viscosity-average molecular weight of the copolymer is 5 million to 18 million; based on the total weight of the copolymer, the content of the structural unit A is 65-90 weight %; the content of the structural unit B is 5-30 weight %, the content of the structural unit C is 1-8 weight %; and the content of the structural unit D is 0.1-2 weight %.

2. The copolymer according to claim 1, wherein R1 is H or Na; and / or, R2 is H; and / or, R3 is H or methyl; And / or, R4 is methyl and R5 is methyl; or R4 is methyl and R5 is n-pentyl; or R4 is methyl and R5 is n-hexyl.

3. The copolymer according to claim 1, wherein The content of the structural unit A is 70-84 wt %; the content of the structural unit B is 12-25 wt %; the content of the structural unit C is 3-6 wt %; and the content of the structural unit D is 0.2-1 wt %.

4. The copolymer according to claim 1, 2 or 3, wherein The viscosity average molecular weight of the copolymer is 12 million to 17 million.

5. A method for preparing a sulfonic acid copolymer, characterized in that: The method comprises: under solution polymerization conditions, in the presence of an initiator, allowing an olefinic monomer to undergo polymerization reaction; wherein the olefinic monomer comprises monomer A', monomer B', monomer C' and monomer D'; wherein the monomer A' is The monomer B' is The monomer C' is The monomer D' is Wherein, R1 is H or an alkali metal element, R2 is H or a methyl group, R3 is H or a methyl group, R4 and R5 are each independently a C1-C6 alkyl group, and when R4 and R5 are each independently a C2-C6 alkyl group, the total number of carbon atoms of R4 and R5 is 6-8; based on the total weight of the olefinic monomer, the content of the monomer A' is 65-90% by weight, the content of the monomer B' is 5-30% by weight, the content of the monomer C' is 1-8% by weight, and the content of the monomer D' is 0.1-2% by weight.

6. The method according to claim 5, wherein: R1 is H or Na; and / or, R2 is H; and / or, R3 is H or methyl; And / or, R4 is methyl and R5 is methyl; or R4 is methyl and R5 is n-pentyl; or R4 is methyl and R5 is n-hexyl.

7. The method according to claim 5, wherein: Based on the total weight of the ethylenic monomers, the content of the monomer A' is 70-84 weight %, the content of the monomer B' is 12-25 weight %, the content of the monomer C' is 3-6 weight %, and the content of the monomer D' is 0.2-1 weight %.

8. The method according to claim 5, wherein: The initiator is used in an amount of 0.0003-0.05 wt % of the weight of the ethylenic monomer; And / or, the initiator is selected from azo initiators and / or redox initiators.

9. The method according to any one of claims 5 to 8, wherein: The solution polymerization reaction conditions include: a starting temperature of -10°C to 30°C, a reaction time of 2-12 hours, and a pH value of 4-8.

10. The sulfonic acid type copolymer obtained by the method according to any one of claims 5 to 9.

11. A control and displacement system, characterized in that: The flooding system contains a cross-linking agent and the sulfonic acid copolymer according to any one of claims 1 to 4 and 10.

12. The control and displacement system according to claim 11, wherein: The content of the sulfonic acid copolymer is 0.3-1.5% by weight.

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