High-temperature-resistant gel composition as well as preparation method and application thereof

Abstract

The invention discloses a high-temperature-resistant gel composition, which is prepared from the following components: 0.3 to 1.2 parts of dendritic polymer; 0.3 to 1.5 parts of a cross-linking agent; 0.2 to 1.5 parts of a deoxidant; 0.3-2 parts of an oil washing agent; and 80 to 110 parts of water. The invention discloses a preparation method of a high-temperature-resistant gel composition. The preparation method comprises the following steps: (1) synthesizing a dendritic polymer; and (2) preparation of the high-temperature-resistant gel composition: 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, the oil washing agent according to the formula ratio and the water according to the formula ratio to obtain the high-temperature-resistant gel composition. The invention discloses application of a high-temperature-resistant gel composition as a high-temperature plugging agent in heavy oil thermal recovery. The invention discloses application of a high-temperature-resistant gel composition as an oil washing agent in heavy oil thermal recovery.

Description

Technical Field

[0001] The invention belongs to the field of heavy oil exploitation, and particularly relates to a high temperature resistant gel composition and a preparation method and application thereof. Background Art

[0002] Thermal oil recovery is the most commonly used method for the development of heavy oil reservoirs in my country. For example, Chinese invention patent application CN103321622A provides a thermal oil recovery well injection and production integrated oil recovery method and device, wherein the method is that during the steam injection process, high-temperature and high-pressure water vapor enters the downhole power fluid pipe and the downhole mixed liquid pipe through the wellhead device with thermal compensation function, and then enters the heavy oil or super heavy oil layer through the downhole hydraulic jet pump working cylinder connected to the downhole power fluid pipe and the downhole mixed liquid pipe, so as to realize the steam injection operation of the oil well; after the steam injection is completed, oil production is carried out, and the power fluid is used to send the pump core of the hydraulic jet pump to the downhole hydraulic jet pump barrel to make the hydraulic jet pump work, and it is continuously lifted to the ground through the annular space between the downhole power fluid pipe and the downhole mixed liquid pipe, and the sealing part in the hydraulic jet pump barrel adopts threaded sealing or metal sealing. For another example, Chinese invention patent application CN 102635342A discloses a thermal chemical oil recovery method for offshore heavy oil. The method comprises the following steps: using high-temperature tail gas or combustion waste heat to heat the injection water in the heat exchanger to 150-200°C; then the injection water carries the surfactant online, and the slug injects the catalyst solution, and the two are injected into the heavy oil layer for chemical enhanced thermal oil recovery.

[0003] However, under reservoir conditions, gravity overburden and crossflow will reduce the effectiveness of thermal oil recovery. In the case of gravity overburden, due to gravity, low-density steam will rise to the top of the reservoir, while the movable oil in the lower part of the reservoir is not affected. In the case of steam crossflow, steam tends to enter the high-permeability layer, but the oil in the surrounding low-permeability layer may not be affected. In addition, due to the high cost of producing steam fuel, the amount of steam injected per cycle during steam stimulation is limited, resulting in repeated heating of the injected steam around the wellbore, and it is difficult to efficiently recover the remaining oil between the wells.

[0004] Gel plugging and adjustment technology can effectively block hyperosmotic channels and force steam to turn, and is an important means to expand steam sweep and improve steam thermal utilization. However, traditional gel plugging agents are mainly polyacrylamide cross-linking systems. The polymer chain is easy to break under high temperature conditions, resulting in the destruction of the three-dimensional network structure of the gel, poor thermal stability, and a short plugging period. To this end, many scholars have designed heat-resistant functional monomers to copolymerize with acrylamide to improve thermal stability. For example, Chinese invention patent application CN 104277802A discloses a high-temperature resistant composite gel plugging agent and its preparation method, which includes the following components by weight: 85-90 parts of water, 0.1-0.5 parts of polyacrylamide, 0.2-0.5 parts of regulator, 1-1.5 parts of gelling agent and 8-15 parts of water-soluble silicate, but limited by the low cross-linking site density and cross-linking strength of the system, the gel strength and plugging period are not significantly improved. Therefore, it is necessary to develop high-temperature resistant polymers with high cross-linking site density to greatly improve thermal stability and then achieve high-strength and long-term plugging.

[0005] Using gel plugging and adjustment technology alone cannot guarantee the thermal recovery effect. Multi-effect composite gel materials have obvious advantages due to their integrated plugging, adjustment and oil washing characteristics. They can be used to plug high-permeability strips and improve sweep effects during heavy oil production. At the same time, after breaking the gel, they can reduce the viscosity of heavy oil and wash oil, thereby improving the thermal recovery effect. Therefore, for thermal recovery of heavy oil reservoirs, it is still necessary to develop temperature-resistant gel materials that integrate plugging, adjustment and oil washing to effectively improve the thermal recovery effect. Summary of the invention

[0006] Purpose of the invention: In view of the deficiencies of the above-mentioned prior art and the demand for thermal recovery of heavy oil reservoirs, the present invention discloses a high temperature resistant gel composition and its preparation method and application, which can be used to block high permeability bands and improve sweep effect during heavy oil recovery, and at the same time, after breaking the gel, the viscosity of the heavy oil can be reduced and the oil can be washed, thereby improving the thermal recovery effect. The gel system can withstand a temperature of 200°C, and after aging at 120°C for 180 days or 200°C for 30 days, the gel plugging strength is 3-10MPa / m, and the dehydration rate is <10%; for crude oil with an apparent viscosity of 5000-30000mPa·s at 50°C, the viscosity reduction rate of the gel system after breaking the gel reaches more than 98%, and the static oil washing rate reaches more than 50%.

[0007] Technical solution: A high temperature resistant gel composition, which consists of the following components in parts by weight:

[0008] 0.3-1.2 parts of dendritic polymer;

[0009] 0.3-1.5 parts of cross-linking agent;

[0010] 0.2-1.5 parts of deoxidizer;

[0011] 0.3-2 parts of oil cleaning agent;

[0012] 80-110 parts of water.

[0013] Further, it is composed of the following components:

[0014] 0.4-0.6 parts of dendritic polymer;

[0015] 0.5-1.0 parts of cross-linking agent;

[0016] 0.4-0.6 parts of deoxidizer;

[0017] 0.5-1 part of detergent;

[0018] 90-100 parts of water.

[0019] Furthermore, the structure of the dendritic polymer is shown in formula (1):

[0020]

[0021] 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;

[0022] Wherein is a polymer chain structure, and its specific structural formula is shown in formula (2) or formula (3):

[0023]

[0024] Wherein: p is any integer or decimal in the range of 200-7000, preferably any integer or decimal in the range of 400-5000;

[0025] q is any integer or decimal in the range of 200-7000, and preferably any integer or decimal in the range of 400-5000.

[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 urotropine, formaldehyde, paraformaldehyde, hexamethylenetetramine, phenol, resorcinol, hydroquinone, water-soluble phenolic resin, and urea-formaldehyde resin, preferably one or more of urotropine, resorcinol, and water-soluble phenolic resin.

[0028] Furthermore, the deoxidizer is one or more of thiourea, sodium thiosulfate, sodium sulfite, and sodium bisulfite, preferably thiourea or sodium sulfite.

[0029] Furthermore, the oil cleaning agent is one or more of anionic surfactants, anionic nonionic surfactants, nonionic surfactants, and zwitterionic surfactants, preferably one or more of anionic surfactants and zwitterionic surfactants.

[0030] Furthermore, the anionic surfactant is one or more of alkyl sulfonates, alkylbenzene sulfonates, alkyl carboxylates, alkylnaphthalene sulfonates, petroleum sulfonates, and α-olefin sulfonates, preferably alkylbenzene sulfonates or α-olefin sulfonates.

[0031] Furthermore, the anionic nonionic surfactant is one or more of alkyl polyether sulfonate and alkyl polyether carboxylate, preferably alkyl polyether sulfonate.

[0032] Furthermore, the nonionic surfactant is one or more of fatty alcohol polyoxyethylene ether and alkylphenol polyoxyethylene ether, preferably fatty alcohol polyoxyethylene ether.

[0033] Furthermore, the zwitterionic surfactant is one or more of alkyl sulfonate betaine, alkyl amide betaine, alkyl betaine, alkyl hydroxysulfonate betaine, preferably alkyl sulfonate betaine.

[0034] Furthermore, the water has a total mineralization of less than 50,000 mg / L.

[0035] The preparation method of the high temperature resistant gel composition comprises the following steps:

[0036] (1) Synthesis of dendrimers;

[0037] (2) Preparation of high temperature resistant gel composition:

[0038] 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, a formulated amount of an oil washing agent, and a formulated amount of water to obtain a high temperature resistant gel composition.

[0039] Further, in terms of molar parts, the specific steps of step (1) are as follows:

[0040] (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;

[0041] (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;

[0042] (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;

[0043] (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;

[0044] (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 sodium 2-acrylamide-2-methylpropanesulfonate or sodium p-styrenesulfonate 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 50-80° C. for 6-12 h to obtain a reaction solution. The reaction solution is then evaporated to remove water. Finally, the product is washed with ethanol for at least 3 times, dried, and ground into powder to obtain a dendritic polymer.

[0045] Furthermore, the molar ratio of ethylenediamine to methyl acrylate in step (11) is 1:(7-9);

[0046] 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);

[0047] 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).

[0048] 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;

[0049] 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);

[0050] 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;

[0051] 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.

[0052] 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;

[0053] 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);

[0054] 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;

[0055] 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.

[0056] 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;

[0057] 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);

[0058] 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;

[0059] 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;

[0060] 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.

[0061] Furthermore, the mass ratio of sodium 2-acrylamide-2-methylpropane sulfonate or sodium p-styrene sulfonate to the dendritic intermediate MAZ in step (15) is 1:(3-19), preferably 1:(4-9);

[0062] In step (15), based on the mixed solution A, the concentration of the sum of the mass of the sodium 2-acrylamide-2-methylpropane sulfonate or sodium p-styrene sulfonate and the dendritic intermediate MAZ is 10-30 wt %;

[0063] The initiator described in step (15) is one of azobisisobutyronitrile, azobisisobutyramidine hydrochloride, and azobisisoheptylonitrile, preferably azobisisobutyronitrile;

[0064] In step (15), based on the mixed solution B, the initiator concentration is 0.05-0.12% by weight.

[0065] The high temperature resistant gel composition is prepared by any one of the preparation methods described above.

[0066] The high temperature resistant gel composition described in any one of the above items is used as a high temperature plugging agent in heavy oil thermal recovery.

[0067] Furthermore, the specific steps of the application are as follows: injecting the high temperature resistant gel composition into the formation, so that the high temperature resistant gel composition is cross-linked in situ in the formation to form a gel. After the structure of the gel is destroyed, the detergent aqueous solution can be released.

[0068] The application of any of the above-mentioned high temperature resistant gel compositions as an oil washing agent in heavy oil thermal recovery.

[0069] The high temperature resistant gel composition of the present invention has much more active sites on the surface of the designed dendritic polymer than polyacrylamide polymers. The crosslinking density of the three-dimensional network structure formed after the reaction with the crosslinking agent and the deoxidizer is very high, and its plugging strength is much higher than the gel plugging strength formed by the polyacrylamide polymer. Therefore, it can be plugged with high strength during the steam injection process, and the hyperosmotic channel can be blocked for a long time after the steam injection is completed, and the water content can be controlled to rise rapidly. In addition, the three-dimensional network structure of the high temperature resistant gel composition is wrapped with a small molecule temperature resistant oil washing agent. After the gel structure is destroyed, the oil washing agent aqueous solution is released, which can further efficiently strip and emulsify crude oil at the steam front, improve the flowability of crude oil, and then improve the thermal recovery effect. The high temperature resistant gel composition has a good application prospect in the thermal oil recovery process of heavy oil reservoirs.

[0070] Beneficial effects: Compared with the prior art, the present invention has the following beneficial effects:

[0071] (1) 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 a dehydration rate of <10%, and has a long effective plugging period;

[0072] (2) For crude oil with an apparent viscosity of 5000-30000 mPa·s at 50°C, the viscosity reduction rate of the gel system after gel breaking reaches more than 98%, and the static oil washing rate reaches more than 50%, realizing the integration of plugging, adjustment and oil washing;

[0073] (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

[0074] Figure 1 The present invention is a flow chart of a method for preparing a high temperature resistant gel composition disclosed in the present invention. DETAILED DESCRIPTION

[0075] 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.

[0076] The reaction equation for preparing the dendritic polymer is as follows:

[0077]

[0078]

[0079] Example 1

[0080] The high temperature resistant gel composition M1 is composed of the following substances in parts by mass:

[0081]

[0082] In another embodiment, the high temperature resistant gel composition M1', in parts by mass, consists of the following components:

[0083] 0.4 parts of dendrimer;

[0084] 0.5 parts of cross-linking agent;

[0085] 0.4 parts of deoxidizer;

[0086] 0.5 oil cleaning agent;

[0087] 90 parts water.

[0088] 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.

[0089] Furthermore, the molecular formula of the dendritic polymer S1 is as follows:

[0090]

[0091] Where ● is the polymer chain structure, as follows:

[0092]

[0093] Among them, a, b, c, d, e, f, g, and h are all 1000, and p is 5000.

[0094] The weight average molecular weight of the dendritic polymer S1 is 2.54×10 6 .

[0095] In another embodiment, the dendritic polymer S1' has the following molecular formula:

[0096]

[0097] Where ● is the polymer chain structure, as follows:

[0098]

[0099] Among them, a, b, c, d, e, f, g, and h are all 400, and p is 200.

[0100] The weight average molecular weight of the dendritic polymer S1' is 0.8×10 6 .

[0101] In another embodiment, the dendritic polymer S1# has the following molecular formula:

[0102]

[0103] Where ● is the polymer chain structure, as follows:

[0104]

[0105] Among them, a, b, c, d, e, f, g, and h are all 3800, and p is 7000.

[0106] The weight average molecular weight of the dendritic polymer S1# is 6×10 6 .

[0107] In another embodiment, the dendritic polymer S1* has the following molecular formula:

[0108]

[0109] Where ● is the polymer chain structure, as follows:

[0110]

[0111] Among them, a, b, c, d, e, f, g, and h are all 1500, and p is 400.

[0112] The weight average molecular weight of the dendritic polymer S1* is 4.35×10 6 .

[0113] In another embodiment, the dendritic polymer S1" has the following molecular formula:

[0114]

[0115] Where ● is the polymer chain structure, as follows:

[0116]

[0117] Among them, a, b, c, d, e, f, g, and h are all 2000, and p is 4000.

[0118] The weight average molecular weight of the dendritic polymer S1" is 3.06×10 6 .

[0119] The preparation method of the high temperature resistant gel composition M1 comprises the following steps:

[0120] (1) Synthesis of dendrimer S1;

[0121] (2) Preparation of high temperature resistant gel composition M1:

[0122] The dendritic polymer S1 prepared in step (1) is mixed uniformly with a formulated amount of a cross-linking agent, a formulated amount of an oxygen scavenger, a formulated amount of an oil washing agent, and a formulated amount of water to obtain a high temperature resistant gel composition M1.

[0123] Further, in terms of molar parts, the specific steps of step (1) are as follows:

[0124] (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.

[0125] (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;

[0126] (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;

[0127] (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;

[0128] (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 sodium 2-acrylamide-2-methylpropanesulfonate 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. Finally, the product is washed with ethanol three times, dried, and ground into powder to obtain a dendritic polymer S1.

[0129] In another embodiment, the molar ratio of ethylenediamine to methyl acrylate in step (11) is 1:7.

[0130] 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.

[0131] The mass ratio of methyl acrylate to methanol in the methanol solution of methyl acrylate described in step (11) is 1:1.

[0132] 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;

[0133] The mass ratio of MA0.5 to methanol in the methanol solution of MA0.5 described in step (12) is 1:1.

[0134] 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.

[0135] 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.

[0136] 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.

[0137] The mass ratio of MA1.0 to methanol in the methanol solution of MA1.0 described in step (13) is 1:1.

[0138] 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.

[0139] 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.

[0140] 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.

[0141] 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.

[0142] The mass ratio of MA1.5 to methanol in the methanol solution of MA1.5 described in step (14) is 1:1.

[0143] 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.

[0144] 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.

[0145] Furthermore, the mass ratio of sodium 2-acrylamide-2-methylpropanesulfonate to the dendritic intermediate MAZ in step (15) is 1:3. In another embodiment, the mass ratio of sodium 2-acrylamide-2-methylpropanesulfonate to the dendritic intermediate MAZ in step (15) is 1:4.

[0146] In step (15), based on the mixed solution A, the concentration of the sum of the mass of the sodium 2-acrylamide-2-methylpropane sulfonate and the dendritic intermediate MAZ is 10 wt %.

[0147] Furthermore, the initiator in step (15) is azobisisobutyronitrile.

[0148] In step (15), based on the mixed solution B, the initiator concentration is 0.05 wt %.

[0149] The high temperature resistant gel composition M1 is prepared by any one of the preparation methods described above.

[0150] The high temperature resistant gel composition M1 described in any one of the above items is used as a high temperature plugging agent in heavy oil thermal recovery.

[0151] Furthermore, the specific steps of the application are as follows: injecting the high temperature resistant gel composition M1 into the formation, so that the high temperature resistant gel composition M1 is cross-linked in situ in the formation to form a gel. After the structure of the gel is destroyed, the detergent aqueous solution can be released.

[0152] The high temperature resistant gel composition M1 described in any one of the above items is used as an oil washing agent in heavy oil thermal recovery.

[0153] Example 2

[0154] The high temperature resistant gel composition M2 is composed of the following substances in parts by mass:

[0155]

[0156]

[0157] In another embodiment, the high temperature resistant gel composition M2', in parts by mass, consists of the following substances:

[0158]

[0159] Furthermore, the water is formation water with a total mineralization of 20,000 mg / L, of which Ca 2+ Mg 2+ Total ion concentration: 1800mg / L.

[0160] The molecular formula of the dendritic polymer S2 is as follows:

[0161]

[0162] Where ● is the polymer chain structure, as follows:

[0163]

[0164] Among them, a, b, c, d, e, f, g, and h are all 1500, and q is 3000.

[0165] The weight average molecular weight of the dendritic polymer S2 is 2.9×10 6 .

[0166] In another embodiment, another dendritic polymer is substantially the same as the dendritic polymer S2, except that q is 7000 and the weight average molecular weight of the dendritic polymer is 4.23×10 6 .

[0167] In another embodiment, another dendritic polymer is substantially the same as the dendritic polymer S2, except that q is 200 and the weight average molecular weight of the dendritic polymer is 1.4×10 6 .

[0168] In another embodiment, another dendritic polymer is substantially the same as the dendritic polymer S2, except that q is 400 and the weight average molecular weight of the dendritic polymer is 1.93×10 6 .

[0169] In another embodiment, another dendritic polymer is substantially the same as the dendritic polymer S2, except that q is 5000 and the weight average molecular weight of the dendritic polymer is 3.72×10 6 .

[0170] The preparation method of the high temperature resistant gel composition M2 comprises the following steps:

[0171] (1) Synthesis of dendrimer S2;

[0172] (2) Preparation of high temperature resistant gel composition M2:

[0173] The dendritic polymer S2 prepared in step (1) is mixed uniformly with a formulated amount of a cross-linking agent, a formulated amount of an oxygen scavenger, a formulated amount of an oil-washing agent, and a formulated amount of water to obtain a high temperature resistant gel composition M2.

[0174] Further, in terms of molar parts, the specific steps of step (1) are as follows:

[0175] (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.

[0176] (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;

[0177] (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;

[0178] (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;

[0179] (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 sodium p-styrene sulfonate 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 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 S2.

[0180] In another embodiment, the molar ratio of ethylenediamine to methyl acrylate in step (11) is 1:9.

[0181] 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.

[0182] Furthermore, the mass ratio of methyl acrylate to methanol in the methanol solution of methyl acrylate described in step (11) is 1:2.

[0183] 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.

[0184] The mass ratio of MA0.5 to methanol in the methanol solution of MA0.5 described in step (12) is 1:2.

[0185] 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.

[0186] 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.

[0187] 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.

[0188] 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.

[0189] 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.

[0190] 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.

[0191] 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;

[0192] 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.

[0193] The mass ratio of MA1.5 to methanol in the methanol solution of MA1.5 described in step (14) is 1:3.

[0194] 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.

[0195] 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.

[0196] Furthermore, the mass ratio of sodium p-styrene sulfonate to the dendritic intermediate MAZ in step (15) is 1:19. In another embodiment, the mass ratio of sodium p-styrene sulfonate to the dendritic intermediate MAZ in step (15) is 1:9.

[0197] In step (15), based on the mixed solution A, the concentration of the sum of the mass of the sodium p-styrene sulfonate and the dendritic intermediate MAZ is 30 wt %.

[0198] Furthermore, the initiator in step (15) is azobisisobutylamidine hydrochloride.

[0199] In step (15), based on the mixed solution B, the initiator concentration is 0.12% by weight.

[0200] The high temperature resistant gel composition M2 is prepared by any one of the preparation methods described above.

[0201] The high temperature resistant gel composition M2 described in any one of the above items is used as a high temperature plugging agent in heavy oil thermal recovery.

[0202] Furthermore, the specific steps of the application are as follows: injecting the high temperature resistant gel composition M2 into the formation, so that the high temperature resistant gel composition M2 is cross-linked in situ in the formation to form a gel. After the structure of the gel is destroyed, the detergent aqueous solution can be released.

[0203] The high temperature resistant gel composition M2 described in any one of the above items is used as an oil washing agent in heavy oil thermal recovery.

[0204] Example 3

[0205] The high temperature resistant gel composition M3 is composed of the following substances in parts by mass:

[0206]

[0207]

[0208] In another embodiment, the high temperature resistant gel composition M3', in parts by mass, consists of the following substances:

[0209]

[0210] Furthermore, the water is formation water with a total mineralization of 50,000 mg / L, of which Ca2+ Mg 2+ Total ion concentration: 3000mg / L.

[0211] The molecular formula of the dendritic polymer S3 is as follows:

[0212]

[0213] Where ● is the polymer chain structure, as follows:

[0214]

[0215] Among them, a, b, c, d, e, f, g, and h are all 2000, and p is 1000.

[0216] The weight average molecular weight of the dendritic polymer S3 is 3.25×10 6 .

[0217] The preparation method of the high temperature resistant gel composition M3 comprises the following steps:

[0218] (1) Synthesis of dendrimer S3;

[0219] (2) Preparation of high temperature resistant gel composition M3:

[0220] The dendritic polymer S3 prepared in step (1) is mixed uniformly with a formulated amount of a cross-linking agent, a formulated amount of an oxygen scavenger, a formulated amount of an oil-washing agent, and a formulated amount of water to obtain a high temperature resistant gel composition M3.

[0221] Further, in terms of molar parts, the specific steps of step (1) are as follows:

[0222] (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.

[0223] (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 55° 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;

[0224] (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;

[0225] (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;

[0226] (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 sodium 2-acrylamide-2-methylpropanesulfonate 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 the dendritic polymer S3.

[0227] The mass ratio of ethylenediamine to methanol in the methanol solution of ethylenediamine described in step (11) is 1:10;

[0228] The mass ratio of methyl acrylate to methanol in the methanol solution of methyl acrylate described in step (11) is 1.5.

[0229] Furthermore, in the mixed solution described in step (12), the molar ratio of ethylenediamine to MA0.5 is 26:1;

[0230] The mass ratio of MA0.5 to methanol in the methanol solution of MA0.5 described in step (12) is 1:1.5.

[0231] 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;

[0232] 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.

[0233] Furthermore, the molar ratio of methyl acrylate to MA1.0 in the mixed solution described in step (13) is 16:1;

[0234] The mass ratio of MA1.0 to methanol in the methanol solution of MA1.0 described in step (13) is 1:1.5.

[0235] Furthermore, the mass ratio of the amount of petroleum ether used in step (13) to the amount of MA1.0 used is 10:1;

[0236] The mass ratio of the amount of ethyl acetate used in step (13) to the amount of MA1.0 used is 10:1.

[0237] Furthermore, the molar ratio of (Z)-3-aminoacrylamide to MA1.5 in the mixed solution described in step (14) is 26:1;

[0238] 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;

[0239] The mass ratio of MA1.5 to methanol in the methanol solution of MA1.5 described in step (14) is 1:2.

[0240] Furthermore, the mass ratio of the amount of petroleum ether used in step (14) to the amount of MA1.5 used is 10:1;

[0241] The mass ratio of the amount of ethyl acetate used in step (14) to the amount of MA1.5 used is 10:1.

[0242] Furthermore, the mass ratio of sodium 2-acrylamide-2-methylpropanesulfonate to the dendritic intermediate MAZ in step (15) is 1:7;

[0243] In step (15), based on the mixed solution A, the concentration of the sum of the mass of the sodium 2-acrylamide-2-methylpropane sulfonate and the dendritic intermediate MAZ is 20% by weight.

[0244] Furthermore, the initiator in step (15) is azobisisoheptanonitrile.

[0245] In step (15), based on the mixed solution B, the initiator concentration is 0.1 wt %.

[0246] The high temperature resistant gel composition M3 is prepared by any one of the preparation methods described above.

[0247] The high temperature resistant gel composition M3 described in any one of the above items is used as a high temperature plugging agent in heavy oil thermal recovery.

[0248] Furthermore, the specific steps of the application are as follows: injecting the high temperature resistant gel composition M3 into the formation, so that the high temperature resistant gel composition M3 is cross-linked in situ in the formation to form a gel. After the structure of the gel is destroyed, the detergent aqueous solution can be released.

[0249] The high temperature resistant gel composition M3 described in any one of the above items is used as an oil washing agent in heavy oil thermal recovery.

[0250] Embodiment 4-12

[0251] The same as Example 1, the only difference is that the cross-linking agent is different

[0252]

[0253]

[0254] Examples 13-16

[0255] It is similar to Example 1, except that the deoxidizer is different:

[0256]

[0257] Examples 17-34

[0258] It is roughly the same as Example 1, except that the washing oil is different:

[0259]

[0260]

[0261] Performance evaluation of high temperature resistant gel compositions M1, M2 and M3

[0262] Test Example 1

[0263] The water used in this experiment is produced water from a block Y of Shengli Oilfield, and the reservoir temperature is 55°C. The oil used in this experiment is an oil sample from this block, and the surface degassed crude oil has a viscosity of 23730 mPa·s and a density of 0.9635 g / cm 3 , the emulsified water content is 21.7%. The water used in this experiment is the formation water from this block, with a total mineralization of 16680 mg / L, including Ca 2+ Content 1258mg / L, Mg 2+ Content: 201mg / L.

[0264] 1. Plugging rate and dehydration rate

[0265] The high temperature resistant gel composition M1, high temperature resistant gel composition M2, high temperature resistant gel composition M3 prepared in Examples 1-3 and the commercially available gel plugging agents RM-1 and RM-2 were respectively placed in a 200°C oven for aging for 30 days, and their plugging pressure gradient and plugging rate were tested. The test method referred to Q / SH10202777-2020 "General Technical Conditions for Thermal Recovery Plugging Agents".

[0266] The water permeability of the prepared core is 2000-2500×10 -3 μm 2 The high temperature resistant gel compositions M1, M2 and M3 prepared in Examples 1-3 and the commercially available gel plugging agents RM-1 and RM-2 were respectively placed in glass tubes and sealed, and the mass m1 of water in the gel solution and the mass m2 of water removed from the gel after aging at 200°C for 30 days were measured, and the dehydration rate was calculated as m2 / m1*100%. The test results are shown in Table 1.

[0267] Table 1 Performance test results of high temperature resistant gel compositions M1, M2, M3 and commercially available gel plugging agents RM-1 and RM-2

[0268]

[0269] According to the above evaluation results, the high temperature resistant gel composition M1, the high temperature resistant gel composition M2, and the high temperature resistant gel composition M3 of the present invention can withstand a temperature of 200°C. After aging at 200°C for 30 days, the gel plugging agent has a plugging strength of 6.8-9.5MPa / m, a dehydration rate of <10%, and a long effective plugging period; while the commercially available gel plugger RM-1 completely breaks down at 200°C and has poor heat resistance. The commercially available gel plugger RM-2 has a plugging strength of only 2.6MPa / m after aging at 200°C for 30 days, and a dehydration rate of 68%. High temperature aging causes part of the gel structure to be destroyed, resulting in severe dehydration, making it difficult to achieve long-term plugging.

[0270] The high temperature resistant gel composition M1, high temperature resistant gel composition M2 and high temperature resistant gel composition M3 of the present invention all meet the relevant requirements of oil fields, have excellent plugging performance compared with commercially available gel plugging agents, and can meet the development needs of multiple rounds of heavy oil reservoirs.

[0271] 2. Viscosity reduction rate and static oil washing rate

[0272] The high temperature resistant gel composition M1, high temperature resistant gel composition M2, and high temperature resistant gel composition M3 prepared in Examples 1-3 were placed in an oven at 250°C for aging for 24 hours to break the gel. After filtering the residue, the viscosity reduction rate and static oil washing rate were tested. The viscosity reduction rate determination method was based on Q / SH 1020 1519-2016 "General Standard for Viscosity Reducers for Heavy Oil", and the static oil washing rate test method was based on Q / SH10202191-2018 "Technical Requirements for Surfactants for Oil Displacement". The test results are shown in Table 2.

[0273] Table 2 Test results of viscosity reduction washing oil performance of high temperature resistant gel compositions M1, M2 and M3 after gel breaking

[0274] project M1 M2 M3 Viscosity reduction rate, % 98.2 99.0 99.3 Static oil washing rate, % 51.5 58.6 73.4

[0275] According to the above evaluation results, the viscosity reduction rate of the high temperature resistant gel composition M1, the high temperature resistant gel composition M2, and the high temperature resistant gel composition M3 of the present invention after gel breaking reaches more than 98%, and the static oil washing rate reaches more than 50%, realizing the integration of plugging, adjustment and oil washing, and effectively improving the thermal recovery effect.

[0276] 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 high temperature resistant gel composition, characterized in that: In parts by weight, it is composed of the following components: 0.3-1.2 parts of dendritic polymer; 0.3-1.5 parts of cross-linking agent; 0.2-1.5 parts of deoxidizer; 0.3-2 parts of oil cleaning agent; 80-110 parts of water.

2. A high temperature resistant gel composition according to claim 1, characterized in that: In parts by weight, it is composed of the following components: 0.4-0.6 parts of dendritic polymer; 0.5-1.0 parts of cross-linking agent; 0.4-0.6 parts of deoxidizer; 0.5-1 part of detergent; 90-100 parts of water.

3. A high temperature resistant gel composition 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 400-3800, preferably a, b, c, d, e, f, g, h are any integer or decimal in the range of 1000-2000; Wherein is a polymer chain structure, and its specific structural formula is shown in formula (2) or formula (3): Wherein: p is any integer or decimal in the range of 200-7000, preferably any integer or decimal in the range of 400-5000; q is any integer or decimal in the range of 200-7000, and preferably any integer or decimal in the range of 400-5000.

4. A high temperature resistant gel composition 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 -4×10 6 .

5. A high temperature resistant gel composition according to claim 1, characterized in that: The crosslinking agent is one or more of urotropine, formaldehyde, paraformaldehyde, hexamethylenetetramine, phenol, resorcinol, hydroquinone, water-soluble phenolic resin, and urea-formaldehyde resin, preferably one or more of urotropine, resorcinol, and water-soluble phenolic resin.

6. A high temperature resistant gel composition according to claim 1, characterized in that: The deoxidizer is one or more of thiourea, sodium thiosulfate, sodium sulfite, and sodium bisulfite, preferably thiourea or sodium sulfite.

7. A high temperature resistant gel composition according to claim 1, characterized in that: The oil cleaning agent is one or more of anionic surfactants, anionic nonionic surfactants, nonionic surfactants, and zwitterionic surfactants, preferably one or more of anionic surfactants and zwitterionic surfactants.

8. A high temperature resistant gel composition according to claim 7, characterized in that: The anionic surfactant is one or more of alkyl sulfonate, alkylbenzene sulfonate, alkyl carboxylate, alkylnaphthalene sulfonate, petroleum sulfonate, α-olefin sulfonate, preferably alkylbenzene sulfonate or α-olefin sulfonate.

9. A high temperature resistant gel composition according to claim 7, characterized in that: The anionic nonionic surfactant is one or more of alkyl polyether sulfonate and alkyl polyether carboxylate, preferably alkyl polyether sulfonate.

10. A high temperature resistant gel composition according to claim 7, characterized in that: The nonionic surfactant is one or more of fatty alcohol polyoxyethylene ether and alkylphenol polyoxyethylene ether, preferably fatty alcohol polyoxyethylene ether.

11. A high temperature resistant gel composition according to claim 7, characterized in that: The zwitterionic surfactant is one or more of alkyl sulfonate betaine, alkyl amide betaine, alkyl betaine, alkyl hydroxysulfonate betaine, preferably alkyl sulfonate betaine.

12. A high temperature resistant gel composition according to claim 7, characterized in that: The water is water with a total mineralization of less than 50000 mg / L.

13. The method for preparing the high temperature resistant gel composition according to any one of claims 1 to 12, characterized in that: The following steps are involved: (1) Synthesis of dendrimers; (2) Preparation of high temperature resistant gel composition: 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, a formulated amount of an oil-washing agent, and a formulated amount of water to obtain a high temperature resistant gel composition.

14. The method for preparing the high temperature resistant gel composition according to claim 13, 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 sodium 2-acrylamide-2-methylpropanesulfonate or sodium p-styrenesulfonate 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 50-80° C. for 6-12 h to obtain a reaction solution. The reaction solution is then evaporated to remove water. Finally, the product is washed with ethanol for at least 3 times, dried, and ground into powder to obtain a dendritic polymer.

15. The method for preparing the high temperature resistant gel composition according to claim 14, 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).

16. The method for preparing the high temperature resistant gel composition according to claim 14, 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.

17. The method for preparing the high temperature resistant gel composition according to claim 14, 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.

18. The method for preparing the high temperature resistant gel composition according to claim 14, 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.

19. The method for preparing the high temperature resistant gel composition according to claim 14, characterized in that: The mass ratio of sodium 2-acrylamide-2-methylpropane sulfonate or sodium p-styrene sulfonate 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 sodium 2-acrylamide-2-methylpropane sulfonate or sodium p-styrene sulfonate 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.

20. A high temperature resistant gel composition, characterized in that: It is prepared by the preparation method described in any one of claims 13 to 19.

21. Use of the high temperature resistant gel composition according to any one of claims 1 to 12 and 20 as a high temperature plugging agent in heavy oil thermal recovery.

22. The use according to claim 21, characterized in that The specific steps of the application are as follows: injecting the high temperature resistant gel composition into a formation, so that the high temperature resistant gel composition is cross-linked in situ in the formation to form a gel.

23. Use of the high temperature resistant gel composition according to any one of claims 1 to 12 and 20 as an oil washing agent in heavy oil thermal recovery.

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