Relative permeability improver capable of efficiently controlling water and increasing oil and preparation method of relative permeability improver

Abstract

The invention discloses a relative permeability improver capable of efficiently controlling water and increasing oil and a preparation method thereof, and belongs to the field of oil-gas field development. The relative permeability improver is multi-component copolymerized polyacrylamide which is synthesized by acrylamide, sodium acrylate, 2-acrylamido-2-methylpropanesulfonic acid, a sulfonate ion-containing hydrophobic monomer and a cationic adsorption monomer; meanwhile, a sulfonate ion-containing hydrophobic monomer is introduced to be matched with a cationic adsorption monomer, through mutual cooperation of the monomers, the water controlling and oil increasing capacity of the relative permeability improving agent in a porous medium is remarkably improved, the flow resistance of a water phase in the porous medium is effectively improved, and meanwhile the oil phase flow resistance can be further reduced due to the lubricating effect; the unexpected oil permeation effect is achieved, the excellent water control and oil increase effects are achieved, and the obvious permeability selection performance can be achieved under the heterogeneous oil reservoir condition; key material support is provided for development of high-water-content oil and gas resources, and the efficient development target of the high-water-content oil and gas resources is guaranteed.

Description

Technical Field

[0001] The present invention relates to the field of improving relative permeability in oil and gas field development, and specifically relates to a relative permeability improver for efficiently controlling water and increasing oil production and a preparation method thereof. Background Art

[0002] After long-term water injection development in oil reservoirs, the properties of oil reservoir formations change, and the formation heterogeneity increases, eventually causing problems such as water flooding, rapid increase in water cut of produced fluid, high water cut, and decline in oil and gas recovery rate. Therefore, it is necessary to seek an efficient method for controlling water and increasing production to meet the increasingly complex oil reservoir environment. Water control technologies at home and abroad are mainly divided into mechanical water control methods and chemical water control methods. The mechanical water control method separates the water-producing layer through a diverter to prevent water from flowing into the wellbore, which is not applicable to complex reservoirs. Chemical water control methods are often polymers, gels, resins, and precipitation-type water shutoff agents, which have the characteristic of a wide application range. Among them, relative permeability improvers are a type of selective water control agent, which has the ability to reduce the permeabilities of the water phase and oil phase in unequal proportions and has good application prospects. At present, domestic and foreign scholars mainly conduct systematic research on the types of polymer-based relative permeability improvers (mainly polyacrylamide and its derivatives), the action mechanism of relative permeability improvers (wall effect, swelling / shrinking effect, oil-water diversion theory, adsorption-entanglement theory, etc.), and the influencing factors of the ability to improve oil and water permeabilities (polymer additional groups and molecular weight, pH, temperature, salinity, wettability, flow rate, permeability, etc.). The research shows that the plugging performance effect of relative permeability improvers on the water / oil phase is related to reservoir conditions and molecular structure.

[0003] Conventional polyacrylamide is widely used in various fields of oil and gas exploitation, but its ability to reduce the permeabilities of the water phase and oil phase in unequal proportions as a relative permeability improver is poor. Therefore, many scholars have introduced various functional groups into the polyacrylamide molecular chain to improve its performance, such as introducing cationic (anionic) groups to improve its adsorption ability in sandstone (carbonate rock); adding hydrophobic association groups to improve its viscoelasticity, temperature resistance, and salt resistance. Liu Jianxin found that the modified polyacrylamide with cationic groups has the advantages of low viscosity, strong adsorption performance, and good water control effect by studying modified polyacrylamides with different functional groups; Zhang Na found that the hydrophobic associative RPM-P has the ability to reduce the permeabilities of the water and oil phases in unequal proportions by studying the hydrophobic associative RPM. Although many scholars have studied relative permeability improvers with different functional groups, there is no report on a relative permeability improver with high-efficiency water control and oil production increase effects and excellent injection performance at the same time.

[0004] Therefore, the present invention synthesizes an adsorption - associative multi - copolymer polyacrylamide by using a sulfonate - containing ionic hydrophobic monomer and a cation - adsorption monomer. Through the synergy of the monomers, the water - control and oil - production ability of the relative permeability improver in porous media can be significantly improved, effectively increasing the flow resistance of the water phase in the porous media. At the same time, due to the lubrication effect, the flow resistance of the oil phase can be further reduced, unexpectedly achieving an oil - permeable effect and excellent water - control and oil - production effects, providing ideas and technical references for the future development, reservoir adaptability and action mechanism of relative permeability improvers. Summary of the Invention

[0005] The object of the present invention is to overcome the shortcomings of the prior art and provide a relative permeability improver for efficient water - control and oil - production and its preparation method, belonging to the technical field of oil and gas field development. The relative permeability improver is an adsorption - associative multi - copolymer polyacrylamide synthesized from acrylamide, sodium acrylate, 2 - acrylamido - 2 - methylpropane sulfonic acid, a sulfonate - containing ionic hydrophobic monomer, and a cation - adsorption monomer. By simultaneously introducing a sulfonate - containing ionic hydrophobic monomer and a cation - adsorption monomer and coordinating them with each other, through the synergy of the monomers, the water - control and oil - production ability of the relative permeability improver in porous media can be significantly improved, effectively increasing the flow resistance of the water phase in the porous media. At the same time, due to the lubrication effect, the flow resistance of the oil phase can be further reduced, unexpectedly achieving an oil - permeable effect and excellent water - control and oil - production effects. It can have significant permeability - selection performance under heterogeneous reservoir conditions. The invention provides key material support for the development of high - water - cut oil and gas resources, ensuring the efficient development goal of high - water - cut oil and gas resources.

[0006] To achieve the above technical effects, the following technical solutions are adopted: A relative permeability improver for efficient water - control and oil - production, which is an adsorption - associative multi - copolymer polyacrylamide polymerized from acrylamide, sodium acrylate, 2 - acrylamido - 2 - methylpropane sulfonic acid, a sulfonate - containing ionic hydrophobic monomer, a cation - adsorption monomer and a composite initiator. The molar ratio of acrylamide, sodium acrylate, 2 - acrylamido - 2 - methylpropane sulfonic acid, the sulfonate - containing ionic hydrophobic monomer, and the cation - adsorption monomer is 61.83 - 68.01:26.5 - 29.15:1.67 - 1.84:0.5 - 5:0.5 - 5. The dosage of the composite initiator in the whole reaction solution is 500 - 1000 mg / L in concentration. After the polymerization reaction is completed, post - hydrolysis is carried out using sodium carbonate, and the dosage of sodium carbonate is 0.1 wt.% - 0.2 wt.% of the whole hydrolysis system. The structural formula of the sulfonate - containing ionic hydrophobic monomer is: ; Among them, the R group is an alkyl group with 14 carbon atoms or an alkyl group with 16 carbon atoms; The cationic adsorption monomer is one or more of vinylbenzyltetradecyldimethylammonium chloride, vinylbenzylhexadecyldimethylammonium chloride, and vinylbenzyloctadecyldimethylammonium chloride; The composite initiator is a multi-component initiator composed of an inorganic oxidant, an organic oxidant, a reducing agent, and a water-soluble azo initiator. The inorganic oxidant is a persulfate, and its addition amount in the reaction system is 100 - 200 mg / L; the organic oxidant is an organic hydroperoxide, and its addition amount in the reaction system is 200 - 400 mg / L; the reducing agent is one of sulfite and bisulfite, and its addition amount in the reaction system is 150 - 300 mg / L; the addition amount of the water-soluble azo initiator in the reaction system is 50 - 100 mg / L.

[0007] Furthermore, the molecular weight range of the relative permeability improver is 3 million - 8 million.

[0008] Furthermore, the inorganic oxidant is one of ammonium persulfate, sodium persulfate, and potassium persulfate; the organic oxidant is one or more of tert-butyl hydroperoxide and cumene hydroperoxide; the water-soluble azo initiator is one of 2,2-azobis(2-(2-imidazolin-2-yl)propane) dihydrochloride, 2,2-azobis(2-methyl-N-(2-hydroxyethyl)acrylamide), and 2,2-azobis(2-methylpropionamidine) hydrochloride.

[0009] Furthermore, the composite initiator is tert-butyl hydroperoxide, ammonium persulfate, sodium bisulfite, and 2,2-azobis(2-(2-imidazolin-2-yl)propane) dihydrochloride.

[0010] Furthermore, the preparation method of the sulfonate ion-containing hydrophobic monomer is as follows: Step S1: In a three-necked flask equipped with a magnetic stirrer, a reflux condenser, a thermometer, and two constant pressure dropping funnels, add tetradecylamine or hexadecylamine and a catalyst in sequence. Add a solution of 2-bromoethylsulfonate or 2-chloroethylsulfonate in one constant pressure funnel, and add a NaOH solution in the other constant pressure dropping funnel; by adjusting the dropping rate of the NaOH solution, control the reaction pH value, and react at a temperature of 50 - 70 °C for 6 - 9 h; after the reaction is completed, precipitate in ethanol, and filter to obtain the intermediate 2-tetradecylaminoethanesulfonate or 2-hexadecylaminoethanesulfonate; Step S2: Dissolve the intermediate prepared in Step S1 in dichloromethane, and simultaneously add Na2CO3 as an acid-binding agent; add acryloyl chloride dropwise from a constant pressure dropping funnel, control the temperature at 15 - 20 °C, and after reacting for 18 - 24 h, distill off dichloromethane under reduced pressure, and then perform recrystallization with ethanol to obtain the target monomer, which is a sulfonate ion-containing hydrophobic monomer.

[0011] Furthermore, in Step S1, the molar ratio of tetradecylamine or hexadecylamine to sodium 2-bromoethylsulfonate or sodium 2-chloroethylsulfonate is 1:0.8 - 1:0.9; the catalyst is tetrabutylammonium bromide, and its content is 1% of the mass of tetradecylamine or hexadecylamine; during the reaction, adjust the dropping rate of the NaOH solution according to the pH change, and control the pH value at 9 - 12; in Step S2, the molar ratio of the intermediate, Na2CO3, and acryloyl chloride is 1:3:3.

[0012] Furthermore, it is characterized in that the preparation method of the relative permeability improver is as follows: Charge acrylamide, sodium acrylate, 2-acrylamido-2-methylpropanesulfonic acid, the sulfonate ion-containing hydrophobic monomer, and the cationic adsorption monomer according to the formula ratio, and prepare a mixed solution with a total monomer mass concentration of 25 - 30% using ultrapure water; then adjust the pH value of the solution to 6.0 - 9.0, lower the system temperature to 0 - 5 °C, and then add a water-soluble azo initiator and a reducing agent; after introducing nitrogen and stirring for 30 - 40 minutes, add an oxidizing agent, and perform adiabatic polymerization for 3 - 8 h. After the adiabatic polymerization is completed, granulate, hydrolyze, dry, and pulverize to obtain the target polymer.

[0013] Furthermore, the pH value of the solution is adjusted using sodium hydroxide and acetic acid; the pH value of the solution is 7.0 - 8.0; the system temperature is 0 °C; the adiabatic polymerization time is 3 - 6 h.

[0014] The relative permeability improver is applied to the field of improving the water-phase and oil-phase permeabilities in oil and gas field development.

[0015] Furthermore, the growth rate of the injection pressure gradient of the relative permeability improver is 0.09 - 0.42; the water-phase water plugging rate is 63.27% - 87.74%; the oil-phase oil plugging rate is -6.69% to -22.98%.

[0016] The beneficial effects of the present invention are as follows: The present invention discloses a relative permeability improver for efficient water control and oil increment and its preparation method, belonging to the technical field of oil and gas field development; the relative permeability improver is an adsorption - association type multi - copolymer polyacrylamide synthesized from acrylamide, sodium acrylate, 2 - acrylamido - 2 - methylpropane sulfonic acid, a sulfonate - containing ionic hydrophobic monomer, and a cationic adsorption monomer; by simultaneously introducing a sulfonate - containing ionic hydrophobic monomer and a cationic adsorption monomer and coordinating them with each other, through the synergy of the monomers, the present invention can significantly improve the water control and oil increment ability of the relative permeability improver in porous media, effectively increase the flow resistance of the water phase in the porous media, and at the same time, due to the lubrication effect, further reduce the flow resistance of the oil phase, unexpectedly achieving an oil - permeable effect and excellent water control and oil increment effects, solving the technical problems of poor water control and oil increment effects and poor injection performance of the relative permeability improver in the prior art; the invention provides key material support for the development of high - water - cut oil and gas resources and ensures the efficient development goal of high - water - cut oil and gas resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. The drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained according to the provided drawings.

[0018] Figure 1 It is the injection pressure curve of the relative permeability improver in Example 1 of the present invention; Figure 2 It is the dynamic adsorption curve of the relative permeability improver in Example 1 of the present invention; Figure 3 It is the injection pressure curve of the relative permeability improver in Example 2 of the present invention; Figure 4 It is the dynamic adsorption curve of the relative permeability improver in Example 2 of the present invention; Figure 5 It is the injection pressure curve of the relative permeability improver in Example 3 of the present invention; Figure 6 It is the dynamic adsorption curve of the relative permeability improver in Example 3 of the present invention; Figure 7 It is the injection pressure curve of the relative permeability improver in Comparative Example 1 of the present invention; Figure 8 It is the dynamic adsorption curve of the relative permeability improver in Comparative Example 1 of the present invention; Figure 9 It is the injection pressure curve of the relative permeability improver in Comparative Example 2 of the present invention; Figure 10 It is the dynamic adsorption curve of the relative permeability improver in Comparative Example 2 of the present invention; Figure 11 is the injection pressure curve of the relative permeability improver in Comparative Example 3 of the present invention; Figure 12 is the dynamic adsorption curve of the relative permeability improver in Comparative Example 3 of the present invention; Figure 13 is the injection pressure curve of the relative permeability improver in Comparative Example 4 of the present invention; Figure 14 is the dynamic adsorption curve of the relative permeability improver in Comparative Example 4 of the present invention; Figure 15 is the injection pressure curve of the relative permeability improver in Comparative Example 5 of the present invention; Figure 16 is the dynamic adsorption curve of the relative permeability improver in Comparative Example 5 of the present invention; Figure 17 is the injection pressure curve of the relative permeability improver in Comparative Example 6 of the present invention; Figure 18 is the dynamic adsorption curve of the relative permeability improver in Comparative Example 6 of the present invention; Figure 19 is the injection pressure curve of the relative permeability improver in Comparative Example 7 of the present invention; Figure 20 is the dynamic adsorption curve of the relative permeability improver in Comparative Example 7 of the present invention; Figure 21 is the injection pressure curve of the relative permeability improver in Comparative Example 8 of the present invention; Figure 22 is the dynamic adsorption curve of the relative permeability improver in Comparative Example 8 of the present invention; Figure 23 is the injection pressure curve of the relative permeability improver in Comparative Example 9 of the present invention; Figure 24 is the dynamic adsorption curve of the relative permeability improver in Comparative Example 9 of the present invention; Figure 25 is the injection pressure curve of the relative permeability improver in Comparative Example 10 of the present invention; Figure 26 is the dynamic adsorption curve of the relative permeability improver in Comparative Example 10 of the present invention; Figure 27 is the injection pressure curve of the relative permeability improver in Comparative Example 11 of the present invention; Figure 28 is the dynamic adsorption curve of the relative permeability improver in Comparative Example 11 of the present invention. Detailed implementation mode

[0019] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0020] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0021] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, and / or combinations thereof.

[0022] First, a sulfonate ion-containing hydrophobic monomer is synthesized, and its preparation method is as follows: Step S1: In a three-necked flask equipped with a magnetic stirrer, a reflux condenser tube, a thermometer, and two constant-pressure dropping funnels, add tetradecylamine or hexadecylamine and a catalyst (tetrabutylammonium bromide) in sequence. Add a solution of 2-bromoethyl sulfonate or 2-chloroethyl sulfonate in one of the constant-pressure funnels, and add a NaOH solution in the other constant-pressure dropping funnel; by adjusting the dropping rate of the NaOH solution, control the reaction pH value, and react at a temperature of 50-70 °C for 6-9 h; after the reaction is completed, precipitate in ethanol, and filter to obtain the intermediate 2-tetradecylaminoethanesulfonate or 2-hexadecylaminoethanesulfonate; In the step S1, the molar ratio of tetradecylamine or hexadecylamine to the solution of 2-bromoethyl sulfonate or 2-chloroethyl sulfonate is 1:0.8-1:0.9; the catalyst is tetrabutylammonium bromide, and its content is 1% of the mass of tetradecylamine or hexadecylamine; the pH value is controlled between 9 and 12 by controlling the dropping rate of the sodium hydroxide solution.

[0023] Step S2: Dissolve the intermediate prepared in step S1 in dichloromethane, and at the same time add Na2CO3 as an acid-binding agent; drop acryloyl chloride from the constant-pressure dropping funnel, control the temperature at 20 °C, distill off dichloromethane under reduced pressure after reacting for 18 h, and then perform recrystallization with ethanol to obtain the target monomer, that is, a sulfonate ion-containing hydrophobic monomer (the R group is an alkyl group of C16 or C14); in the step S2, the molar ratio of the intermediate, Na2CO3, and acryloyl chloride is 1:3:3.

[0024] The evaluation method of the relative permeability improver is as follows: (1)The evaluation method for water control and oil stabilization by relative permeability improver is as follows (evaluating the oil / water relative permeability improvement ability of relative permeability improver through core displacement): As known from the literature, the common core displacement experiment steps are as follows: (1)The core is saturated with water, and the pore volume (PV) and initial water-phase permeability (K) are measured; (2)The oil phase is injected forward until the pressure is stable, and the oil-phase permeability (oil-phase permeability K under the irreducible water saturation before the oil displacement) is measured; O1 ); (3)The water phase is injected forward until the pressure is stable, and the water-phase permeability (water-phase permeability K under the residual oil saturation before the water displacement) is measured; W1 ); (4)Inject 12PV of relative permeability improver solution (kinematic viscosity 5 mm / s) into the core in the reverse direction; 2 ); (5)Inject the water phase forward until the pressure is stable, and measure the water-phase permeability (post-waterflood water-phase permeability K); W2 ); (6)Inject the oil phase forward until the pressure is stable, and measure the oil-phase permeability (post-oilflood oil-phase permeability K). O2 );

[0025] Therefore, referring to the above experimental steps, the core displacement process adopted in the present invention is as follows: Core saturation with water - pre-oil displacement - pre-water displacement - reverse injection of relative permeability improver solution - post-water displacement - post-oil displacement, wherein the displacement flow rate for injecting the relative permeability improver is 3 m / d, and the other displacement flow rates are all 9 m / d.

[0026] Quantification method for water plugging rate / oil plugging rate: According to the above evaluation method for the effect of relative permeability improver, the phase permeability improvement performance effect of the relative permeability improver is made more intuitive by quantifying the oil / water phase plugging performance, as shown in Equations (1), (2), and (3): (1) (2) (3) In the formula: K w1 is the water-phase permeability under the residual oil saturation before the water displacement, mD; K w2 is the water-phase permeability after the water displacement, mD; K O1 is the oil-phase permeability under the irreducible water saturation before the oil displacement, mD; K O2$K_{ro}$ is the oil-phase permeability after water flooding, mD; N w $R_w$ is the water shutoff rate, %; N O $R_o$ is the oil shutoff rate, %; M is the ratio of the water-oil plugging rate, dimensionless.

[0027] (2) The evaluation method for the injection performance of the relative permeability modifier is as follows: The relative permeability modifier can be injected into the reservoir where water control is required, which is a prerequisite for its phase permeability adjustment function. Therefore, the injection selectivity of the relative permeability modifier is determined by the injection pressure gradient curve. At the same time, the injection ability of the relative permeability modifier is divided into four grades by the growth rate ($\lambda$) of the injection pressure gradient of the relative permeability modifier solution, and the injectability of the relative permeability modifier is quantitatively analyzed. The experimental steps are as follows.

[0028] (1) Test the injection pressure gradient ($P_1$) when the relative permeability modifier is injected with 1 PV. If the pressure drops after injecting 1 PV, select the injection pressure gradient at 2 PV at this time; (2) Test the injection pressure gradient ($P_2$) when the relative permeability modifier is injected with 10 PV; (3) Take the growth rate ($\lambda$) of the injection pressure gradient as the evaluation standard for its injection ability. The larger $\lambda$ is, the worse the injection performance is, as shown in Table 1. The growth rate ($\lambda$) of the injection pressure gradient is shown in Equation (4): (4) Where: $\lambda$ is the growth rate, %; $P_1$ is the injection pressure gradient at 1 PV; MPa·m -1 ; $P_2$ is the injection pressure gradient at 10 PV; MPa·m -1 .

[0029] Table 1 Classification of injection performance Injection performance grading One (excellent) Two (good) Three (fair) Four (poor) Growth rate 0~0.5 0.5~1.0 1.0~1.5 ＞1.5 (3) The evaluation method for the dynamic adsorption amount of the relative permeability modifier is as follows: (1) Use artificial cores, saturate them with simulated brine at 70 °C, and test the core permeability and pore volume; (2) Select a relative permeability modifier solution with a kinematic viscosity of about 5 mm / s 2 and inject 10 PV of the relative permeability modifier solution into the artificial core saturated with water at a flow rate of 3 m / d; (3) Continuously detect the polymer concentration C of the produced liquid at the outlet end of the core within a certain period of time i , and measure the concentration of the produced liquid by referring to the starch-iodide chromate method used in the static adsorption experiment. The concentration retention rate of the polymer in the core is shown in Equation (5).

[0030] (5) Wherein: C0: Initial concentration of polymer, mg / L; C i : Polymer production liquid concentration at a certain time period, mg / L; θ: Concentration retention rate, %.

[0031] (4) The evaluation method for the heterogeneity selectivity of the relative permeability improver is as follows: Refer to the experimental procedure in the evaluation method for water control and oil stabilization of the relative permeability improver. Just replace the homogeneous core in the evaluation method for water control and oil stabilization of the relative permeability improver with two cores with different permeabilities (high permeability: about 200 mD; low permeability: about 5 mD) and conduct a parallel experiment simultaneously. Other conditions are the same as those in the evaluation method for water control and oil stabilization of the relative permeability improver, which can not only investigate the injection selectivity of the relative permeability improver but also its ability to improve the phase permeability after injection.

[0032] Example 1 Charge acrylamide, sodium acrylate, 2-acrylamido-2-methylpropanesulfonic acid, sulfonate group-containing ionic hydrophobic monomer (R group is C14 alkyl) and cationic adsorption monomer vinylbenzyltetradecyldimethylammonium chloride according to the formulation ratio of molar ratio 68.01:29.15:1.84:0.5:0.5, and prepare a mixed solution with a total monomer mass concentration of 25% using ultrapure water; then adjust the pH value of the solution to 7.0 using sodium hydroxide and acetic acid, add sodium formate with a mass concentration of 2500 mg / L as a molecular weight regulator, adjust the system temperature to 0 °C, add 150 ppm of sodium bisulfite and 50 ppm of azo initiator 2,2-azobis(2-(2-imidazolin-2-yl)propane) dihydrochloride; after stirring with nitrogen for 30 minutes, add 200 ppm of tert-butyl hydroperoxide and 100 ppm of ammonium persulfate, and conduct adiabatic polymerization for 4 h. After the adiabatic polymerization is completed, granulate, hydrolyze (post-hydrolyze using sodium carbonate, and the addition amount of sodium carbonate is 0.2 wt.% of the whole hydrolysis system), dry, and pulverize to obtain the target polymer. Use an Ubbelohde viscometer (0.55 mm tube diameter) to test and calculate according to GB / T 12005.10-92 that the viscosity-average molecular weight of the relative permeability improver obtained in Example 1 is 3.26 million, and the relative permeability improver obtained in Example 1 is denoted as A 0.5 B 0.5 -300 (The feeding ratio of cationic adsorption monomer vinylbenzyltetradecyldimethylammonium chloride A to sulfonate group-containing ionic hydrophobic monomer B (R group is C14 alkyl) is 0.5:0.5, and the molecular weight is about 3 million).

[0033] Using the above experimental scheme and evaluation method, for Example 1 (A 0.5 B0.5 -300) was used to conduct water control and oil stabilization performance tests, injection pressure tests, dynamic adsorption performance tests, and heterogeneous selectivity tests, and the results are as follows: As shown in Table 2, the water plugging rate of Example 1 reached 63.27%, and the oil plugging rate reached -22.98%, showing good water control and oil production increase performance. As Figure 1 shown, and λ = 0.09 < 0.5, the injection performance was excellent, and it could be quickly injected into the formation. As Figure 2 shown, the average concentration retention rate of dynamic adsorption was 96.45%, showing good transfer ability, and less loss of phase permeability agent could enter the deeper formation to achieve efficient water control and oil production increase. As shown in Table 3, during the injection of A 0.5 B 0.5 -300, the diversion rate in the high-permeability zone reached 93.73%, while the diversion rate in the low-permeability zone was only 6.27%. After diversion, the A 0.5 B 0.5 -300 had good water control and oil production increase performance, and the water plugging rate was much higher than the oil plugging rate, indicating that its injection selectivity was good, it could autonomously choose to enter the pore channels with higher permeability, and a small part entered the low-permeability channels. At the same time, it also demonstrated the good oil / water phase improvement ability of A 0.5 B 0.5 -300 at different permeabilities.

[0034] Table 2 Water Control and Oil Stabilization Performance of Example 1 Table 3 Heterogeneous Selectivity of Example 1 Example 2 Acrylamide, sodium acrylate, 2-acrylamido-2-methylpropanesulfonic acid, a sulfonate ion-containing hydrophobic monomer (with an alkyl group of C16 for the R group), and a cationic adsorption monomer vinylbenzylhexadecyldimethylammonium chloride were fed according to the formulation ratio of a molar ratio of 65.26:27.97:1.77:2.5:2.5, and were formulated into a mixed solution with a total monomer mass concentration of 25% using ultrapure water; then the pH value of the solution was adjusted to 7.0 using sodium hydroxide and acetic acid, sodium formate with a mass concentration of 1250 mg / L as a molecular weight regulator was added, after adjusting the system temperature to 0 °C, 150 ppm of sodium bisulfite and 50 ppm of an azo initiator 2,2-azobis(2-(2-imidazolin-2-yl)propane) dihydrochloride were added; after purging with nitrogen and stirring for 30 minutes, 200 ppm of tert-butyl hydroperoxide and 100 ppm of ammonium persulfate were added, and adiabatic polymerization was carried out for 4 h. After the adiabatic polymerization was completed, granulation, hydrolysis (post-hydrolysis was carried out using sodium carbonate, and the addition amount of sodium carbonate was 0.2 wt.% of the entire hydrolysis system), drying, and pulverization were carried out to obtain the target polymer. Using an Ubbelohde viscometer (with a tube diameter of 0.55 mm), the viscosity-average molecular weight of the relative permeability improver obtained in Example 1 was tested and calculated according to GB / T 12005.10-92 to be 5.07 million, and the relative permeability improver obtained in Example 1 was denoted as A 2.5 B 2.5 -500 (The feeding ratio of the cationic adsorption monomer vinylbenzylhexadecyldimethylammonium chloride A to the sulfonate ion-containing hydrophobic monomer B (with an alkyl group of C16 for the R group) is 2.5:2.5, and the molecular weight is about 5 million).

[0035] Using the above experimental scheme and evaluation method, for Example 2 (A 2.5 B 2.5 -500), water control and oil stabilization performance, injection pressure test, dynamic adsorption performance, and heterogeneity selectivity test were carried out, and the results are as follows: As shown in Table 4, the water plugging rate of Example 2 reached 72.76%, and the oil plugging rate reached -17.34%, showing good water control and oil production enhancement performance. As Figure 3 shown, and λ = 0.23 < 0.5, the injection performance is excellent, and it can be quickly injected into the formation. As Figure 4 shown, the average concentration retention rate of dynamic adsorption is 95.02%, showing good transfer ability, and it can enter the deeper formation with less loss of phase permeability improver, realizing efficient water control and oil production enhancement. As shown in Table 5, during the injection of A 2.5 B 2.5 -500, the diversion rate in the high-permeability zone reached 94.34%, while the diversion rate in the low-permeability zone was only 5.66%. After diversion, A 2.5 B 2.5-500 shows good water control and oil production performance, and the water plugging rate is much higher than the oil plugging rate, indicating that it has good injection selectivity and can independently choose to enter the pore channels with higher permeability, with a small part entering the low-permeability channels, and at the same time it also shows A 2.5 B 2.5 -500's good oil / water phase improvement ability at different permeabilities.

[0036] Table 4 Water control and oil stabilization performance of Example 2 Table 5 Heterogeneous selectivity of Example 2 Example 3 Charge acrylamide, sodium acrylate, 2-acrylamido-2-methylpropanesulfonic acid, sulfonate ion-containing hydrophobic monomer (R group is C16 alkyl) and cationic adsorption monomer vinylbenzyl octadecyldimethylammonium chloride according to the formulation ratio of molar ratio 61.83:26.50:1.67:5:5, and prepare a mixed solution with a total monomer mass concentration of 25% using ultrapure water; then adjust the pH value of the solution to 7.0 using sodium hydroxide and acetic acid, adjust the system temperature to 0 °C, add sodium formate with a mass concentration of 500 mg / L as a molecular weight regulator, adjust the system temperature to 0 °C, add 150 ppm of sodium bisulfite and 50 ppm of azo initiator 2,2-azobis(2-(2-imidazolin-2-yl)propane) dihydrochloride; after stirring with nitrogen for 30 minutes, add 200 ppm of tert-butyl hydroperoxide and 100 ppm of ammonium persulfate, and carry out adiabatic polymerization for 4 h. After the adiabatic polymerization is completed, granulate, hydrolyze (post-hydrolyze using sodium carbonate, and the addition amount of sodium carbonate is 0.2 wt.% of the whole hydrolysis system), dry, and pulverize to obtain the target polymer. Use an Ubbelohde viscometer (0.55 mm tube diameter) to test and calculate according to GB / T 12005.10-92 that the viscosity-average molecular weight of the relative permeability improver obtained in Example 1 is 7.12 million. The relative permeability improver obtained in Example 1 is denoted as A5B5-700 (the feeding ratio of cationic adsorption monomer vinylbenzyl octadecyldimethylammonium chloride A to sulfonate ion-containing hydrophobic monomer B (R group is C16 alkyl) is 5:5, and the molecular weight is about 7 million).

[0037] Using the above experimental scheme and evaluation method, carry out water control and oil stabilization performance, injection pressure test, dynamic adsorption performance and heterogeneous selectivity test on Example 3 (A5B5-700), and the results are as follows: As shown in Table 6, the water plugging rate of Example 3 reaches 87.74%, and the oil plugging rate reaches -6.69%, showing good water control and oil production performance, as Figure 5 shown, and λ = 0.42 < 0.5, with excellent injection performance and can be quickly injected into the formation. As Figure 6As shown, the average concentration retention rate of dynamic adsorption is 93.11%, showing good transfer ability. It can enter deeper formations with less loss of phase permeability improver, achieving efficient water control and oil production increase. As shown in Table 7, during the injection of A5B5-700, the diversion rate in the high-permeability zone reaches 94.01%, while the diversion rate in the low-permeability zone is only 5.99%. After diversion, the water control and oil production performance of A5B5-700 is good, and the water plugging rate is much higher than the oil plugging rate, indicating that its injection selectivity is better. It can autonomously choose to enter the pore channels with higher permeability and enter the low-permeability channels in a small part. At the same time, it also shows the good oil / water phase improvement ability of A5B5-700 at different permeabilities.

[0038] Table 6 Water control and oil stabilization performance of Example 3 Table 7 Heterogeneous selectivity of Example 3 Comparative Example 1 It was carried out according to the method of Example 2, with the difference that: the mass concentration of the molecular weight regulator sodium formate was 2500 mg / L, and the others were kept the same as in Example 2 to obtain the target polymer. The viscosity-average molecular weight of the relative permeability improver obtained in Comparative Example 1 was calculated to be 1.56 million by using an Ubbelohde viscometer (0.55 mm tube diameter) according to GB / T 12005.10-92. The relative permeability improver obtained in Comparative Example 1 was denoted as A 2.5 B 2.5 -150 (The feeding ratio of the cationic adsorption monomer vinylbenzyl hexadecyl dimethyl ammonium chloride A to the sulfonate group-containing hydrophobic monomer B (R group is an alkyl group with 16 carbon atoms) is 2.5:2.5, and the molecular weight is about 1.5 million).

[0039] Using the above experimental scheme and evaluation method, the water control and oil stabilization performance, injection pressure test, and dynamic adsorption performance of Comparative Example 1 (A 2.5 B 2.5 -150) were carried out, and the results were as follows: As shown in Table 8, the water plugging rate of Comparative Example 1 was only 32.98%, and the oil plugging rate was -10.41%. The water plugging rate was poor, and the water control and oil production performance was poor. As Figure 7 shown, and λ = 0.39 < 0.5, the injection performance was excellent. As Figure 8 shown, the average concentration retention rate of dynamic adsorption was 89.00%.

[0040] Table 8 Water control and oil stabilization performance of Comparative Example 1 Comparative Example 2 It was carried out according to the method of Example 2, with the difference that the mass concentration of the molecular weight regulator sodium formate was 250 mg / L, and the others remained unchanged as in Example 2, to obtain the target polymer. Using an Ubbelohde viscometer (0.55 mm tube diameter), the viscosity-average molecular weight of the relative permeability improver obtained in Comparative Example 2 was measured and calculated according to GB / T 12005.10-92 to be 12.31 million, and the relative permeability improver obtained in Comparative Example 2 was denoted as A 2.5 B 2.5 -1200 (The feeding ratio of the cationic adsorption monomer vinylbenzyl cetyl dimethyl ammonium chloride A to the sulfonate group-containing ionic hydrophobic monomer B (R group is an alkyl group with 16 carbon atoms) was 2.5:2.5, and the molecular weight was about 12 million).

[0041] Using the above experimental scheme and evaluation method, for Comparative Example 2 (A 2.5 B 2.5 -1200), the water control and oil stabilization performance, injection pressure test, and dynamic adsorption performance were carried out, and the results are as follows: As shown in Table 9, the water plugging rate of Comparative Example 2 reached 93.32%, but the oil plugging rate was 52.25%. The water plugging rate was relatively high, but at the same time, the oil phase was also blocked, and the effect of water control and oil increase was poor. As Figure 9 shown, 0.5 < λ = 0.56 < 1.0, and the injection performance was good. As Figure 10 shown, the average concentration retention rate of dynamic adsorption was 90.28%.

[0042] Table 9 Water control and oil stabilization performance of Comparative Example 2 Comparative Example 3 It was carried out according to the method of Example 2, with the difference that the feeding ratio of the cationic adsorption monomer to the sulfonate group-containing ionic hydrophobic monomer was 7.5:2.5, and the content of the molecular weight regulator sodium formate was 250 mg / L. The others remained unchanged as in Example 2, to obtain the target polymer. Using an Ubbelohde viscometer (0.55 mm tube diameter), the viscosity-average molecular weight of the relative permeability improver obtained in Comparative Example 3 was measured and calculated according to GB / T 12005.10-92 to be 5.09 million, and the relative permeability improver obtained in Comparative Example 3 was denoted as A 7.5 B 2.5 -500 (The feeding ratio of the cationic adsorption monomer vinylbenzyl cetyl dimethyl ammonium chloride A to the sulfonate group-containing ionic hydrophobic monomer B (R group is an alkyl group with 16 carbon atoms) was 7.5:2.5, and the molecular weight was about 5 million).

[0043] Using the above experimental scheme and evaluation method, for Comparative Example 3 (A 7.5 B 2.5 -500), the water control and oil stabilization performance, injection pressure test, and dynamic adsorption performance were carried out, and the results are as follows: As shown in Table 10, the water plugging rate of Comparative Example 3 reached 90.17%, but the oil plugging rate was 48.77%. The water plugging rate was relatively high, but at the same time, the oil phase was also blocked, resulting in poor water control and oil production enhancement effect. As Figure 11 shown, λ = 2.88 > 1.5, indicating poor injection performance. As Figure 12 shown, the retention rate of the average dynamic adsorption concentration was 65.51%. The adsorption and retention amount of the phase permeability modifier in the porous medium was relatively large, resulting in significant losses and difficulty in transferring to deep formations.

[0044] Table 10 Water control and oil stabilization performance of Comparative Example 3 Comparative Example 4 It was carried out according to the method of Example 2, with the difference being that acrylamide, sodium acrylate, 2-acrylamido-2-methylpropanesulfonic acid, sulfonate group-containing hydrophobic monomer (R group is C16 alkyl), and cationic adsorption monomer vinylbenzyl hexadecyl dimethyl ammonium chloride were in a molar ratio of 66.81:28.63:1.81:2.5:0.25, and the mass concentration of the molecular weight regulator sodium formate was 2500 mg / L. Other conditions remained the same as in Example 2 to obtain the target polymer. The viscosity-average molecular weight of the relative permeability improver obtained in Comparative Example 4 was calculated to be 5.11 million by testing with an Ubbelohde viscometer (0.55 mm tube diameter) according to GB / T 12005.10-92. The relative permeability improver obtained in Comparative Example 4 was denoted as A 0.25 B 2.5 -500 (the feeding ratio of the cationic adsorption monomer vinylbenzyl hexadecyl dimethyl ammonium chloride A to the sulfonate group-containing hydrophobic monomer B (R group is C16 alkyl) is 0.25:2.5, with a molecular weight of about 5 million).

[0045] Using the above experimental scheme and evaluation method, the water control and oil stabilization performance, injection pressure test, and dynamic adsorption performance of Comparative Example 4 (A 0.25 B 2.5 -500) were tested, and the results were as follows: As shown in Table 11, the water plugging rate of Comparative Example 4 was only 54.53%, but the oil plugging rate was -8.86%. The water plugging rate was relatively low, resulting in poor water control and oil production enhancement effect. As Figure 13 shown, λ = 1.77 > 1.5, indicating poor injection performance. As Figure 14 shown, the retention rate of the average dynamic adsorption concentration was 81.62%. The adsorption and retention amount of the phase permeability modifier in the porous medium was relatively large, resulting in significant losses and difficulty in transferring to deep formations.

[0046] Table 11 Water control and oil stabilization performance of Comparative Example 4 Comparative Example 5 The method of Example 2 was followed, with the difference that the feeding ratio of the cationic adsorption monomer to the sulfonate group-containing ionic hydrophobic monomer was 2.5:7.5, and the mass concentration of the molecular weight regulator sodium formate was 250 mg / L. The other conditions were the same as those in Example 2, and the target polymer was obtained. Using an Ubbelohde viscometer (with a tube diameter of 0.55 mm), the viscosity-average molecular weight of the relative permeability improver obtained in Comparative Example 5 was measured and calculated according to GB / T 12005.10-92 to be 4.97 million, and the relative permeability improver obtained in Comparative Example 5 was denoted as A 2.5 B 7.5 -500 (The feeding ratio of the cationic adsorption monomer vinylbenzyl hexadecyl dimethyl ammonium chloride A to the sulfonate group-containing ionic hydrophobic monomer B (with an R group of C16 alkyl) was 2.5:7.5, and the molecular weight was about 5 million).

[0047] Using the above experimental scheme and evaluation method, for Comparative Example 5 (A 2.5 B 7.5 -500), the water control and oil stabilization performance, injection pressure test, and dynamic adsorption performance were carried out, and the results were as follows: As shown in Table 12, the water plugging rate of Comparative Example 5 was only 59.38%, but the oil plugging rate was 18.85%. The water plugging rate was low, and at the same time, the oil plugging rate was high, resulting in a poor water control and oil increment effect. As Figure 15 shown, λ = 3.29 > 1.5. As Figure 16 shown, the injection performance was poor. The average concentration retention rate of dynamic adsorption was 56.70%. The adsorption retention amount of the phase permeability improver in the porous medium was relatively large, and the loss was large, making it difficult to transfer to the deep formation.

[0048] Table 12 Water control and oil stabilization performance of Comparative Example 5 Comparative Example 6 The method of Comparative Example 4 was followed, with the difference that the feeding ratio of the cationic adsorption monomer to the sulfonate group-containing ionic hydrophobic monomer was 2.5:0.25, and the other conditions were the same as those in Comparative Example 4, and the target polymer was obtained. Using an Ubbelohde viscometer (with a tube diameter of 0.55 mm), the viscosity-average molecular weight of the relative permeability improver obtained in Comparative Example 6 was measured and calculated according to GB / T 12005.10-92 to be 5.02 million, and the relative permeability improver obtained in Comparative Example 6 was denoted as A 2.5 B 0.25 -500 (The feeding ratio of the cationic adsorption monomer vinylbenzyl hexadecyl dimethyl ammonium chloride A to the sulfonate group-containing ionic hydrophobic monomer B (with an R group of C16 alkyl) was 2.5:0.25, and the molecular weight was about 5 million).

[0049] Using the above experimental scheme and evaluation method, for Comparative Example 6 (A 2.5 B 0.25-500) the water control and oil stabilization performance, injection pressure test, and dynamic adsorption performance were carried out, and the results are as follows: As shown in Table 13, for Comparative Example 6, the water plugging rate was only 60.72%, and the oil plugging rate was 4.28%. The water plugging rate was relatively high, but there was no oil increase phenomenon, and the water control and oil increase effect was poor. As Figure 17 shown, λ = 3.65 > 1.5, and the injection performance was poor. As Figure 18 shown, the average concentration retention rate of dynamic adsorption was 63.76%. The adsorption retention amount of the phase permeability modifier in the porous medium was relatively large, and the loss was large, making it difficult to transfer to the deep formation.

[0050] Table 13 Water Control and Oil Stabilization Performance of Comparative Example 6 Comparative Example 7 It was carried out according to the method of Example 2, with the difference that: the cationic adsorption monomer was removed, and the cationic adsorption monomer was not added during feeding. The molar ratio of acrylamide, sodium acrylate, 2-acrylamido-2-methylpropanesulfonic acid, and sulfonate group-containing hydrophobic monomer (R group is C16 alkyl) was 66.98:28.71:1.81:2.5. The concentration of the molecular weight regulator sodium formate was 2500 mg / L, and the others were kept the same as in Example 2 to obtain the target polymer. The viscosity-average molecular weight of the relative permeability improver obtained in Comparative Example 7 was calculated to be 5.14 million by using an Ubbelohde viscometer (0.55 mm tube diameter) according to GB / T 12005.10-92. The relative permeability improver obtained in Comparative Example 7 was denoted as A0B 2.5 -500 (the feeding ratio of the cationic adsorption monomer vinylbenzyl hexadecyl dimethyl ammonium chloride A to the sulfonate group-containing hydrophobic monomer B (R group is C16 alkyl) is 0:2.5, and the molecular weight is about 5 million).

[0051] Using the above experimental scheme and evaluation method, for Comparative Example 7 (A0B 2.5 -500) the water control and oil stabilization performance, injection pressure test, and dynamic adsorption performance were carried out, and the results are as follows: As shown in Table 14, for Comparative Example 7, the water plugging rate was only 51.67%, and the oil plugging rate reached -14.36%. Although there was an oil increase performance, the water plugging rate was relatively low, and the water control and oil increase performance was poor. As Figure 19 shown, λ = 0.18 < 0.5, and the injection performance was excellent. As Figure 20 shown, the average concentration retention rate of dynamic adsorption was 88.36%.

[0052] Table 14 Water Control and Oil Stabilization Performance of Comparative Example 7 Comparative Example 8 It was carried out according to the method of Example 2, with the difference that the sulfonate group-containing hydrophobic monomer was removed and not added during feeding. The molar ratio of acrylamide, sodium acrylate, 2-acrylamido-2-methylpropanesulfonic acid, and the cationic adsorption monomer vinylbenzylhexadecyldimethylammonium chloride was 66.98:28.71:1.81:2.5. The concentration of the molecular weight regulator sodium formate was 2500 mg / L, and the others were kept the same as in Example 2 to obtain the target polymer. The viscosity-average molecular weight of the relative permeability improver obtained in Comparative Example 8 was measured and calculated to be 4.97 million using an Ubbelohde viscometer (0.55 mm tube diameter) according to GB / T 12005.10-92. The relative permeability improver obtained in Comparative Example 8 was denoted as A 2.5 B0-500 (the feeding ratio of the cationic adsorption monomer vinylbenzylhexadecyldimethylammonium chloride A to the sulfonate group-containing hydrophobic monomer B (R group is an alkyl group with 16 carbon atoms) is 2.5:0, and the molecular weight is about 5 million).

[0053] Using the above experimental scheme and evaluation method, the water control and oil stabilization performance, injection pressure test, and dynamic adsorption performance of Comparative Example 8 (A 2.5 B0-500) were carried out, and the results are as follows: As shown in Table 15, the water plugging rate of Comparative Example 8 was only 78.25%, and the oil plugging rate was 22.74%. The oil plugging rate was relatively high, and there was no oil production increase effect. Therefore, the water control and oil production increase effect was poor. As Figure 21 shown, λ = 3.14 > 1.5, and the injection performance was poor, making it difficult to inject into the core. As Figure 22 shown, the average concentration retention rate of dynamic adsorption was 76.35%. The adsorption retention amount of the relative permeability improver in the porous medium was relatively large, and the loss was large, making it difficult to transfer to the deep formation.

[0054] Table 15 Water control and oil stabilization performance of Comparative Example 8 Comparative Example 9 It was carried out according to the method of Example 2, with the difference that the cationic adsorption monomer vinylbenzylhexadecyldimethylammonium chloride A was replaced by methacryloyloxyethyltrimethylammonium chloride C, and the feeding ratio remained unchanged. The others were kept the same as in Example 2 to obtain the target polymer. The viscosity-average molecular weight of the relative permeability improver obtained in Comparative Example 9 was measured and calculated to be 5.06 million using an Ubbelohde viscometer (0.55 mm tube diameter) according to GB / T 12005.10-92. The relative permeability improver obtained in Comparative Example 9 was denoted as C 2.5 B 2.5 -500 (the feeding ratio of the cationic adsorption monomer methacryloyloxyethyltrimethylammonium chloride C to the sulfonate group-containing hydrophobic monomer B (R group is an alkyl group with 16 carbon atoms) is 2.5:2.5, and the molecular weight is about 5 million).

[0055] Using the above experimental scheme and evaluation method, for Comparative Example 9 (C 2.5 B 2.5 -500), water control and oil stabilization performance, injection pressure test, dynamic adsorption performance and heterogeneity selectivity test were carried out, and the results are as follows: As shown in Table 16, the water plugging rate of Comparative Example 9 was only 59.13%, and the oil plugging rate was 8.26%. The water plugging rate was low, and the oil plugging rate was low. There was no oil increase phenomenon, and the water control and oil increase effect was poor. As Figure 23 shown, λ = 1.66 > 1.5, and the injection performance was poor. As Figure 24 shown, the average concentration retention rate of dynamic adsorption was 82.13%. The adsorption retention amount of the phase permeability agent in the porous medium was large, and the loss was large, making it difficult to transfer to the deep formation. As shown in Table 17, during the injection of C 2.5 B 2.5 -500, the diversion rate in the high permeability zone reached 91.97%, while the diversion rate in the low permeability zone was only 8.03%. After diversion, the water and oil plugging rates of C 2.5 B 2.5 -500 were relatively high, and there was no oil breakthrough phenomenon. Its injection selectivity was good, and it could enter the pore channels with higher permeability more autonomously and enter the low permeability channels in a small part.

[0056] Table 16 Water control and oil stabilization performance of Comparative Example 9 Table 17 Heterogeneity selectivity of Comparative Example 9 Comparative Example 10 It was carried out according to the method of Example 2, and the difference was that the sulfonate group-containing ionic hydrophobic monomer B (R group is a C16 alkyl group) was replaced by cetyl dimethyl allyl ammonium chloride D, and the feed ratio remained unchanged. Other conditions were the same as those in Example 2 to obtain the target polymer. The viscosity-average molecular weight of the relative permeability improver obtained in Comparative Example 10 was measured and calculated to be 5.17 million using an Ubbelohde viscometer (0.55 mm tube diameter) according to GB / T 12005.10-92. The relative permeability improver obtained in Comparative Example 10 was denoted as A 2.5 D 2.5 -500 (the feed ratio of the cationic adsorption monomer vinyl benzyl cetyl dimethyl ammonium chloride A to cetyl dimethyl allyl ammonium chloride D is 2.5:2.5, and the molecular weight is about 5 million).

[0057] Using the above experimental scheme and evaluation method, for Comparative Example 10 (A 2.5 D 2.5 -500), water control and oil stabilization performance, injection pressure test, dynamic adsorption performance and heterogeneity selectivity test were carried out, and the results are as follows: As shown in Table 18, the water plugging rate of Comparative Example 10 is only 63.39%, and the oil plugging rate is 12.27%. The water plugging rate is relatively high, and the oil plugging rate is relatively low, but there is no oil production increase phenomenon, and the effect of water control and oil increase is poor. As Figure 25 shown, λ = 1.52 > 1.5, and the injection performance is poor. As Figure 26 shown, the average concentration retention rate of dynamic adsorption is 84.07%. The adsorption retention amount of the phase permeability agent in the porous medium is relatively large, and the loss is relatively large, making it difficult to transfer to the deep formation. As shown in Table 19, during the injection of A 2.5 D 2.5 -500, the diversion rate in the high-permeability zone reaches 92.59%, while the diversion rate in the low-permeability zone is only 7.41%. After diversion, the water and oil plugging rates of A 2.5 D 2.5 -500 are relatively high, and there is no oil leakage phenomenon. Its injection selectivity is good, and it can enter the pore channels with higher permeability more autonomously and a small part enters the low-permeability channels.

[0058] Table 18 Water control and oil stabilization performance of Comparative Example 10 Table 19 Heterogeneity selectivity of Comparative Example 10 Comparative Example 11 It was carried out according to the method of Example 2, with the differences being: replacing the cationic adsorption monomer vinylbenzyl cetyl dimethyl ammonium chloride A with methacryloyloxyethyl trimethyl ammonium chloride C, and replacing the sulfonate ion-containing hydrophobic monomer B (with R group being C16 alkyl) with cetyl dimethyl allyl ammonium chloride D. The feed ratio remained unchanged, and other conditions were the same as in Example 2 to obtain the target polymer. Using an Ubbelohde viscometer (0.55 mm tube diameter), the viscosity-average molecular weight of the relative permeability improver obtained in Comparative Example 11 was tested and calculated according to GB / T 12005.10-92 to be 5.03 million. The relative permeability improver obtained in Comparative Example 11 is denoted as C 2.5 D 2.5 -500 (the feed ratio of the cationic adsorption monomer methacryloyloxyethyl trimethyl ammonium chloride C to cetyl dimethyl allyl ammonium chloride D is 2.5:2.5, and the molecular weight is about 5 million).

[0059] Using the above experimental scheme and evaluation method, the water control and oil stabilization performance, injection pressure test, dynamic adsorption performance, and heterogeneity selectivity test were carried out on Comparative Example 11 (C 2.5 D 2.5 -500), and the results are as follows: As shown in Table 20, the water plugging rate of Comparative Example 11 is 70.67%, and the oil plugging rate is 23.36%. The water plugging rate is relatively high, and the oil plugging rate is relatively high. There is no oil production increase phenomenon, and the effect of water control and oil increase is poor. As Figure 27As shown, λ = 0.73, the injection performance is good, such as Figure 28 As shown, the average concentration retention rate of dynamic adsorption is 84.70%. The adsorption and retention amount of the phase permeability agent in the porous medium is relatively large, and the loss is large, making it difficult to transfer to the deep formation. As shown in Table 21, during the injection of C 2.5 D 2.5 -500, the diversion rate in the high-permeability zone reaches 92.94%, while the diversion rate in the low-permeability zone is only 7.06%. After diversion, the C 2.5 D 2.5 -500 water and oil plugging rates are relatively low, and there is no oil breakthrough phenomenon. Its injection selectivity is good, and it can enter the pore channels with higher permeability more autonomously, and a small part enters the low-permeability channels.

[0060] Table 20 Water Control and Oil Stabilization Performance of Comparative Example 11 Table 21 Heterogeneous Selectivity of Comparative Example 11 Comparative Example 12 It was carried out according to the method of Example 2, with the difference that: the azo component was not added to the initiator system, and the others remained unchanged as in Example 2. It could not polymerize sufficiently and the target polymer could not be obtained.

[0061] Comparative Example 13 It was carried out according to the method of Example 2, with the difference that: ammonium persulfate was not added to the initiator system, and the others remained unchanged as in Example 2. It could not polymerize sufficiently and the target polymer could not be obtained.

[0062] Comparative Example 14 It was carried out according to the method of Example 2, with the difference that: tert-butyl hydroperoxide was not added to the initiator system, and the others remained unchanged as in Example 2. It could not polymerize and the target polymer could not be obtained.

[0063] Comparative Example 15 It was carried out according to the method of Example 2, with the difference that: sodium bisulfite was not added to the initiator system, and the others remained unchanged as in Example 2. It could not polymerize and the target polymer could not be obtained.

[0064] In summary, the present invention discloses a relative permeability improver for efficient water control and oil increment and its preparation method, belonging to the technical field of oil and gas field development; the relative permeability improver is a multi-component copolymerized polyacrylamide synthesized from acrylamide, sodium acrylate, 2-acrylamido-2-methylpropanesulfonic acid, a sulfonate ion-containing hydrophobic monomer, and a cationic adsorption monomer; by simultaneously introducing a sulfonate ion-containing hydrophobic monomer and a cationic adsorption monomer to cooperate with each other, through the synergism of monomers, the present invention can significantly improve the water control and oil increment ability of the relative permeability improver in porous media, effectively increase the flow resistance of the water phase in porous media, and at the same time, due to the lubricating effect, further reduce the flow resistance of the oil phase, unexpectedly achieving an oil-permeable effect and excellent water control and oil increment effects, and being able to have significant permeability selectivity performance under heterogeneous reservoir conditions; the invention provides key material support for the development of high-water-cut oil and gas resources, and guarantees the efficient development goal of high-water-cut oil and gas resources.

[0065] At this point, those skilled in the art recognize that although the embodiments of the present invention have been shown and described in detail herein, many other variations or modifications that conform to the principles of the present invention can still be directly determined or derived from the content disclosed in the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and recognized as covering all these other variations or modifications.

Claims

1. A relative permeability improver for efficient water control and oil production increase, characterized in that The relative permeability improver is an adsorption - association type polyacrylamide copolymerized from acrylamide, sodium acrylate, 2 - acrylamido - 2 - methylpropanesulfonic acid, a sulfonate - containing hydrophobic monomer, a cationic adsorption monomer and a composite initiator; The molar ratio of acrylamide, sodium acrylate, 2 - acrylamido - 2 - methylpropanesulfonic acid, the sulfonate - containing hydrophobic monomer, and the cationic adsorption monomer is 61.83 - 68.01:26.5 - 29.15:1.67 - 1.84:0.5 - 5:0.5 - 5; The addition amount of the composite initiator in the whole reaction solution is 500 - 1000 mg / L; After the polymerization reaction is completed, post - hydrolysis is carried out with sodium carbonate, and the addition amount of sodium carbonate is 0.1 wt.% - 0.2 wt.% of the whole hydrolysis system; The structural formula of the sulfonate - containing hydrophobic monomer is: ； Among them, the R group is an alkyl group with 14 carbon atoms or an alkyl group with 16 carbon atoms; The cationic adsorption monomer is one or more of vinylbenzyltetradecyldimethylammonium chloride, vinylbenzylhexadecyldimethylammonium chloride and vinylbenzyloctadecyldimethylammonium chloride; The composite initiator is a multi - component initiator composed of an inorganic oxidant, an organic oxidant, a reducing agent and a water - soluble azo initiator. The inorganic oxidant is a persulfate, and its addition amount in the reaction system is 100 - 200 mg / L; the organic oxidant is an organic hydroperoxide, and its addition amount in the reaction system is 200 - 400 mg / L; the reducing agent is one of sulfite and bisulfite, and its addition amount in the reaction system is 150 - 300 mg / L; the addition amount of the water - soluble azo initiator in the reaction system is 50 - 100 mg / L.

2. The relative permeability improver for efficiently controlling water and increasing oil production according to claim 1, wherein The molecular weight range of the relative permeability improver is 3 million - 8 million.

3. An efficient water control and oil production increasing relative permeability improver as described in claim 1, characterized in that The inorganic oxidant is one of ammonium persulfate, sodium persulfate and potassium persulfate; the organic oxidant is one or more of tert - butyl hydroperoxide and cumene hydroperoxide; the water - soluble azo initiator is one of 2,2 - azobis(2 - (2 - imidazolin - 2 - yl)propane) dihydrochloride, 2,2 - azobis(2 - methyl - N - (2 - hydroxyethyl)acrylamide) and 2,2 - azobis(2 - methylpropionamidine) hydrochloride.

4. An improved relative permeability agent for efficient water control and oil production as described in claim 1, characterized in that The composite initiator is tert - butyl hydroperoxide, ammonium persulfate, sodium bisulfite and 2,2 - azobis(2 - (2 - imidazolin - 2 - yl)propane) dihydrochloride.

5. An efficient water control and oil production increasing relative permeability improver as described in claim 1, characterized in that, The preparation method of the sulfonate - containing hydrophobic monomer is: Step S1: In a three-necked flask equipped with a magnetic stirrer, a reflux condenser, a thermometer, and two constant-pressure dropping funnels, add tetradecylamine or hexadecylamine and a catalyst in sequence. Add a solution of sodium 2-bromoethylsulfonate or sodium 2-chloroethylsulfonate to one of the constant-pressure funnels, and add a NaOH solution to the other constant-pressure dropping funnel. By adjusting the dropping rate of the NaOH solution, control the reaction pH value and react at a temperature of 50-70 °C for 6-9 h. After the reaction is completed, precipitate in ethanol and filter to obtain the intermediate sodium 2-tetradecylaminoethanesulfonate or sodium 2-hexadecylaminoethanesulfonate. Step S2: Dissolve the intermediate obtained in Step S1 in dichloromethane, and simultaneously add Na2CO3 as an acid-binding agent. Drop acryloyl chloride from the constant-pressure dropping funnel, control the temperature at 15-20 °C, and after reacting for 18-24 h, distill off dichloromethane under reduced pressure, and then perform recrystallization using ethanol to obtain the target monomer, which is a sulfonate ion-containing hydrophobic monomer.

6. An efficient water control and oil production relative permeability improver as described in claim 5, characterized in that, In Step S1, the molar ratio of tetradecylamine or hexadecylamine to sodium 2-bromoethylsulfonate or sodium 2-chloroethylsulfonate is 1:0.8 - 1:0.9; the catalyst is tetrabutylammonium bromide, and its content is 1% of the mass of tetradecylamine or hexadecylamine; during the reaction, adjust the dropping rate of the NaOH solution according to the pH change to control the pH value at 9-12; in Step S2, the molar ratio of the intermediate, Na2CO3, and acryloyl chloride is 1:3:

3.

7. The preparation method of a relative permeability improver for efficient water control and oil increment as described in any one of claims 1-6, characterized in that, The preparation method is as follows: Charge acrylamide, sodium acrylate, 2-acrylamido-2-methylpropanesulfonic acid, a sulfonate ion-containing hydrophobic monomer, and a cationic adsorption monomer according to the formula ratio, and prepare a mixed solution with a total monomer mass concentration of 25-30% using ultrapure water. Then adjust the pH value of the solution to 6.0-9.0, lower the system temperature to 0-5 °C, add a water-soluble azo initiator and a reducing agent, stir for 30-40 minutes after introducing nitrogen, add an oxidizing agent, and perform adiabatic polymerization for 3-8 h. After the adiabatic polymerization is completed, granulate, hydrolyze, dry, and pulverize to obtain the target polymer.

8. The preparation method according to claim 7, characterized in that, The pH value of the solution is adjusted using sodium hydroxide and acetic acid; the pH value of the solution is 7.0-8.0; the system temperature is 0 °C; the adiabatic polymerization time is 3-6 h.

9. Use of a relative permeability improver for efficiently controlling water and increasing oil production according to claim 1, characterized in that, The relative permeability improver is applied to the field of improving the water-phase and oil-phase permeabilities in oil and gas field development.

10. The application as described in claim 9, wherein, The growth rate of the injection pressure gradient of the relative permeability improver is 0.09-0.42; the water-phase water plugging rate is 63.27%-87.74%; the oil-phase oil plugging rate is -6.69%~-22.98%.

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