A high-efficiency water-controlling and oil-increasing relative permeability improver and its preparation method

Abstract

The invention discloses a relative permeability improver for efficient water control and oil increase and a preparation method thereof, belonging to the 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. The sulfonate ion-containing hydrophobic monomer and the cationic adsorption monomer are simultaneously introduced to cooperate with each other. Through the mutual synergy of the monomers, the water control and oil increase capability of the relative permeability improver in porous media is significantly improved, the flow resistance of the water phase in the porous medium is effectively increased, and the flow resistance of the oil phase can be further reduced due to the lubrication effect, thereby unexpectedly achieving an oil permeability effect, achieving an excellent water control and oil increase effect, and being able to have significant permeability selectivity under heterogeneous oil reservoir conditions. The invention provides key material support for the development of high-water-content oil and gas resources, ensuring the goal of efficient development of high-water-content oil and gas resources.

Description

Technical Field

[0001] The present invention relates to the field of relative permeability improvement in oil and gas field development, and in particular to a relative permeability improver for efficient water control and oil increase and a preparation method thereof. Background Art

[0002] After long-term water injection development of oil reservoirs, the reservoir properties change and the formation heterogeneity increases, eventually leading to problems such as water flooding, rapid increase in water content in the produced fluid, high water content, and decreased oil and gas recovery rates. Therefore, it is necessary to find an efficient way to control water and increase production to meet the increasingly complex reservoir environment. Water control technologies at home and abroad are mainly divided into mechanical water control and chemical water control. Mechanical water control uses separators to separate the water-producing layer to prevent water from flowing into the wellbore, which is not suitable for complex reservoirs. Chemical water control methods often use polymers, gels, resins, and precipitation-type water plugging agents, which have a wide range of applications. Among them, relative permeability improvers are a type of selective water control agent that has the ability to reduce the permeability of the water phase and oil phase in unequal proportions and has good application prospects. At present, domestic and foreign scholars have conducted systematic research on the types of polymer relative permeability improvers (mainly polyacrylamide and its derivatives), the action mechanism of relative permeability improvers (wall effect, expansion / contraction effect, oil-water diversion theory, adsorption-entanglement theory, etc.), and the factors affecting the oil-water permeability improvement ability (polymer additional groups and molecular weight, pH, temperature, salinity, wettability, flow rate, permeability, etc.). Studies have shown that the effect of relative permeability improvers on water / oil phase plugging performance is related to reservoir conditions and molecular structure.

[0003] Conventional polyacrylamide is widely used in various fields of oil and gas extraction, but its ability to reduce the permeabilities of the water and oil phases unequally as a relative permeability improver is relatively poor. Consequently, numerous researchers have introduced various functional groups into the polyacrylamide molecular chain to improve its performance. For example, cationic (anionic) groups enhance its adsorption capacity in sandstone (carbonate) rocks, while hydrophobic associating groups are added to enhance its viscoelasticity, temperature resistance, and salt tolerance. Liu Jianxin, through studying modified polyacrylamides with different functional groups, found that those with cationic groups exhibited advantages such as low viscosity, strong adsorption properties, and excellent water control. Zhang Na, through studying hydrophobically associating RPM-P, found that this hydrophobically associating RPM-P exhibited the ability to reduce the permeabilities of the water and oil phases unequally. Despite numerous studies on relative permeability improvers with various functional groups, no relative permeability improver has been reported that combines high water control and oil enhancement with excellent injectability.

[0004] Therefore, the present invention adopts sulfonate ion-containing hydrophobic monomers and cationic adsorption monomers to synthesize adsorption-associated multi-polymer polyacrylamide; through the mutual synergy of the monomers, the water-controlling and oil-increasing ability of the relative permeability improver in porous media can be significantly improved, and the flow resistance of the water phase in the porous medium can be effectively improved. At the same time, due to the lubricating effect, the flow resistance of the oil phase can be further reduced, and the oil permeability effect is unexpectedly achieved, achieving an excellent water-control and oil-increasing effect; providing ideas and technical references for the future development of relative permeability improvers, reservoir adaptability and action mechanism. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a relative permeability improver with high efficiency in water control and oil increase and a preparation method thereof, belonging to the technical field of oil and gas field development; the relative permeability improver is an adsorption-associated multi-polymer polyacrylamide synthesized from acrylamide, sodium acrylate, 2-acrylamido-2-methylpropanesulfonic acid, a sulfonate ion-containing hydrophobic monomer, and a cationic adsorption monomer; the present invention simultaneously introduces a sulfonate ion-containing hydrophobic monomer and a cationic adsorption monomer to cooperate with each other, and through the mutual synergy of the monomers, can significantly improve the water control and oil increase ability of the relative permeability improver in porous media, effectively improve the flow resistance of the water phase in the porous medium, and at the same time, due to the lubricating effect, can further reduce the flow resistance of the oil phase, unexpectedly achieve an oil permeability effect, and achieve an excellent water control and oil increase effect; it can have significant permeability selection performance under heterogeneous oil reservoir conditions; the invention provides key material support for the development of high-water-content oil and gas resources, and ensures the goal of efficient development of high-water-content oil and gas resources.

[0006] In order to achieve the above technical effects, the following technical solutions are adopted:

[0007] A high-efficiency relative permeability improver for controlling water and increasing oil content, wherein the relative permeability improver is an adsorption-association type multi-component copolymerized polyacrylamide formed by polymerization reaction of acrylamide, sodium acrylate, 2-acrylamido-2-methylpropanesulfonic acid, a sulfonate-containing ion-type hydrophobic monomer, a cationic adsorption monomer, and a composite initiator;

[0008] The molar ratio of acrylamide, sodium acrylate, 2-acrylamido-2-methylpropanesulfonic acid, sulfonate-containing ion-type hydrophobic monomer, and cationic adsorption monomer is 61.83-68.01: 26.5-29.15: 1.67-1.84: 0.5-5: 0.5-5;

[0009] The composite initiator is added to a concentration of 500-1000 mg / L in the entire reaction solution;

[0010] After the polymerization reaction is completed, sodium carbonate is used for post-hydrolysis, and the amount of sodium carbonate added is 0.1wt.%-0.2wt.% of the entire hydrolysis system;

[0011] The structural formula of the sulfonate ion-containing hydrophobic monomer is:

[0012] ;

[0013] Wherein, the R group is a C14 alkyl group or a C16 alkyl group;

[0014] The cationic adsorption monomer is one or more of vinylbenzyltetradecyldimethylammonium chloride, vinylbenzylhexadecyldimethylammonium chloride and vinylbenzyloctadecyldimethylammonium chloride;

[0015] The composite initiator is a multi-component initiator, which is composed of an inorganic oxidant, an organic oxidant, a reducing agent and a water-soluble azo initiator. The inorganic oxidant is a persulfate, and the concentration of the added amount in the reaction system is 100-200 mg / L; the organic oxidant is an organic hydrogen peroxide, and the concentration of the added amount in the reaction system is 200-400 mg / L; the reducing agent is one of a sulfite and a bisulfite, and the concentration of the added amount in the reaction system is 150-300 mg / L; the concentration of the added amount of the water-soluble azo initiator in the reaction system is 50-100 mg / L.

[0016] Furthermore, the relative permeability improver has a molecular weight range of 3-8 million.

[0017] 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 isopropylbenzene hydroperoxide; and the water-soluble azo initiator is one of 2,2-azo(2-(2-imidazolin-2-yl)propane) dihydrochloride, 2,2-azo(2-methyl-N-(2-hydroxyethyl)acrylamide), and 2,2-azobis(2-methylpropionamide) hydrochloride.

[0018] Furthermore, the composite initiator is tert-butyl hydroperoxide, ammonium persulfate, sodium bisulfite, and 2,2-azo(2-(2-imidazolin-2-yl)propane) dihydrochloride.

[0019] Furthermore, the preparation method of the sulfonate ion-containing hydrophobic monomer is as follows:

[0020] Step S1: Tetradecylamine or hexadecylamine and a catalyst are sequentially added to a three-necked flask equipped with a magnetic stirrer, a reflux cold flow tube, a thermometer, and two constant-pressure dropping funnels. A solution of sodium 2-bromoethylsulfonate or sodium 2-chloroethylsulfonate is added to one constant-pressure funnel, and a NaOH solution is added to the other constant-pressure dropping funnel; the pH value of the reaction is controlled by adjusting the dropping rate of the NaOH solution, and the reaction is carried out at a temperature of 50-70° C. for 6-9 hours. After the reaction is completed, a precipitate is precipitated in ethanol and filtered to obtain the intermediate sodium 2-tetradecylaminoethanesulfonate or sodium 2-hexadecylaminoethanesulfonate;

[0021] Step S2: The intermediate obtained in step S1 is dissolved in dichloromethane, and Na2CO3 is added as an acid-binding agent; acryloyl chloride is added dropwise from a constant pressure dropping funnel, the temperature is controlled at 15-20°C, and the dichloromethane is removed by vacuum distillation after reacting for 18-24 hours. The target monomer is then recrystallized from ethanol to obtain a hydrophobic monomer containing a sulfonate ion.

[0022] 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% by mass of tetradecylamine or hexadecylamine; during the reaction, the dropwise addition rate of the NaOH solution is adjusted according to the pH change to control the pH value at 9-12; and in step S2, the molar ratio of the intermediate, Na2CO3, and acryloyl chloride is 1:3:3.

[0023] Furthermore, it is characterized in that the preparation method of the relative permeability improver is:

[0024] Acrylamide, sodium acrylate, 2-acrylamido-2-methylpropanesulfonic acid, a sulfonate-containing ion-type hydrophobic monomer, and a cationic adsorption monomer are added according to a formula ratio, and ultrapure water is used to prepare a mixed solution with a total monomer mass concentration of 25-30%; then, the pH value of the solution is adjusted to 6.0-9.0, and the system temperature is lowered to 0-5°C before adding a water-soluble azo initiator and a reducing agent; nitrogen is introduced and stirred for 30-40 minutes, and then an oxidant is added, and adiabatic polymerization is carried out for 3-8 hours. After the completion of the adiabatic polymerization, granulation, hydrolysis, drying, and pulverization are performed to obtain the target polymer.

[0025] 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.; and the insulating polymer time is 3-6 hours.

[0026] The relative permeability improver is used in the field of improving the permeability of water phase and oil phase in oil and gas field development.

[0027] Furthermore, the relative permeability improver injection pressure gradient growth rate is 0.09-0.42; the water phase water blocking rate is 63.27%-87.74%; and the oil phase oil blocking rate is -6.69%~-22.98%.

[0028] The beneficial effects of the present invention are:

[0029] The invention discloses a relative permeability improver for efficient water control and oil increase and a preparation method thereof, belonging to the technical field of oil and gas field development. The relative permeability improver is an adsorption-association type 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. The invention simultaneously introduces the sulfonate ion-containing hydrophobic monomer and the cationic adsorption monomer to cooperate with each other. Through the synergy of the monomers, the water control and oil increase capability of the relative permeability improver in a porous medium can be significantly improved, the flow resistance of the water phase in the porous medium can be effectively improved, and the flow resistance of the oil phase can be further reduced due to the lubrication effect, thereby unexpectedly achieving an oil permeability effect and an excellent water control and oil increase effect, thereby solving the technical problems of poor water control and oil increase effect and poor injection performance of the phase permeation agent in the prior art. The invention provides key material support for the development of high-water-content oil and gas resources, ensuring the goal of efficient development of high-water-content oil and gas resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. The drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0031] Figure 1 is the injection pressure curve of the relative permeability improver in Example 1 of the present invention;

[0032] Figure 2 is the dynamic adsorption curve of the relative permeability improver in Example 1 of the present invention;

[0033] Figure 3 is the injection pressure curve of the relative permeability improver in Example 2 of the present invention;

[0034] Figure 4 is the dynamic adsorption curve of the relative permeability improver in Example 2 of the present invention;

[0035] Figure 5 is the injection pressure curve of the relative permeability improver in Example 3 of the present invention;

[0036] Figure 6is the dynamic adsorption curve of the relative permeability improver in Example 3 of the present invention;

[0037] Figure 7 is the injection pressure curve of the relative permeability improver in Comparative Example 1 of the present invention;

[0038] Figure 8 is the dynamic adsorption curve of the relative permeability improver in Comparative Example 1 of the present invention;

[0039] Figure 9 is the injection pressure curve of the relative permeability improver in Comparative Example 2 of the present invention;

[0040] Figure 10 is the dynamic adsorption curve of the relative permeability improver in Comparative Example 2 of the present invention;

[0041] Figure 11 is the injection pressure curve of the relative permeability improver in Comparative Example 3 of the present invention;

[0042] Figure 12 is the dynamic adsorption curve of the relative permeability improver in Comparative Example 3 of the present invention;

[0043] Figure 13 is the injection pressure curve of the relative permeability improver in Comparative Example 4 of the present invention;

[0044] Figure 14 is the dynamic adsorption curve of the relative permeability improver in Comparative Example 4 of the present invention;

[0045] Figure 15 is the injection pressure curve of the relative permeability improver in Comparative Example 5 of the present invention;

[0046] Figure 16 is the dynamic adsorption curve of the relative permeability improver in Comparative Example 5 of the present invention;

[0047] Figure 17 is the injection pressure curve of the relative permeability improver in Comparative Example 6 of the present invention;

[0048] Figure 18 is the dynamic adsorption curve of the relative permeability improver in Comparative Example 6 of the present invention;

[0049] Figure 19 is the injection pressure curve of the relative permeability improver in Comparative Example 7 of the present invention;

[0050] Figure 20 is the dynamic adsorption curve of the relative permeability improver in Comparative Example 7 of the present invention;

[0051] Figure 21 is the injection pressure curve of the relative permeability improver in Comparative Example 8 of the present invention;

[0052] Figure 22 is the dynamic adsorption curve of the relative permeability improver in Comparative Example 8 of the present invention;

[0053] Figure 23 is the injection pressure curve of the relative permeability improver in Comparative Example 9 of the present invention;

[0054] Figure 24 is the dynamic adsorption curve of the relative permeability improver in Comparative Example 9 of the present invention;

[0055] Figure 25 is the injection pressure curve of the relative permeability improver in Comparative Example 10 of the present invention;

[0056] Figure 26 is the dynamic adsorption curve of the relative permeability improver in Comparative Example 10 of the present invention;

[0057] Figure 27 is the injection pressure curve of the relative permeability improver in Comparative Example 11 of the present invention;

[0058] Figure 28 This is the dynamic adsorption curve of the relative permeability improver in Comparative Example 11 of the present invention. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0060] It should be noted that the following detailed descriptions are exemplary and 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 skilled in the art to which the present invention belongs.

[0061] 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 intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations and / or combinations thereof.

[0062] First, a sulfonate ion-containing hydrophobic monomer is synthesized, and the preparation method is as follows:

[0063] Step S1: Tetradecylamine or hexadecylamine and a catalyst (tetrabutylammonium bromide) are sequentially added to a three-necked flask equipped with a magnetic stirrer, a reflux cold flow tube, a thermometer, and two constant-pressure dropping funnels. A solution of sodium 2-bromoethylsulfonate or sodium 2-chloroethylsulfonate is added to one constant-pressure funnel, and a NaOH solution is added to the other constant-pressure dropping funnel. The pH value of the reaction is controlled by adjusting the dropwise addition rate of the NaOH solution, and the reaction is carried out at 50-70°C for 6-9 hours. After the reaction is completed, a precipitate is precipitated in ethanol and filtered to obtain the intermediate sodium 2-tetradecylaminoethanesulfonate or sodium 2-hexadecylaminoethanesulfonate.

[0064] In step S1, the molar ratio of tetradecylamine or hexadecylamine to sodium 2-bromoethylsulfonate or sodium 2-chloroethylsulfonate solution is 1:0.8-1:0.9; the catalyst is tetrabutylammonium bromide, and its content is 1% by mass of tetradecylamine or hexadecylamine; and the pH value is controlled between 9 and 12 by controlling the dripping rate of the sodium hydroxide solution.

[0065] Step S2: The intermediate prepared in step S1 is dissolved in dichloromethane, and Na2CO3 is added as an acid-binding agent; acryloyl chloride is added dropwise from a constant pressure dropping funnel, the temperature is controlled at 20°C, and the dichloromethane is removed by vacuum distillation after reacting for 18 hours. The target monomer is then recrystallized from ethanol to obtain a sulfonate ion-containing hydrophobic monomer (the R group is a C16 or C14 alkyl group). In step S2, the molar ratio of the intermediate, Na2CO3, and acryloyl chloride is 1:3:3.

[0066] The evaluation method of the relative permeability improver is:

[0067] (1) The evaluation method for the water control and oil stabilization of relative permeability improvers is as follows (core flooding to evaluate the oil / water relative permeability improvement ability of relative permeability improvers):

[0068] The common core flooding experimental steps found in the literature are as follows:

[0069] (1) Saturate the core with water and test the pore volume (PV) and initial water permeability (K);

[0070] (2) Inject the oil phase forward until the pressure stabilizes and test the oil phase permeability (oil phase permeability K under the bound water saturation before oil flooding). O1 );

[0071] (3) Inject water phase forward until the pressure is stable, and test the water phase permeability (water phase permeability K under residual oil saturation before water flooding) W1 );

[0072] (4) Inject 12PV relative permeability improver solution (kinematic viscosity 5 mm / s) into the core in reverse order. 2 );

[0073] (5) Forward injection of water phase until the pressure is stable, test the water phase permeability (post-water flooding water phase permeability K W2 );

[0074] (6) Inject the oil phase forward until the pressure is stable and test the oil phase permeability (post-oil flooding oil phase permeability K O2 ).

[0075] Therefore, referring to the above experimental steps, the core flooding process adopted by the present invention is as follows:

[0076] Core saturated with water - front oil drive - front water drive - reverse injection of relative permeability improver solution - back water drive - back oil drive,

[0077] The displacement flow rate of the relative permeability improver injection was 3 m / d, and the other displacement flow rates were all 9 m / d.

[0078] Quantification method of water blocking rate / oil blocking rate:

[0079] According to the above relative permeability improver effect evaluation method, the relative permeability improver performance effect is made more intuitive by quantifying the oil / water phase plugging performance, as shown in formula (1), formula (2), and formula (3):

[0080] (1)

[0081] (2)

[0082] (3)

[0083] Where:

[0084] K w1 is the water phase permeability at the residual oil saturation before water flooding, mD;

[0085] K w2 is the water phase permeability after water flooding, mD;

[0086] K O1 is the oil phase permeability at the irreducible water saturation before oil flooding, mD;

[0087] K O2 is the oil phase permeability after oil flooding, mD;

[0088] N w is the water blocking rate, %;

[0089] N O is the oil blocking rate, %;

[0090] M is the oil-water blocking ratio, dimensionless.

[0091] (2) The evaluation method for the injection performance of relative permeability improver is as follows:

[0092] The ability of the relative permeability improver to be injected into the desired water-control reservoir is a prerequisite for it to produce the relative permeability regulation function. Therefore, the injection selectivity of the relative permeability improver is determined by the injection pressure gradient curve. At the same time, the injection pressure gradient growth rate (λ) of the relative permeability improver solution is used to divide its injection capacity into four levels to quantitatively analyze the injectivity of the relative permeability improver. The experimental steps are as follows.

[0093] (1) Test the injection pressure gradient (P1) when the relative permeability improver is injected at 1 PV. If the pressure drops after 1 PV injection, the injection pressure gradient at 2 PV should be selected.

[0094] (2) Testing the injection pressure gradient (P2) when the relative permeability improver is injected at 10 PV;

[0095] (3) The injection pressure gradient growth rate (λ) is used as the injection capability evaluation standard. The larger the λ, the worse the injection performance, as shown in Table 1. The injection pressure gradient growth rate (λ) is shown in formula (4):

[0096] (4)

[0097] Where:

[0098] λ is the growth rate, %;

[0099] P1 is the injection pressure gradient of 1 PV; MPa.m -1 ;

[0100] P2 is the injection pressure gradient of 10 PV; MPa.m -1 .

[0101] Table 1 Injection performance classification

[0102] Injection performance grading 1 (Excellent) 2 (better) Three (good) Four (bad) growth rate 0~0.5 0.5~1.0 1.0~1.5 ＞1.5

[0103] (3) The evaluation method of the dynamic adsorption capacity of the relative permeability improver is as follows:

[0104] (1) Using artificial cores, saturate with simulated brine at 70°C, and test the core permeability and pore volume; (2) Using a kinematic viscosity of approximately 5 mm / s 2 The relative permeability improver solution of 10PV was injected into the artificial core saturated with water at a flow rate of 3 m / d; (3) the polymer concentration C of the produced fluid was continuously detected at the core outlet within a certain period of time. i , referring to the starch-chromium iodide method used in the static adsorption experiment to determine the concentration of the produced fluid, the concentration retention rate of the polymer in the core is shown in formula (5).

[0105] (5)

[0106] Where:

[0107] C0: initial polymer concentration, mg / L;

[0108] C i : Concentration of polymer output liquid in a certain period of time, mg / L;

[0109] θ: concentration retention rate, %.

[0110] (4) The evaluation method for heterogeneous selectivity of relative permeability improvers is as follows:

[0111] Refer to the experimental process in the water-control and oil-stabilization evaluation method of relative permeability improver, except that the homogeneous core in the water-control and oil-stabilization evaluation method is replaced by two cores with different permeabilities (high permeability: about 200 mD; low permeability: about 5 mD) and parallel experiments are performed at the same time. Other procedures are consistent with the water-control and oil-stabilization evaluation method of relative permeability improver. This can examine the injection selectivity of the relative permeability improver and its relative permeability improvement ability after injection.

[0112] Example 1

[0113] Acrylamide, sodium acrylate, 2-acrylamido-2-methylpropanesulfonic acid, a sulfonate-containing ion-type hydrophobic monomer (R group is a C14 alkyl group) and a cationic adsorption monomer vinylbenzyltetradecyldimethylammonium chloride were added in a molar ratio of 68.01:29.15:1.84:0.5:0.5, and ultrapure water was used to prepare a mixed solution with a total monomer mass concentration of 25%; then, sodium hydroxide and acetic acid were used to adjust the solution pH to 7.0, and a mass concentration of The molecular weight regulator sodium formate was 2500 mg / L, and after the system temperature was adjusted to 0°C, 150 ppm of sodium bisulfite and 50 ppm of azo initiator 2,2-azo(2-(2-imidazolin-2-yl)propane) dihydrochloride were added; nitrogen was introduced and stirred for 30 minutes, followed by the addition of 200 ppm of tert-butyl hydroperoxide and 100 ppm of ammonium persulfate. Adiabatic polymerization was carried out for 4 hours. After the completion of the adiabatic polymerization, the polymer was granulated, hydrolyzed (post-hydrolysis was performed using sodium carbonate, with the amount of sodium carbonate added being 0.2 wt.% of the entire hydrolysis system), dried, and pulverized to obtain the target polymer. The viscosity-average molecular weight of the relative permeability improver obtained in Example 1 was measured and calculated using an Ubbelohde viscometer (0.55 mm diameter) in accordance with GB / T 12005.10-92, and was found to be 3.26 million. The relative permeability improver obtained in Example 1 is denoted as A. 0.5 B 0.5-300 (the feed ratio of cationic adsorption monomer vinylbenzyltetradecyldimethylammonium chloride A and sulfonate ion-containing hydrophobic monomer B (R group is C14 alkyl) is 0.5:0.5, and the molecular weight is about 3 million).

[0114] Using the above experimental scheme and evaluation method, Example 1 (A 0.5 B 0.5 -300) were tested for water control and oil stabilization performance, injection pressure test, dynamic adsorption performance and heterogeneous selectivity test. The results are as follows:

[0115] As shown in Table 2, the water blocking rate of Example 1 reached 63.27%, and the oil blocking rate reached -22.98%, showing good water control and oil increase performance. Figure 1 As shown, and λ=0.09<0.5, the injection performance is excellent and can be quickly injected into the formation. Figure 2 As shown in Table 3, the average dynamic adsorption concentration retention rate is 96.45%, showing good transfer ability, which can enter deeper formations with less loss of phase penetration agent, achieving efficient water control and oil increase. 0.5 B 0.5 During the injection of -300, the diversion rate of the high permeability zone reached 93.73%, while the diversion rate of the low permeability zone was only 6.27%. 0.5 B 0.5 -300 has good water control and oil increase performance, and the water blocking rate is much higher than the oil blocking rate, which shows that its injection selectivity is good, and it can independently choose to enter the pore channel with higher permeability, and a small part enters the low permeability channel. It also shows A 0.5 B 0.5 -300 has good oil / water phase improvement ability at different permeabilities.

[0116] Table 2 Water control and oil stabilization performance of Example 1

[0117]

[0118] Table 3 Heterogeneous selectivity of Example 1

[0119]

[0120] Example 2

[0121] Acrylamide, sodium acrylate, 2-acrylamido-2-methylpropanesulfonic acid, a sulfonate-containing ion-type hydrophobic monomer (R group is a C16 alkyl group) and a cationic adsorption monomer vinylbenzyl hexadecyldimethylammonium chloride were added in a molar ratio of 65.26:27.97:1.77:2.5:2.5, and ultrapure water was used to prepare a mixed solution with a total monomer mass concentration of 25%; then, sodium hydroxide and acetic acid were used to adjust the solution pH to 7.0, and a mass concentration of The molecular weight regulator sodium formate was 1250 mg / L, and after the system temperature was adjusted to 0°C, 150 ppm of sodium bisulfite and 50 ppm of azo initiator 2,2-azo(2-(2-imidazolin-2-yl)propane) dihydrochloride were added; nitrogen was introduced and stirred for 30 minutes, followed by the addition of 200 ppm of tert-butyl hydroperoxide and 100 ppm of ammonium persulfate. Adiabatic polymerization was carried out for 4 hours. After the completion of the adiabatic polymerization, the polymer was granulated, hydrolyzed (post-hydrolysis was performed using sodium carbonate, with the amount of sodium carbonate added being 0.2 wt.% of the entire hydrolysis system), dried, and pulverized to obtain the target polymer. The viscosity-average molecular weight of the relative permeability improver obtained in Example 1 was measured and calculated using an Ubbelohde viscometer (0.55 mm diameter) in accordance with GB / T 12005.10-92, and was found to be 5.07 million. The relative permeability improver obtained in Example 1 is denoted as A. 2.5 B 2.5 -500 (the feed ratio of cationic adsorption monomer vinylbenzyl hexadecyldimethylammonium chloride A and sulfonate ion-containing hydrophobic monomer B (R group is C16 alkyl) is 2.5:2.5, and the molecular weight is about 5 million).

[0122] Using the above experimental scheme and evaluation method, Example 2 (A 2.5 B 2.5 -500) were tested for water control and oil stabilization performance, injection pressure test, dynamic adsorption performance and heterogeneous selectivity test. The results are as follows:

[0123] As shown in Table 4, the water blocking rate of Example 2 reached 72.76%, and the oil blocking rate reached -17.34%, showing good water control and oil increase performance. Figure 3 As shown, and λ=0.23<0.5, the injection performance is excellent and can be quickly injected into the formation. Figure 4 As shown in Table 5, the average dynamic adsorption concentration retention rate is 95.02%, showing good transfer ability, which can enter deeper formations with less loss of phase penetration agent, achieving efficient water control and oil increase. 2.5 B 2.5 During the injection of -500, the diversion rate of the high permeability zone reached 94.34%, while the diversion rate of the low permeability zone was only 5.66%. 2.5 B 2.5-500 has good water control and oil increase performance, and the water blocking rate is much higher than the oil blocking rate, which shows that its injection selectivity is good, and it can independently choose to enter the pore channel with higher permeability, and a small part enters the low permeability channel. It also shows A 2.5 B 2.5 -500 has good oil / water phase improvement ability at different permeabilities.

[0124] Table 4 Water control and oil stabilization performance of Example 2

[0125]

[0126] Table 5 Heterogeneous Selectivity of Example 2

[0127]

[0128] Example 3

[0129] Acrylamide, sodium acrylate, 2-acrylamido-2-methylpropanesulfonic acid, a sulfonate-containing ion-type hydrophobic monomer (R group is a C16 alkyl group) and a cationic adsorption monomer vinylbenzyl octadecyldimethylammonium chloride were added in a molar ratio of 61.83:26.50:1.67:5:5, and ultrapure water was used to prepare a mixed solution with a total monomer mass concentration of 25%; then, sodium hydroxide and acetic acid were used to adjust the solution pH to 7.0, and after the system temperature was adjusted to 0°C, the solution was added. Sodium formate, a molecular weight regulator, was added with a mass concentration of 500 mg / L. After the system temperature was adjusted to 0°C, 150 ppm of sodium bisulfite and 50 ppm of 2,2-azo(2-(2-imidazolin-2-yl)propane) dihydrochloride as an azo initiator were added. Nitrogen was introduced and stirred for 30 minutes, followed by the addition of 200 ppm of tert-butyl hydroperoxide and 100 ppm of ammonium persulfate. Adiabatic polymerization was carried out for 4 hours. After completion of the adiabatic polymerization, the target polymer was granulated, hydrolyzed (post-hydrolysis was performed using sodium carbonate, and the amount of sodium carbonate added was 0.2 wt.% of the entire hydrolysis system), dried, and pulverized to obtain the target polymer. The viscosity-average molecular weight of the relative permeability improver obtained in Example 1 was measured and calculated using an Ubbelohde viscometer (0.55 mm tube diameter) in accordance with GB / T 12005.10-92, and was found to be 7.12 million. The relative permeability improver obtained in Example 1 was designated A5B5-700 (the feed ratio of the cation-adsorbing monomer vinylbenzyl octadecyldimethylammonium chloride A to the sulfonate-containing ion-type hydrophobic monomer B (R group being a C16 alkyl group) was 5:5, and the molecular weight was approximately 7 million).

[0130] Using the above experimental scheme and evaluation method, Example 3 (A5B5-700) was tested for water control and oil stabilization performance, injection pressure, dynamic adsorption performance, and heterogeneous selectivity. The results are as follows:

[0131] As shown in Table 6, the water blocking rate of Example 3 reached 87.74%, and the oil blocking rate reached -6.69%, showing good water control and oil increase performance. Figure 5 As shown, and λ=0.42<0.5, the injection performance is excellent and can be quickly injected into the formation. Figure 6 As shown in Table 7, the average dynamic adsorption concentration retention rate is 93.11%, which shows good transfer ability. It can enter deeper formations with less loss of phase permeability agent, achieving efficient water control and oil increase. As shown in Table 7, during the injection process of A5B5-700, the diversion rate in the high permeability zone reached 94.01%, while the diversion rate in the low permeability zone was only 5.99%. After diversion, A5B5-700 has good water control and oil increase performance, and the water blocking rate is much higher than the oil blocking rate, indicating that its injection selectivity is good, and it can independently choose to enter pore channels with higher permeability, and a small part enters low permeability channels. At the same time, it also shows the good oil / water phase improvement ability of A5B5-700 under different permeabilities.

[0132] Table 6 Water control and oil stabilization performance of Example 3

[0133]

[0134] Table 7 Heterogeneous Selectivity of Example 3

[0135]

[0136] Comparative Example 1

[0137] The method of Example 2 was followed, except that the mass concentration of the molecular weight regulator sodium formate was 2500 mg / L, and the other parameters remained unchanged from Example 2 to obtain the target polymer. The viscosity-average molecular weight of the relative permeability improver obtained in Comparative Example 1 was measured and calculated using an Ubbelohde viscometer (0.55 mm diameter) according to GB / T 12005.10-92, and the relative permeability improver obtained in Comparative Example 1 was 1.56 million. The relative permeability improver obtained in Comparative Example 1 is denoted as A. 2.5 B 2.5 -150 (the feed ratio of cationic adsorption monomer vinylbenzyl hexadecyldimethylammonium chloride A and sulfonate ion-containing hydrophobic monomer B (R group is C16 alkyl) is 2.5:2.5, and the molecular weight is about 1.5 million).

[0138] Using the above experimental scheme and evaluation method, the comparative example 1 (A 2.5 B 2.5 -150) were tested for water control and oil stabilization performance, injection pressure test, and dynamic adsorption performance. The results are as follows:

[0139] As shown in Table 8, the water blocking rate of comparative example 1 is only 32.98%, and the oil blocking rate is -10.41%. The water blocking rate is poor, and the water control and oil increase performance is poor. Figure 7 As shown, and λ=0.39<0.5, the injection performance is excellent. Figure 8 As shown, the average concentration retention rate of dynamic adsorption is 89.00%.

[0140] Table 8 Water control and oil stabilization performance of comparative example 1

[0141]

[0142] Comparative Example 2

[0143] The method of Example 2 was followed, except that the mass concentration of the molecular weight regulator sodium formate was 250 mg / L, and the other parameters remained unchanged from Example 2 to obtain the target polymer. The viscosity average molecular weight of the relative permeability improver obtained in Comparative Example 2 was measured and calculated using an Ubbelohde viscometer (0.55 mm diameter) according to GB / T12005.10-92, and the relative permeability improver obtained in Comparative Example 2 was 12.31 million. The relative permeability improver obtained in Comparative Example 2 was recorded as A. 2.5 B 2.5 -1200 (the feed ratio of cationic adsorption monomer vinylbenzyl hexadecyldimethylammonium chloride A and sulfonate ion-containing hydrophobic monomer B (R group is C16 alkyl) is 2.5:2.5, and the molecular weight is about 12 million).

[0144] Using the above experimental scheme and evaluation method, the comparative example 2 (A 2.5 B 2.5 -1200) were used to test water control and oil stabilization performance, injection pressure, and dynamic adsorption performance. The results are as follows:

[0145] As shown in Table 9, the water blocking rate of Comparative Example 2 is 93.32%, but the oil blocking rate is 52.25%. The water blocking rate is high, but the oil phase is also blocked at the same time, and the water control and oil increase effect is poor. Figure 9 As shown in , 0.5<λ=0.56<1.0, the injection performance is good. Figure 10 As shown, the average concentration retention rate of dynamic adsorption is 90.28%.

[0146] Table 9 Water control and oil stabilization performance of comparative example 2

[0147]

[0148] Comparative Example 3

[0149] The method of Example 2 was followed, except that the feed ratio of the cationic adsorption monomer to the sulfonate-containing hydrophobic monomer was 7.5:2.5, the content of the molecular weight regulator sodium formate was 250 mg / L, and all other factors 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 3 was measured and calculated using an Ubbelohde viscometer (0.55 mm diameter) in accordance with GB / T 12005.10-92, and the relative permeability improver obtained in Comparative Example 3 was 5.09 million. The relative permeability improver obtained in Comparative Example 3 is denoted as A.7.5 B 2.5 -500 (the feed ratio of cationic adsorption monomer vinylbenzyl hexadecyldimethylammonium chloride A and sulfonate ion-containing hydrophobic monomer B (R group is C16 alkyl) is 7.5:2.5, and the molecular weight is about 5 million).

[0150] Using the above experimental scheme and evaluation method, the comparative example 3 (A 7.5 B 2.5 -500) to test water control and oil stabilization performance, injection pressure test, and dynamic adsorption performance. The results are as follows:

[0151] As shown in Table 10, the water blocking rate of Comparative Example 3 reached 90.17%, but the oil blocking rate was 48.77%. The water blocking rate was high, but the oil phase was also blocked at the same time, and the water control and oil increase effect was poor. Figure 11 As shown, λ=2.88>1.5, the injection performance is poor, such as Figure 12 As shown in the figure, the average dynamic adsorption concentration retention rate is 65.51%. The adsorption retention of the phase penetration agent in the porous medium is large, the loss is large, and it is difficult to be transferred to the deep formation.

[0152] Table 10 Water control and oil stabilization performance of comparative example 3

[0153]

[0154] Comparative Example 4

[0155] The method of Example 2 was followed, except that the molar ratios of acrylamide, sodium acrylate, 2-acrylamido-2-methylpropanesulfonic acid, sulfonate-containing ionic hydrophobic monomer (R group is a C16 alkyl group), and cationic adsorption monomer vinylbenzyl hexadecyldimethylammonium chloride were 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. All other factors 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 measured and calculated using an Ubbelohde viscometer (0.55 mm diameter) in accordance with GB / T 12005.10-92, and the relative permeability improver obtained in Comparative Example 4 was 5.11 million. The relative permeability improver obtained in Comparative Example 4 is designated as A. 0.25 B 2.5 -500 (the feed ratio of cationic adsorption monomer vinylbenzyl hexadecyldimethylammonium chloride A and sulfonate ion-containing hydrophobic monomer B (R group is C16 alkyl) is 0.25:2.5, and the molecular weight is about 5 million).

[0156] Using the above experimental scheme and evaluation method, the comparative example 4 (A 0.25 B 2.5 -500) to test water control and oil stabilization performance, injection pressure test, and dynamic adsorption performance. The results are as follows:

[0157] As shown in Table 11, the water blocking rate of Comparative Example 4 is only 54.53%, but the oil blocking rate is -8.86%, which is a low water blocking rate and poor water control and oil increase effect. Figure 13 As shown, λ=1.77>1.5, the injection performance is poor, such as Figure 14 As shown in the figure, the average dynamic adsorption concentration retention rate is 81.62%. The adsorption retention of the phase penetration agent in the porous medium is large, the loss is large, and it is difficult to be transferred to the deep formation.

[0158] Table 11 Water control and oil stabilization performance of comparative example 4

[0159]

[0160] Comparative Example 5

[0161] The method of Example 2 was followed, except that the feed ratio of the cationic adsorption monomer to the sulfonate-containing hydrophobic monomer was 2.5:7.5, the mass concentration of the molecular weight regulator sodium formate was 250 mg / L, and all other factors 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 5 was measured and calculated using an Ubbelohde viscometer (0.55 mm diameter) in accordance with GB / T 12005.10-92, and the relative permeability improver obtained in Comparative Example 5 was 4.97 million. The relative permeability improver obtained in Comparative Example 5 is denoted as A. 2.5 B 7.5 -500 (the feed ratio of cationic adsorption monomer vinylbenzyl hexadecyldimethylammonium chloride A and sulfonate ion-containing hydrophobic monomer B (R group is C16 alkyl) is 2.5:7.5, and the molecular weight is about 5 million).

[0162] Using the above experimental scheme and evaluation method, the comparative example 5 (A 2.5 B 7.5 -500) to test water control and oil stabilization performance, injection pressure test, and dynamic adsorption performance. The results are as follows:

[0163] As shown in Table 12, the water blocking rate of comparative example 5 is only 59.38%, but the oil blocking rate is 18.85%. The water blocking rate is low, while the oil blocking rate is high, and the water control and oil increase effect is poor. Figure 15 As shown, λ=3.29>1.5, as Figure 16 As shown, the injection performance is poor. The average dynamic adsorption concentration retention rate is 56.70%. The adsorption retention of the phase penetration agent in the porous medium is large, the loss is large, and it is difficult to be transferred to the deep formation.

[0164] Table 12 Water control and oil stabilization performance of comparative example 5

[0165]

[0166] Comparative Example 6

[0167] The method of Comparative Example 4 was followed, except that the feed ratio of the cationic adsorption monomer to the sulfonate ion-containing hydrophobic monomer was 2.5:0.25, and other conditions remained unchanged from Comparative Example 4 to obtain the target polymer. The viscosity-average molecular weight of the relative permeability improver obtained in Comparative Example 6 was measured and calculated using an Ubbelohde viscometer (0.55 mm diameter) in accordance with GB / T 12005.10-92, and the relative permeability improver obtained in Comparative Example 6 was 5.02 million. The relative permeability improver obtained in Comparative Example 6 is denoted as A. 2.5 B 0.25 -500 (the feed ratio of cationic adsorption monomer vinylbenzyl hexadecyldimethylammonium chloride A and sulfonate ion-containing hydrophobic monomer B (R group is C16 alkyl) is 2.5:0.25, and the molecular weight is about 5 million).

[0168] Using the above experimental scheme and evaluation method, the comparative example 6 (A 2.5 B 0.25 -500) to test water control and oil stabilization performance, injection pressure test, and dynamic adsorption performance. The results are as follows:

[0169] As shown in Table 13, the water blocking rate of Comparative Example 6 is only 60.72%, and the oil blocking rate is 4.28%. The water blocking rate is relatively high, but there is no oil increase phenomenon, and the water control and oil increase effect is poor. Figure 17 As shown, λ=3.65>1.5, the injection performance is poor, such as Figure 18 As shown in the figure, the average dynamic adsorption concentration retention rate is 63.76%. The adsorption retention of the phase penetration agent in the porous medium is large, the loss is large, and it is difficult to be transferred to the deep formation.

[0170] Table 13 Water control and oil stabilization performance of comparative example 6

[0171]

[0172] Comparative Example 7

[0173] The method of Example 2 was followed, except that the cationic adsorption monomer was omitted and not added during the feeding. The molar ratio of acrylamide, sodium acrylate, 2-acrylamido-2-methylpropanesulfonic acid, and sulfonate-containing hydrophobic monomer (R group being a C16 alkyl) was 66.98:28.71:1.81:2.5. The concentration of the molecular weight regulator, sodium formate, was 2500 mg / L. All 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 7 was measured and calculated using an Ubbelohde viscometer (0.55 mm diameter) in accordance with GB / T 12005.10-92, and was found to be 5.14 million. The relative permeability improver obtained in Comparative Example 7 is designated A0B. 2.5-500 (the feed ratio of cationic adsorption monomer vinylbenzyl hexadecyldimethylammonium chloride A and sulfonate ion-containing hydrophobic monomer B (R group is C16 alkyl) is 0:2.5, and the molecular weight is about 5 million).

[0174] Using the above experimental scheme and evaluation method, the comparative example 7 (A0B 2.5 -500) to test water control and oil stabilization performance, injection pressure test, and dynamic adsorption performance. The results are as follows:

[0175] As shown in Table 14, the water blocking rate of comparative example 7 is only 51.67%, and the oil blocking rate is -14.36%. Although it has oil-increasing performance, the water blocking rate is low, and the water control and oil-increasing performance is poor. Figure 19 As shown in Figure 1, λ = 0.18 < 0.5, and the injection performance is excellent. Figure 20 As shown, the average concentration retention rate of dynamic adsorption is 88.36%.

[0176] Table 14 Water control and oil stabilization performance of comparative example 7

[0177]

[0178] Comparative Example 8

[0179] The method of Example 2 was followed, except that the sulfonate-containing hydrophobic monomer was removed and no sulfonate-containing hydrophobic monomer was added during the feeding. The molar ratio of acrylamide, sodium acrylate, 2-acrylamido-2-methylpropanesulfonic acid, and cationic adsorption monomer vinylbenzyl hexadecyldimethylammonium chloride was 66.98:28.71:1.81:2.5, and the concentration of the molecular weight regulator sodium formate was 2500 mg / L. Other factors 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 8 was measured and calculated using an Ubbelohde viscometer (0.55 mm diameter) in accordance with GB / T 12005.10-92. The relative permeability improver obtained in Comparative Example 8 was 4.97 million. The relative permeability improver obtained in Comparative Example 8 is designated as A. 2.5 B0-500 (the feed ratio of cationic adsorption monomer vinylbenzyl hexadecyldimethylammonium chloride A and sulfonate ion-containing hydrophobic monomer B (R group is C16 alkyl) is 2.5:0, and the molecular weight is about 5 million).

[0180] Using the above experimental scheme and evaluation method, the comparative example 8 (A 2.5 B0-500) were tested for water control and oil stabilization performance, injection pressure test, and dynamic adsorption performance. The results are as follows:

[0181] As shown in Table 15, the water blocking rate of Comparative Example 8 is only 78.25%, and the oil blocking rate is 22.74%. The oil blocking rate is relatively high, and there is no oil increase effect. Therefore, the water control and oil increase effect is poor. Figure 21As shown in the figure, λ=3.14>1.5, the injection performance is poor and it is difficult to inject into the core. Figure 22 As shown in the figure, the average dynamic adsorption concentration retention rate is 76.35%. The adsorption retention of the phase penetration agent in the porous medium is large, the loss is large, and it is difficult to be transferred to the deep formation.

[0182] Table 15 Water control and oil stabilization performance of comparative example 8

[0183]

[0184] Comparative Example 9

[0185] The method of Example 2 was followed, except that the cationic adsorption monomer vinylbenzyl hexadecyldimethylammonium chloride A was replaced with methacryloyloxyethyltrimethylammonium chloride C, the feed ratio remained unchanged, and all other factors 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 9 was measured and calculated using an Ubbelohde viscometer (0.55 mm diameter) in accordance with GB / T 12005.10-92, and the relative permeability improver obtained in Comparative Example 9 was 5.06 million. The relative permeability improver obtained in Comparative Example 9 is denoted as C. 2.5 B 2.5 -500 (the feed ratio of the cationic adsorption monomer methacryloyloxyethyl trimethyl ammonium chloride C and the sulfonate-containing ion-type hydrophobic monomer B (R group is a C16 alkyl) is 2.5:2.5, and the molecular weight is about 5 million).

[0186] Using the above experimental scheme and evaluation method, the comparative example 9 (C 2.5 B 2.5 -500) were tested for water control and oil stabilization performance, injection pressure test, dynamic adsorption performance and heterogeneous selectivity test. The results are as follows:

[0187] As shown in Table 16, the water blocking rate of Comparative Example 9 is only 59.13%, and the oil blocking rate is 8.26%. The water blocking rate is low, the oil blocking rate is low, there is no oil increase phenomenon, and the water control and oil increase effect is poor. Figure 23 As shown, λ=1.66>1.5, the injection performance is poor, such as Figure 24 As shown in Table 17, the average dynamic adsorption concentration retention rate is 82.13%. The adsorption retention of the phase penetration agent in the porous medium is large, the loss is large, and it is difficult to transfer to the deep formation. 2.5 B 2.5 During the injection of -500, the diversion rate of the high permeability zone reached 91.97%, while the diversion rate of the low permeability zone was only 8.03%. 2.5 B 2.5 -500 has a high water and oil blocking rate, and no oil seepage occurs. It has good injection selectivity and can relatively autonomously enter pore channels with higher permeability, with a small portion entering low-permeability channels.

[0188] Table 16 Water control and oil stabilization performance of comparative example 9

[0189]

[0190] Table 17 Heterogeneous selectivity of Comparative Example 9

[0191]

[0192] Comparative Example 10

[0193] The method of Example 2 was followed, except that the sulfonate-containing hydrophobic monomer B (R group is a C16 alkyl group) was replaced with hexadecyldimethylallyl ammonium chloride D. The feed ratio remained unchanged, and all other factors 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 10 was measured and calculated using an Ubbelohde viscometer (0.55 mm diameter) in accordance with GB / T 12005.10-92, and the relative permeability improver obtained in Comparative Example 10 was 5.17 million. The relative permeability improver obtained in Comparative Example 10 is designated as A. 2.5 D 2.5 -500 (the feed ratio of cationic adsorption monomer vinylbenzyl hexadecyldimethylammonium chloride A and hexadecyldimethylallylammonium chloride D is 2.5:2.5, and the molecular weight is about 5 million).

[0194] Using the above experimental scheme and evaluation method, the comparative example 10 (A 2.5 D 2.5 -500) were tested for water control and oil stabilization performance, injection pressure test, dynamic adsorption performance and heterogeneous selectivity test. The results are as follows:

[0195] As shown in Table 18, the water blocking rate of Comparative Example 10 is only 63.39%, and the oil blocking rate is 12.27%. The water blocking rate is high, and the oil blocking rate is low, but there is no oil increase phenomenon, and the water control and oil increase effect is poor. Figure 25 As shown, λ=1.52>1.5, the injection performance is poor, such as Figure 26 As shown in Table 19, the average dynamic adsorption concentration retention rate is 84.07%. The adsorption retention of the phase penetration agent in the porous medium is large, the loss is large, and it is difficult to transfer to the deep formation. 2.5 D 2.5 During the injection of -500, the diversion rate of the high permeability zone reached 92.59%, while the diversion rate of the low permeability zone was only 7.41%. 2.5 D 2.5 -500 has a high water and oil blocking rate, and no oil seepage occurs. It has good injection selectivity and can relatively autonomously enter pore channels with higher permeability, with a small portion entering low-permeability channels.

[0196] Table 18 Water control and oil stabilization performance of comparative example 10

[0197]

[0198] Table 19 Heterogeneous selectivity of Comparative Example 10

[0199]

[0200] Comparative Example 11

[0201] The method of Example 2 was followed, except that the cationic adsorption monomer vinylbenzyl hexadecyldimethylammonium chloride A was replaced with methacryloyloxyethyltrimethylammonium chloride C, and the sulfonate-containing ion-type hydrophobic monomer B (R group is a C16 alkyl group) was replaced with hexadecyldimethylallyl ammonium chloride D. The feed ratio remained unchanged, and all other factors 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 11 was measured and calculated using an Ubbelohde viscometer (0.55 mm diameter) in accordance with GB / T 12005.10-92, and the relative permeability improver obtained in Comparative Example 11 was 5.03 million. The relative permeability improver obtained in Comparative Example 11 is designated as C. 2.5 D 2.5 -500 (the feed ratio of the cationic adsorption monomers methacryloyloxyethyltrimethylammonium chloride C and hexadecyldimethylallylammonium chloride D is 2.5:2.5, and the molecular weight is about 5 million).

[0202] Using the above experimental scheme and evaluation method, the comparative example 11 (C 2.5 D 2.5 -500) were tested for water control and oil stabilization performance, injection pressure test, dynamic adsorption performance and heterogeneous selectivity test. The results are as follows:

[0203] As shown in Table 20, the water blocking rate of comparative example 11 is 70.67%, while the oil blocking rate is 23.36%. The water blocking rate is high, the oil blocking rate is high, and there is no oil increase phenomenon. The water control and oil increase effect is poor. Figure 27 As shown, λ = 0.73, the injection performance is good, as shown in Figure 28 As shown in Table 21, the average dynamic adsorption concentration retention rate is 84.70%. The adsorption retention of the phase permeation agent in the porous medium is large, the loss is large, and it is difficult to transfer to the deep formation. 2.5 D 2.5 During the injection of -500, the diversion rate of the high permeability zone reached 92.94%, while the diversion rate of the low permeability zone was only 7.06%. 2.5 D 2.5 -500 has a low water and oil blocking rate, and no oil seepage occurs. It has good injection selectivity and can relatively autonomously enter pore channels with higher permeability, with a small portion entering low-permeability channels.

[0204] Table 20 Water control and oil stabilization performance of comparative example 11

[0205]

[0206] Table 21 Heterogeneous selectivity of Comparative Example 11

[0207]

[0208] Comparative Example 12

[0209] The method of Example 2 was followed, except that no azo component was added to the initiator system, and other aspects remained unchanged from Example 2. However, the polymerization could not be fully completed, and the target polymer could not be obtained.

[0210] Comparative Example 13

[0211] The method of Example 2 was followed, except that ammonium persulfate was not added to the initiator system. Other aspects remained the same as in Example 2. However, the polymerization could not be fully completed and the target polymer could not be obtained.

[0212] Comparative Example 14

[0213] The method of Example 2 was followed, except that tert-butyl hydroperoxide was not added to the initiator system. Other aspects remained unchanged from Example 2. However, polymerization could not be achieved and the target polymer could not be obtained.

[0214] Comparative Example 15

[0215] The method of Example 2 was followed, except that sodium bisulfite was not added to the initiator system. Other aspects remained unchanged from Example 2. However, polymerization could not be achieved and the target polymer could not be obtained.

[0216] In summary, the present invention discloses a relative permeability improver with high efficiency in controlling water and increasing oil production and a preparation method thereof, which belongs 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; the present invention simultaneously introduces a sulfonate ion-containing hydrophobic monomer and a cationic adsorption monomer to cooperate with each other, and through the mutual synergy of the monomers, the water control and oil increase ability of the relative permeability improver in porous media can be significantly improved, and the flow resistance of the water phase in the porous medium can be effectively improved. At the same time, due to the lubricating effect, the flow resistance of the oil phase can be further reduced, and the oil permeability effect is unexpectedly achieved, achieving an excellent water control and oil increase effect, and being able to have significant permeability selection performance under heterogeneous oil reservoir conditions; the invention provides key material support for the development of high-water-content oil and gas resources, and ensures the goal of efficient development of high-water-content oil and gas resources.

[0217] At this point, those skilled in the art will recognize that, although the embodiments of the present invention have been shown and described in detail herein, many other variations or modifications consistent with the principles of the present invention may be directly determined or derived from the disclosure of 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 deemed to cover all such other variations or modifications.

Claims

1. A high-efficiency water-controlling and oil-increasing relative permeability improver, characterized in that: The relative permeability improver is an adsorption-association type multi-component copolymerized polyacrylamide formed by polymerization of acrylamide, sodium acrylate, 2-acrylamido-2-methylpropanesulfonic acid, a sulfonate-containing ion-type hydrophobic monomer, a cationic adsorption monomer, and a composite initiator; The molar ratio of acrylamide, sodium acrylate, 2-acrylamido-2-methylpropanesulfonic acid, sulfonate-containing ion-type hydrophobic monomer, and cationic adsorption monomer is 61.83-68.01: 26.5-29.15: 1.67-1.84: 0.5-5: 0.5-5; The concentration of the composite initiator added in the entire reaction solution is 500-1000 mg / L; After the polymerization reaction is completed, sodium carbonate is used for post-hydrolysis, and the amount of sodium carbonate added is 0.1wt.%-0.2wt.% of the entire hydrolysis system; The structural formula of the sulfonate ion-containing hydrophobic monomer is: ； Wherein, the R group is a C14 alkyl group or a C16 alkyl group; The cationic adsorption monomer is one or more of vinylbenzyltetradecyldimethylammonium chloride, vinylbenzylhexadecyldimethylammonium chloride and vinylbenzyloctadecyldimethylammonium chloride; The composite initiator is a multi-component initiator, which is composed of an inorganic oxidant, an organic oxidant, a reducing agent and a water-soluble azo initiator. The inorganic oxidant is a persulfate, and the concentration of the added amount in the reaction system is 100-200 mg / L; the organic oxidant is an organic hydrogen peroxide, and the concentration of the added amount in the reaction system is 200-400 mg / L; the reducing agent is one of a sulfite and a bisulfite, and the concentration of the added amount in the reaction system is 150-300 mg / L; the concentration of the added amount of the water-soluble azo initiator in the reaction system is 50-100 mg / L; The relative permeability improver has a molecular weight range of 3-8 million.

2. A high-efficiency water-controlling and oil-increasing relative permeability improver as claimed 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 isopropylbenzene hydroperoxide; the water-soluble azo initiator is one of 2,2-azo(2-(2-imidazolin-2-yl)propane) dihydrochloride, 2,2-azo(2-methyl-N-(2-hydroxyethyl)acrylamide), and 2,2-azobis(2-methylpropionamide) hydrochloride.

3. A high-efficiency water-controlling and oil-increasing relative permeability improver as claimed in claim 1, characterized in that: The composite initiator is tert-butyl hydroperoxide, ammonium persulfate, sodium bisulfite, and 2,2-azo(2-(2-imidazolin-2-yl)propane) dihydrochloride.

4. A high-efficiency water-controlling and oil-increasing relative permeability improver as claimed in claim 1, characterized in that: The preparation method of the sulfonate ion-containing hydrophobic monomer is as follows: Step S1: Tetradecylamine or hexadecylamine and a catalyst are sequentially added to a three-necked flask equipped with a magnetic stirrer, a reflux cold flow tube, a thermometer, and two constant-pressure dropping funnels. A solution of sodium 2-bromoethylsulfonate or sodium 2-chloroethylsulfonate is added to one constant-pressure funnel, and a NaOH solution is added to the other constant-pressure dropping funnel; the pH value of the reaction is controlled by adjusting the dropping rate of the NaOH solution, and the reaction is carried out at a temperature of 50-70° C. for 6-9 hours. After the reaction is completed, a precipitate is precipitated in ethanol and filtered to obtain the intermediate sodium 2-tetradecylaminoethanesulfonate or sodium 2-hexadecylaminoethanesulfonate; Step S2: The intermediate obtained in step S1 is dissolved in dichloromethane, and Na2CO3 is added as an acid-binding agent; acryloyl chloride is added dropwise from a constant pressure dropping funnel, the temperature is controlled at 15-20°C, and the dichloromethane is removed by vacuum distillation after reacting for 18-24 hours. The target monomer is then recrystallized from ethanol to obtain a hydrophobic monomer containing a sulfonate ion.

5. A high-efficiency water-controlling and oil-increasing relative permeability improver as claimed in claim 4, 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% by mass of tetradecylamine or hexadecylamine; during the reaction, the dropping speed of the NaOH solution is adjusted 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.

6. The method for preparing a high-efficiency water-controlling and oil-increasing relative permeability improver according to any one of claims 1 to 5, characterized in that: The preparation method is: Acrylamide, sodium acrylate, 2-acrylamido-2-methylpropanesulfonic acid, a sulfonate-containing ion-type hydrophobic monomer, and a cationic adsorption monomer are added according to a formula ratio, and ultrapure water is used to prepare a mixed solution with a total monomer mass concentration of 25-30%; then, the pH value of the solution is adjusted to 6.0-9.0, and the system temperature is lowered to 0-5°C before adding a water-soluble azo initiator and a reducing agent; nitrogen is introduced and stirred for 30-40 minutes, and then an oxidant is added, and adiabatic polymerization is carried out for 3-8 hours. After the completion of the adiabatic polymerization, granulation, hydrolysis, drying, and pulverization are performed to obtain the target polymer.

7. The preparation method according to claim 6, wherein The pH value of the solution is adjusted by sodium hydroxide and acetic acid; the pH value of the solution is 7.0-8.0; the temperature of the system is 0° C.; and the thermal insulation polymerization time is 3-6 hours.

8. The use of a high-efficiency water-controlling and oil-increasing relative permeability improver as claimed in claim 1, characterized in that: The relative permeability improver is used in the field of improving the permeability of water phase and oil phase in oil and gas field development.

9. The use according to claim 8, characterized in that The relative permeability improver injection pressure gradient growth rate is 0.09-0.42; the water phase water blocking rate is 63.27%-87.74%; and the oil phase oil blocking rate is -6.69%~-22.98%.

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