Gel plugging agent as well as preparation method and application thereof

Abstract

The invention discloses a gel plugging agent, which is composed of the following components: 0.3-1.2 parts of a dendritic polymer; 0.2 to 1.5 parts of a cross-linking agent; 0.2 to 1.5 parts of a deoxidant; and 80 to 110 parts of water. The invention discloses a preparation method of a gel plugging agent. The preparation method comprises the following steps: (1) synthesizing a dendritic polymer; and (2) preparation of the gel plugging agent: uniformly mixing the dendritic polymer prepared in the step (1) according to the formula ratio, the cross-linking agent according to the formula ratio, the deoxidant according to the formula ratio and the water according to the formula ratio to obtain the gel plugging agent. The invention further discloses application of the gel plugging agent as a water plugging and profile control agent in thickened oil recovery. The invention has the following beneficial effects: (1) the plugging strength is high; (2) the temperature resistance is 120-200 DEG C, the high-temperature stability is good, and the plugging validity period is long; and (3) 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 gel plugging agent and a preparation method and application thereof. Background Art

[0002] my country has abundant reserves of heavy oil resources, and the exploitation of heavy oil reservoirs is mainly carried out by water drive and thermal recovery. For example, Chinese invention patent application CN110863808A discloses a heavy oil exploitation method that uses electric heating to enhance water drive efficiency. First, an electric heating pipe or electric heating cable is fixed in a ring shape to the outside of a grooved isolation pipe, and is lowered to the target reservoir through a production string. The isolation pipe is expanded to make the heating pipe close to the production casing to heat the formation near the wellbore; after the heating distance reaches a preset value, the heating is continued, and the heating power is adjusted to continuously reduce the viscosity, flow resistance and mobility ratio of the heavy oil in the area near the production well; the ordinary heavy oil water drive exploitation process is started, and a displacement fluid is injected into the injection well to displace the crude oil in the formation toward the production well; the crude oil, water and gas flowing to the production well are lifted to the ground by the lifting device in the production well. Chinese invention patent application CN 108868718A discloses a combined thermal recovery method for a gas-capped heavy oil reservoir, which heats the top of the oil layer by igniting the gas cap, and uses the heat from the combustion of the top gas layer to heat the entire oil layer, thereby reducing the viscosity of crude oil on the contact surface between the gas cap and the heavy oil layer, and realizing inter-well communication between vertical wells and horizontal wells. At the same time, the flue gas generated after combustion further reduces the viscosity of the heavy oil, and provides energy to the entire oil reservoir.

[0003] For water-driven heavy oil, after years of exploitation, all major oil fields have entered the high water content period or even the ultra-high water content period development stage. High permeability strips are developed, and the injected water advances rapidly, making it difficult to start the medium and low permeability oil layers, and the sweep efficiency is low. For thermal recovery heavy oil, most of the heavy oil reservoirs in Shengli, Xinjiang, Henan and other oil fields in my country have entered the high-cycle throughput stage, with serious steam overburden. At the same time, affected by the heterogeneity of the reservoir, steam easily migrates along the high permeability strips, resulting in a low oil-gas ratio and even steam channeling. Water plugging and profile control technology is one of the main technologies for plugging high permeability strips, improving sweep effects, and increasing the degree of reservoir utilization. Among them, gel plugging and adjustment has become one of the leading processes for water plugging and profile control due to its advantages such as good injectability and high plugging strength.

[0004] At present, the gel plugging agents used in China are mainly "polymer + cross-linking agent". The polymer used is mainly a linear acrylamide homopolymer or copolymer, which reacts with a cross-linking agent to form a high-strength gel with a three-dimensional network structure. Chinese invention patent application CN 111087992A provides a gel plugging agent composition and its preparation method and application. The gel plugging agent composition comprises: an acrylamide polymer, a water-soluble melamine formaldehyde resin, a deoxidizer, a urea compound and water, and the urea compound has a structure shown in formula (1) and / or formula (2), wherein R1 and R2 are each independently selected from hydrogen or 2-propynyl; R3 and R4 are each independently selected from oxygen, sulfur or imino. The invention mainly solves the problem of achieving long-term water plugging at a higher temperature, but the gel plugging agent composition provided by the invention is prepared from acrylamide polymers, etc., has poor shear resistance, large strength loss during entering the deep formation, and limited throughput effect.

[0005] After decades of continuous development, the oil saturation of the near-well area of ​​major heavy oil reservoirs is low, and the residual oil is enriched between wells or deep in the formation. Therefore, gel plugging agents need to enter the deep formation for high-strength plugging, and the shear resistance and plugging strength of gel plugging agents are increasingly required. However, gel plugging agents formed by polyacrylamide polymers are greatly affected by shear. During the formation flow process, they are affected by pore throat shear, and the viscosity loss is as high as 40-80%. It is difficult to achieve high-strength and long-term plugging in the deep formation, which in turn affects the effect of heavy oil development. Summary of the invention

[0006] Purpose of the invention: In view of the above-mentioned deficiencies of the prior art, the present invention discloses a gel plugging agent and its preparation method and application, which can be used to plug high permeability bands and improve the sweep effect during heavy oil production. -1 The viscosity retention rate after high-speed shearing is more than 90%, and the plugging strength is 5-20MPa / m at 50-120℃; it can withstand temperatures of 120-200℃, and after aging at 120℃ for 180 days or 200℃ for 30 days, the plugging strength of the gel plugging agent is 3-10MPa / m; it is suitable for formation water mineralization of 0-50000mg / L, including calcium and magnesium ions of 0-3000mg / L, and is suitable for reservoir temperature of 50-120℃.

[0007] Technical solution: A gel plugging agent, which is composed of the following components by weight:

[0008] 0.3-1.2 parts of dendritic polymer;

[0009] 0.2-1.5 parts of cross-linking agent;

[0010] 0.2-1.5 parts of deoxidizer;

[0011] 80-110 parts of water.

[0012] Further, it is composed of the following components:

[0013] 0.4-0.6 parts of dendritic polymer;

[0014] 0.5-1 part of cross-linking agent;

[0015] 0.5-0.8 parts of deoxidizer;

[0016] 90-100 parts of water.

[0017] Furthermore, the structure of the dendritic polymer is shown in formula (1):

[0018]

[0019] Wherein: a, b, c, d, e, f, g, h are any integer or decimal in the range of 400-3800, preferably a, b, c, d, e, f, g, h are any integer or decimal in the range of 1000-2000;

[0020] ● is a polymer chain structure, and the specific structure is shown in formula (2) or formula (3) or formula (4):

[0021]

[0022]

[0023] Wherein: x is any integer or decimal in the range of 210-7800, preferably any integer or decimal in the range of 500-5300;

[0024] y is any integer or decimal between 270 and 10000, preferably any integer or decimal between 550 and 6800;

[0025] z is any integer or decimal in the range of 250-9200, and preferably any integer or decimal in the range of 500-6200.

[0026] Furthermore, the weight average molecular weight of the dendritic polymer is 0.8×10 6 -6×10 6 , preferably 1.6×10 6 -4×10 6 .

[0027] Furthermore, the cross-linking agent is one or more of formaldehyde, paraformaldehyde, hexamethylenetetramine, phenol, resorcinol, hydroquinone, water-soluble phenolic resin, urea-formaldehyde resin, and organic chromium, preferably one or more of water-soluble phenolic resin and organic chromium.

[0028] Furthermore, the cross-linking agent is a composition of a water-soluble phenolic resin and an organic chromium, and the mass ratio of the water-soluble phenolic resin to the organic chromium is (1-4):1, preferably (2-3):1.

[0029] Furthermore, the organic chromium is one or more of chromium oxalate, chromium acetate, chromium citrate, chromium malonate, chromium propionate, and chromium lactate, preferably chromium lactate.

[0030] Furthermore, the deoxidizer is one or more of thiourea, sodium thiosulfate, sodium sulfite, and sodium bisulfite, preferably thiourea.

[0031] Furthermore, the water has a total mineralization of less than 50,000 mg / L.

[0032] The preparation method of the above-mentioned gel plugging agent comprises the following steps:

[0033] (1) Synthesis of dendrimers;

[0034] (2) Preparation of gel plugging agent:

[0035] The dendritic polymer prepared in step (1) is mixed evenly with a formulated amount of a cross-linking agent, a formulated amount of an oxygen scavenger, and a formulated amount of water to obtain a gel plugging agent.

[0036] Further, in terms of molar parts, the specific steps of step (1) are as follows:

[0037] (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;

[0038] (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;

[0039] (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;

[0040] (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;

[0041] (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-carboxyphenylacetic acid or p-vinylbenzoic acid or p-vinylphenylacetic acid 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 then the product is washed with ethanol at least 3 times, dried, and ground into powder to obtain a dendritic polymer.

[0042] Furthermore, the molar ratio of ethylenediamine to methyl acrylate in step (11) is 1:(7-9);

[0043] 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);

[0044] 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).

[0045] 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;

[0046] 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);

[0047] 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;

[0048] 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.

[0049] 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;

[0050] 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);

[0051] 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;

[0052] 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.

[0053] 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;

[0054] 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);

[0055] 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;

[0056] 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;

[0057] 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.

[0058] Furthermore, the mass ratio of p-carboxyphenylacetic acid or p-vinylbenzoic acid or p-vinylphenylacetic acid to the dendritic intermediate MAZ in step (15) is 1:(3-19), preferably 1:(4-9);

[0059] In step (15), based on the mixed solution A, the concentration of the sum of the mass of the p-carboxyphenylacetic acid or p-vinylbenzoic acid or p-vinylphenylacetic acid and the dendritic intermediate MAZ is 10-30% by weight.

[0060] The initiator described in step (15) is one of azobisisobutyronitrile, azobisisobutyramidine hydrochloride, and azobisisoheptylonitrile, preferably azobisisobutyronitrile;

[0061] In step (15), based on the mixed solution B, the initiator concentration is 0.05-0.12% by weight.

[0062] The gel plugging agent is prepared by any one of the preparation methods described above.

[0063] The gel plugging agent is used as a water plugging and profile control agent in heavy oil production.

[0064] Furthermore, the specific steps of the application are as follows: under the pre-injection condition, the gel plugging agent is injected into the formation from the wellbore, so that the gel plugging agent is cross-linked in situ in the formation to form a gel, thereby blocking the high permeability strip, inhibiting the invasion of edge and bottom water, and expanding the effective impact of the subsequent injection fluid.

[0065] The dendritic polymer in the gel plugging agent of the present invention has a large number of reactive groups on its surface, and after reacting with a cross-linking agent, an interpenetrating network structure can be formed, so that the prepared gel plugging agent has the advantages of high plugging strength, good shear resistance, long plugging effective period, good reservoir adaptability, etc., and has a good promotion prospect in the process of heavy oil reservoir exploitation.

[0066] Beneficial effects: Compared with the prior art, the present invention has the following beneficial effects:

[0067] (1) The gel plugging agent has high plugging strength, with a breakthrough pressure gradient of 5-20MPa / m at 50-120℃; it is less affected by pore throat shear and can be used for 50s. -1 The viscosity retention rate after high-speed shearing is more than 90%, and it can be transported to the deep formation for effective plugging;

[0068] (2) The gel plugging agent can withstand temperatures of 120-200°C. After aging at 120°C for 180 days or 200°C for 30 days, the gel plugging agent breaks through a pressure gradient of 3-10MPa / m, has good high temperature stability, and a long effective plugging period;

[0069] (3) The gel plugging agent is suitable for formation water with a mineralization of 0 to 50,000 mg / L, including 0 to 3,000 mg / L of calcium and magnesium ions, and is suitable for reservoir temperatures of 50 to 120°C, with strong reservoir adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 The present invention is a flow chart of the preparation method of the gel plugging agent disclosed in the present invention. DETAILED DESCRIPTION

[0071] The present invention will be further described in detail below in conjunction with specific examples and with reference to data. It should be understood that these examples are only intended to illustrate the present invention and are not intended to limit the scope of the present invention in any way.

[0072] The reaction equation for preparing the dendritic polymer is as follows:

[0073]

[0074]

[0075] Example 1

[0076] Gel plugging agent G1, by mass, is composed of the following substances:

[0077]

[0078] In another embodiment, the gel plugging agent G1', by weight, is composed of the following substances:

[0079]

[0080] Furthermore, the water is formation water with a total mineralization of 30,000 mg / L, of which Ca 2+ Mg 2+ Total ion concentration: 2000mg / L.

[0081] Furthermore, the molecular formula of the dendritic polymer J1 is as follows:

[0082]

[0083] Where ● is the polymer chain structure, as shown in formula (2):

[0084]

[0085] Among them, a, b, c, d, e, f, g, h are all 1000, and x is 3000.

[0086] The weight average molecular weight of the dendritic polymer J1 is 2.1×10 6 .

[0087] In another embodiment, the dendritic polymer J1' has the following molecular formula:

[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 400, and x is 210.

[0092] The weight average molecular weight of the dendritic polymer J1' is 0.81×10 6 .

[0093] In another embodiment, the dendritic polymer J1* 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, and h are all 3800, and x is 7800.

[0098] The weight average molecular weight of the dendritic polymer J1* is 6.0×10 6 .

[0099] In another embodiment, the dendritic polymer J1" 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 2000, and x is 500.

[0104] The weight average molecular weight of the dendritic polymer J1" is 1.62×10 6 .

[0105] In another embodiment, the dendritic polymer J1# 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 1500, and x is 5300.

[0110] The weight average molecular weight of the dendritic polymer J1# is 4.01×10 6 .

[0111] The preparation method of the gel plugging agent G1 comprises the following steps:

[0112] (1) Synthesis of dendrimer J1;

[0113] (2) Preparation of gel plugging agent G1:

[0114] The dendritic polymer J1 prepared in step (1) is mixed uniformly with a formulated amount of a cross-linking agent, a formulated amount of an oxygen scavenger, and a formulated amount of water to obtain a gel plugging agent G1.

[0115] Further, in terms of molar parts, the specific steps of step (1) are as follows:

[0116] (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, and the mixture was stirred 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, and a light yellow transparent liquid MA0.5 was obtained.

[0117] (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, distill the reaction solution under reduced pressure at 40° C. to remove methanol and excess ethylenediamine, wash once with petroleum ether, then wash once with ethyl acetate, and remove unreacted MA0.5 by rotary evaporation to obtain a light yellow viscous liquid MA1.0;

[0118] (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;

[0119] (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;

[0120] (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-carboxyphenylacetic acid 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 50° C. for 12 h to obtain a reaction solution. The reaction solution is then evaporated to remove water. The product is then washed with ethanol three times, dried, and ground into powder to obtain a dendritic polymer J1.

[0121] In another embodiment, the molar ratio of ethylenediamine to methyl acrylate in step (11) is 1:7.

[0122] 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.

[0123] The mass ratio of methyl acrylate to methanol in the methanol solution of methyl acrylate described in step (11) is 1:1.

[0124] 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;

[0125] The mass ratio of MA0.5 to methanol in the methanol solution of MA0.5 described in step (12) is 1:1.

[0126] 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.

[0127] 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.

[0128] 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.

[0129] The mass ratio of MA1.0 to methanol in the methanol solution of MA1.0 described in step (13) is 1:1.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] The mass ratio of MA1.5 to methanol in the methanol solution of MA1.5 described in step (14) is 1:1.

[0135] 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.

[0136] 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.

[0137] Furthermore, the mass ratio of p-carboxyphenylvinyl acid to the dendritic intermediate MAZ in step (15) is 1:3. In another embodiment, the mass ratio of p-carboxyphenylvinyl acid to the dendritic intermediate MAZ in step (15) is 1:4.

[0138] In step (15), based on the mixed solution A, the concentration of the sum of the mass of the p-carboxyphenylethylene acid and the dendritic intermediate MAZ is 10 wt %.

[0139] Furthermore, the initiator in step (15) is azobisisobutyronitrile.

[0140] In step (15), based on the mixed solution B, the initiator concentration is 0.05 wt %.

[0141] The gel plugging agent G1 is prepared by any one of the preparation methods described above.

[0142] The gel plugging agent G1 is used as a water plugging and profile control agent in heavy oil production.

[0143] Furthermore, the specific steps of the application are as follows: under the pre-injection condition, the gel plugging agent G1 is injected into the formation from the wellbore, so that the gel plugging agent G1 is cross-linked in situ in the formation to form a gel, thereby blocking the high permeability strip, inhibiting the invasion of edge and bottom water, and expanding the effective impact of the injected fluid.

[0144] Example 2

[0145] Gel plugging agent G2, by mass, is composed of the following substances:

[0146]

[0147] In another embodiment, the gel plugging agent G2' is composed of the following substances in parts by mass:

[0148]

[0149]

[0150] 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.

[0151] The molecular formula of the dendritic polymer J2 is as follows:

[0152]

[0153] Where ● is the polymer chain structure, as follows:

[0154]

[0155] Among them, a, b, c, d, e, f, g, and h are all 1500, and y is 5000.

[0156] Furthermore, the weight average molecular weight of the dendritic polymer J2 is 3.03×10 6 .

[0157] In another embodiment, another dendritic polymer is substantially the same as the dendritic polymer J2, except that y is 270 and the weight average molecular weight of the dendritic polymer is 0.85×10 6 .

[0158] In another embodiment, another dendritic polymer is substantially the same as the dendritic polymer J2, except that y is 10,000 and the weight average molecular weight of the dendritic polymer is 4.91×10 6 .

[0159] In another embodiment, another dendritic polymer is substantially the same as the dendritic polymer J2, except that y is 550 and the weight average molecular weight of the dendritic polymer is 1.82×10 6 .

[0160] In another embodiment, another dendritic polymer is substantially the same as the dendritic polymer J2, except that y is 6800 and the weight average molecular weight of the dendritic polymer is 4.42×10 6 .

[0161] The preparation method of the gel plugging agent G2 comprises the following steps:

[0162] (1) Synthesis of dendrimer J2;

[0163] (2) Preparation of gel plugging agent G2:

[0164] The dendritic polymer J2 prepared in step (1) is mixed uniformly with a formulated amount of a cross-linking agent, a formulated amount of an oxygen scavenger, and a formulated amount of water to obtain a gel plugging agent G2.

[0165] Further, in terms of molar parts, the specific steps of step (1) are as follows:

[0166] (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.

[0167] (12) In an ice bath and with helium flowing, 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, and the mixture is stirred for reaction at 30° C. for 10 h to obtain a reaction solution, and the reaction solution is subjected to reduced pressure distillation at 70° C. to remove methanol and excess ethylenediamine, and the mixture is washed with petroleum ether for 3 times, and then washed with ethyl acetate for 3 times, and then rotary distilled to remove unreacted MA0.5 to obtain a light yellow viscous liquid MA1.0;

[0168] (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;

[0169] (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;

[0170] (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 p-vinylbenzoic acid 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. The product is then washed with ethanol 5 times, dried, and ground into powder to obtain a dendritic polymer J2.

[0171] In another embodiment, the molar ratio of ethylenediamine to methyl acrylate in step (11) is 1:9.

[0172] 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.

[0173] Furthermore, the mass ratio of methyl acrylate to methanol in the methanol solution of methyl acrylate described in step (11) is 1:2.

[0174] 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.

[0175] The mass ratio of MA0.5 to methanol in the methanol solution of MA0.5 described in step (12) is 1:2.

[0176] 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.

[0177] 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.

[0178] 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.

[0179] 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.

[0180] 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.

[0181] 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.

[0182] 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;

[0183] 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.

[0184] The mass ratio of MA1.5 to methanol in the methanol solution of MA1.5 described in step (14) is 1:3.

[0185] 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.

[0186] 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.

[0187] Furthermore, the mass ratio of p-vinylbenzoic acid to the dendritic intermediate MAZ in step (15) is 1:19. In another embodiment, the mass ratio of p-vinylbenzoic acid to the dendritic intermediate MAZ in step (15) is 1:9.

[0188] In step (15), based on the mixed solution A, the concentration of the sum of the mass of the p-vinylbenzoic acid and the dendritic intermediate MAZ is 30 wt %.

[0189] Furthermore, the initiator in step (15) is azobisisobutylamidine hydrochloride.

[0190] In step (15), based on the mixed solution B, the initiator concentration is 0.12% by weight.

[0191] The gel plugging agent G2 is prepared by any one of the preparation methods described above.

[0192] The gel plugging agent G2 is used as a water plugging and profile control agent in heavy oil production.

[0193] Furthermore, the specific steps of the application are as follows: under the pre-injection condition, the gel plugging agent G2 is injected into the formation from the wellbore, so that the gel plugging agent G2 is cross-linked in situ in the formation to form a gel, thereby blocking the high permeability strip, inhibiting the invasion of edge and bottom water, and expanding the effective impact of the injected fluid.

[0194] Example 3

[0195] Gel plugging agent G3, by mass, is composed of the following substances:

[0196]

[0197] In another embodiment, the gel plugging agent G3' is composed of the following substances in parts by mass:

[0198]

[0199] 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.

[0200] The molecular formula of the dendritic polymer J3 is as follows:

[0201]

[0202] Where ● is the polymer chain structure, as follows:

[0203]

[0204] Among them, a, b, c, d, e, f, g, h are all 2000, and z is 1000.

[0205] Furthermore, the weight average molecular weight of the dendritic polymer J3 is 3.2×10 6 .

[0206] In another embodiment, another dendritic polymer is substantially the same as the dendritic polymer J3, except that z is 250 and the weight average molecular weight of the dendritic polymer is 0.93×10 6 .

[0207] In another embodiment, another dendritic polymer is substantially the same as the dendritic polymer J3, except that z is 9200 and the weight average molecular weight of the dendritic polymer is 5.21×10 6 .

[0208] In another embodiment, another dendritic polymer is substantially the same as the dendritic polymer J3, except that z is 500 and the weight average molecular weight of the dendritic polymer is 2.18×10 6 .

[0209] In another embodiment, another dendritic polymer is substantially the same as the dendritic polymer J3, except that z is 6200 and the weight average molecular weight of the dendritic polymer is 4.51×10 6 .

[0210] The preparation method of the gel plugging agent G3 comprises the following steps:

[0211] (1) Synthesis of dendrimer J3;

[0212] (2) Preparation of gel plugging agent G3:

[0213] The dendritic polymer J3 prepared in step (1) is mixed uniformly with a formulated amount of a cross-linking agent, a formulated amount of an oxygen scavenger, and a formulated amount of water to obtain a gel plugging agent G3.

[0214] Further, in terms of molar parts, the specific steps of step (1) are as follows:

[0215] (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, and a light yellow transparent liquid MA0.5 was obtained.

[0216] (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, distill the reaction solution under reduced pressure at 50° C. to remove methanol and excess ethylenediamine, wash the reaction solution twice with petroleum ether, then wash it twice with ethyl acetate, and remove unreacted MA0.5 by rotary evaporation to obtain a light yellow viscous liquid MA1.0;

[0217] (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 60° 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;

[0218] (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;

[0219] (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 p-vinylphenylacetic acid 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 60° C. for 8 h to obtain a reaction solution. The reaction solution is then evaporated to remove water. The product is then washed with ethanol four times, dried, and ground into powder to obtain a dendritic polymer J3.

[0220] The mass ratio of ethylenediamine to methanol in the methanol solution of ethylenediamine described in step (11) is 1:10;

[0221] The mass ratio of methyl acrylate to methanol in the methanol solution of methyl acrylate described in step (11) is 1.5.

[0222] Furthermore, in the mixed solution described in step (12), the molar ratio of ethylenediamine to MA0.5 is 26:1;

[0223] The mass ratio of MA0.5 to methanol in the methanol solution of MA0.5 described in step (12) is 1:1.5.

[0224] 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;

[0225] 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.

[0226] Furthermore, the molar ratio of methyl acrylate to MA1.0 in the mixed solution described in step (13) is 16:1;

[0227] The mass ratio of MA1.0 to methanol in the methanol solution of MA1.0 described in step (13) is 1:1.5.

[0228] Furthermore, the mass ratio of the amount of petroleum ether used in step (13) to the amount of MA1.0 used is 10:1;

[0229] The mass ratio of the amount of ethyl acetate used in step (13) to the amount of MA1.0 used is 10:1.

[0230] Furthermore, the molar ratio of (Z)-3-aminoacrylamide to MA1.5 in the mixed solution described in step (14) is 26:1;

[0231] 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;

[0232] The mass ratio of MA1.5 to methanol in the methanol solution of MA1.5 described in step (14) is 1:2.

[0233] Furthermore, the mass ratio of the amount of petroleum ether used in step (14) to the amount of MA1.5 used is 10:1;

[0234] The mass ratio of the amount of ethyl acetate used in step (14) to the amount of MA1.5 used is 10:1.

[0235] Furthermore, the mass ratio of p-vinylphenylacetic acid to the dendritic intermediate MAZ in step (15) is 1:7;

[0236] In step (15), based on the mixed solution A, the concentration of the sum of the mass of the p-vinylphenylacetic acid and the dendritic intermediate MAZ is 20 wt %.

[0237] Furthermore, the initiator in step (15) is azobisisoheptanonitrile.

[0238] In step (15), based on the mixed solution B, the initiator concentration is 0.1 wt %.

[0239] The gel plugging agent G3 is prepared by any one of the preparation methods described above.

[0240] The gel plugging agent G3 is used as a water plugging and profile control agent in heavy oil production.

[0241] Furthermore, the specific steps of the application are as follows: under the pre-injection condition, the gel plugging agent G3 is injected into the formation from the wellbore, so that the gel plugging agent G3 is cross-linked in situ in the formation to form a gel, thereby blocking the high permeability strip, inhibiting the invasion of edge and bottom water, and expanding the effective impact of the injected fluid.

[0242] Example 4-21

[0243] The same as Example 1, the only difference is that the cross-linking agent is different

[0244]

[0245]

[0246] Examples 22-26

[0247] It is roughly the same as Example 1, except that the deoxidizer is different:

[0248] Performance evaluation of gel plugging agents G1, G2 and G3

[0249] Test Example 1

[0250] The water used in this experiment is produced water from a certain block H of Shengli Oilfield. The reservoir temperature is 68℃ and the total mineralization is 26680mg / L, including Ca 2+ Content: 2249mg / L, Mg 2+ Content: 251mg / L.

[0251] The gel plugging agents G1, G2, G3 prepared in Examples 1-3 and the commercially available gel plugging agents KR-1 and KR-2 were respectively placed in an oven at 68°C, and their gelation time, elastic modulus, breakthrough pressure gradient and water plugging rate were evaluated. The measurement method referred to Q / SH10201493-2019 "Performance Indicators and Test Methods of Gel-Based Water Plugging and Profile Control Agents".

[0252] The shear resistance of the gel plugging agents G1, G2, G3 prepared in Examples 1-3 and the commercially available gel plugging agents KR-1 and KR-2 was evaluated. The specific method of the test was to use a rheometer to firstly -1 Determination of initial viscosity of gel under shear rate conditions μ 0 Next, the gel was heated for 50 s. -1 Shearing was carried out for 100 s under the shear rate conditions and finally at 7.2 s -1 Determination of gel shear viscosity μ under shear rate conditions 1 The viscosity retention rate is

[0253] calculate.

[0254] The gel plugging agents G1, G2, G3 prepared in Examples 1 and 3 and the commercially available gel plugging agent KR-1 were evaluated for their temperature resistance by aging them at 200° C. for 30 days and then measuring the breakthrough pressure gradient. The test results are shown in Table 1.

[0255] Table 1 Performance test results of gel plugging agents G1, G2, G3 and commercially available gel plugging agents KR-1 and KR-2

[0256]

[0257] According to the above evaluation results, the gel plugging agents G1, G2 and G3 of the present invention have good gelling performance, plugging performance and shear resistance at reservoir temperature, among which the gel plugging agents G1 and G3 used for thermal recovery of heavy oil also have good temperature resistance.

[0258] At reservoir temperature, the gel plugging agents G1, G2 and G3 of the present invention have a gelling time of 21-72 h, an elastic modulus greater than 8 Pa, and a breakthrough pressure gradient greater than 6 MPa / m. The gelling time of the commercially available gel plugging agents KR-1 and KR-2 is equivalent to that of G1, G2 and G3, but the elastic modulus is less than 8 Pa, and the breakthrough pressure gradient is less than 5 MPa / m, which is significantly lower than that of the present invention.

[0259] The water blocking rates of the gel plugging agents G1, G2 and G3 of the present invention are all greater than 99%, while the water blocking rates of the commercially available gel plugging agents KR-1 and KR-2 are 99.2% and 98.7% respectively, and the water blocking rates of the several plugging agents are comparable.

[0260] The gel plugging agents G1, G2 and G3 of the present invention were subjected to 50 s -1 The viscosity retention rates after shearing are greater than 90%, while the viscosity retention rates of commercially available gel plugging agents KR-1 and KR-2 are 48-62%, which are significantly lower than those of the present invention.

[0261] The breakthrough pressure gradient of the gel plugging agent G1, gel plugging agent G2 and gel plugging agent G3 for thermal recovery of heavy oil of the present invention is maintained above 5MPa / m after aging at 200°C for 30 days, while the strength of the commercially available gel plugging agent KR-1 after high temperature aging is less than 3MPa / m. The gel plugging agent G1, gel plugging agent G2 and gel plugging agent G3 of the present invention all meet the relevant requirements of the oil field, and have excellent comprehensive performance compared with the commercially available gel plugging agents, and can meet the development needs of multiple rounds of heavy oil reservoirs.

[0262] 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. A 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; 0.2-1.5 parts of cross-linking agent; 0.2-1.5 parts of deoxidizer; 80-110 parts of water.

2. A gel plugging agent as claimed in claim 1, characterized in that: It is composed of the following components: 0.4-0.6 parts of dendritic polymer; 0.5-1 part of cross-linking agent; 0.5-0.8 parts of deoxidizer; 90-100 parts of water.

3. A gel plugging agent as claimed in 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 400-3800, 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 210-7800, preferably any integer or decimal in the range of 500-5300; y is any integer or decimal in the range of 270-10000, preferably any integer or decimal in the range of 550-6800; z is any integer or decimal in the range of 250-9200, and preferably any integer or decimal in the range of 500-6200.

4. A gel plugging agent as claimed in 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 -4×10 6 .

5. A gel plugging agent as claimed in claim 1, characterized in that: The cross-linking agent is one or more of formaldehyde, paraformaldehyde, hexamethylenetetramine, phenol, resorcinol, hydroquinone, water-soluble phenolic resin, urea-formaldehyde resin, and organic chromium, preferably one or more of water-soluble phenolic resin and organic chromium.

6. A gel plugging agent as claimed in claim 5, characterized in that: The cross-linking agent is a composition of a water-soluble phenolic resin and an organic chromium, and the mass ratio of the water-soluble phenolic resin to the organic chromium is (1-4):1, preferably (2-3):

1.

7. A gel plugging agent as claimed in claim 5, characterized in that: The organic chromium is one or more of chromium oxalate, chromium acetate, chromium citrate, chromium malonate, chromium propionate and chromium lactate, preferably chromium lactate.

8. A gel plugging agent as claimed in claim 1, characterized in that: The deoxidizer is one or more of thiourea, sodium thiosulfate, sodium sulfite, and sodium bisulfite, preferably thiourea.

9. A gel plugging agent as claimed in 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 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 gel plugging agent: The dendritic polymer prepared in step (1), the cross-linking agent, the deoxidizer and the water are mixed evenly to obtain a gel plugging agent.

11. The method for preparing the 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-carboxyphenylacetic acid or p-vinylbenzoic acid or p-vinylphenylacetic acid 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 then 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 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 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 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 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 gel plugging agent according to claim 11, characterized in that: The mass ratio of p-carboxyphenylacetic acid or p-vinylbenzoic acid or p-vinylphenylacetic acid 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 the p-carboxyphenylacetic acid or p-vinylbenzoic acid or p-vinylphenylacetic acid 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. A 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 gel plugging agent according to any one of claims 1 to 9 and 17 as a water plugging and profile control agent in heavy oil production.

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