Carbon dioxide-responsive core-shell polymer channeling regulator and preparation method thereof

Abstract

The present application belongs to the technical field of oil exploitation, and particularly relates to a carbon dioxide responsive core-shell polymer gas channeling regulator and a preparation method thereof. The raw materials include an ionic hydrophilic monomer, an amine group-containing CO2 responsive monomer and a pair of orthogonal reaction monomers (A-B). Through the design of RAFT polymerization combined with emulsion polymerization and the introduction of the pair of orthogonal reaction monomers (A-B), the structure controllability and function synergy are realized. The prepared regulator contains a hydrophilic shell layer and a hydrophobic core layer. When CO2 is not passed, monomers A and B do not react due to spatial isolation, and the solution is in a low-viscosity stable state. After CO2 is passed, the amine group-containing CO2 responsive monomer in the core layer is protonated, the core layer is gradually hydrophilized, the particle is water-swelled and the particle size is increased. When the core layer is completely protonated, the particle is dissolved, monomers A and B are contacted and orthogonal reaction occurs, the hydrophilic polymer chain is crosslinked to form a three-dimensional hydrogel network, the solution viscosity is increased, and the problem of gas channeling caused by strong reservoir heterogeneity during CO2 flooding can be effectively solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of oil exploitation, and particularly relates to a carbon dioxide responsive core-shell polymer gas channeling regulating agent and a preparation method thereof. BACKGROUND

[0002] The water shutoff technology has been an effective means for improving water injection development effect and realizing reservoir stimulation in oilfields. Traditional inorganic regulating agents are prone to precipitation and cannot enter the deep formation for plugging, movable weak gel has poor crosslinking controllability and high cost, and water-swelling polymer gel has large particles and has a contradiction between injection depth and plugging strength, and is invalid quickly.

[0003] The CO2 flooding technology has important application prospects in the field of improving oil recovery due to its high oil displacement efficiency and carbon sequestration. However, due to strong reservoir heterogeneity and large difference in CO2 and oil mobility ratio, CO2 is prone to gas channeling along high-permeability channels during displacement, which significantly reduces the sweep efficiency. This problem is particularly prominent in low-permeability reservoirs - the coexistence of matrix pores and fractures makes the gas channeling channel more complex, and traditional regulating agents are difficult to effectively plug.

[0004] Patent CN118206687A provides a temperature-resistant and salt-resistant CO2 stimulation viscosity-increasing polymer for preventing gas channeling in the CO2 flooding process and a preparation method thereof. The acrylamide monomer, CO2 responsive monomer, amphiphilic functional monomer solution and cosolvent are mixed, and then the initiator solution is added, N2 is introduced and sealed for reaction to obtain a polymer dry powder. The viscosity-increasing mechanism of the polymer in this patent relies on the protonation of tertiary amine groups into quaternary ammonium salt by CO2, thereby increasing the hydrophilicity and electrostatic repulsion of the molecular chain. However, this process is highly reversible, resulting in temporary plugging and inability to form a long-term and stable plugging plug. Patent CN119529204A provides a three-block swelling and viscosity-increasing carbon dioxide gas channeling profile control agent and a preparation method thereof. The prepared profile control agent can form a gel-like plugging body, but it is difficult to realize fracture-pore collaborative regulation, and the multi-step synthesis has low production efficiency, high time and economic costs, and is difficult to be industrialized and scaled up.

[0005] Existing plugging agents are mainly designed for macroscopic fractures and cannot enter micro-nano matrix pores, making it difficult to achieve fracture-pore collaborative regulation and resulting in short-term plugging. Moreover, under high temperature and high salinity formation conditions, conventional polymers are prone to hydrolysis or salting out, resulting in a rapid decrease in viscosity and even precipitation failure, which cannot form a long-term and stable plugging and cannot meet the actual reservoir needs. Therefore, developing a collaborative plugging material with nano-sized permeability, high temperature and high salt stability, and intelligent CO2 responsiveness has become a key to breaking through the bottleneck of CO2 flooding gas channeling regulation technology. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a carbon dioxide responsive core-shell polymer gas channeling regulator and a preparation method thereof.

[0007] The technical scheme adopted is as follows:

[0008] The carbon dioxide responsive core-shell polymer gas channeling regulator comprises, in terms of molar fraction, 2-100 parts of an ionic hydrophilic monomer, 2-100 parts of an amine group-containing CO2 responsive monomer, and 1-50 parts of a pair of orthogonal reaction monomers.

[0009] The pair of orthogonal reaction monomers is composed of orthogonal reaction monomer A and orthogonal reaction monomer B, that is, any one of the following pairs: an acrylic ester carboxyl monomer-an acrylic ester aziridine monomer, an acrylic ester aldehyde monomer-an acrylic ester cyano monomer, and an acrylic ester azide monomer-an acrylic ester alkyne monomer; and the molar ratio of the orthogonal reaction monomer A to the orthogonal reaction monomer B is 1:0.5-2.

[0010] The ionic hydrophilic monomer is any one of 2-methacryloyloxyethyl trimethyl ammonium chloride, 2-acrylamido-2-methylpropanesulfonic acid, N,N-dimethyl(methacryloyloxyethyl)aminopropanesulfonic acid inner salt, trimethyl glycine methacrylate, and phosphorylcholine methacrylate.

[0011] The amine group-containing CO2 responsive monomer is any one of acrylic acid N,N-diethylaminoethyl ester, N,N-dimethyl acrylamide, N,N-dimethyl methacrylamidoethyl ester, N,N-diethyl methacrylamidoethyl ester, and N,N-dimethyl p-styrene.

[0012] The preparation method of the carbon dioxide responsive core-shell polymer gas channeling regulator comprises the following steps:

[0013] (1) Synthesis of a macromolecular chain transfer agent:

[0014] The trithioester 2-(dodecyl trithio carbonate)-2-isobutyric acid, deionized water, the orthogonal reaction monomer A, the ionic hydrophilic monomer, and the initiator I are added to a reactor, and then the reactor is heated after nitrogen purging; after the reaction is completed, the reaction solution is poured into a precipitant for precipitation;

[0015] The precipitate is filtered to obtain a filter cake, and the filter cake is vacuum dried to obtain the macromolecular chain transfer agent.

[0016] The initiator I is any one of ammonium persulfate and cerium nitrate; the precipitant is any one of methanol or acetone;

[0017] (2) Synthesis of the CO2-responsive core-shell polymer nanoparticles:

[0018] In a three-necked flask, an organic solvent is added, and then the macromolecular chain transfer agent aqueous solution prepared in step (1) (i.e., the macromolecular chain transfer agent is dissolved in water and stirred to be uniform to obtain), the orthogonal reaction monomer B and the amine group-containing CO2-responsive monomer, and the initiator II are added, and ultrasonic stirring is performed for 10-30 min to emulsify the dispersed droplets, and then the reaction is performed after nitrogen blowing to obtain the CO2-responsive core-shell polymer nanoparticles, i.e., the CO2-responsive core-shell polymer nanoparticle gas channeling control agent.

[0019] The initiator II is any one of azobisisobutyronitrile or dimethyl azobisisobutyrate.

[0020] Preferably, in step (1), the molar ratio of the trithioester 2-(dodecyltrithiocarbonate)-2-isobutyric acid, the ionic hydrophilic monomer, the orthogonal reaction monomer A and the initiator I is 1-4:10-200:5-100:0.1-1.

[0021] Preferably, the molar ratio of the orthogonal reaction monomer A to the ionic hydrophilic monomer is 1:4.

[0022] Preferably, in step (1), the heating reaction temperature is 60-80°C, and the reaction time is 3-24 hours.

[0023] Preferably, in step (2), the organic solvent is any one of toluene, xylene and anisole.

[0024] Preferably, in step (2), the molar ratio of the macromolecular chain transfer agent, the amine group-containing CO2-responsive monomer, the orthogonal reaction monomer B and the initiator II is 1-4:10-200:5-100:0.1-1.

[0025] As a further preference, the molar ratio of the orthogonal reaction monomer B to the amine group-containing CO2-responsive monomer is 3:17.

[0026] Preferably, in step (2), the reaction temperature is 60-80°C, and the reaction time is 8-24 hours.

[0027] Compared with the prior art, the present application has the following beneficial effects:

[0028] The carbon dioxide response type core-shell polymer gas channeling control agent prepared by the application has good CO2 response expansion and viscosity increasing properties, before CO2 is introduced, the orthogonal reaction groups A and the orthogonal reaction groups B are respectively in the hydrophilic shell layer and the hydrophobic core layer, and cannot contact and react orthogonally in space, so that the solution can maintain stable low viscosity; after CO2 is introduced, the CO2 response functional groups in the polymer nanoparticle core layer are protonated, the core layer is gradually changed into hydrophilic, and the nanoparticle is also gradually increased in particle size due to water absorption swelling; when the amine group containing CO2 response monomers in the hydrophobic core layer are completely protonated, the whole nanoparticle is completely dissolved in water to form a polymer aqueous solution, at this time, the orthogonal reaction groups A and B contact and react orthogonally, the hydrophilic polymer chains are crosslinked to form a three-dimensional hydrogel network, and the solution viscosity is significantly increased; the initial particle size and expansion ratio of the prepared CO2 response type core-shell polymer nanoparticle can be adjusted, the final viscosity increasing degree can be adjusted, and the customization function can be realized according to the specific conditions of the oil reservoir, and the viscosity increasing effect can also be well realized in the high salinity formation water.

[0029] The RAFT chain transfer agent ensures uniform polymer chain length, avoids the wide distribution defect of traditional emulsion polymerization, makes the nanoparticle size uniform, and has excellent injection effect. The orthogonal reaction monomer pair cooperates with the amine group containing CO2 response monomer, and improves the plugging efficiency in the fracture-pore composite formation.

[0030] The preparation method of the application is simple, the reaction conditions are easy to realize, and can be widely promoted. DETAILED DESCRIPTION

[0031] Figure 1 The figure is a chemical structure schematic diagram of the CO2 response type core-shell polymer nanoparticle gas channeling control agent prepared by the application.

[0032] Figure 2 The figure is a CO2 response expansion and viscosity increasing principle schematic diagram of the CO2 response type core-shell polymer nanoparticle prepared by the application.

[0033] Figure 3 The figure is a chemical structure schematic diagram of the CO2 response type core-shell polymer nanoparticle prepared by example 1 of the application.

[0034] Figure 4 The figure is a Fourier infrared spectrum (FTIR) diagram of the CO2 response type core-shell polymer nanoparticle prepared by example 1 of the application.

[0035] Figure 5 The figure is a state diagram of the CO2 response type core-shell polymer nanoparticle prepared by example 1 of the application before (a) and after (b) CO2 (100 mol% relative to CO2 response groups on the polymer chain) is introduced.

[0036] Figure 6Transmission electron microscopy (TEM) images of CO2-responsive core-shell polymer nanoparticles prepared in Example 1 with different amounts of CO2 injected.

[0037] Figure 7 Scanning electron microscope (SEM) image of the CO2-responsive core-shell polymer nanoparticles prepared in Example 1 after being crosslinked with sufficient CO2.

[0038] Figure 8 The storage modulus and loss modulus of the CO2-responsive core-shell polymer nanoparticles prepared in Example 1 after being injected with CO2 (100 mol% relative to the CO2-responsive groups on the polymer chain) and then thickened to form a gel are shown in the figure.

[0039] Figure 9 The particle size of the CO2-responsive core-shell polymer nanoparticles prepared in Example 1 varies with the amount of CO2 injected (relative to the mol% of CO2-responsive groups on the polymer chain).

[0040] Figure 10 The viscosity of the CO2-responsive core-shell polymer nanoparticles prepared in Example 1 varies with the amount of CO2 injected (relative to the CO2-responsive groups on the polymer chain).

[0041] Figure 11 The viscosity of the CO2-responsive core-shell polymer nanoparticles prepared in Example 4 varies with the amount of CO2 injected (relative to the CO2-responsive groups on the polymer chain).

[0042] Figure 12 The graph shows the effect of temperature on the particle size of CO2-responsive core-shell polymer nanoparticles prepared in Examples 1-4.

[0043] Figure 13 The graph shows the effect of salt concentration on the particle size of CO2-responsive core-shell polymer nanoparticles prepared in Examples 1-4.

[0044] Figure 14 The graph shows the change in final viscosity of the CO2-responsive core-shell polymer nanoparticles prepared in Examples 1-4 as a function of temperature after CO2 (relative to the CO2-responsive groups on the polymer chain) is injected.

[0045] Figure 15 The final viscosity of the CO2-responsive core-shell polymer nanoparticles prepared in Examples 1-4 after CO2 injection (relative to the CO2-responsive groups on the polymer chain) varies with salt concentration.

[0046] Figure 16 The particle size changes of CO2-responsive core-shell polymer nanoparticles prepared in Examples 1-4 during a 180-day storage period. Detailed Implementation

[0047] The accompanying drawings are only for illustrative purposes; the specific embodiments of the present application will be clearly and completely described below in combination with the drawings and examples, and the described examples are only a part of the total embodiments, which embody the technical features, objects and effects of the present application. For the process parameters not specifically mentioned, the conventional technology can be referred to. Unless specifically stated, the reagents, methods and equipment used in the present application are conventional reagents, methods and equipment in the technical field.

[0048] As shown in Figure 1 , 2 , the present application prepares CO2-responsive core-shell polymer nanoparticles by a two-step method through the method of RAFT polymerization (reversible addition-fragmentation chain transfer polymerization) combined with emulsion polymerization. The ion hydrophilic monomer, amine group-containing CO2-responsive monomer and orthogonal reaction monomer pair are prepared. Trithioester 2-(dodecyl trithio carbonate)-2-isobutyric acid is used as a RAFT reagent to control polymerization through a reversible chain transfer reaction. Macromolecular chain transfer reagents are used as macromolecular emulsifiers and chain transfer agents to construct a core-shell structure by step polymerization. Among them, Figure 2 R A is the group of orthogonal reaction monomer A, and R B is the group of orthogonal reaction monomer A.

[0049] The core layer: orthogonal reaction monomer B and amine group-containing CO2-responsive monomer are polymerized in an organic solvent to form a hydrophobic core.

[0050] The shell layer: the ion hydrophilic monomer and the orthogonal reaction monomer A are wrapped around the core layer under the guidance of the hydrophilic macromolecular chain transfer agent to form an outer shell.

[0051] Before CO2 is introduced, the orthogonal reaction group A of the shell layer and the orthogonal reaction group B of the core layer basically do not contact and do not react. After a small amount of CO2 is introduced, the CO2-responsive components in the core layer of the polymer nanoparticles are partially protonated, repel each other, and cause the core layer to swell and increase. After further introduction of CO2, all the CO2-responsive components are protonated, change from a hydrophobic state to a hydrophilic state, and the core layer is dissociated. At this time, the polymer chains are fully stretched in the solution, the orthogonal reaction group A and the orthogonal reaction group B contact each other and react, resulting in crosslinking of the polymer to form a three-dimensional network structure, which significantly increases the solution viscosity.

[0052] Example 1: A preparation method of a carbon dioxide-responsive core-shell polymer channeling control agent, a carbon dioxide-induced swelling and viscosity-increasing core-shell polymer nanoparticle is prepared by the method of RAFT polymerization combined with emulsion polymerization. The control agent has the characteristics of CO2-responsive swelling and viscosity-increasing, high temperature resistance and salt resistance, and its preparation process includes the following steps:

[0053] S1. Synthesis of macromolecular chain transfer agent:

[0054] Add 0.01 g of RAFT to each of the three-necked flasks. 365 20 mL of deionized water, 1.44 g of orthogonal monomer A (acrylic acid monomer), 1 g of N,N-dimethyl(methacryloyloxyethyl)aminopropanesulfonic acid inner salt, and 2 mg of ammonium persulfate were added. After purging with nitrogen, the mixture was ultrasonically stirred at 70 °C for 12 hours. After the reaction was completed, the reaction solution was poured into methanol to precipitate the product, filtered, and the resulting filter cake was vacuum dried to obtain the macromolecular chain transfer reagent.

[0055] S2. Synthesis of CO2-responsive core-shell polymer nanoparticles:

[0056] In a three-necked flask, 5 mL of an aqueous solution containing 0.05 g of macromolecular chain transfer reagent prepared in S1, 10 mL of toluene, 1.2 g of N,N-diethylaminoethyl acrylate, 0.6 g of orthogonal monomer B-aziridine monomer, and 2 mg of azobisisobutyronitrile were added. The mixture was ultrasonically stirred for 20 min to emulsify it into small-sized dispersed droplets. After purging with nitrogen, the mixture was stirred at 70 °C for 12 h to obtain CO2-responsive core-shell polymer nanoparticles.

[0057] Example 2: A method for preparing a carbon dioxide responsive core-shell polymer gas channeling regulator. The difference in the synthesis of CO2 responsive core-shell polymer nanoparticles is that the orthogonal reaction monomer A used in step S1 is 0.72 g of acrylic acid monomer, which yields CO2 responsive core-shell polymer nanoparticles.

[0058] The rest of the unmentioned parts are the same as in Example 1.

[0059] Example 3: A method for preparing a carbon dioxide-responsive core-shell polymer gas channeling regulator. The difference in the synthesis of CO2-responsive core-shell polymer nanoparticles is that the orthogonal reaction monomer A used in step S1 is 1.71 g of 5-acrylamidoic acid, which yields CO2-responsive core-shell polymer nanoparticles.

[0060] The rest of the unmentioned parts are the same as in Example 1.

[0061] Example 4: A method for preparing a carbon dioxide-responsive core-shell polymer gas channeling regulator. The difference in the synthesis of CO2-responsive core-shell polymer nanoparticles is that the orthogonal reaction monomer A used in step S1 is 1.57 g of 4-acrylamidobutyric acid, which yields CO2-responsive core-shell polymer nanoparticles.

[0062] The rest of the unmentioned parts are the same as in Example 1.

[0063] The carbon dioxide-responsive core-shell polymer gas channeling modulators prepared in Examples 1-4 were tested.

[0064] 1) CO2-responsive test.

[0065] a. Swelling performance: The CO2-responsive core-shell polymer nanoparticles in Example 1-Example 4 were selected to measure the hydrodynamic diameter of the nanoparticles in CO2 environment and air environment by dynamic light scattering instrument to characterize the CO2-responsive swelling behavior of the nanoparticles.

[0066] The initial particle size of the polymer nanoparticles prepared in Example 1 was 250-300 nm at 25℃ before CO2 injection, and the particle size was 950-1300 nm after CO2 injection (20 mol% of tertiary amine on the polymer);

[0067] The initial particle size of the polymer nanoparticles prepared in Example 2 was 320-380 nm before CO2 injection, and the particle size was 1020-1350 nm after CO2 injection (20 mol% of tertiary amine on the polymer);

[0068] The initial particle size of the polymer nanoparticles prepared in Example 3 was 200-280 nm before CO2 injection, and the particle size was 800-1000 nm after CO2 injection (20 mol% of tertiary amine on the polymer);

[0069] The initial particle size of the polymer nanoparticles prepared in Example 4 was 380-430 nm before CO2 injection, and the particle size was 1200-1500 nm after CO2 injection (20 mol% of tertiary amine on the polymer).

[0070] b. Viscosity test: The core-shell polymer nanoparticles in Example 1-Example 4 were selected to measure the viscosity change of the nanoparticles after swelling in air and CO2 at different temperatures (10-110℃) by the flat plate measurement system in the rotary rheometer, wherein the shear strain was 1% and the oscillation frequency was 10 Hz.

[0071] The initial viscosity of the polymer nanoparticles prepared in Example 1 was 43-48 mPa·s at 25℃ before CO2 injection, and the particle size was 83000-88000 mPa·s after CO2 injection (20 mol% of tertiary amine on the polymer);

[0072] The initial viscosity of the polymer nanoparticles prepared in Example 2 was 31-35 mPa·s before CO2 injection, and the particle size was 71000-76000 mPa·s after CO2 injection (20 mol% of tertiary amine on the polymer);

[0073] The initial viscosity of the polymer nanoparticles prepared in Example 3 was 57-65 mPa·s before CO2 injection, and the particle size was 85000-100000 mPa·s after CO2 injection (20 mol% of tertiary amine on the polymer);

[0074] The initial viscosity of the polymer nanoparticles prepared in Example 4 before CO2 injection was 84-92 mPa·s, and the particle size after CO2 injection (20 mol% of tertiary amine on the polymer) was 92000-115000 mPa·s.

[0075] Therefore, the particle size and viscosity increased significantly after CO2 injection.

[0076] 2) Temperature and salt resistance test.

[0077] The core-shell polymer nanoparticles in Examples 1-4 were selected to test the viscosity change and particle size change of the nanoparticles in different temperatures (25℃-100℃) and different salt concentrations (0%-15 wt%) of NaCl solution. The test results are shown in Figures 10-13 .

[0078] 3) Stability test.

[0079] The core-shell polymer nanoparticles in Examples 1-4 were selected to test the particle size change of the nanoparticles within 180 days. The test results are shown in Figure 14 .

[0080] The carbon dioxide-responsive core-shell polymer channeling regulator of the present application has a shell layer comprising a hydrophilic component and an orthogonal reaction group A, and a core layer comprising a CO2-responsive component and an orthogonal reaction group B.

[0081] As can be seen from Figure 4 , the infrared characteristic absorption peak 1189 cm −1 and 1067 cm −1 of the core-shell structure polymer nanoparticles prepared in Example 1 correspond to the asymmetric stretching vibration and symmetric stretching vibration of the sulfonic acid group (-SO3 − ), respectively. The characteristic peak 3320 cm −1 is attributed to the stretching vibration of N-H in the amide group (-CONH - ). The peaks at 1451 cm −1 and 1550 cm −1 are the mixed surface bending vibration peaks of C-N and N-H in -CONH-. The peaks at 1660 cm −1 and 3192 cm −1 are the stretching vibration peak of O-H in the carboxyl group and the stretching vibration peak of C=O, respectively. As can be seen above, from the perspective of molecular design, the core-shell structure polymer nanoparticles are successfully prepared.

[0082] As can be seen from Figure 5It can be seen that the 10 mg / mL core-shell polymer nanoparticle system prepared in Example 1 thickens into a gel after CO2 is injected (100 mol% relative to the CO2-responsive groups on the polymer chains) (b in the figure).

[0083] It can be seen that the 10 mg / mL core-shell polymer nanoparticle system prepared in Example 1 begins to swell after CO2 is injected (20 mol% relative to the CO2-responsive groups on the polymer chains), and the nanoparticles dissociate when the amount of CO2 injection is further increased (100 mol% relative to the CO2-responsive groups on the polymer chains). Figure 6 It can be seen that the 10 mg / mL core-shell polymer nanoparticle system prepared in Example 1 begins to swell after CO2 is injected (20 mol% relative to the CO2-responsive groups on the polymer chains), and the nanoparticles dissociate when the amount of CO2 injection is further increased (100 mol% relative to the CO2-responsive groups on the polymer chains).

[0084] Figure 7 It can be seen that the gel generated after the core-shell polymer nanoparticles prepared in Example 1 are injected with CO2 (100 mol% relative to the CO2-responsive groups on the polymer chains) has a typical three-dimensional network structure.

[0085] It can be seen that the gel generated after the core-shell polymer nanoparticles prepared in Example 1 are injected with CO2 (100 mol% relative to the CO2-responsive groups on the polymer chains) has a typical three-dimensional network structure. Figure 8 It can be seen that the gel generated after the core-shell polymer nanoparticles prepared in Example 1 are injected with CO2 (100 mol% relative to the CO2-responsive groups on the polymer chains) has a typical three-dimensional network structure.

[0086] Figure 9 It can be seen that, within the range of 0-25 mol% CO2 injection (relative to the CO2-responsive groups on the polymer chains), the particle size of the nanoparticles prepared in Example 1 gradually increases with the increase of CO2 injection (from 250±30 nm to 1265±91 nm); the particle size of the nanoparticles sharply decreases to 18±4 nm when CO2 injection continues, indicating that the nanoparticles have dissociated into a polymer solution at this time.

[0087] It can be seen that, within the range of 0-25 mol% CO2 injection (relative to the CO2-responsive groups on the polymer chains), the particle size of the nanoparticles prepared in Example 1 gradually increases with the increase of CO2 injection (from 250±30 nm to 1265±91 nm); the particle size of the nanoparticles sharply decreases to 18±4 nm when CO2 injection continues, indicating that the nanoparticles have dissociated into a polymer solution at this time. Figure 10 It can be seen that, within the range of 0-25 mol% CO2 injection (relative to the CO2-responsive groups on the polymer chains), the particle size of the nanoparticles prepared in Example 1 gradually increases with the increase of CO2 injection (from 250±30 nm to 1265±91 nm); the particle size of the nanoparticles sharply decreases to 18±4 nm when CO2 injection continues, indicating that the nanoparticles have dissociated into a polymer solution at this time.

[0088] Figure 11 ​​​It can be seen that, in the range of 0~20 mol% of CO2 injection amount (relative to the CO2 responsive group on the polymer chain), the viscosity of the 10 mg / mL core-shell polymer nanoparticle system prepared in Example 4 slowly increases due to the swelling of the nanoparticles, and the viscosity decreases at a CO2 injection amount of 25 mol%, which is due to the dissociation of the nanoparticles. Subsequently, the viscosity of the system increases sharply with the increase of the CO2 injection amount, and the viscosity reaches 101692±8352 mPa·s when the CO2 injection amount is 55 mol%; subsequently, the viscosity slowly increases with the increase of the CO2 injection amount and finally reaches 111425±5538 mPa·s.

[0089] It can be seen that, in the range of 0~20 mol% of CO2 injection amount (relative to the CO2 responsive group on the polymer chain), the viscosity of the 10 mg / mL core-shell polymer nanoparticle system prepared in Example 4 slowly increases due to the swelling of the nanoparticles, and the viscosity decreases at a CO2 injection amount of 25 mol%, which is due to the dissociation of the nanoparticles. Subsequently, the viscosity of the system increases sharply with the increase of the CO2 injection amount, and the viscosity reaches 101692±8352 mPa·s when the CO2 injection amount is 55 mol%; subsequently, the viscosity slowly increases with the increase of the CO2 injection amount and finally reaches 111425±5538 mPa·s. Figure 12 It can be seen that, in the range of 25~100℃, with the increase of temperature, the particle size of 10 mg / mL nanoparticles of Examples 1-4 gradually increases, but the increase is small, and the overall is relatively stable, and the temperature has little effect on the particle size of the nanoparticles.

[0090] It can be seen that, in the range of 25~100℃, with the increase of temperature, the particle size of 10 mg / mL nanoparticles of Examples 1-4 gradually increases, but the increase is small, and the overall is relatively stable, and the temperature has little effect on the particle size of the nanoparticles. Figure 13 It can be seen that, in the range of 25~100℃, with the increase of temperature, the particle size of 10 mg / mL nanoparticles of Examples 1-4 gradually increases, but the increase is small, and the overall is relatively stable, and the temperature has little effect on the particle size of the nanoparticles.

[0091] It can be seen that, in the range of 25~100℃, with the increase of temperature, the particle size of 10 mg / mL nanoparticles of Examples 1-4 gradually increases, but the increase is small, and the overall is relatively stable, and the temperature has little effect on the particle size of the nanoparticles. Figure 14 It can be seen that, in the range of 25~100℃, with the increase of temperature, the particle size of 10 mg / mL nanoparticles of Examples 1-4 gradually increases, but the increase is small, and the overall is relatively stable, and the temperature has little effect on the particle size of the nanoparticles.

[0092] It can be seen that, in the range of 25~100℃, with the increase of temperature, the particle size of 10 mg / mL nanoparticles of Examples 1-4 gradually increases, but the increase is small, and the overall is relatively stable, and the temperature has little effect on the particle size of the nanoparticles. Figure 15 It can be seen that, in the range of 25~100℃, with the increase of temperature, the particle size of 10 mg / mL nanoparticles of Examples 1-4 gradually increases, but the increase is small, and the overall is relatively stable, and the temperature has little effect on the particle size of the nanoparticles.

[0093] It can be seen that, in the range of 25~100℃, with the increase of temperature, the particle size of 10 mg / mL nanoparticles of Examples 1-4 gradually increases, but the increase is small, and the overall is relatively stable, and the temperature has little effect on the particle size of the nanoparticles. Figure 16 It can be seen that, in the range of 25~100℃, with the increase of temperature, the particle size of 10 mg / mL nanoparticles of Examples 1-4 gradually increases, but the increase is small, and the overall is relatively stable, and the temperature has little effect on the particle size of the nanoparticles.

[0094] Example 5: A preparation method of a carbon dioxide responsive core-shell polymer gas channeling control agent, comprising the following steps:

[0095] S1. Synthesis of macromolecular chain transfer reagent:

[0096] In a three-necked flask, 0.02 g of RAFT365, 40 mL of deionized water, 1.76 g of benzaldehyde acrylate as orthogonal reaction monomer A, 3.2 g of 2-acrylamide-2-methylpropane sulfonic acid, 3 mg of cerium nitrate ammonium, after nitrogen purging, ultrasonic stirring at 75℃ for 10 hours. After the reaction, the reaction solution was poured into acetone for precipitation, filtration, and vacuum drying of the filter cake to obtain the macromolecular chain transfer agent.

[0097] S2. Synthesis of CO2-responsive core-shell polymer nanoparticles:

[0098] In a three-necked flask, 10 mL of macromolecular chain transfer agent aqueous solution containing 0.1 g prepared in S1, 20 mL of toluene, 2.56 g of N,N-dimethylacrylamide propyl acrylate, 1.97 g of acrylate cyanide (monomer obtained by reacting HEMA and cyanoacetic acid), 3 mg of dimethyl azobisisobutyrate, ultrasonic stirring to emulsify into small scale droplets, nitrogen purging, stirring at 70℃ for 16 hours to obtain CO2-responsive core-shell polymer nanoparticles.

[0099] Example 6: A preparation method of a carbon dioxide-responsive core-shell polymer gas channeling regulator, the difference in the synthesis of CO2-responsive core-shell polymer nanoparticles is that orthogonal reaction monomer A used in S1 step is 2.69 g of acrylate azide (monomer obtained by reacting HEMA and 6-azidohexanoic acid) and orthogonal reaction monomer B used in S2 step is 1.82 g of acrylate alkyne (monomer obtained by reacting HEMA and propargyl acid), to obtain CO2-responsive core-shell polymer nanoparticles.

[0100] The rest is not mentioned in Example 5.

[0101] The preparation method of a carbon dioxide-responsive core-shell polymer gas channeling regulator of the present application has good CO2-responsive viscosity increasing, temperature resistance and salt resistance, etc. characteristics, and can realize gas channeling channel plugging and flow regulation in the process of CO2 displacement under high temperature and high salinity.

[0102] Of course, the above description is not a limitation of the present application, and the present application is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present application should also be within the scope of the present application.

Claims

1. A method for preparing a carbon dioxide-responsive core-shell polymer gas channeling modulator, characterized in that, A carbon dioxide-responsive core-shell polymer gas channeling regulator comprises, by molar amount: 2-100 parts of ionic hydrophilic monomer, 2-100 parts of amino-containing CO2-responsive monomer, and 1-50 parts of orthogonal reaction monomer pair; Among them, the orthogonal reaction monomer pair is composed of orthogonal reaction monomer A-orthogonal reaction monomer B, that is, any one of the following pairs: acrylate carboxyl monomer-acrylate aziridine monomer, acrylate aldehyde monomer-acrylate cyano monomer, acrylate azide monomer-acrylate alkyne monomer; the molar ratio of orthogonal reaction monomer A to orthogonal reaction monomer B is 1:0.5-2. The ionic hydrophilic monomer is any one of 2-methacryloyloxyethyltrimethylammonium chloride, 2-acrylamide-2-methylpropanesulfonic acid, N,N-dimethyl(methacryloyloxyethyl)aminopropanesulfonic acid inner salt, trimethylglycine methacrylate and phosphorylcholine methacrylate, which have temperature and salt resistance properties. The amino-containing CO2-responsive monomer is any one of N,N-diethylaminoethyl acrylate, N,N-dimethylacrylamide, N,N-dimethylacrylamide ethyl ester, N,N-diethylmethylacrylamide ethyl ester, and N,N-dimethyl-p-styrene. The preparation method includes the following steps: (1) Synthesis of macromolecular chain transfer reagents: Trithioester 2-(dodecyltrithiocarbonate)-2-isobutyric acid, deionized water, orthogonal monomer A, ionic hydrophilic monomer, and initiator I were added to a reactor, purged with nitrogen, and heated to react. After the reaction was completed, the reaction solution was poured into a precipitant to precipitate. Precipitation and filtration were performed to obtain a filter cake, which was then vacuum dried to obtain a macromolecular chain transfer reagent. (2) Synthesis of CO2-responsive core-shell polymer nanoparticles: Organic solvent was added to a three-necked flask, followed by the aqueous solution of the macromolecular chain transfer reagent prepared in step (1), orthogonal reaction monomer B, amine-containing CO2-responsive monomer, and initiator II. The mixture was ultrasonically stirred for 10–30 min to emulsify it into dispersed droplets. After purging with nitrogen, the reaction was carried out to obtain CO2-responsive core-shell polymer nanoparticles, namely CO2-responsive core-shell polymer nanoparticle gas channeling regulators.

2. The preparation method of a carbon dioxide-responsive core-shell polymer gas channeling modulator according to claim 1, characterized in that, The initiator I is either ammonium persulfate or cerium ammonium nitrate; the precipitant is either methanol or acetone; and the initiator II is either azobisisobutyronitrile or dimethyl azobisisobutyrate.

3. The method for preparing a carbon dioxide-responsive core-shell polymer gas channeling modulator according to claim 1, characterized in that, In step (1), the molar ratio of trithioester 2-(dodecyl trithiocarbonate)-2-isobutyric acid, ionic hydrophilic monomer, orthogonal monomer A and initiator I is 1-4:10-200:5-100:0.1-1.

4. The preparation method of a carbon dioxide-responsive core-shell polymer gas channeling modulator according to claim 3, characterized in that, The molar ratio of orthogonal reaction monomer A to ionic hydrophilic monomer is 1:

4.

5. The method for preparing a carbon dioxide-responsive core-shell polymer gas channeling modifier according to claim 1, characterized in that, In step (1), the heating reaction temperature is 60-80℃ and the reaction time is 3-24 hours.

6. The method for preparing a carbon dioxide-responsive core-shell polymer gas channeling modulator according to claim 1, characterized in that, In step (2), the organic solvent is any one of toluene, xylene, and anisole.

7. The preparation method of a carbon dioxide-responsive core-shell polymer gas channeling modulator according to claim 1, characterized in that, In step (2), the molar ratio of macromolecular chain transfer reagent, amino-containing CO2-responsive monomer, orthogonal reaction monomer B and initiator II is 1-4:10-200:5-100:0.1-1.

8. The method for preparing a carbon dioxide-responsive core-shell polymer gas channeling modulator according to claim 7, characterized in that, The molar ratio of orthogonal reaction monomer B to amine-containing CO2-responsive monomer is 3:

17.

9. The method for preparing a carbon dioxide-responsive core-shell polymer gas channeling modifier according to claim 1, characterized in that, In step (2), the reaction temperature is 60 ~ 80℃ and the reaction time is 8 ~ 24 hours.

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