Self-repairing gel plugging agent, preparation method and application thereof

Abstract

The application discloses a self-repairing gel plugging agent which is composed of 0.3-1.2 parts of dendritic polymer, 0.2-1.2 parts of organic chromium crosslinking agent, 0.2-1.5 parts of phenolic resin crosslinking agent, 0.2-1.5 parts of reinforcing agent and 80-110 parts of water. The application further discloses a preparation method of the self-repairing gel plugging agent, which comprises the following steps: (1) synthesis of dendritic polymer; (2) preparation of self-repairing gel plugging agent: uniformly mixing formula amount of the dendritic polymer synthesized in step (1), formula amount of organic chromium crosslinking agent, formula amount of phenolic resin crosslinking agent, formula amount of reinforcing agent and formula amount of water, so as to obtain the self-repairing gel plugging agent. The application further discloses application of the self-repairing gel plugging agent as a water plugging and profile control agent for edge and bottom water thick oil reservoirs. The application has the following beneficial effects: high plugging strength, small influence of pore throat shearing, long effective plugging period and strong adaptability to reservoirs.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of heavy oil recovery, and particularly relates to a self-repairing gel plugging agent and a preparation method and application thereof. BACKGROUND

[0002] Due to sufficient energy, the exploitation of edge-bottom water heavy oil reservoirs is prone to high water cut, a large amount of water production in oil wells, and water channeling. The reservoir heterogeneity aggravates edge-bottom water coning, and the degree of water channeling is high. In addition, affected by the large difference in oil-water mobility, the high production pressure difference required for heavy oil development aggravates the dynamic heterogeneity of the reservoir, resulting in low oil saturation and high permeability in the well section, and obvious water channeling. Affected by edge-bottom water invasion, the cost of exploitation per ton of oil is high, which seriously affects the development benefit.

[0003] Too much water in oil wells not only causes huge economic waste, but also causes many other problems, such as consumption of formation energy, equipment corrosion, fouling, pump efficiency reduction, oil well mechanical failure, underground oil reservoir internal structure damage, oil-water separation technology difficulty increase, oil production economic cost substantial increase and many other problems. Because of the problem of high water cut, many production blocks with still a large amount of recoverable reserves have to be abandoned. Therefore, controlling the amount of produced water has become one of the most important goals in the oil and gas industry. For this reason, some work has been done. For example, Chinese patent application CN 102212349A discloses a micro-linear cluster water plugging agent for high water cut and low yield oil wells and an injection method. The micro-linear cluster water plugging agent for high water cut and low yield oil wells is composed of positive charge micro-linear cluster, spacer fluid and negative charge micro-linear cluster. The positive charge micro-linear cluster is a quaternary ammonium salt type polymer with a mass fraction of 0.05%-0.20%, the negative charge micro-linear cluster is a partially hydrolyzed polyacrylamide with a mass fraction of 0.05%-0.20%, the positive and negative charge micro-linear clusters are separated by a spacer fluid, and the spacer fluid is produced water. The volume ratio of the positive charge micro-linear cluster, the negative charge micro-linear cluster and the spacer fluid is 1:1:(0.3-0.5). For high water cut and low yield oil wells, the positive charge micro-linear cluster with a mass fraction of 0.05%-0.20% and the negative charge micro-linear cluster with a mass fraction of 0.05%-0.20% are injected alternately. Chinese patent application CN108625836A discloses a water control and yield increase method for high water cut oil wells in low permeability bottom water reservoirs. A nano composite high strength plugging agent and water are mixed in a mass ratio of 4-7:5; the mixture is injected into the formation under the condition of 0-90℃ to form a seal on the water outlet and the cracks; the nano composite high strength plugging agent is replaced by clear water into the oil well reservoir; the well is closed and allowed to condense; the well is opened to the bottom; the pressure is tested by a cement truck; radial hydraulic jetting fracturing is performed on the top of the reservoir sand body; and the well is opened for pumping production.

[0004] Water plugging of oil well is an important means to maintain normal production of oil well, increase sweep efficiency and improve recovery ratio in heavy oil reservoir with edge and bottom water, which has important significance for sustainable development and stable production of oilfield. Gel plugging agent can block the area with high permeability and high water saturation, prevent water permeation, so that the injected fluid can flow through the low permeability zone that has not been swept before, thereby improving oil displacement efficiency and sweep efficiency and increasing oil production. Gel plugging agent has the advantages of good injectability, high plugging strength, deep migration, low price and simple construction.

[0005] However, the traditional gel plugging agent is mainly a gel system formed by partially hydrolyzed polyacrylamide and crosslinking agent. For example, CN 102399543A discloses a preparation method of partially hydrolyzed polyacrylamide gel plugging agent. The molar ratio of chromium acid salt, reducing agent and propionic acid is 1∶(2.5-5.5)∶(8-20), the reaction temperature is 10-120℃, and the reaction time is 5-10 hours. The mass percentage of each component of the auxiliary is as follows: C2-C5 alcohol 1-8%, sulfur-containing oxygen scavenger 0.5-1.5%, polymeric polycarboxylic acid 2-8%, sodium hydroxide 30-40% and distilled water 50-60%. The reaction temperature is 50-100℃, and the reaction time is 2-5 hours. The preparation of partially hydrolyzed polyacrylamide gel plugging agent: the mass percentage of each component is as follows: partially hydrolyzed polyacrylamide 1-3%, chromium propionate crosslinking agent 0.2-0.6% and auxiliary 0.2-0.4%, and the rest is water. The auxiliary has the functions of delaying, stabilizing and adjusting pH value. Since the partially hydrolyzed polyacrylamide has poor temperature resistance, salt resistance and shear resistance, the formed gel plugging agent is easily sheared and broken during pore throat migration or when invaded by edge and bottom water, quickly loses effectiveness and has a short plugging period.

[0006] At present, the optimization of gel plugging agent by domestic and foreign scholars mainly focuses on improving the strength and temperature resistance and salt resistance, without fully considering the interaction between gel fragments and the interaction between gel plugging agent and rock wall surface, so that the plugging is quickly lost after being applied to heavy oil reservoir with edge and bottom water. Therefore, it is urgent to develop a gel plugging agent with strong adhesion to rock wall surface and self-repairing of gel fragments for heavy oil reservoir with edge and bottom water, so as to realize high-strength plugging and long-term plugging. SUMMARY

[0007] The present application discloses a self-repairing gel plugging agent, a preparation method and application thereof. The present application realizes strong adhesion to rock wall surface and self-repairing of gel fragments by strengthening the interaction between gel and rock and the internal physical action of gel, which can be used for plugging high permeability channel and inhibiting edge and bottom water invasion in the process of heavy oil reservoir with edge and bottom water.

[0008] temperature 50-120℃, permeability 500-8000×10 -3 μm 2Under the condition, the gel blocking agent has a blocking strength of 3-50 MPa / m and an apparent viscosity of 10,000-100,000 mPa·s; and the viscosity retention rate is 90% or more after high-speed shearing -1 The viscosity retention rate is 90% or more after high-speed shearing; and the formation water salinity is 0-50,000 mg / L, wherein the calcium and magnesium ions are 0-3,000 mg / L.

[0009] Technical solution: The self-repairing gel blocking agent is composed of the following components in parts by weight:

[0010] 0.3-1.2 parts of dendritic polymer;

[0011] 0.2-1.2 parts of organic chromium crosslinking agent;

[0012] 0.2-1.5 parts of phenolic resin crosslinking agent;

[0013] 0.2-1.5 parts of reinforcing agent;

[0014] 80-110 parts of water.

[0015] Further, the self-repairing gel blocking agent is composed of the following components:

[0016] 0.4-0.6 parts of dendritic polymer;

[0017] 0.5-0.8 parts of organic chromium crosslinking agent;

[0018] 0.5-1.0 parts of phenolic resin crosslinking agent;

[0019] 0.3-0.8 parts of reinforcing agent;

[0020] 85-105 parts of water.

[0021] Further, the structure of the dendritic polymer is shown in formula (1):

[0022]

[0023] wherein a, b, c, d, e, f, g, and h are any integer or decimal number in the range of 500-3,000, preferably a, b, c, d, e, f, g, and h are any integer or decimal number in the range of 1,000-2,000;

[0024] It is a polymer chain structure, and the specific structure is shown in formula (2) or formula (3) or formula (4):

[0025]

[0026]

[0027] Wherein: x is any integer or decimal number in the range of 330-12500, preferably any integer or decimal number in the range of 700-8500;

[0028] y is any integer or decimal number in the range of 300-11400, preferably any integer or decimal number in the range of 600-7600;

[0029] z is any integer or decimal number in the range of 450-17000, preferably any integer or decimal number in the range of 900-11500.

[0030] Further, the weight average molecular weight of the dendrimer is 0.8×10 6 -6×10 6 , preferably 1.6×10 6 -4.0×10 6 .

[0031] Further, the organic chromium crosslinking agent is one or more of chromium oxalate, chromium acetate, chromium citrate, chromium malonate, chromium propionate, and chromium lactate, preferably chromium lactate.

[0032] Further, the phenolic resin crosslinking agent is a water-soluble phenolic resin prepolymer, the water-soluble phenolic resin prepolymer contains phenolic structural units A and aldehyde structural units B, the phenolic structural units A are derived from one of phenol, hydroquinone, resorcinol, and catechol, the aldehyde structural units B are derived from formaldehyde, the molar ratio of the phenolic structural units A to the aldehyde structural units B in the water-soluble phenolic resin prepolymer is (0.2-0.75):1, and the weight average molecular weight of the water-soluble phenolic resin prepolymer is 10000-100000.

[0033] The phenolic resin crosslinking agent is polymerized from a phenolic compound and formaldehyde under the condition that the pH value is 8-9, wherein:

[0034] The phenolic compound is one of phenol, hydroquinone, resorcinol, and catechol;

[0035] The molar ratio of the phenolic compound to formaldehyde is 0.2-0.75;

[0036] The weight average molecular weight of the water-soluble phenolic resin prepolymer is 10000-100000.

[0037] Further, the reinforcing agent is one or more of sodium tripolyphosphate, polyphosphate ester, nano-silicon dioxide, diatomite, and tea polyphenol, preferably one of sodium tripolyphosphate and nano-silicon dioxide.

[0038] Still further, the nano-silicon dioxide is hydrophilic nano-silicon dioxide, and the median particle size D50 is 20-30 nm.

[0039] Further, the water is water with total mineralization less than 50000 mg / L.

[0040] The preparation method of the self-repairing gel plugging agent described above comprises the following steps:

[0041] (1) synthesis of dendritic polymers;

[0042] (2) preparation of self-repairing gel plugging agent:

[0043] Mixing the formula amount of the dendritic polymers synthesized in step (1), the formula amount of organic chromium crosslinking agent, the formula amount of phenolic resin crosslinking agent, the formula amount of reinforcing agent, and the formula amount of water uniformly, to obtain the self-repairing gel plugging agent.

[0044] Further, the specific steps of step (1) are as follows in terms of molar parts:

[0045] (11) Under the conditions of ice bath, nitrogen or inert gas protection, 1 part of ethylenediamine and 6-10 parts of methyl acrylate are dissolved in an appropriate amount of methanol to obtain a methanol solution of ethylenediamine and a methanol solution of methyl acrylate, respectively, the methanol solution of excess methyl acrylate is added dropwise into the methanol solution of ethylenediamine, and the reaction liquid is obtained by stirring at 20-30℃ for 10-24h, and the methanol and excess methyl acrylate are removed by distillation under reduced pressure at 40-70℃ to obtain a light yellow transparent liquid MA0.5;

[0046] (12) Under the conditions of ice bath, nitrogen or inert gas protection, an appropriate amount of the light yellow transparent liquid MA0.5 obtained in step (11) is added into an appropriate amount of methanol to obtain a methanol solution of MA0.5, then the methanol solution of excess ethylenediamine is added dropwise into the methanol solution of MA0.5 to obtain a mixed solution, and the reaction liquid is obtained by stirring at 20-30℃ for 10-24h, and the methanol and excess ethylenediamine are removed by distillation under reduced pressure at 40-70℃, then the reaction liquid is washed with petroleum ether at least once, washed with ethyl acetate at least once, and rotary evaporated to remove unreacted MA0.5, to obtain a light yellow viscous liquid MA1.0;

[0047] (13) Under the conditions of ice bath, nitrogen or inert gas protection, an appropriate amount of the light yellow viscous liquid MA1.0 obtained in step (12) is added into an appropriate amount of methanol to obtain a methanol solution of MA1.0, then the methanol solution of excess methyl acrylate is added dropwise into the methanol solution of MA1.0 to obtain a mixed solution, and the reaction liquid is obtained by stirring at 20-30℃ for 10-24h, and the methanol and excess methyl acrylate are removed by distillation under reduced pressure at 40-70℃, then the reaction liquid is washed with petroleum ether at least once, washed with ethyl acetate at least once, and rotary evaporated to remove unreacted MA1.0, to obtain a light yellow viscous liquid MA1.5;

[0048] (14) Under the condition of ice-bath, nitrogen or inert gas protection, a proper amount of the yellowish viscous liquid MA1.5 obtained in step (13) is added into a proper amount of methanol to obtain a methanol solution of MA1.5, then (Z)-3-aminoacrylamide is dissolved in a proper amount of methanol to obtain a methanol solution of (Z)-3-aminoacrylamide, then an excess amount of the methanol solution of (Z)-3-aminoacrylamide is added dropwise into the methanol solution of MA1.5 to obtain a mixed solution, the mixed solution is stirred at 20-30°C for 24-48h to obtain a reaction liquid, the reaction liquid is distilled under reduced pressure at 40-70°C to remove methanol and excess (Z)-3-aminoacrylamide, then the reaction liquid is washed with petroleum ether at least once, washed with ethyl acetate at least once, and rotary evaporated to remove unreacted MA1.5, thereby obtaining a dendritic intermediate MAZ;

[0049] (15) Under the condition of nitrogen or inert gas protection, a proper amount of the dendritic intermediate MAZ obtained in step (14) is dissolved in a proper amount of water, then p-hydroxystyrene or diethyleneglycol monovinyl ether or ethyleneglycol monovinyl ether is added, and after complete dissolution, a mixed solution A is obtained, then an initiator is added into the mixed solution A to obtain a mixed solution B, the mixed solution B is stirred at 50-80°C for 6-12h to obtain a reaction liquid, then the reaction liquid is rotary evaporated to remove water, finally the product is washed with ethanol at least three times, dried, and ground into powder, thereby obtaining a dendritic polymer.

[0050] Further, the molar ratio of ethylenediamine to methyl acrylate in step (11) is 1:(7-9);

[0051] The mass ratio of ethylenediamine to methanol in the methanol solution of ethylenediamine in step (11) is 1:(3-15), preferably 1:(8-12);

[0052] The mass ratio of methyl acrylate to methanol in the methanol solution of methyl acrylate in step (11) is 1:(1-2), preferably 1:(1-1.5).

[0053] Further, the molar ratio of ethylenediamine to MA0.5 in the mixed solution in step (12) is (20-28):1, preferably (25-27):1;

[0054] The mass ratio of MA0.5 to methanol in the methanol solution of MA0.5 in step (12) is 1:(1-2), preferably 1:(1-1.5).

[0055] Further, the mass ratio of the amount of petroleum ether to the amount of MA0.5 in step (12) is (3-15):1, preferably (8-12):1;

[0056] The mass ratio of the amount of the ethyl acetate used in step (12) to the amount of MA0.5 used in step (12) is (3-15):1, preferably (8-12):1.

[0057] Further, the molar ratio of methyl acrylate to MA1.0 in the mixture in step (13) is (14-18):1, preferably (15-17):1.

[0058] The mass ratio of MA1.0 to methanol in the methanol solution of MA1.0 in step (13) is 1:(1-2), preferably 1:(1-1.5).

[0059] Further, the mass ratio of the amount of the petroleum ether used in step (13) to the amount of MA1.0 used is (3-15):1, preferably (8-12):1.

[0060] The mass ratio of the amount of the ethyl acetate used in step (13) to the amount of MA1.0 used is (3-15):1, preferably (8-12):1.

[0061] Further, the molar ratio of (Z)-3-aminopropenamide to MA1.5 in the mixture in step (14) is (20-28):1, preferably (25-27):1.

[0062] The mass ratio of (Z)-3-aminopropenamide to methanol in the methanol solution of (Z)-3-aminopropenamide in step (14) is 1:(3-6), preferably 1:(4-5).

[0063] The mass ratio of MA1.5 to methanol in the methanol solution of MA1.5 in step (14) is 1:(1-3), preferably 1:2.

[0064] Further, the mass ratio of the amount of the petroleum ether used in step (14) to the amount of MA1.5 used is (3-15):1, preferably (8-12):1.

[0065] The mass ratio of the amount of the ethyl acetate used in step (14) to the amount of MA1.5 used is (3-15):1, preferably (8-12):1.

[0066] Further, the mass ratio of p-hydroxystyrene or diethylene glycol monovinyl ether or ethylene glycol monovinyl ether to dendritic intermediate MAZ in step (15) is 1:(3-19), preferably 1:(4-9).

[0067] In step (15), the concentration of the sum of the mass of the p-hydroxystyrene or diethylene glycol monovinyl ether or ethylene glycol monovinyl ether and the dendritic intermediate MAZ is 10-30% by weight, based on the mixed solution A.

[0068] Further, the initiator in step (15) is one of azobisisobutyronitrile, azobisisobutylamidine hydrochloride and azobisisoheptyl nitrile, preferably azobisisobutyronitrile.

[0069] In step (15), the concentration of the initiator is 0.05-0.12% by weight, based on the mixed solution B.

[0070] The self-repairing gel plugging agent is prepared by the preparation method in any one of the above.

[0071] The self-repairing gel plugging agent in any one of the above is applied as a water plugging and profile control agent for edge and bottom water thick oil reservoirs.

[0072] The dendritic polymer in the self-repairing gel plugging agent disclosed in the application has the following advantages: on the one hand, the surface of the dendritic polymer carries a large number of reactive groups, and after reacting with a crosslinking agent, the dendritic polymer can form a three-dimensional network structure of interpenetration and crosslinking; on the other hand, the functional monomers ((Z)-3-aminoacrylamide, p-hydroxystyrene or diethylene glycol monovinyl ether or ethylene glycol monovinyl ether) of the dendritic polymer carry hydroxyl groups, amide groups and ether groups, and can form multiple hydrogen bonding effects between and within the molecules; during migration in a reservoir, the gel fragments formed by shearing of pore throats can be assembled again by hydrogen bonding effects, so that the gel plugging agent is self-repaired, and the effective period of plugging is prolonged. In addition, the hydroxyl groups, amide groups and ether groups in the functional monomers can also form multiple hydrogen bonding effects with the silicon hydroxyl groups on the surface of sandstone rocks, so that the gel plugging agent has strong adhesion to hydrophilic / neutral rocks, the water plugging and profile control capacity of the gel plugging agent is further improved, and the edge and bottom water thick oil reservoirs are effectively plugged. The prepared gel plugging agent has the advantages of high plugging strength, good shearing resistance, long effective period of plugging and good adaptability to reservoirs, and has a good popularization prospect in the exploitation of edge and bottom water thick oil reservoirs.

[0073] Advantages: Compared with the prior art, the application has the following advantages:

[0074] (1) The gel plugging agent has high plugging strength, and under the conditions of a temperature of 50-120℃, a permeability of 500-8000×10 -3 μm 2 , a breakthrough pressure gradient of 3-50MPa / m and an apparent viscosity of 10000-100000mPa·s, the gel plugging agent can achieve high-strength plugging of edge and bottom water thick oil reservoirs;

[0075] (2) The gel plugging agent is less affected by pore throat shearing, and after being sheared for 10-500s -1The viscosity retention rate after high-speed shearing is 90% or more, the gel fragment self-repairing ability is strong, and long-acting plugging is realized.

[0076] (3) The gel plugging agent is suitable for formation water salinity of 0-50000 mg / L, wherein the calcium and magnesium ions are 0-3000 mg / L, and the reservoir adaptability is strong. BRIEF DESCRIPTION OF DRAWINGS

[0077] Figure 1 The flow chart of the preparation method of the self-repairing gel plugging agent disclosed in the application is shown. DETAILED DESCRIPTION

[0078] The specific embodiments of the application are described in detail below.

[0079] The reaction equation for preparing the dendritic polymer is as follows:

[0080]

[0081]

[0082] Example 1

[0083] The self-repairing gel plugging agent L1 is composed of the following substances in mass fraction:

[0084] In another embodiment, the self-repairing gel plugging agent L1' is composed of the following substances in mass fraction:

[0085]

[0086] Further, the water is formation water, the total salinity is 30000 mg / L, and the total concentration of Ca 2+ and Mg 2+ ions is 2000 mg / L.

[0087] Further, the dendritic polymer K1 has the following molecular formula:

[0088]

[0089] wherein ● is a polymer chain structure, and specifically shown in formula (2):

[0090]

[0091] wherein a, b, c, d, e, f, g, and h are all 1000, and x is 8000.

[0092] The weight average molecular weight of the dendritic polymer K1 is 2.5×10 6 .

[0093] In another embodiment, dendrimer K1', whose molecular formula is as follows:

[0094]

[0095] wherein ● is a polymer chain structure, specifically as shown in formula (2):

[0096]

[0097] wherein a, b, c, d, e, f, g, h are all 500, and x is 330.

[0098] The weight average molecular weight of the dendrimer is 0.8 x 10 6 .

[0099] In another embodiment, dendrimer K1", whose molecular formula is as follows:

[0100]

[0101] wherein ● is a polymer chain structure, specifically as shown in formula (2):

[0102]

[0103] wherein a, b, c, d, e, f, g, h are all 1000, and x is 700.

[0104] The weight average molecular weight of the dendrimer is 1.6 x 10 6 .

[0105] In another embodiment, dendrimer K1*, whose molecular formula is as follows:

[0106]

[0107] wherein ● is a polymer chain structure, specifically as shown in formula (2):

[0108]

[0109] wherein a, b, c, d, e, f, g, h are all 2000, and x is 8500.

[0110] The weight average molecular weight of the dendrimer is 4.0 x 10 6 .

[0111] In another embodiment, dendrimer K1#, whose molecular formula is as follows:

[0112]

[0113] wherein ● is a polymer chain structure, specifically as shown in formula (2) :

[0114]

[0115] wherein a, b, c, d, e, f, g, h are all 3000, and x is 12500.

[0116] The weight average molecular weight of the dendrimer is 6.0 x 10 6 .

[0117] Further, the phenolic resin crosslinking agent is a water-soluble phenolic resin prepolymer, the water-soluble phenolic resin prepolymer contains phenolic structural units A and aldehyde structural units B, the phenolic structural units A are derived from phenol, and the aldehyde structural units B are derived from formaldehyde, the molar ratio of the phenolic structural units A to the aldehyde structural units B in the water-soluble phenolic resin prepolymer is 0.2:1, and the weight average molecular weight of the water-soluble phenolic resin prepolymer is 10000.

[0118] In another embodiment, the phenolic resin crosslinking agent is a water-soluble phenolic resin prepolymer, the water-soluble phenolic resin prepolymer contains phenolic structural units A and aldehyde structural units B, the phenolic structural units A are derived from hydroquinone, and the aldehyde structural units B are derived from formaldehyde, the molar ratio of the phenolic structural units A to the aldehyde structural units B in the water-soluble phenolic resin prepolymer is 0.75:1, and the weight average molecular weight of the water-soluble phenolic resin prepolymer is 10000.

[0119] In another embodiment, the phenolic resin crosslinking agent is a water-soluble phenolic resin prepolymer, the water-soluble phenolic resin prepolymer contains phenolic structural units A and aldehyde structural units B, the phenolic structural units A are derived from m-dihydroxybenzene, and the aldehyde structural units B are derived from formaldehyde, the molar ratio of the phenolic structural units A to the aldehyde structural units B in the water-soluble phenolic resin prepolymer is 0.5:1, and the weight average molecular weight of the water-soluble phenolic resin prepolymer is 42000.

[0120] In another embodiment, the phenolic resin crosslinking agent is a water-soluble phenolic resin prepolymer, the water-soluble phenolic resin prepolymer contains phenolic structural units A and aldehyde structural units B, the phenolic structural units A are derived from m-dihydroxybenzene, and the aldehyde structural units B are derived from formaldehyde, the molar ratio of the phenolic structural units A to the aldehyde structural units B in the water-soluble phenolic resin prepolymer is 0.5:1, and the weight average molecular weight of the water-soluble phenolic resin prepolymer is 42000.

[0121] The preparation method of the self-repairing gel blocking agent L1 described above comprises the following steps:

[0122] (1) Synthesis of dendrimer K1;

[0123] (2) Preparation of self-repairing gel plugging agent:

[0124] Mixing the formula amount of the dendrimer K1 synthesized in step (1), the formula amount of chromium acetate, the formula amount of water-soluble phenolic resin prepolymer (i.e. phenolic resin crosslinking agent), the formula amount of sodium tripolyphosphate, and the formula amount of water uniformly to obtain a self-repairing gel plugging agent L1.

[0125] Further, the specific steps of step (1) are as follows in terms of mole fraction:

[0126] (11) Under the conditions of ice bath and nitrogen protection, 1 part of ethylenediamine and 6 parts of methyl acrylate are dissolved in an appropriate amount of methanol to obtain a methanol solution of ethylenediamine and a methanol solution of methyl acrylate, respectively. The methanol solution of methyl acrylate is added dropwise to the methanol solution of ethylenediamine, and the reaction is stirred at 20°C for 24h to obtain a reaction liquid. The reaction liquid is distilled at 40°C under reduced pressure to remove methanol and excess methyl acrylate, and a light yellow transparent liquid MA0.5 is obtained;

[0127] (12) Under the conditions of ice bath and nitrogen protection, an appropriate amount of the light yellow transparent liquid MA0.5 obtained in step (11) is added to an appropriate amount of methanol to obtain a methanol solution of MA0.5, and then an excess amount of the methanol solution of ethylenediamine is added dropwise to the methanol solution of MA0.5 to obtain a mixed solution. The reaction is stirred at 2°C for 24h to obtain a reaction liquid. The reaction liquid is distilled at 40°C under reduced pressure to remove methanol and excess ethylenediamine, and then washed once with petroleum ether and once with ethyl acetate, and then rotary evaporated to remove unreacted MA0.5, and a light yellow viscous liquid MA1.0 is obtained;

[0128] (13) Under the conditions of ice bath and nitrogen protection, an appropriate amount of the light yellow viscous liquid MA1.0 obtained in step (12) is added to an appropriate amount of methanol to obtain a methanol solution of MA1.0, and then an excess amount of the methanol solution of methyl acrylate is added dropwise to the methanol solution of MA1.0 to obtain a mixed solution. The reaction is stirred at 20°C for 24h to obtain a reaction liquid. The reaction liquid is distilled at 40°C under reduced pressure to remove methanol and excess methyl acrylate, and then washed once with petroleum ether and once with ethyl acetate, and then rotary evaporated to remove unreacted MA1.0, and a light yellow viscous liquid MA1.5 is obtained;

[0129] (14) Under the condition of ice-bath and nitrogen protection, a proper amount of the yellowish viscous liquid MA1.5 obtained in step (13) was added into a proper amount of methanol to obtain a methanol solution of MA1.5, then (Z)-3-aminoacrylamide was dissolved in a proper amount of methanol to obtain a methanol solution of (Z)-3-aminoacrylamide, then an excess amount of the methanol solution of (Z)-3-aminoacrylamide was added dropwise into the methanol solution of MA1.5 to obtain a mixed solution, the mixed solution was stirred at 20℃ for 48h to obtain a reaction liquid, the reaction liquid was distilled under reduced pressure at 40℃ to remove methanol and excess (Z)-3-aminoacrylamide, then the reaction liquid was washed once with petroleum ether and once with ethyl acetate, and then was rotary evaporated to remove unreacted MA1.5, thereby a dendritic intermediate MAZ was obtained;

[0130] (15) Under the condition of nitrogen protection, a proper amount of the dendritic intermediate MAZ obtained in step (14) was dissolved in a proper amount of water, then p-hydroxystyrene was added to obtain a mixed solution A, then an initiator was added into the mixed solution A to obtain a mixed solution B, the mixed solution B was stirred at 50℃ for 12h to obtain a reaction liquid, then the reaction liquid was rotary evaporated to remove water, and finally the product was washed with ethanol for 3 times, dried, and ground into powder, thereby a dendritic polymer K1 was obtained.

[0131] In another embodiment, the molar ratio of ethylenediamine to methyl acrylate in step (11) is 1:7.

[0132] Further, the mass ratio of ethylenediamine to methanol in the methanol solution of ethylenediamine in step (11) is 1:3. In another embodiment, the mass ratio of ethylenediamine to methanol in the methanol solution of ethylenediamine in step (11) is 1:8.

[0133] The mass ratio of methyl acrylate to methanol in the methanol solution of methyl acrylate in step (11) is 1:1.

[0134] Further, the molar ratio of ethylenediamine to MA0.5 in the mixed solution in step (12) is 20:1. In another embodiment, the molar ratio of ethylenediamine to MA0.5 in the mixed solution in step (12) is 25:1.

[0135] The mass ratio of MA0.5 to methanol in the methanol solution of MA0.5 in step (12) is 1:1.

[0136] Further, the mass ratio of the amount of petroleum ether to the amount of MA0.5 in step (12) is 3:1. In another embodiment, the mass ratio of the amount of petroleum ether to the amount of MA0.5 in step (12) is 8:1.

[0137] The amount of ethyl acetate used in step (12) is 3:1 by mass ratio to the amount of MA0.5 used in step (12). In another embodiment, it is preferable that the amount of ethyl acetate used in step (12) is 8:1 by mass ratio to the amount of MA0.5 used in step (12).

[0138] Further, the molar ratio of methyl acrylate to MA1.0 in the mixture in step (13) is 14:1. In another embodiment, the molar ratio of methyl acrylate to MA1.0 in the mixture in step (13) is 15:1.

[0139] Further, the molar ratio of methyl acrylate to MA1.0 in the mixture in step (13) is 14:1. In another embodiment, the molar ratio of methyl acrylate to MA1.0 in the mixture in step (13) is 15:1.

[0140] Further, the molar ratio of methyl acrylate to MA1.0 in the mixture in step (13) is 14:1. In another embodiment, the molar ratio of methyl acrylate to MA1.0 in the mixture in step (13) is 15:1.

[0141] Further, the molar ratio of methyl acrylate to MA1.0 in the mixture in step (13) is 14:1. In another embodiment, the molar ratio of methyl acrylate to MA1.0 in the mixture in step (13) is 15:1.

[0142] Further, the molar ratio of methyl acrylate to MA1.0 in the mixture in step (13) is 14:1. In another embodiment, the molar ratio of methyl acrylate to MA1.0 in the mixture in step (13) is 15:1.

[0143] Further, the molar ratio of methyl acrylate to MA1.0 in the mixture in step (13) is 14:1. In another embodiment, the molar ratio of methyl acrylate to MA1.0 in the mixture in step (13) is 15:1.

[0144] Further, the molar ratio of methyl acrylate to MA1.0 in the mixture in step (13) is 14:1. In another embodiment, the molar ratio of methyl acrylate to MA1.0 in the mixture in step (13) is 15:1.

[0145] Further, the molar ratio of methyl acrylate to MA1.0 in the mixture in step (13) is 14:1. In another embodiment, the molar ratio of methyl acrylate to MA1.0 in the mixture in step (13) is 15:1.

[0146] The mass ratio of the amount of ethyl acetate to the amount of MA1.5 in step (14) is 3:1. In another embodiment, the mass ratio of the amount of ethyl acetate to the amount of MA1.5 in step (14) is 8:1.

[0147] Further, the mass ratio of p-hydroxystyrene to dendritic intermediate MAZ in step (15) is 1:3. In another embodiment, the mass ratio of p-hydroxystyrene to dendritic intermediate MAZ in step (15) is 1:4.

[0148] In step (15), the concentration of the sum of the mass of p-hydroxystyrene and dendritic intermediate MAZ is 10% by weight, based on the mixed solution A.

[0149] Further, the initiator in step (15) is azobisisobutyronitrile.

[0150] In step (15), the concentration of the initiator is 0.05% by weight, based on the mixed solution B.

[0151] The self-repairing gel plugging agent is prepared by any one of the preparation methods described above.

[0152] The self-repairing gel plugging agent L1 described above is used as a water plugging and profile control agent for edge and bottom water thick oil reservoirs.

[0153] Example 2

[0154] The self-repairing gel plugging agent L2 consists of the following substances in mass fraction:

[0155]

[0156] In another embodiment, the self-repairing gel plugging agent L2’ consists of the following substances in mass fraction:

[0157]

[0158] Further, the water is formation water with a total salinity of 5000 mg / L, wherein the total concentration of Ca 2+ , Mg 2+ ions is 600 mg / L.

[0159] Further, the dendritic polymer K2 has the following molecular formula:

[0160]

[0161] wherein ● is a polymer chain structure, specifically as shown in the following formula (3):

[0162]

[0163] wherein a, b, c, d, e, f, g, h are all 1500, and y is 5000.

[0164] The weight average molecular weight of the dendrimer K2 is 2.95 x 10 6 .

[0165] In another embodiment, another dendrimer is substantially the same as the dendrimer K2, except that y is 300, and the weight average molecular weight of the dendrimer is 1.02 x 10 6 .

[0166] In another embodiment, another dendrimer is substantially the same as the dendrimer K2, except that y is 11400, and the weight average molecular weight of the dendrimer is 3.8 x 10 6 .

[0167] In another embodiment, another dendrimer is substantially the same as the dendrimer K2, except that y is 600, and the weight average molecular weight of the dendrimer is 1.42 x 10 6 .

[0168] In another embodiment, another dendrimer is substantially the same as the dendrimer K2, except that y is 7600, and the weight average molecular weight of the dendrimer is 3.4 x 10 6 .

[0169] Further, the water-soluble phenolic resin prepolymer contains phenolic structural units A from hydroquinone and aldehyde structural units B from formaldehyde, the molar ratio of the phenolic structural units A to the aldehyde structural units B in the water-soluble phenolic resin prepolymer is 0.3:1, and the weight average molecular weight of the water-soluble phenolic resin prepolymer is 18000.

[0170] Further, the median particle size D50 of the hydrophilic nano-silica is 20 nm. In another embodiment, the median particle size D50 of the hydrophilic nano-silica is 30 nm. In another embodiment, the median particle size D50 of the hydrophilic nano-silica is 25 nm.

[0171] The preparation method of the self-repairing gel plugging agent L2 described above comprises the following steps:

[0172] (1) synthesis of a dendrimer;

[0173] (2) preparation of the self-repairing gel plugging agent L2:

[0174] Mixing the formula amount of the dendrimer K2 synthesized in step (1), the formula amount of the organic chromium crosslinking agent, the formula amount of the phenolic resin crosslinking agent, the formula amount of the reinforcing agent, and the formula amount of water uniformly, a self-repairing gel plugging agent L2 is obtained.

[0175] Further, the specific steps of step (1) are as follows in terms of mole parts:

[0176] (11) Under ice bath and helium atmosphere, 1 part of ethylenediamine and 10 parts of methyl acrylate are dissolved in appropriate amount of methanol to obtain a methanol solution of ethylenediamine and a methanol solution of methyl acrylate, respectively. The methanol solution of methyl acrylate is added dropwise into the methanol solution of ethylenediamine, and the mixture is stirred at 30°C for 10 hours to obtain a reaction liquid. The reaction liquid is distilled at 70°C under reduced pressure to remove methanol and excess methyl acrylate, and a light yellow transparent liquid MA0.5 is obtained;

[0177] (12) Under ice bath and helium atmosphere, appropriate amount of the light yellow transparent liquid MA0.5 obtained in step (11) is added into appropriate amount of methanol to obtain a methanol solution of MA0.5, and then excess methanol solution of ethylenediamine is added dropwise into the methanol solution of MA0.5 to obtain a mixture. The mixture is stirred at 30°C for 10 hours to obtain a reaction liquid. The reaction liquid is distilled at 70°C under reduced pressure to remove methanol and excess ethylenediamine, and then washed with petroleum ether for 3 times, washed with ethyl acetate for 3 times, and rotary evaporated to remove unreacted MA0.5, and a light yellow viscous liquid MA1.0 is obtained;

[0178] (13) Under ice bath and helium atmosphere, appropriate amount of the light yellow viscous liquid MA1.0 obtained in step (12) is added into appropriate amount of methanol to obtain a methanol solution of MA1.0, and then excess methanol solution of methyl acrylate is added dropwise into the methanol solution of MA1.0 to obtain a mixture. The mixture is stirred at 30°C for 10 hours to obtain a reaction liquid. The reaction liquid is distilled at 70°C under reduced pressure to remove methanol and excess methyl acrylate, and then washed with petroleum ether for 3 times, washed with ethyl acetate for 3 times, and rotary evaporated to remove unreacted MA1.0, and a light yellow viscous liquid MA1.5 is obtained;

[0179] (14) under ice-bath, under helium, a proper amount of the yellowish viscous liquid MA1.5 obtained in step (13) was added into a proper amount of methanol to obtain a methanol solution of MA1.5, then (Z)-3-aminoprop-2-enoic amide was dissolved in a proper amount of methanol to obtain a methanol solution of (Z)-3-aminoprop-2-enoic amide, then a proper amount of the methanol solution of (Z)-3-aminoprop-2-enoic amide was added dropwise into the methanol solution of MA1.5 to obtain a mixed solution, the mixed solution was stirred at 30°C for 24h to obtain a reaction liquid, the reaction liquid was distilled under reduced pressure at 70°C to remove methanol and excess (Z)-3-aminoprop-2-enoic amide, then the reaction liquid was washed with petroleum ether for 3 times, washed with ethyl acetate for 3 times, and rotary evaporated to remove unreacted MA1.5, thus a dendritic intermediate MAZ was obtained;

[0180] (15) under helium, a proper amount of the dendritic intermediate MAZ obtained in step (14) was dissolved in a proper amount of water, then diethylene glycol monovinyl ether was added to obtain a mixed solution A, then an initiator was added into the mixed solution A to obtain a mixed solution B, the mixed solution B was stirred at 80°C for 6h to obtain a reaction liquid, then the reaction liquid was rotary evaporated to remove water, finally the product was washed with ethanol for 5 times, dried, and ground into powder, thus a dendritic polymer K2 was obtained.

[0181] In another embodiment, the molar ratio of ethylenediamine to methyl acrylate in step (11) is 1:9.

[0182] Further, the mass ratio of ethylenediamine to methanol in the methanol solution of ethylenediamine in step (11) is 1:15. In another embodiment, the mass ratio of ethylenediamine to methanol in the methanol solution of ethylenediamine in step (11) is 1:12.

[0183] Further, the mass ratio of methyl acrylate to methanol in the methanol solution of methyl acrylate in step (11) is 1:2.

[0184] Further, the molar ratio of ethylenediamine to MA0.5 in the mixed solution in step (12) is 28:1. In another embodiment, the molar ratio of ethylenediamine to MA0.5 in the mixed solution in step (12) is 27:1.

[0185] The mass ratio of MA0.5 to methanol in the methanol solution of MA0.5 in step (12) is 1:2.

[0186] Further, the mass ratio of the amount of petroleum ether to the amount of MA0.5 in step (12) is 15:1. In another embodiment, the mass ratio of the amount of petroleum ether to the amount of MA0.5 in step (12) is 12:1.

[0187] The mass ratio of the amount of ethyl acetate used in step (12) to the amount of MA0.5 used in step (12) is 15:1. In another embodiment, the mass ratio of the amount of ethyl acetate used in step (12) to the amount of MA0.5 used in step (12) is 12:1.

[0188] Further, the molar ratio of methyl acrylate to MA1.0 in the mixture in step (13) is 18:1. In another embodiment, the molar ratio of methyl acrylate to MA1.0 in the mixture in step (13) is 17:1.

[0189] Further, the mass ratio of the amount of methyl acrylate used in step (13) to the amount of MA1.0 used in step (13) is 15:1. In another embodiment, the mass ratio of the amount of methyl acrylate used in step (13) to the amount of MA1.0 used in step (13) is 12:1.

[0190] Further, the mass ratio of the amount of methyl acrylate used in step (13) to the amount of MA1.0 used in step (13) is 15:1. In another embodiment, the mass ratio of the amount of methyl acrylate used in step (13) to the amount of MA1.0 used in step (13) is 12:1.

[0191] Further, the mass ratio of the amount of methyl acrylate used in step (13) to the amount of MA1.0 used in step (13) is 15:1. In another embodiment, the mass ratio of the amount of methyl acrylate used in step (13) to the amount of MA1.0 used in step (13) is 12:1.

[0192] Further, the molar ratio of (Z)-3-aminoacrylamide to MA1.5 in the mixture in step (14) is 28:1. In another embodiment, the molar ratio of (Z)-3-aminoacrylamide to MA1.5 in the mixture in step (14) is 27:1.

[0193] Further, the mass ratio of the amount of methyl acrylate used in step (13) to the amount of MA1.0 used in step (13) is 15:1. In another embodiment, the mass ratio of the amount of methyl acrylate used in step (13) to the amount of MA1.0 used in step (13) is 12:1.

[0194] Further, the mass ratio of the amount of methyl acrylate used in step (13) to the amount of MA1.0 used in step (13) is 15:1. In another embodiment, the mass ratio of the amount of methyl acrylate used in step (13) to the amount of MA1.0 used in step (13) is 12:1.

[0195] Further, the mass ratio of the amount of methyl acrylate used in step (13) to the amount of MA1.0 used in step (13) is 15:1. In another embodiment, the mass ratio of the amount of methyl acrylate used in step (13) to the amount of MA1.0 used in step (13) is 12:1.

[0196] The mass ratio of the amount of ethyl acetate to the amount of MA1.5 in step (14) is 15:1. In another embodiment, the mass ratio of the amount of ethyl acetate to the amount of MA1.5 in step (14) is 12:1.

[0197] Further, the mass ratio of diethylene glycol monovinyl ether to dendritic intermediate MAZ in step (15) is 1:19. In another embodiment, the mass ratio of diethylene glycol monovinyl ether to dendritic intermediate MAZ in step (15) is 1:9.

[0198] In step (15), the concentration of the sum of the mass of diethylene glycol monovinyl ether and dendritic intermediate MAZ, based on the mixed solution A, is 30% by weight.

[0199] Further, the initiator in step (15) is azobisdimethylamidine hydrochloride.

[0200] In step (15), the concentration of the initiator, based on the mixed solution B, is 0.12% by weight.

[0201] The self-repairing gel plugging agent L2 is prepared by any one of the preparation methods described above.

[0202] The self-repairing gel plugging agent L2 described in any one of the above is used as a water plugging and profile control agent for edge and bottom water thick oil reservoirs.

[0203] Example 3

[0204] The self-repairing gel plugging agent L3 is composed of the following substances in mass fraction:

[0205]

[0206]

[0207] In another embodiment, the self-repairing gel plugging agent L3' is composed of the following substances in mass fraction:

[0208]

[0209] Further, the water is formation water with a total salinity of 50000 mg / L, wherein the total concentration of Ca 2+ , Mg 2+ ions is 3000 mg / L.

[0210] The dendritic polymer K3 has the following molecular formula:

[0211]

[0212] Wherein ● is a polymer chain structure, and is specifically as follows:

[0213]

[0214] Wherein, a, b, c, d, e, f, g, h are all 2000, and z is 3000.

[0215] The weight average molecular weight of the dendrimer K3 is 3.3×10 6 .

[0216] In another embodiment, another dendrimer is substantially the same as the dendrimer K3, and the only difference is that z is 450, and the weight average molecular weight of the dendrimer is 1.87×10 6 .

[0217] In another embodiment, another dendrimer is substantially the same as the dendrimer K3, and the only difference is that z is 17000, and the weight average molecular weight of the dendrimer is 5.4×10 6 .

[0218] In another embodiment, another dendrimer is substantially the same as the dendrimer K3, and the only difference is that z is 900, and the weight average molecular weight of the dendrimer is 2.49×10 6 .

[0219] In another embodiment, another dendrimer is substantially the same as the dendrimer K3, and the only difference is that z is 11500, and the weight average molecular weight of the dendrimer is 4.32×10 6 .

[0220] Further, the water-soluble phenolic resin prepolymer contains phenolic structural units A and aldehyde structural units B, the phenolic structural units A are from resorcinol, and the aldehyde structural units B are from formaldehyde, the molar ratio of the phenolic structural units A to the aldehyde structural units B in the water-soluble phenolic resin prepolymer is 0.5:1, and the weight average molecular weight of the water-soluble phenolic resin prepolymer is 60000.

[0221] The preparation method of the self-repairing gel plugging agent L3 described above comprises the following steps:

[0222] (1) Synthesis of the dendrimer K3;

[0223] (2) Preparation of the self-repairing gel plugging agent L3:

[0224] Mixing the formula amount of the dendrimer K3 synthesized in step (1), the formula amount of the organic chromium crosslinking agent, the formula amount of the phenolic resin crosslinking agent, the formula amount of the reinforcing agent, and the formula amount of water uniformly, and the self-repairing gel plugging agent L3 is obtained.

[0225] Further, the specific steps of step (1) are as follows in terms of mole fraction:

[0226] (11) Under ice-bath and argon atmosphere, 1 part of ethylenediamine and 8 parts of methyl acrylate were dissolved in appropriate amount of methanol to obtain a methanol solution of ethylenediamine and a methanol solution of methyl acrylate respectively, the methanol solution of methyl acrylate was added dropwise into the methanol solution of ethylenediamine, and the reaction was stirred at 25°C for 15h to obtain a reaction liquid, and the reaction liquid was distilled at 50°C under reduced pressure to remove methanol and excess methyl acrylate, thereby obtaining a light yellow transparent liquid MA0.5;

[0227] (12) Under ice-bath and argon atmosphere, appropriate amount of the light yellow transparent liquid MA0.5 obtained in step (11) was added into appropriate amount of methanol to obtain a methanol solution of MA0.5, and then excess methanol solution of ethylenediamine was added dropwise into the methanol solution of MA0.5 to obtain a mixed liquid, and the reaction was stirred at 25°C for 16h to obtain a reaction liquid, and the reaction liquid was distilled at 55°C under reduced pressure to remove methanol and excess ethylenediamine, and then washed with petroleum ether twice, washed with ethyl acetate twice, and rotary evaporated to remove unreacted MA0.5, thereby obtaining a light yellow viscous liquid MA1.0;

[0228] (13) Under ice-bath and argon atmosphere, appropriate amount of the light yellow viscous liquid MA1.0 obtained in step (12) was added into appropriate amount of methanol to obtain a methanol solution of MA1.0, and then excess methanol solution of methyl acrylate was added dropwise into the methanol solution of MA1.0 to obtain a mixed liquid, and the reaction was stirred at 25°C for 16h to obtain a reaction liquid, and the reaction liquid was distilled at 55°C under reduced pressure to remove methanol and excess methyl acrylate, and then washed with petroleum ether twice, washed with ethyl acetate twice, and rotary evaporated to remove unreacted MA1.0, thereby obtaining a light yellow viscous liquid MA1.5;

[0229] (14) Under ice-bath and argon atmosphere, appropriate amount of the light yellow viscous liquid MA1.5 obtained in step (13) was added into appropriate amount of methanol to obtain a methanol solution of MA1.5, and then (Z)-3-aminopropenamide was dissolved in appropriate amount of methanol to obtain a methanol solution of (Z)-3-aminopropenamide, and then excess methanol solution of (Z)-3-aminopropenamide was added dropwise into the methanol solution of MA1.5 to obtain a mixed liquid, and the reaction was stirred at 25°C for 36h to obtain a reaction liquid, and the reaction liquid was distilled at 55°C under reduced pressure to remove methanol and excess (Z)-3-aminopropenamide, and then washed with petroleum ether twice, washed with ethyl acetate twice, and rotary evaporated to remove unreacted MA1.5, thereby obtaining a dendritic intermediate MAZ;

[0230] (15) under argon, a proper amount of the dendritic intermediate MAZ obtained in step (14) is dissolved in a proper amount of water, then ethylene glycol monovinyl ether is added, after complete dissolution, a mixed solution A is obtained, then an initiator is added to the mixed solution A to obtain a mixed solution B, the mixed solution B is stirred at 60°C for 8h to obtain a reaction solution, then the reaction solution is rotary evaporated to remove water, finally the product is washed with ethanol for 4 times, dried, ground into powder, thus a dendritic polymer K3 is obtained.

[0231] The mass ratio of ethylenediamine to methanol in the methanol solution of ethylenediamine in step (11) is 1:10;

[0232] The mass ratio of methyl acrylate to methanol in the methanol solution of methyl acrylate in step (11) is 1.5.

[0233] Further, in the mixed solution in step (12), the molar ratio of ethylenediamine to MA0.5 is 26:1;

[0234] The mass ratio of MA0.5 to methanol in the methanol solution of MA0.5 in step (12) is 1:1.5.

[0235] Further, in step (12), the mass ratio of the amount of petroleum ether to the amount of MA0.5 is 10:1;

[0236] The mass ratio of the amount of ethyl acetate to the amount of MA0.5 in step (12) is 10:1.

[0237] Further, in the mixed solution in step (13), the molar ratio of methyl acrylate to MA1.0 is 16:1;

[0238] The mass ratio of MA1.0 to methanol in the methanol solution of MA1.0 in step (13) is 1:1.5.

[0239] Further, in step (13), the mass ratio of the amount of petroleum ether to the amount of MA1.0 is 10:1;

[0240] The mass ratio of the amount of ethyl acetate to the amount of MA1.0 in step (13) is 10:1.

[0241] Further, in the mixed solution in step (14), the molar ratio of (Z)-3-aminopropenamide to MA1.5 is 26:1;

[0242] The mass ratio of (Z)-3-aminopropenamide to methanol in the methanol solution of (Z)-3-aminopropenamide in step (14) is 1:4.5;

[0243] The mass ratio of MA1.5 to methanol in the methanol solution of MA1.5 in step (14) is 1:2.

[0244] Further, the mass ratio of the amount of petroleum ether to the amount of MA1.5 in step (14) is 10:1.

[0245] The mass ratio of the amount of ethyl acetate to the amount of MA1.5 in step (14) is 10:1.

[0246] Further, the mass ratio of ethylene glycol monovinyl ether to dendritic intermediate MAZ in step (15) is 1:7.

[0247] In step (15), the concentration of the sum of the mass of ethylene glycol monovinyl ether and dendritic intermediate MAZ, based on the mixed solution A, is 20% by weight.

[0248] Further, the initiator in step (15) is azobisisoheptane nitrile.

[0249] In step (15), the concentration of the initiator, based on the mixed solution B, is 0.1% by weight.

[0250] The self-repairing gel plugging agent L3 is prepared by any one of the preparation methods described above.

[0251] The self-repairing gel plugging agent L3 described above is used as a water plugging and profile control agent for edge and bottom water thick oil reservoirs.

[0252] Examples 4-9

[0253] The same as Example 1, except that the organic chromium crosslinking agent is different:

[0254]

[0255]

[0256] Examples 10-14

[0257] The same as Example 1, except that the reinforcing agent is different:

[0258]

[0259] Performance evaluation of self-repairing gel plugging agents L1, L2 and L3

[0260] Test Example 1

[0261] The water used in this experiment is produced water R from a block in Shengli Oilfield, the reservoir temperature is 63℃, and the total mineralization is 19880mg / L, of which Ca 2+1714mg / L, Mg 2+ 283mg / L.

[0262] The self-repairing gel plugging agent L1, the self-repairing gel plugging agent L2, the self-repairing gel plugging agent L3 prepared in examples 1-3 and the commercial gel plugging agents RD-1, RD-2 were placed in an oven at 63℃, and their gelation time, elastic modulus, breakthrough pressure gradient and water plugging rate were evaluated.

[0263] The determination method refers to Q / SH10201493-2019 "Performance index and test method of gel type water plugging and profile control agent".

[0264] The self-repairing gel plugging agent L1, the self-repairing gel plugging agent L2, the self-repairing gel plugging agent L3 prepared in examples 1-3 and the commercial gel plugging agents RD-1, RD-2 were evaluated for shear resistance, and the determination method was as follows: using a rheometer, the apparent viscosity μ0 of the gel plugging agent was first determined under a shear rate of 7.2s -1 , then the gel plugging agent was sheared for 100s under a shear rate of 50s -1 or 500s -1 , and finally the viscosity μ1 of the gel plugging agent after shearing was determined under a shear rate of 7.2s -1 . The viscosity retention rate was calculated as (μ0-μ1) / μ0*100%. The test results are shown in Table 1.

[0265] Table 1 Performance test results of the self-repairing gel plugging agents L1, L2, L3 and the commercial gel plugging agents RD-1, RD-2

[0266] Gel blocking agent L1 L2 L3 RD-1 RD-2 Gelation time, h 56 38 18 24 18 Elastic modulus, Pa 8.6 13.4 24.8 5.4 4.7 Breakthrough pressure gradient, MPa / m 9.1 17.5 34.6 4.5 3.8 Water blocking rate, % 99.3 99.5 99.6 99.2 98.7 Apparent viscosity, mPa-s 17050 36500 87800 8650 6770 After 50 s -1 Shear viscosity retention, % after 95.4 96.8 98.8 62 48 After 500 s -1 Shear viscosity retention, % after 91.7 94.6 96.5 23 15

[0267] According to the above evaluation results, the self-repairing gel plugging agent L1, the self-repairing gel plugging agent L2, the self-repairing gel plugging agent L3 of the present application have good gelation performance, plugging performance and shear resistance at reservoir temperature.

[0268] At reservoir temperature, the self-repairing gel plugging agent L1, the self-repairing gel plugging agent L2, the self-repairing gel plugging agent L3 of the present application have a gelation time of 18-56h, an elastic modulus of 8.6-24.8Pa and a breakthrough pressure gradient of 9.1-34.6MPa / m, while the commercial gel plugging agents RD-1, RD-2 have a gelation time comparable to that of the self-repairing gel plugging agents L2, L3, but the elastic modulus is less than 6Pa and the breakthrough pressure gradient is less than 5MPa / m, and the plugging strength is significantly lower than that of the present application.

[0269] The water plugging rate of the self-repairing gel plugging agent L1, the self-repairing gel plugging agent L2, the self-repairing gel plugging agent L3 of the present application is greater than 99%, and the water plugging rates of the commercial gel plugging agents RD-1, RD-2 are 99.2% and 98.7% respectively, and the water plugging rates of the several plugging agents are comparable.​

[0270] The apparent viscosity of the self-repairing gel plugging agent L1, the self-repairing gel plugging agent L2 and the self-repairing gel plugging agent L3 is 17050-87800 mPa·s, while the apparent viscosity of the commercial gel plugging agent RD-1 and RD-2 is less than 10000 mPa·s, which is obviously lower than that of the present application.

[0271] The self-repairing gel plugging agent L1, the self-repairing gel plugging agent L2 and the self-repairing gel plugging agent L3 of the present application have a viscosity retention rate of more than 90% after shearing for 50 s -1 , 500 s -1 , while the viscosity retention rate of the commercial gel plugging agent RD-1 and RD-2 is 48-62% after shearing for 50 s -1 , and 15-23% after shearing for 500 s -1 , which is obviously lower than that of the present application.

[0272] The self-repairing gel plugging agent L1, the self-repairing gel plugging agent L2 and the self-repairing gel plugging agent L3 of the present application all meet the requirements of oil fields, and have excellent comprehensive performance compared with the commercial gel plugging agent, which can meet the requirements of plugging and adjusting in the edge and bottom water heavy oil reservoir.

[0273] The above has described the embodiments of the present application in detail. However, the present application is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the spirit of the present application.

Claims

1. A self-healing gel plug characterized in that, 0.3-1.2 parts of dendritic polymer by weight; 0.2-1.2 parts of organic chromium crosslinking agent by weight; 0.2-1.5 parts of phenolic resin crosslinking agent by weight; 0.2-1.5 parts of reinforcing agent by weight; 80-110 parts of water by weight, wherein: The structure of the dendritic polymer is shown in formula (1): Wherein: a, b, c, d, e, f, g, h are each an integer or decimal number in the range of 500-3000; is a polymer chain structure, and its specific structure is shown in formula (2) or formula (3) or formula (4): x is any integer or decimal number in the range of 330-12500; y is any integer or decimal number in the range of 300-11400; z is any integer or decimal number in the range of 450-17000; The reinforcing agent is one or more of sodium tripolyphosphate, polyphosphate ester, nano-silicon dioxide, diatomite, and tea polyphenol.

2. The self-healing gel plug of claim 1, wherein, The composition comprises: 0.4-0.6 parts of dendritic polymer by weight; 0.5-0.8 parts of organic chromium crosslinking agent by weight; 0.5-1.0 parts of phenolic resin crosslinking agent by weight; 0.3-0.8 parts of reinforcing agent by weight; 85-105 parts of water by weight.

3. The self-healing gel plug of claim 1, wherein, The structure of the dendritic polymer is shown in formula (1): a, b, c, d, e, f, g, and h are any integer or decimal number in the range of 1000-2000; is a polymer chain structure, and its specific structure is shown in formula (2) or formula (3) or formula (4): x is any integer or decimal number in the range of 700-8500; y is any integer or decimal number in the range of 600-7600; z is any integer or decimal number in the range of 900-11500.

4. The self-healing gel plug of claim 1, wherein, The reinforcing agent is one of sodium tripolyphosphate and nano-silicon dioxide.

5. The self-healing gel plug of claim 1, wherein, The weight average molecular weight of the dendrimer is 0.8 x 10 6 -6 x 10 6 .

6. The self-healing gel plug of claim 5, wherein, The weight average molecular weight of the dendrimer is 1.6 x 10 6 -4.0 x 10 6 .

7. The self-healing gel plug of claim 1, wherein, The organic chromium crosslinking agent is one or more of chromium oxalate, chromium acetate, chromium citrate, chromium malonate, chromium propionate, and chromium lactate.

8. The self-healing gel plug of claim 7, wherein, The organic chromium crosslinking agent is chromium lactate.

9. The self-healing gel plug of claim 1, wherein, The phenolic resin crosslinking agent is a water-soluble phenolic resin prepolymer, which contains phenolic structural units A and aldehyde structural units B. The phenolic structural units A are derived from one of phenol, p-dihydroxybenzene, m-dihydroxybenzene, and o-dihydroxybenzene, and the aldehyde structural units B are derived from formaldehyde. The molar ratio of the phenolic structural units A to the aldehyde structural units B in the water-soluble phenolic resin prepolymer is (0.2-0.75):1, and the weight average molecular weight of the water-soluble phenolic resin prepolymer is 10000-100000.

10. The self-healing gel plug of claim 1, wherein, The nano-silicon dioxide is hydrophilic nano-silicon dioxide with a median particle size D50 of 20-30 nm.

11. The self-healing gel plug of claim 1, wherein, The water is water with a total mineralization degree of less than 50000 mg / L.

12. A method of preparing a self-healing gel plug according to any one of claims 1 to 11, characterized in that, The method comprises the following steps: (1) synthesis of dendritic polymer; (2) preparation of self-repairing gel plugging agent: Mix the formula amount of the dendritic polymer synthesized in step (1), the formula amount of the organic chromium crosslinking agent, the formula amount of the phenolic resin crosslinking agent, the formula amount of the reinforcing agent, and the formula amount of water uniformly to obtain the self-repairing gel plugging agent.

13. The method of claim 12, wherein the self-healing gel plug is prepared by, The specific steps of step (1) are as follows: (11) under the conditions of ice-bath, protection of nitrogen or inert gas, 1 part of ethylenediamine and 6-10 parts of methyl acrylate are dissolved in appropriate amount of methanol respectively to obtain methanolic solution of ethylenediamine and methanolic solution of methyl acrylate, the methanolic solution of methyl acrylate is added dropwise into the methanolic solution of ethylenediamine, the reaction is carried out at 20-30℃ for 10-24 hours to obtain reaction liquid, the reaction liquid is distilled under reduced pressure at 40-70℃ to remove methanol and excess methyl acrylate, and a light yellow transparent liquid MA0.5 is obtained; (12) under the conditions of ice-bath, protection of nitrogen or inert gas, appropriate amount of light yellow transparent liquid MA0.5 obtained in step (11) is added into appropriate amount of methanol to obtain methanolic solution of MA0.5, then the methanolic solution of excess ethylenediamine is added dropwise into the methanolic solution of MA0.5 to obtain a mixed solution, the reaction is carried out at 20-30℃ for 10-24 hours to obtain reaction liquid, the reaction liquid is distilled under reduced pressure at 40-70℃ to remove methanol and excess ethylenediamine, then the reaction liquid is washed with petroleum ether at least once, washed with ethyl acetate at least once, and rotary evaporated to remove unreacted MA0.5, and a light yellow viscous liquid MA1.0 is obtained; (13) under the conditions of ice-bath, protection of nitrogen or inert gas, appropriate amount of light yellow viscous liquid MA1.0 obtained in step (12) is added into appropriate amount of methanol to obtain methanolic solution of MA1.0, then the methanolic solution of excess methyl acrylate is added dropwise into the methanolic solution of MA1.0 to obtain a mixed solution, the reaction is carried out at 20-30℃ for 10-24 hours to obtain reaction liquid, the reaction liquid is distilled under reduced pressure at 40-70℃ to remove methanol and excess methyl acrylate, then the reaction liquid is washed with petroleum ether at least once, washed with ethyl acetate at least once, and rotary evaporated to remove unreacted MA1.0, and a light yellow viscous liquid MA1.5 is obtained; (14) under the conditions of ice-bath, protection of nitrogen or inert gas, appropriate amount of light yellow viscous liquid MA1.5 obtained in step (13) is added into appropriate amount of methanol to obtain methanolic solution of MA1.5, then (Z)-3-aminopropenamide is dissolved in appropriate amount of methanol to obtain methanolic solution of (Z)-3-aminopropenamide, then the methanolic solution of excess (Z)-3-aminopropenamide is added dropwise into the methanolic solution of MA1.5 to obtain a mixed solution, the reaction is carried out at 20-30℃ for 24-48 hours to obtain reaction liquid, the reaction liquid is distilled under reduced pressure at 40-70℃ to remove methanol and excess (Z)-3-aminopropenamide, then the reaction liquid is washed with petroleum ether at least once, washed with ethyl acetate at least once, and rotary evaporated to remove unreacted MA1.5, and a dendritic intermediate MAZ is obtained; (15) Under the condition of nitrogen or inert gas protection, a proper amount of the dendritic intermediate MAZ obtained in step (14) is dissolved in a proper amount of water, then p-hydroxystyrene or diethylene glycol monovinyl ether or ethylene glycol monovinyl ether is added, a mixed solution A is obtained after complete dissolution, then an initiator is added to the mixed solution A to obtain a mixed solution B, the mixed solution B is stirred at 50-80℃ for 6-12h to obtain a reaction solution, then the reaction solution is rotary evaporated to remove water, finally the product is washed with ethanol for at least 3 times, dried, ground into powder, and a dendritic polymer is obtained.

14. The method of claim 13, wherein the self-healing gel plug is prepared by, The molar ratio of the ethylenediamine to the methyl acrylate in step (11) is 1:(7-9); The mass ratio of the ethylenediamine to the methanol in the methanol solution of the ethylenediamine in step (11) is 1:(3-15); The mass ratio of the methyl acrylate to the methanol in the methanol solution of the methyl acrylate in step (11) is 1:(1-2).

15. The method of claim 14, wherein the self-healing gel plug is prepared by, The mass ratio of the ethylenediamine to the methanol in the methanol solution of the ethylenediamine in step (11) is 1:(8-12); The mass ratio of the methyl acrylate to the methanol in the methanol solution of the methyl acrylate in step (11) is 1:(1-1.5).

16. The method of claim 13, wherein the self-healing gel plug is prepared by, The molar ratio of the ethylenediamine to the MA0.5 in the mixed solution in step (12) is (20-28):1; The mass ratio of the MA0.5 to the methanol in the methanol solution of the MA0.5 in step (12) is 1:(1-2); The mass ratio of the petroleum ether to the MA0.5 in step (12) is (3-15):1; The mass ratio of the ethyl acetate to the MA0.5 in step (12) is (3-15):

1.

17. The method of claim 16, wherein the self-healing gel plug is prepared by, The molar ratio of the ethylenediamine to the MA0.5 in the mixed solution in step (12) is (25-27):1; The mass ratio of the MA0.5 to the methanol in the methanol solution of the MA0.5 in step (12) is 1:(1-1.5); The mass ratio of the petroleum ether to the MA0.5 in step (12) is (8-12):1; The mass ratio of the ethyl acetate to the MA0.5 in step (12) is (8-12):

1.

18. The method of claim 13, wherein the self-healing gel plug is prepared by, The molar ratio of the methyl acrylate to the MA1.0 in the mixed solution in step (13) is (14-18):1; The mass ratio of the MA1.0 to the methanol in the methanol solution of the MA1.0 in step (13) is 1:(1-2); The mass ratio of the petroleum ether to the MA1.0 in step (13) is (3-15):1; The mass ratio of the ethyl acetate to the MA1.0 in step (13) is (3-15):

1.

19. The method of claim 18, wherein the self-healing gel plug is prepared by, The molar ratio of the methyl acrylate to the MA1.0 in the mixed solution in step (13) is (15-17):1; The mass ratio of the MA1.0 to the methanol in the methanol solution of the MA1.0 in step (13) is 1:(1-1.5); The mass ratio of the petroleum ether to the MA1.0 in step (13) is (8-12):1; The mass ratio of the ethyl acetate to the MA1.0 in step (13) is (8-12):

1.

20. The method of claim 13, wherein the self-healing gel plug is prepared by, The molar ratio of (Z)-3-aminoacrylamide to MA1.5 in the mixed solution in step (14) is (20-28):1; The mass ratio of (Z)-3-aminoacrylamide to methanol in the methanol solution of (Z)-3-aminoacrylamide in step (14) is 1:(3-6); The mass ratio of MA1.5 to methanol in the methanol solution of MA1.5 in step (14) is 1:(1-3); The mass ratio of the petroleum ether to the MA1.5 in step (14) is (3-15):1; The mass ratio of the ethyl acetate to the MA1.5 in step (14) is (3-15):

1.

21. The method of making a self-healing gel plug according to claim 20, wherein, The molar ratio of (Z)-3-aminoacrylamide to MA1.5 in the mixed solution in step (14) is (25-27):1; The mass ratio of (Z)-3-aminoacrylamide to methanol in the methanol solution of (Z)-3-aminoacrylamide in step (14) is 1:(4-5); The mass ratio of MA1.5 to methanol in the methanol solution of MA1.5 in step (14) is 1:2; The mass ratio of the petroleum ether to the MA1.5 in step (14) is (8-12):1; The mass ratio of the ethyl acetate to the MA1.5 in step (14) is (8-12):

1.

22. The method of claim 13, wherein the self-healing gel plug is prepared by, The mass ratio of the p-hydroxystyrene or diethylene glycol monovinyl ether or ethylene glycol monovinyl ether to the dendritic intermediate MAZ in step (15) is 1:(3-19); The concentration of the sum of the mass of the p-hydroxystyrene or diethylene glycol monovinyl ether or ethylene glycol monovinyl ether and the dendritic intermediate MAZ in step (15) is 10-30% by weight based on the mixed solution A; The initiator in step (15) is one of azobisisobutyronitrile, azobisisobutyramidine hydrochloride and azobisisoheptyl nitrile; The concentration of the initiator in step (15) is 0.05-0.12% by weight based on the mixed solution B.

23. The method of claim 22, wherein the self-healing gel plug is prepared by, The mass ratio of the p-hydroxystyrene or diethylene glycol monovinyl ether or ethylene glycol monovinyl ether to the dendritic intermediate MAZ in step (15) is 1:(4-9); The initiator in step (15) is azobisisobutyronitrile.

24. A self-healing gel plug characterized in that, Prepared by the preparation method of any one of claims 12-23.

25. The use of the self-repairing gel plugging agent of any one of claims 1-11 and 24 as a water plugging and profile control agent for edge and bottom water thick oil reservoirs.

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