Self-repairing gel plugging agent as well as preparation method and application thereof

Abstract

The invention discloses a self-repairing gel plugging agent, which is composed of the following components: 0.3-1.2 parts of a dendritic polymer; 0.2 to 1.2 parts of an organic chromium cross-linking agent; 0.2 to 1.5 parts of a phenolic resin cross-linking agent; 0.2 to 1.5 parts of a reinforcing agent; and 80 to 110 parts of water. The invention also discloses a preparation method of the self-repairing gel plugging agent. The preparation method comprises the following steps: (1) synthesizing the dendritic polymer; and (2) preparation of the self-repairing gel plugging agent: uniformly mixing the dendritic polymer synthesized in the step (1) according to the formula ratio, the organic chromium cross-linking agent according to the formula ratio, the phenolic resin cross-linking agent according to the formula ratio, the reinforcing agent according to the formula ratio and the water according to the formula ratio to obtain the self-repairing gel plugging agent. The invention further discloses application of the self-repairing gel plugging agent as a water plugging and profile control agent for the edge-bottom water heavy oil reservoir. The invention has the following beneficial effects: the plugging strength is high; the influence of pore throat shearing is small, and the plugging validity period is long; the oil reservoir adaptability is high.

Description

Technical Field

[0001] The invention belongs to the field of heavy oil exploitation, and particularly relates to a self-repairing gel plugging agent and a preparation method and application thereof. Background Art

[0002] Due to the sufficient energy, the heavy oil reservoir with edge and bottom water is prone to high water content during exploitation, and the oil wells produce a large amount of water, resulting in water channeling. The heterogeneity of the reservoir exacerbates the cone advance of edge and bottom water, and the degree of water channeling is high. In addition, due to the large difference in oil and water mobility, the high production pressure difference required for heavy oil development exacerbates the dynamic heterogeneity of the reservoir, resulting in obvious water channeling in the well sections with low oil saturation and high permeability. Affected by the invasion of edge and bottom water, the cost of producing a ton of oil is high, which seriously affects its development benefits.

[0003] Excessive water production in oil wells not only causes huge economic waste, but also causes many other problems, such as consumption of formation energy, equipment corrosion, scaling, reduced pump efficiency, mechanical failure of oil wells, damage to the internal structure of underground oil layers, increased difficulty in oil-water separation technology, and a significant increase in the economic cost of oil production. Because of the high water content problem, many production blocks that still have 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 of the oil and gas industry. To this end, some work has been done. For example, Chinese invention patent application CN 102212349A discloses a micro-coil water plugging agent and injection method for high-water-content, low-yield oil wells. A micro-coil plugging agent for high-water-content low-yield oil wells, comprising positively charged micro-coils, spacer fluid and negatively charged micro-coils, wherein the positively charged micro-coils are quaternary ammonium salt polymers with a mass fraction of 0.05%-0.20%, the negatively charged micro-coils are partially hydrolyzed polyacrylamide with a mass fraction of 0.05%-0.20%, the positively charged micro-coils and the negatively charged micro-coils are separated by spacer fluid, the spacer fluid is produced water, and the volume ratio of the positively charged micro-coils to the spacer fluid is 1:1:(0.3-0.5). For high-water-content low-yield oil wells, positively charged micro-coils with a mass fraction of 0.05%-0.20% and negatively charged micro-coils with a mass fraction of 0.05%-0.20% are alternately injected. Chinese invention patent application CN108625836A discloses a method for controlling water and increasing production in high-water-content oil wells in low-permeability bottom-water reservoirs, comprising the steps of mixing a nano-composite high-strength plugging agent and clean water in a mass ratio of 4-7:5; injecting the mixture into the formation at 0-90°C to plug water outlets and cracks; using clean water to balance and displace the nano-composite high-strength plugging agent into the oil well reservoir; shutting down the well to wait for setting; dredging the well to the bottom of the well; testing the pressure with a cement truck; performing radial hydraulic jet fracturing on the top of the reservoir sand body; and opening the well for pumping and production.

[0004] Water plugging in oil wells is an important means to maintain normal production of oil wells, increase sweep coefficient and improve recovery rate in edge and bottom water heavy oil reservoirs. It is of great significance to the sustainable development and stable production of oil fields. Gel plugging agents can plug areas with high formation permeability and high water saturation, prevent water penetration, and allow injected fluids to flow through low permeability zones that were not swept before, thereby improving oil recovery efficiency and sweep efficiency and increasing oil production. Gel plugging agents have 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 a crosslinking agent, such as the Chinese invention patent application CN 102399543A discloses a method for preparing a partially hydrolyzed polyacrylamide gel plugging agent, wherein the molar ratio of chromate: reducing agent: propionic acid is 1: (2.5-5.5): (8-20), the reaction temperature is 10-120°C, and the reaction time is 5-10 hours; the components of the auxiliary agent are, by mass percentage, 1-8% of C2-C5 alcohol, 0.5-1.5% of sulfur-containing oxygen scavenger, 2-8% of polycarboxylic acid, 30-40% of sodium hydroxide and 50-60% of distilled water, the reaction temperature is 50-100°C, and the reaction time is 2-5 hours; the preparation of the partially hydrolyzed polyacrylamide gel plugging agent: the components are, by mass percentage, 1-3% of partially hydrolyzed polyacrylamide, 0.2-0.6% of chromium propionate cross-linking agent and 0.2-0.4% of auxiliary agent, and the rest is water; the auxiliary agent has delaying property, stability and pH value regulating effect. Since partially hydrolyzed polyacrylamide has poor heat and salt resistance and shear resistance, the resulting gel plugging agent is easily sheared and broken during pore throat migration or when invaded by edge and bottom water, resulting in rapid failure and a short effective period of plugging.

[0006] At present, the optimization of gel plugging agents by relevant scholars at home and abroad mainly focuses on improving strength and temperature and salt resistance, without fully considering the interaction between gel fragments and the interaction between gel plugging agents and rock walls. After being applied to edge bottom water heavy oil reservoirs, the plugging fails quickly. Therefore, for edge bottom water heavy oil reservoirs, it is urgent to develop gel plugging agents that can strongly adhere to the rock wall and self-repair gel fragments to achieve high-strength plugging and long-term plugging. Summary of the invention

[0007] Purpose of the invention: In view of the deficiencies of the above-mentioned prior art, the present invention discloses a self-repairing gel plugging agent and its preparation method and application. The present invention achieves strong adhesion on the rock wall and self-repair of gel fragments by strengthening the interaction between gel and rock and the physical action inside the gel. It can be used to block high-permeability channels and inhibit the invasion of bottom water in the process of exploitation of bottom water heavy oil reservoirs.

[0008] Temperature 50-120℃, permeability 500-8000×10 -3 μm 2Under the following conditions, the gel plugging agent has a plugging strength of 3-50MPa / m and an apparent viscosity of 10000-100000mPa·s; after 10-500s -1 The viscosity retention rate after high-speed shearing is more than 90%; it is applicable to formation water with a mineralization of 0-50000mg / L, including 0-3000mg / L of calcium and magnesium ions.

[0009] Technical solution: The self-repairing gel plugging agent is composed of the following components 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 enhancer;

[0014] 80-110 parts water.

[0015] Further, it 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 enhancer;

[0020] 85-105 parts water.

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

[0022]

[0023] Wherein: a, b, c, d, e, f, g, h are any integer or decimal in the range of 500-3000, preferably a, b, c, d, e, f, g, h are any integer or decimal in the range of 1000-2000;

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

[0025]

[0026]

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

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

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

[0030] Furthermore, the weight average molecular weight of the dendritic polymer is 0.8×10 6 -6×10 6 , preferably 1.6×10 6 -4.0×10 6 .

[0031] Furthermore, the organic chromium cross-linking agent is one or more of chromium oxalate, chromium acetate, chromium citrate, chromium malonate, chromium propionate, and chromium lactate, preferably chromium lactate.

[0032] Furthermore, the phenolic resin crosslinking agent is a water-soluble phenolic resin prepolymer, which contains a phenolic structural unit A and an aldehyde structural unit B, wherein the phenolic structural unit A is derived from one of phenol, hydroquinone, resorcinol, and catechol, and the aldehyde structural unit B is derived from formaldehyde. In the water-soluble phenolic resin prepolymer, the molar ratio of the phenolic structural unit A to the aldehyde structural unit B 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 by phenolic compounds and formaldehyde at a pH value of 8-9, wherein:

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

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

[0036] The weight average molecular weight of the water-soluble phenolic resin prepolymer is 10,000-100,000.

[0037] Furthermore, the enhancer is one or more of sodium tripolyphosphate, polyphosphate, nano-silicon dioxide, diatomaceous earth, and tea polyphenols, preferably one of sodium tripolyphosphate and nano-silicon dioxide.

[0038] Furthermore, the nano-silica is hydrophilic nano-silica, and the median particle size D50 is 20-30nm.

[0039] Furthermore, the water has a total mineralization of less than 50,000 mg / L.

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

[0041] (1) Synthesis of dendrimers;

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

[0043] The dendritic polymer synthesized in step (1) is mixed evenly with a formula amount of an organic chromium crosslinking agent, a formula amount of a phenolic resin crosslinking agent, a formula amount of a reinforcing agent, and a formula amount of water to obtain a self-repairing gel plugging agent.

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

[0045] (11) In an ice bath, nitrogen or inert gas protection conditions, 1 part of ethylenediamine and 6-10 parts of methyl acrylate are dissolved in appropriate amounts of methanol to obtain a methanol solution of ethylenediamine and a methanol solution of methyl acrylate, respectively; an excess of the methanol solution of methyl acrylate is added dropwise to the methanol solution of ethylenediamine; the mixture is stirred and reacted at 20-30° C. for 10-24 h to obtain a reaction solution; the reaction solution is subjected to reduced pressure distillation at 40-70° C. to remove methanol and excess methyl acrylate, to obtain a light yellow transparent liquid MA0.5;

[0046] (12) In an ice bath, nitrogen or inert gas protection conditions, add an appropriate amount of the light yellow transparent liquid MA0.5 obtained in step (11) to an appropriate amount of methanol to obtain a methanol solution of MA0.5, then dropwise add an excess of the methanol solution of ethylenediamine to the methanol solution of MA0.5 to obtain a mixed solution, stir and react at 20-30° C. for 10-24 hours to obtain a reaction solution, distill the reaction solution under reduced pressure at 40-70° C. to remove methanol and excess ethylenediamine, wash with petroleum ether at least once, then wash with ethyl acetate at least once, and rotary evaporate to remove unreacted MA0.5 to obtain a light yellow viscous liquid MA1.0;

[0047] (13) In an ice bath, nitrogen or inert gas protection conditions, add an appropriate amount of the light yellow viscous liquid MA1.0 obtained in step (12) to an appropriate amount of methanol to obtain a methanol solution of MA1.0, then add an excess amount of the methanol solution of methyl acrylate dropwise to the methanol solution of MA1.0 to obtain a mixed solution, stir and react at 20-30° C. for 10-24 h to obtain a reaction solution, distill the reaction solution under reduced pressure at 40-70° C. to remove methanol and excess methyl acrylate, wash with petroleum ether at least once, then wash with ethyl acetate at least once, and rotary evaporate to remove unreacted MA1.0 to obtain a light yellow viscous liquid MA1.5;

[0048] (14) In an ice bath, nitrogen or inert gas protection conditions, add an appropriate amount of the light yellow viscous liquid MA1.5 obtained in step (13) to an appropriate amount of methanol to obtain a methanol solution of MA1.5, then dissolve (Z)-3-aminoacrylamide in an appropriate amount of methanol to obtain a methanol solution of (Z)-3-aminoacrylamide, then add an excess of the methanol solution of (Z)-3-aminoacrylamide dropwise to the methanol solution of MA1.5 to obtain a mixed solution, stir and react at 20-30° C. for 24-48 hours to obtain a reaction solution, distill the reaction solution under reduced pressure at 40-70° C. to remove methanol and excess (Z)-3-aminoacrylamide, wash with petroleum ether at least once, then wash with ethyl acetate at least once, and remove unreacted MA1.5 by rotary evaporation to obtain a dendritic intermediate MAZ;

[0049] (15) Under nitrogen or inert gas protection conditions, an appropriate amount of the dendritic intermediate MAZ obtained in step (14) is dissolved in an appropriate amount of water, and then p-hydroxystyrene or diethylene glycol monovinyl ether or ethylene glycol monovinyl ether is added to obtain a mixed solution A after complete dissolution, and then an initiator is added to the mixed solution A to obtain a mixed solution B, and the mixed solution B is stirred and reacted at 50-80° C. for 6-12 h to obtain a reaction solution, and then the reaction solution is evaporated to remove water, and finally the product is washed with ethanol at least 3 times, dried, and ground into powder to obtain a dendritic polymer.

[0050] Furthermore, 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 described 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 described in step (11) is 1:(1-2), preferably 1:(1-1.5).

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

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

[0055] Furthermore, the mass ratio of the amount of petroleum ether in step (12) 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 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] Furthermore, the molar ratio of methyl acrylate to MA1.0 in the mixed solution 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 described in step (13) is 1:(1-2), preferably 1:(1-1.5).

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

[0061] Furthermore, the molar ratio of (Z)-3-aminoacrylamide to MA1.5 in the mixed solution in step (14) is (20-28):1, preferably (25-27):1;

[0062] The mass ratio of (Z)-3-aminoacrylamide to methanol in the methanol solution of (Z)-3-aminoacrylamide 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 described in step (14) is 1:(1-3), preferably 1:2.

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

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

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

[0068] Furthermore, the initiator described in step (15) is one of azobisisobutyronitrile, azobisisobutyramidine hydrochloride, and azobisisoheptylonitrile, preferably azobisisobutyronitrile.

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

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

[0071] Application of any one of the above-mentioned self-repairing gel plugging agents as water plugging and profile control agents in edge-bottom water heavy oil reservoirs.

[0072] The dendritic polymer in the self-repairing gel plugging agent disclosed in the present invention, on the one hand, has a large number of reactive groups on its surface, and after reacting with a cross-linking agent, it can form an interpenetrating three-dimensional network structure. On the other hand, the functional monomers of the dendritic polymer ((Z)-3-aminoacrylamide, p-hydroxystyrene or diethylene glycol monovinyl ether or ethylene glycol monovinyl ether) have hydroxyl groups, amide groups, and ether groups, and multiple hydrogen bonds can be formed between molecules and within molecules. During the migration of the reservoir, the gel fragments formed by the pore throat shearing effect can be assembled and aggregated by hydrogen bonding to achieve self-repair of the gel plugging agent and improve the effective period of plugging. In addition, the hydroxyl groups, amide groups, ether groups, etc. in the functional monomers can also form multiple hydrogen bonds with the silicon hydroxyl groups on the surface of the sandstone rock, increase the effect of the gel plugging agent on the hydrophilic / neutral rock, achieve strong adhesion of the gel plugging agent, further improve the water plugging and profile control capabilities, and effectively plug the edge bottom water heavy oil reservoir. The prepared gel plugging agent has the advantages of high plugging strength, good shear resistance, long plugging validity period, good reservoir adaptability, etc., and has good promotion prospects in the exploitation process of edge and bottom water heavy oil reservoirs.

[0073] Beneficial effects: Compared with the prior art, the present invention has the following beneficial effects:

[0074] (1) The gel plugging agent has high plugging strength at a temperature of 50-120°C and a permeability of 500-8000×10 -3 μm 2 Under the following conditions, the breakthrough pressure gradient of the gel plugging agent is 3-50MPa / m, and the apparent viscosity is 10000-100000mPa·s, achieving high-strength plugging of edge-bottom water heavy oil reservoirs;

[0075] (2) The gel plugging agent is less affected by pore throat shear and lasts for 10-500 seconds. -1The viscosity retention rate after high-speed shearing is more than 90%, and the gel fragments have strong self-repairing ability, achieving long-term plugging;

[0076] (3) The gel plugging agent is suitable for formation water with a mineralization of 0-50000 mg / L, including 0-3000 mg / L of calcium and magnesium ions, and has strong adaptability to oil reservoirs. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

[0080]

[0081]

[0082] Example 1

[0083] Self-repairing gel plugging agent L1, by mass, is composed of the following substances:

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

[0085]

[0086] Furthermore, the water is formation water with a total mineralization of 30,000 mg / L, of which Ca 2+ Mg 2+ The total ion concentration is 2000 mg / L.

[0087] Furthermore, the molecular formula of the dendritic polymer K1 is as follows:

[0088]

[0089] Where ● is the polymer chain structure, as shown in formula (2):

[0090]

[0091] Among them, 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, the dendrimer K1' has the following molecular formula:

[0094]

[0095] Where ● is the polymer chain structure, as shown in formula (2):

[0096]

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

[0098] The weight average molecular weight of the dendritic polymer is 0.8×10 6 .

[0099] In another embodiment, the dendrimer K1″ has the following molecular formula:

[0100]

[0101] Where ● is the polymer chain structure, as shown in formula (2):

[0102]

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

[0104] The weight average molecular weight of the dendritic polymer is 1.6×10 6 .

[0105] In another embodiment, the dendrimer K1* has the following molecular formula:

[0106]

[0107] Where ● is the polymer chain structure, as shown in formula (2):

[0108]

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

[0110] The weight average molecular weight of the dendritic polymer is 4.0×10 6 .

[0111] In another embodiment, the dendritic polymer K1# has the following molecular formula:

[0112]

[0113] Where ● is the polymer chain structure, as shown in formula (2):

[0114]

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

[0116] The weight average molecular weight of the dendritic polymer is 6.0×10 6 .

[0117] Furthermore, the phenolic resin crosslinking agent is a water-soluble phenolic resin prepolymer, which contains a phenolic structural unit A and an aldehyde structural unit B, wherein the phenolic structural unit A comes from phenol and the aldehyde structural unit B comes from formaldehyde. In the water-soluble phenolic resin prepolymer, the molar ratio of the phenolic structural unit A to the aldehyde structural unit B is 0.2:1, and the weight average molecular weight of the water-soluble phenolic resin prepolymer is 10,000.

[0118] In another embodiment, the phenolic resin crosslinker is a water-soluble phenolic resin prepolymer, which contains a phenolic structural unit A and an aldehyde structural unit B, wherein the phenolic structural unit A is derived from hydroquinone, and the aldehyde structural unit B is derived from formaldehyde. In the water-soluble phenolic resin prepolymer, the molar ratio of the phenolic structural unit A to the aldehyde structural unit B is 0.75:1, and the weight average molecular weight of the water-soluble phenolic resin prepolymer is 10,000.

[0119] In another embodiment, the phenolic resin crosslinker is a water-soluble phenolic resin prepolymer, which contains a phenolic structural unit A and an aldehyde structural unit B, wherein the phenolic structural unit A is derived from resorcinol, and the aldehyde structural unit B is derived from formaldehyde. In the water-soluble phenolic resin prepolymer, the molar ratio of the phenolic structural unit A to the aldehyde structural unit B is 0.5:1, and the weight average molecular weight of the water-soluble phenolic resin prepolymer is 42,000.

[0120] In another embodiment, the phenolic resin crosslinker is a water-soluble phenolic resin prepolymer, which contains a phenolic structural unit A and an aldehyde structural unit B, wherein the phenolic structural unit A is derived from catechol, and the aldehyde structural unit B is derived from formaldehyde. In the water-soluble phenolic resin prepolymer, the molar ratio of the phenolic structural unit A to the aldehyde structural unit B is 0.75:1, and the weight average molecular weight of the water-soluble phenolic resin prepolymer is 100,000.

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

[0122] (1) Synthesis of dendrimer K1;

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

[0124] The dendritic polymer K1 synthesized in step (1) is mixed uniformly with a formulated amount of chromium acetate, a formulated amount of water-soluble phenolic resin prepolymer (i.e., phenolic resin crosslinking agent), a formulated amount of sodium tripolyphosphate, and a formulated amount of water to obtain a self-repairing gel plugging agent L1.

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

[0126] (11) In an ice bath and under nitrogen protection, 1 part of ethylenediamine and 6 parts of methyl acrylate were dissolved in appropriate amounts of methanol to obtain a methanol solution of ethylenediamine and a methanol solution of methyl acrylate, respectively. An excess amount of the methanol solution of methyl acrylate was added dropwise to the methanol solution of ethylenediamine. The mixture was stirred and reacted at 20° C. for 24 h to obtain a reaction solution. The reaction solution was subjected to reduced pressure distillation at 40° C. to remove methanol and excess methyl acrylate, to obtain a light yellow transparent liquid MA0.5.

[0127] (12) In an ice bath and under nitrogen protection, add an appropriate amount of the light yellow transparent liquid MA0.5 obtained in step (11) to an appropriate amount of methanol to obtain a methanol solution of MA0.5, then add an excess amount of the methanol solution of ethylenediamine dropwise to the methanol solution of MA0.5 to obtain a mixed solution, stir and react at 2° C. for 24 h to obtain a reaction solution, perform reduced pressure distillation on the reaction solution at 40° C. to remove methanol and excess ethylenediamine, wash once with petroleum ether, then wash once with ethyl acetate, and perform rotary evaporation to remove unreacted MA0.5 to obtain a light yellow viscous liquid MA1.0;

[0128] (13) In an ice bath and under nitrogen protection, add an appropriate amount of the light yellow viscous liquid MA1.0 obtained in step (12) to an appropriate amount of methanol to obtain a methanol solution of MA1.0, then add an excess amount of the methanol solution of methyl acrylate dropwise to the methanol solution of MA1.0 to obtain a mixed solution, stir and react at 20° C. for 24 h to obtain a reaction solution, distill the reaction solution under reduced pressure at 40° C. to remove methanol and excess methyl acrylate, wash once with petroleum ether, then wash once with ethyl acetate, and rotary evaporate to remove unreacted MA1.0 to obtain a light yellow viscous liquid MA1.5;

[0129] (14) In an ice bath and under nitrogen protection, an appropriate amount of the light yellow viscous liquid MA1.5 obtained in step (13) is added to an appropriate amount of methanol to obtain a methanol solution of MA1.5, and then (Z)-3-aminoacrylamide is dissolved in an appropriate amount of methanol to obtain a methanol solution of (Z)-3-aminoacrylamide, and then an excess amount of the methanol solution of (Z)-3-aminoacrylamide is added dropwise to the methanol solution of MA1.5 to obtain a mixed solution, and the mixture is stirred for reaction at 20° C. for 48 h to obtain a reaction solution, and the reaction solution is subjected to reduced pressure distillation at 40° C. to remove methanol and excess (Z)-3-aminoacrylamide, and the reaction solution is washed once with petroleum ether, and then washed once with ethyl acetate, and unreacted MA1.5 is removed by rotary evaporation to obtain a dendritic intermediate MAZ;

[0130] (15) Under nitrogen protection, an appropriate amount of the dendritic intermediate MAZ obtained in step (14) is dissolved in an appropriate amount of water, and then p-hydroxystyrene 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 and reacted at 50° C. for 12 h to obtain a reaction solution. The reaction solution is then evaporated to remove water. Finally, the product is washed with ethanol three times, dried, and ground into powder to obtain a dendritic polymer K1.

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

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

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

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

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

[0137] The mass ratio of the amount of ethyl acetate used in step (12) to the amount of MA0.5 used in step (12) is 3: 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 preferably 8: 1.

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

[0139] The mass ratio of MA1.0 to methanol in the methanol solution of MA1.0 described in step (13) is 1:1.

[0140] Furthermore, the mass ratio of the amount of petroleum ether used in step (13) to the amount of MA1.0 used is 3: 1. In another embodiment, the mass ratio of the amount of petroleum ether used in step (13) to the amount of MA1.0 used is 8: 1.

[0141] The mass ratio of the amount of ethyl acetate used in step (13) to the amount of MA1.0 used is 3:1. In another embodiment, the mass ratio of the amount of ethyl acetate used in step (13) to the amount of MA1.0 used is 8:1.

[0142] Furthermore, the molar ratio of (Z)-3-aminoacrylamide to MA1.5 in the mixed solution in step (14) is 20: 1. In another embodiment, the molar ratio of (Z)-3-aminoacrylamide to MA1.5 in the mixed solution in step (14) is 25:1.

[0143] The mass ratio of (Z)-3-aminoacrylamide to methanol in the methanol solution of (Z)-3-aminoacrylamide in step (14) is 1:3. In another embodiment, the mass ratio of (Z)-3-aminoacrylamide to methanol in the methanol solution of (Z)-3-aminoacrylamide in step (14) is 1:4.

[0144] The mass ratio of MA1.5 to methanol in the methanol solution of MA1.5 described in step (14) is 1:1.

[0145] Furthermore, the mass ratio of the amount of petroleum ether used in step (14) to the amount of MA1.5 used is 3: 1. In another embodiment, the mass ratio of the amount of petroleum ether used in step (14) to the amount of MA1.5 used is 8: 1.

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

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

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

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

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

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

[0152] Application of the self-repairing gel plugging agent L1 described in any one of the above as a water plugging and profile control agent for edge-bottom water heavy oil reservoirs.

[0153] Example 2

[0154] Self-repairing gel plugging agent L2, by mass, is composed of the following substances:

[0155]

[0156] In another embodiment, the self-repairing gel plugging agent L2', by weight, is composed of the following substances:

[0157]

[0158] Furthermore, the water is formation water with a total mineralization of 5000 mg / L, of which Ca 2+ Mg 2+ Total ion concentration: 600 mg / L.

[0159] Furthermore, the molecular formula of the dendritic polymer K2 is as follows:

[0160]

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

[0162]

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

[0164] The weight average molecular weight of the dendritic polymer K2 is 2.95×10 6 .

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

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

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

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

[0169] Furthermore, the water-soluble phenolic resin prepolymer contains a phenolic structural unit A and an aldehyde structural unit B, wherein the phenolic structural unit A comes from hydroquinone, and the aldehyde structural unit B comes from formaldehyde. In the water-soluble phenolic resin prepolymer, the molar ratio of the phenolic structural unit A to the aldehyde structural unit B is 0.3:1, and the weight average molecular weight of the water-soluble phenolic resin prepolymer is 18,000.

[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 comprises the following steps:

[0172] (1) Synthesis of dendrimers;

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

[0174] The dendritic polymer K2 synthesized in step (1) is mixed evenly with a formulated amount of an organic chromium crosslinking agent, a formulated amount of a phenolic resin crosslinking agent, a formulated amount of a reinforcing agent, and a formulated amount of water to obtain a self-repairing gel plugging agent L2.

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

[0176] (11) In an ice bath and under helium gas, 1 part of ethylenediamine and 10 parts of methyl acrylate were dissolved in appropriate amounts of methanol to obtain a methanol solution of ethylenediamine and a methanol solution of methyl acrylate, respectively. An excess amount of the methanol solution of methyl acrylate was added dropwise to the methanol solution of ethylenediamine, and the mixture was stirred at 30° C. for 10 h to obtain a reaction solution. The reaction solution was subjected to reduced pressure distillation at 70° C. to remove methanol and excess methyl acrylate, and a light yellow transparent liquid MA0.5 was obtained.

[0177] (12) In an ice bath and with helium flowing, add an appropriate amount of the light yellow transparent liquid MA0.5 obtained in step (11) to an appropriate amount of methanol to obtain a methanol solution of MA0.5, then add an excess amount of the methanol solution of ethylenediamine dropwise to the methanol solution of MA0.5 to obtain a mixed solution, stir and react at 30° C. for 10 h to obtain a reaction solution, perform reduced pressure distillation on the reaction solution at 70° C. to remove methanol and excess ethylenediamine, wash with petroleum ether 3 times, then wash with ethyl acetate 3 times, and perform rotary evaporation to remove unreacted MA0.5 to obtain a light yellow viscous liquid MA1.0;

[0178] (13) In an ice bath and with helium flowing, add an appropriate amount of the light yellow viscous liquid MA1.0 obtained in step (12) to an appropriate amount of methanol to obtain a methanol solution of MA1.0, then add an excess amount of the methanol solution of methyl acrylate dropwise to the methanol solution of MA1.0 to obtain a mixed solution, stir and react at 30° C. for 10 h to obtain a reaction solution, distill the reaction solution under reduced pressure at 70° C. to remove methanol and excess methyl acrylate, wash the reaction solution three times with petroleum ether, then wash it three times with ethyl acetate, and rotary evaporate to remove unreacted MA1.0 to obtain a light yellow viscous liquid MA1.5;

[0179] (14) In an ice bath and under the flow of helium, an appropriate amount of the light yellow viscous liquid MA1.5 obtained in step (13) is added to an appropriate amount of methanol to obtain a methanol solution of MA1.5, and then (Z)-3-aminoacrylamide is dissolved in an appropriate amount of methanol to obtain a methanol solution of (Z)-3-aminoacrylamide, and then an excess amount of the methanol solution of (Z)-3-aminoacrylamide is added dropwise to the methanol solution of MA1.5 to obtain a mixed solution, and the mixture is stirred and reacted at 30° C. for 24 hours to obtain a reaction solution, and the reaction solution is subjected to reduced pressure distillation at 70° C. to remove methanol and excess (Z)-3-aminoacrylamide, and the reaction solution is washed with petroleum ether three times, and then washed with ethyl acetate three times, and then rotary evaporated to remove unreacted MA1.5, thereby obtaining a dendritic intermediate MAZ;

[0180] (15) Under helium, an appropriate amount of the dendritic intermediate MAZ obtained in step (14) is dissolved in an appropriate amount of water, and then diethylene glycol monovinyl ether is added to obtain a mixed solution A 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 and reacted at 80° C. for 6 h to obtain a reaction solution. The reaction solution is then evaporated to remove water. Finally, the product is washed with ethanol 5 times, dried, and ground into powder to obtain the dendritic polymer K2.

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

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

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

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

[0186] Furthermore, the mass ratio of the amount of petroleum ether 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 petroleum ether used in step (12) to the amount of MA0.5 used 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] Furthermore, the molar ratio of methyl acrylate to MA1.0 in the mixed solution described in step (13) is 18: 1. In another embodiment, the molar ratio of methyl acrylate to MA1.0 in the mixed solution described in step (13) is 17:1.

[0189] The mass ratio of MA1.0 to methanol in the methanol solution of MA1.0 described in step (13) is 1:2. In another embodiment, the mass ratio of MA1.0 to methanol in the methanol solution of MA1.0 described in step (13) is 1:1.5.

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

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

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

[0193] The mass ratio of (Z)-3-aminoacrylamide to methanol in the methanol solution of (Z)-3-aminoacrylamide in step (14) is 1:6. In another embodiment, the mass ratio of (Z)-3-aminoacrylamide to methanol in the methanol solution of (Z)-3-aminoacrylamide in step (14) is 1:5.

[0194] The mass ratio of MA1.5 to methanol in the methanol solution of MA1.5 described in step (14) is 1:3.

[0195] Furthermore, the mass ratio of the amount of petroleum ether used in step (14) to the amount of MA1.5 used is 15: 1. In another embodiment, the mass ratio of the amount of petroleum ether used in step (14) to the amount of MA1.5 used is 12:1.

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

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

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

[0199] Furthermore, the initiator in step (15) is azobisisobutyramidine hydrochloride.

[0200] In step (15), based on the mixed solution B, the initiator concentration 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] Application of the self-repairing gel plugging agent L2 described in any one of the above as a water plugging and profile control agent for edge-bottom water heavy oil reservoirs.

[0203] Example 3

[0204] Self-repairing gel plugging agent L3, by mass, is composed of the following substances:

[0205]

[0206]

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

[0208]

[0209] Furthermore, the water is formation water with a total mineralization of 50,000 mg / L, of which Ca 2+ Mg 2+ Total ion concentration: 3000mg / L.

[0210] The molecular formula of the dendritic polymer K3 is as follows:

[0211]

[0212] Where ● is the polymer chain structure, as follows:

[0213]

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

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

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

[0217] In another embodiment, another dendritic polymer is substantially the same as the dendritic polymer K3, except that z is 17,000 and the weight average molecular weight of the dendritic polymer is 5.4×10 6 .

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

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

[0220] Furthermore, the water-soluble phenolic resin prepolymer contains a phenolic structural unit A and an aldehyde structural unit B, wherein the phenolic structural unit A comes from resorcinol, and the aldehyde structural unit B comes from formaldehyde. In the water-soluble phenolic resin prepolymer, the molar ratio of the phenolic structural unit A to the aldehyde structural unit B is 0.5:1, and the weight average molecular weight of the water-soluble phenolic resin prepolymer is 60,000.

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

[0222] (1) Synthesis of dendrimer K3;

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

[0224] The dendritic polymer K3 synthesized in step (1) is mixed evenly with a formulated amount of an organic chromium crosslinking agent, a formulated amount of a phenolic resin crosslinking agent, a formulated amount of a reinforcing agent, and a formulated amount of water to obtain a self-repairing gel plugging agent L3.

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

[0226] (11) In an ice bath and under argon, 1 part of ethylenediamine and 8 parts of methyl acrylate were dissolved in appropriate amounts of methanol to obtain a methanol solution of ethylenediamine and a methanol solution of methyl acrylate, respectively. An excess amount of the methanol solution of methyl acrylate was added dropwise to the methanol solution of ethylenediamine, and the mixture was stirred for reaction at 25° C. for 15 h to obtain a reaction solution. The reaction solution was subjected to reduced pressure distillation at 50° C. to remove methanol and excess methyl acrylate, to obtain a light yellow transparent liquid MA0.5.

[0227] (12) In an ice bath and with argon gas, add an appropriate amount of the light yellow transparent liquid MA0.5 obtained in step (11) to an appropriate amount of methanol to obtain a methanol solution of MA0.5, then add an excess amount of the methanol solution of ethylenediamine dropwise to the methanol solution of MA0.5 to obtain a mixed solution, stir and react at 25° C. for 16 h to obtain a reaction solution, perform reduced pressure distillation on the reaction solution at 55° C. to remove methanol and excess ethylenediamine, wash twice with petroleum ether, then wash twice with ethyl acetate, and perform rotary evaporation to remove unreacted MA0.5 to obtain a light yellow viscous liquid MA1.0;

[0228] (13) In an ice bath and with argon gas, add an appropriate amount of the light yellow viscous liquid MA1.0 obtained in step (12) to an appropriate amount of methanol to obtain a methanol solution of MA1.0, then add an excess amount of the methanol solution of methyl acrylate dropwise to the methanol solution of MA1.0 to obtain a mixed solution, stir and react at 25° C. for 16 h to obtain a reaction solution, distill the reaction solution under reduced pressure at 55° C. to remove methanol and excess methyl acrylate, wash the reaction solution twice with petroleum ether, then wash it twice with ethyl acetate, and remove unreacted MA1.0 by rotary evaporation to obtain a light yellow viscous liquid MA1.5;

[0229] (14) In an ice bath and with argon, add an appropriate amount of the light yellow viscous liquid MA1.5 obtained in step (13) to an appropriate amount of methanol to obtain a methanol solution of MA1.5, then dissolve (Z)-3-aminoacrylamide in an appropriate amount of methanol to obtain a methanol solution of (Z)-3-aminoacrylamide, then add an excess of the methanol solution of (Z)-3-aminoacrylamide dropwise to the methanol solution of MA1.5 to obtain a mixed solution, stir and react at 25° C. for 36 hours to obtain a reaction solution, distill the reaction solution under reduced pressure at 55° C. to remove methanol and excess (Z)-3-aminoacrylamide, wash twice with petroleum ether, then wash twice with ethyl acetate, and remove unreacted MA1.5 by rotary evaporation to obtain a dendritic intermediate MAZ;

[0230] (15) Under argon, an appropriate amount of the dendritic intermediate MAZ obtained in step (14) is dissolved in an appropriate amount of water, and then ethylene glycol monovinyl ether is added to obtain a mixed solution A 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 and reacted at 60° C. for 8 h to obtain a reaction solution. The reaction solution is then evaporated to remove water. Finally, the product is washed with ethanol four times, dried, and ground into powder to obtain a dendritic polymer K3.

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

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

[0233] Furthermore, in the mixed solution described 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 described in step (12) is 1:1.5.

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

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

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

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

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

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

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

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

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

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

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

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

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

[0248] Furthermore, the initiator in step (15) is azobisisoheptanonitrile.

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

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

[0251] Application of the self-repairing gel plugging agent L3 described in any one of the above as a water plugging and profile control agent for edge-bottom water heavy oil reservoirs.

[0252] Embodiment 4-9

[0253] It is substantially the same as Example 1, except that the organic chromium cross-linking agent is different:

[0254]

[0255]

[0256] Examples 10-14

[0257] It is similar to implementation 1, except that the enhancer 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 from a block R of Shengli Oilfield. The reservoir temperature is 63℃ and the total mineralization is 19880mg / L, including Ca 2+Content 1714mg / L, Mg 2+ Content 283mg / L.

[0262] The self-repairing gel plugger L1, self-repairing gel plugger L2, self-repairing gel plugger L3 prepared in Examples 1-3 and commercially available gel pluggers RD-1 and RD-2 were placed in a 63°C oven, 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 indicators and test methods of gel-type water plugging and profile control agents".

[0264] The shear resistance of the self-repairing gel plugging agents L1, L2, L3 and commercially available gel plugging agents RD-1 and RD-2 prepared in Examples 1-3 was evaluated. The specific method of the test was to use a rheometer to firstly -1 The apparent viscosity of the gel plugging agent was measured under the shear rate condition. Then, the gel plugging agent was heated for 50 s. -1 or 500s -1 Shearing was carried out for 100 s under the shear rate conditions and finally at 7.2 s -1 The viscosity of the gel plugging agent after shearing was measured under the shear rate condition. The test results are shown in Table 1.

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

[0266] Gel plugging 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 <![CDATA[After 50 s -1 Retention rate of shear viscosity, %]]> 95.4 96.8 98.8 62 48 <![CDATA[After 500 s -1 Viscosity retention rate after shearing, %]]> 91.7 94.6 96.5 23 15

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

[0268] At reservoir temperature, the gelling time of the self-repairing gel pluggers L1, L2 and L3 of the present invention is 18-56h, the elastic modulus is 8.6-24.8Pa, and the breakthrough pressure gradient is 9.1-34.6MPa / m. The gelling time of the commercially available gel pluggers RD-1 and RD-2 is equivalent to that of the self-repairing gel pluggers L2 and L3, but the elastic modulus is less than 6Pa, the breakthrough pressure gradient is less than 5MPa / m, and the plugging strength is significantly lower than that of the present invention.

[0269] The water blocking rates of the self-repairing gel plugging agents L1, L2 and L3 of the present invention are all greater than 99%. The water blocking rates of the commercially available gel plugging agents RD-1 and RD-2 are 99.2% and 98.7% respectively. The water blocking rates of the plugging agents are comparable.

[0270] The apparent viscosities of the self-repairing gel plugging agents L1, L2 and L3 of the present invention are 17050-87800 mPa·s, while the apparent viscosities of the commercially available gel plugging agents RD-1 and RD-2 are less than 10000 mPa·s, which are significantly lower than those of the present invention.

[0271] The self-repairing gel plugging agent L1, self-repairing gel plugging agent L2 and self-repairing gel plugging agent L3 of the present invention were heated for 50 seconds. -1 , 500s -1 The viscosity retention rate after shearing is greater than 90%, and the shear resistance is excellent. The commercially available gel plugging agents RD-1 and RD-2 -1 After shearing, the viscosity retention rate is 48-62%, after 500s -1 The viscosity retention rate after shearing is 15-23%, which is significantly lower than that of the present invention.

[0272] The self-repairing gel plugging agent L1, self-repairing gel plugging agent L2 and self-repairing gel plugging agent L3 of the present invention all meet the relevant requirements of oil fields, have excellent comprehensive performance compared with commercially available gel plugging agents, and can meet the plugging and adjustment needs of edge and bottom water heavy oil reservoirs.

[0273] The above describes the embodiments of the present invention in detail. However, the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. Self-repairing gel plugging agent, characterized in that: In parts by weight, it is composed of the following components: 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 enhancer; 80-110 parts water.

2. The self-repairing gel plugging agent according to claim 1, characterized in that: It is composed of the following components: 0.4-0.6 parts of dendritic polymer; 0.5-0.8 parts of organic chromium crosslinking agent; 0.5-1.0 parts of phenolic resin crosslinking agent; 0.3-0.8 parts of enhancer; 85-105 parts water.

3. The self-repairing gel plugging agent according to claim 1, characterized in that: The structure of the dendritic polymer is shown in formula (1): Wherein: a, b, c, d, e, f, g, h are any integer or decimal in the range of 500-3000, preferably a, b, c, d, e, f, g, h are any integer or decimal in the range of 1000-2000; It is a polymer chain structure, and its specific structure is shown in formula (2) or formula (3) or formula (4): Wherein: x is any integer or decimal in the range of 330-12500, preferably any integer or decimal in the range of 700-8500; y is any integer or decimal in the range of 300-11400, preferably any integer or decimal in the range of 600-7600; z is any integer or decimal in the range of 450-17000, and preferably any integer or decimal in the range of 900-11500.

4. The self-repairing gel plugging agent according to claim 1, characterized in that: The weight average molecular weight of the dendritic polymer is 0.8×10 6 -6×10 6 , preferably 1.6×10 6 -4.0×10 6 .

5. The self-repairing gel plugging agent according to claim 1, characterized in that: The organic chromium cross-linking agent is one or more of chromium oxalate, chromium acetate, chromium citrate, chromium malonate, chromium propionate and chromium lactate, preferably chromium lactate.

6. The self-repairing gel plugging agent according to claim 1, characterized in that: The phenolic resin crosslinking agent is a water-soluble phenolic resin prepolymer, which contains a phenolic structural unit A and an aldehyde structural unit B. The phenolic structural unit A comes from one of phenol, hydroquinone, resorcinol and catechol, and the aldehyde structural unit B comes from formaldehyde. In the water-soluble phenolic resin prepolymer, the molar ratio of the phenolic structural unit A to the aldehyde structural unit B is (0.2-0.75):1, and the weight average molecular weight of the water-soluble phenolic resin prepolymer is 10000-100000.

7. The self-repairing gel plugging agent according to claim 1, characterized in that: The reinforcing agent is one or more of sodium tripolyphosphate, polyphosphate, nano silicon dioxide, diatomaceous earth, and tea polyphenols, preferably one of sodium tripolyphosphate and nano silicon dioxide.

8. The self-repairing gel plugging agent according to claim 7, characterized in that: The nano silicon dioxide is hydrophilic nano silicon dioxide, and the median particle size D50 is 20-30nm.

9. The self-repairing gel plugging agent according to claim 1, characterized in that: The water is water with a total mineralization of less than 50000 mg / L.

10. The method for preparing the self-repairing gel plugging agent according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) Synthesis of dendrimers; (2) Preparation of self-repairing gel plugging agent: The dendritic polymer synthesized in step (1) is mixed evenly with a formula amount of an organic chromium crosslinking agent, a formula amount of a phenolic resin crosslinking agent, a formula amount of a reinforcing agent, and a formula amount of water to obtain a self-repairing gel plugging agent.

11. The method for preparing the self-repairing gel plugging agent according to claim 10, characterized in that: In terms of molar parts, the specific steps of step (1) are as follows: (11) In an ice bath, nitrogen or inert gas protection, 1 part of ethylenediamine and 6-10 parts of methyl acrylate are dissolved in appropriate amounts of methanol to obtain a methanol solution of ethylenediamine and a methanol solution of methyl acrylate, respectively; an excess amount of the methanol solution of methyl acrylate is added dropwise to the methanol solution of ethylenediamine; the mixture is stirred and reacted at 20-30° C. for 10-24 h to obtain a reaction solution; the reaction solution is subjected to reduced pressure distillation at 40-70° C. to remove methanol and excess methyl acrylate, to obtain a light yellow transparent liquid MA0.5; (12) In an ice bath, nitrogen or inert gas protection conditions, add an appropriate amount of the light yellow transparent liquid MA0.5 obtained in step (11) to an appropriate amount of methanol to obtain a methanol solution of MA0.5, then dropwise add an excess of the methanol solution of ethylenediamine to the methanol solution of MA0.5 to obtain a mixed solution, stir and react at 20-30° C. for 10-24 hours to obtain a reaction solution, distill the reaction solution under reduced pressure at 40-70° C. to remove methanol and excess ethylenediamine, wash with petroleum ether at least once, then wash with ethyl acetate at least once, and rotary evaporate to remove unreacted MA0.5 to obtain a light yellow viscous liquid MA1.0; (13) In an ice bath, nitrogen or inert gas protection conditions, add an appropriate amount of the light yellow viscous liquid MA1.0 obtained in step (12) to an appropriate amount of methanol to obtain a methanol solution of MA1.0, then add an excess amount of the methanol solution of methyl acrylate dropwise to the methanol solution of MA1.0 to obtain a mixed solution, stir and react at 20-30° C. for 10-24 h to obtain a reaction solution, distill the reaction solution under reduced pressure at 40-70° C. to remove methanol and excess methyl acrylate, wash with petroleum ether at least once, then wash with ethyl acetate at least once, and rotary evaporate to remove unreacted MA1.0 to obtain a light yellow viscous liquid MA1.5; (14) In an ice bath, nitrogen or inert gas protection conditions, add an appropriate amount of the light yellow viscous liquid MA1.5 obtained in step (13) to an appropriate amount of methanol to obtain a methanol solution of MA1.5, then dissolve (Z)-3-aminoacrylamide in an appropriate amount of methanol to obtain a methanol solution of (Z)-3-aminoacrylamide, then add an excess of the methanol solution of (Z)-3-aminoacrylamide dropwise to the methanol solution of MA1.5 to obtain a mixed solution, stir and react at 20-30° C. for 24-48 hours to obtain a reaction solution, distill the reaction solution under reduced pressure at 40-70° C. to remove methanol and excess (Z)-3-aminoacrylamide, wash with petroleum ether at least once, then wash with ethyl acetate at least once, and remove unreacted MA1.5 by rotary evaporation to obtain a dendritic intermediate MAZ; (15) Under nitrogen or inert gas protection conditions, an appropriate amount of the dendritic intermediate MAZ obtained in step (14) is dissolved in an appropriate amount of water, and then p-hydroxystyrene or diethylene glycol monovinyl ether or ethylene glycol monovinyl ether is added to obtain a mixed solution A after complete dissolution, and then an initiator is added to the mixed solution A to obtain a mixed solution B, and the mixed solution B is stirred and reacted at 50-80° C. for 6-12 h to obtain a reaction solution, and then the reaction solution is evaporated to remove water, and finally the product is washed with ethanol at least 3 times, dried, and ground into powder to obtain a dendritic polymer.

12. The method for preparing the self-repairing gel plugging agent according to claim 11, characterized in that: The molar ratio of ethylenediamine to methyl acrylate in step (11) is 1:(7-9); The mass ratio of ethylenediamine to methanol in the methanol solution of ethylenediamine described in step (11) is 1:(3-15), preferably 1:(8-12); The mass ratio of methyl acrylate to methanol in the methanol solution of methyl acrylate described in step (11) is 1:(1-2), preferably 1:(1-1.5).

13. The method for preparing the self-repairing gel plugging agent according to claim 11, characterized in that: In the mixed solution described in step (12), the molar ratio of ethylenediamine to MA0.5 is (20-28):1, preferably (25-27):1; The mass ratio of MA0.5 to methanol in the methanol solution of MA0.5 described in step (12) is 1:(1-2), preferably 1:(1-1.5); The mass ratio of the amount of petroleum ether in step (12) to the amount of MA0.5 in step (12) is (3-15):1, preferably (8-12):1; The mass ratio of the amount of ethyl acetate used in step (12) to the amount of MA0.5 used in step (12) is (3-15):1, preferably (8-12):

1.

14. The method for preparing the self-repairing gel plugging agent according to claim 11, characterized in that: The molar ratio of methyl acrylate to MA1.0 in the mixed solution described in step (13) is (14-18):1, preferably (15-17):1; The mass ratio of MA1.0 to methanol in the methanol solution of MA1.0 described in step (13) is 1:(1-2), preferably 1:(1-1.5); The mass ratio of the amount of petroleum ether used in step (13) to the amount of MA1.0 used is (3-15):1, preferably (8-12):1; The mass ratio of the amount of ethyl acetate used in step (13) to the amount of MA1.0 used is (3-15):1, preferably (8-12):

1.

15. The method for preparing the self-repairing gel plugging agent according to claim 11, characterized in that: The molar ratio of (Z)-3-aminoacrylamide to MA1.5 in the mixed solution in step (14) is (20-28):1, preferably (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:(3-6), preferably 1:(4-5); The mass ratio of MA1.5 to methanol in the methanol solution of MA1.5 described in step (14) is 1:(1-3), preferably 1:2; The mass ratio of the amount of petroleum ether used in step (14) to the amount of MA1.5 used is (3-15):1, preferably (8-12):1; The mass ratio of the amount of ethyl acetate used in step (14) to the amount of MA1.5 used is (3-15):1, preferably (8-12):

1.

16. The method for preparing the self-repairing gel plugging agent according to claim 11, characterized in that: The mass ratio of p-hydroxystyrene or diethylene glycol monovinyl ether or ethylene glycol monovinyl ether to the dendritic intermediate MAZ in step (15) is 1:(3-19), preferably 1:(4-9); In step (15), based on the mixed solution A, the concentration of the sum of the mass of p-hydroxystyrene or diethylene glycol monovinyl ether or ethylene glycol monovinyl ether and the dendritic intermediate MAZ is 10-30 wt %; The initiator described in step (15) is one of azobisisobutyronitrile, azobisisobutyramidine hydrochloride, and azobisisoheptylonitrile, preferably azobisisobutyronitrile; In step (15), based on the mixed solution B, the initiator concentration is 0.05-0.12% by weight.

17. Self-repairing gel plugging agent, characterized in that: It is prepared by the preparation method according to any one of claims 10 to 16.

18. Use of the self-repairing gel plugging agent according to any one of claims 1 to 9 and 17 as a water plugging and profile control agent for edge-bottom water heavy oil reservoirs.

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