Method for steam development of heavy oil reservoir by aid of high-temperature-resistant oil-displacing agent

Abstract

The invention provides a method for steam development of a heavy oil reservoir through a high-temperature-resistant oil-displacing agent, and relates to the technical field of oilfield development. The method comprises the steps that water is added into a high-temperature-resistant oil-displacing agent to prepare a high-temperature-resistant oil-displacing agent solution, and then the high-temperature-resistant oil-displacing agent solution is continuously injected into a steam injection well in the steam flooding exploitation process of the heavy Wherein the high-temperature-resistant oil displacement agent is prepared from the following raw materials in parts by weight: 35 to 50 parts of linear alkylbenzene sulfonate, 10 to 15 parts of fatty alcohol-polyoxyethylene ether, 2 to 5 parts of lignin and 3 to 8 parts of amino-terminated polyurethane modified TiO2. Compared with traditional steam flooding, the high-temperature-resistant oil displacement agent is used for assisting steam development, the swept area can be increased, and the recovery efficiency can be effectively improved.

Description

Technical Field

[0001] This application relates to the field of oilfield development technology, and in particular to a method for steam-assisted development of heavy oil reservoirs using a high-temperature resistant oil displacement agent. Background Technology

[0002] Heavy oil resources represent a vast potential resource in my country. Rich in asphaltenes and resins, heavy oil has extremely high density, viscosity, and poor fluidity, posing significant challenges to extraction and transportation. Therefore, effectively reducing the viscosity and improving the fluidity of heavy oil is crucial for solving problems in its extraction, transportation, and refining. Currently, the main method for heavy oil development is steam injection, primarily through steam huff and puff. Steam flooding is a thermal recovery method employed to further enhance oil recovery in heavy oil reservoirs after steam huff and puff. However, in simple steam flooding, the steam injected from the injection well gradually condenses into hot water as it advances through the formation. Hot water has a significantly lower oil displacement efficiency than steam, resulting in a large amount of crude oil remaining underground and affecting the overall recovery rate. Therefore, improving oil displacement efficiency during steam flooding is a pressing issue requiring new technologies. Practice has proven that injecting highly efficient oil displacement agents during steam flooding is an effective way to improve the recovery rate of heavy oil reservoirs.

[0003] However, steam flooding development places high demands on the temperature and salt resistance of the displacement agents. Firstly, displacement agents meeting the requirements for heavy oil steam flooding need to withstand temperatures above 300℃. Existing displacement agents often fail to meet this requirement. Secondly, the high salinity of formation water in some heavy oil reservoirs reduces the solubility of the displacement agent molecules in water, altering its hydrophilic-lipophilic balance and reducing or even eliminating its interfacial activity.

[0004] Patent CN117986591A discloses a method for preparing a high-temperature oil displacement agent for steam flooding. The method involves a hydrosilylation reaction of methyl hydrogen silicone oil, 1-(3-olefinpyridin-2-yl)piperazine, allyl alcohol polyoxyethylene ether, and 2-vinylpyridine under the action of a catalyst, in the presence of a solvent, and under nitrogen protection. While this oil displacement agent meets the high-temperature resistance requirements of steam flooding, its salt and salinity resistance needs improvement. Furthermore, the macromolecular chain structure of this oil displacement agent is susceptible to formation adsorption; after formation adsorption, its performance deteriorates significantly, resulting in limited improvement in oil recovery. Summary of the Invention

[0005] The purpose of this application is to provide a method for developing heavy oil reservoirs using steam-assisted high-temperature displacement agents, addressing the shortcomings of existing technologies.

[0006] To achieve the above objectives, the technical solution adopted in this application is as follows: According to one aspect of this application, a method for steam-assisted development of heavy oil reservoirs using a high-temperature resistant oil displacement agent is provided, comprising preparing a high-temperature resistant oil displacement agent solution by adding water to the high-temperature resistant oil displacement agent solution, and then continuously injecting the solution into a steam injection well during the steam-driven development of the heavy oil reservoir; wherein the high-temperature resistant oil displacement agent comprises the following raw materials in parts by weight: 35-50 parts of linear alkylbenzene sulfonate, 10-15 parts of fatty alcohol polyoxyethylene ether, 2-5 parts of lignin, and 3-8 parts of amino-terminated polyurethane modified TiO2.

[0007] Preferably, the high-temperature oil displacement agent comprises the following raw materials in parts by weight: 40 parts of linear alkylbenzene sulfonate, 15 parts of fatty alcohol polyoxyethylene ether, 3 parts of lignin, and 25 parts of amino-terminated polyurethane modified TiO.

[0008] Furthermore, the amino-terminated polyurethane modified TiO2 is obtained by first reacting a polymeric diol, cashew nut glycol, nano-TiO2, and polyisocyanate to obtain an isocyanate-terminated prepolymer modified TiO2, then adding an aminosilane to modify the isocyanate-terminated prepolymer, and finally adding a molecular chain regulator to react; wherein, The raw materials, by weight, include: 40-55 parts of polymeric diol, 10-15 parts of cashew nut alcohol, 30-40 parts of nano-TiO2, 10-20 parts of polyisocyanate, 3-5 parts of aminosilane, and 10-20 parts of molecular chain regulator.

[0009] Preferably, in the preparation process of the amino-terminated polyurethane modified TiO2, the raw materials, by weight, include: 48 parts of polymeric diol, 12 parts of cashew nut glycol, 35 parts of nano-TiO2, 16 parts of polyisocyanate, 4 parts of aminosilane, and 13 parts of molecular chain regulator.

[0010] Optionally, the polymeric diol is selected from one or a combination of polyethylene glycol, polypropylene glycol, and polytetrahydrofuran glycol.

[0011] Optionally, the polyisocyanate is selected from polyisocyanate monomers containing at least two polyisocyanate groups, preferably a mixture of 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 1,3-phenylene diisocyanate and 1,4-phenylene diisocyanate, p-phenylene diisothiocyanate, xylene-1,4-diisothiocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, a mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate, and xylene-1,4-diisocyanate. The following are included: a mixture of xylene-1,3-diisocyanate, xylene-1,4-diisocyanate and xylene-1,3-diisocyanate; 1,3,5-trimethylbenzene-2,4-diisocyanate; 1,3,5-triisopropylbenzene-2,4-diisocyanate; diphenylmethane-4,4'-diisocyanate; 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate; 4,4'-diphenylpropane diisocyanate; and toluene-2,4,6-triisocyanate.

[0012] Optionally, the aminosilane is selected from any one or a combination of several of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and γ-(β-aminoethyl)aminopropyltrimethoxysilane.

[0013] Optionally, the molecular chain regulator is selected from at least one of diethanolamine, monoisopropanolamine, diisopropanolamine, diethylene glycolamine, and triethylene glycolamine, and preferably any one or a combination of ethanol, diethanolamine, diisopropanolamine, and diethylene glycolamine.

[0014] Further, the linear alkylbenzene sulfonate is a C20-C24 sodium alkylbenzene sulfonate; the fatty alcohol polyoxyethylene ether has the molecular formula RO-(CH2CH2O)nH, where R is an alkyl group with 8-14 carbons and n is a positive integer from 9 to 20.

[0015] Furthermore, the lignin is further modified with diisocyanate before use. The preparation method of diisocyanate-modified lignin is as follows: Lignin was dispersed in a solvent, and diisocyanate was added. The mixture was reacted at 80-95℃ for 3-5 hours. After the reaction was complete, the mixture was centrifuged and dried to obtain diisocyanate-modified lignin. The amount of diisocyanate used was 15-25% of the lignin mass.

[0016] Optionally, the diisocyanate is any one of 1,3-phenyl diisocyanate, 1,4-phenyl diisocyanate, xylene-1,4-diisothiocyanate, 2,4-toluene diisocyanate, and 2,6-toluene diisocyanate.

[0017] Optionally, the solvent is any one of toluene, xylene, N,N-dimethylformamide, and N,N-dimethylacetamide; the amount of the solvent used is at least three times the amount of lignin.

[0018] Furthermore, the mass concentration of the high-temperature resistant oil displacement agent is 0.3-1%.

[0019] Furthermore, during steam-driven extraction, the steam injection temperature is 250-300°C, the single-well steam injection rate is 100-150 t / d, the production-injection ratio is 1-1.5, and the steam dryness reaching the bottom of the well is controlled to be greater than 40%.

[0020] Furthermore, steam and high-temperature resistant oil displacement agent are injected simultaneously, with a mass ratio of steam to high-temperature resistant oil displacement agent of (0.001-0.3):1.

[0021] Furthermore, the conditions for heavy oil reservoirs are: oil layer burial depth 900-1500m, oil layer thickness ≥8m, and crude oil viscosity >100mPa·s.

[0022] Compared with the prior art, this application has the following beneficial effects: 1. This application provides a method for steam-assisted development of heavy oil reservoirs using a high-temperature resistant oil displacement agent. Compared with traditional steam drive, this application enhances the steam drive development of heavy oil by injecting a high-temperature resistant oil displacement agent during the steam drive process, thereby improving the thermal utilization efficiency and recovery rate of the steam drive and improving the steam drive development effect.

[0023] 2. The method for steam-assisted development of heavy oil reservoirs using a high-temperature resistant oil displacement agent described in this application utilizes linear alkylbenzene sulfonates and fatty alcohol polyoxyethylene ethers in the oil displacement agent. These components possess strong emulsifying abilities, significantly reducing the oil-water interfacial tension and providing good viscosity reduction. However, their high-temperature resistance is relatively poor, failing to adequately meet the requirements of steam-driven development. Adding a certain amount of amino-terminated polyurethane-modified TiO2 to the oil displacement agent reduces the interfacial tension between the agent and crude oil to 10 after withstanding temperatures up to 300℃. -3 The viscosity reduction rate reaches over 90% at the mN / m level. Adding diisocyanate-modified lignin to the oil displacement agent not only helps prevent excessive lignin addition from deteriorating high-temperature resistance and further improves the high-temperature resistance of the oil displacement agent, but also exhibits a certain synergistic effect between isocyanate-modified lignin and amino-terminated polyurethane-modified TiO2. This effectively reduces the interaction between the oil displacement agent and the rock, decreases rock adsorption, and thus better improves crude oil recovery. Detailed Implementation

[0024] The following non-limiting embodiments are intended to enable those skilled in the art to gain a more comprehensive understanding of this application, but do not limit this application in any way. The following content is merely an exemplary description of the scope of protection claimed in this application, and those skilled in the art can make various changes and modifications to the invention based on the disclosed content, which should also fall within the scope of protection claimed in this application.

[0025] Unless otherwise specified, all chemical reagents used in the embodiments of this application were obtained through conventional commercial means. In the specific embodiments below, the cashew nut shell alcohol was prepared by the following method: cashew nut shell alcohol was mixed with epichlorohydrin and sodium hydroxide in a molar ratio of 1:2:1 and reacted at 90°C for 2 hours. After the reaction was completed, the product was rotary evaporated to obtain epoxidized cashew nut shell alcohol. The epoxidized cashew nut shell alcohol was mixed with dilute sulfuric acid (volume concentration 10%) in a mass ratio of 10:3 and reacted at 70°C for 2 hours. After the reaction was completed, the mixture was separated, triethylamine was added to remove residual dilute sulfuric acid, and the product was rotary evaporated to obtain cashew nut shell alcohol.

[0026] The present application will be further described below by way of specific embodiments.

[0027] Example 1 A method for developing heavy oil reservoirs using a high-temperature resistant oil displacement agent-assisted steam injection includes preparing a high-temperature resistant oil displacement agent solution by adding water to the high-temperature resistant oil displacement agent solution, and then continuously injecting it into steam injection wells during the steam drive development of the heavy oil reservoir; wherein the high-temperature resistant oil displacement agent comprises the following raw materials in parts by weight: 35 parts of linear alkylbenzene sulfonate, 15 parts of fatty alcohol polyoxyethylene ether, 2 parts of lignin, and 8 parts of amino-terminated polyurethane modified TiO2; the high-temperature resistant oil displacement agent solution is prepared to a mass concentration of 0.3% before use.

[0028] Among them, the linear alkylbenzene sulfonate is C20 sodium alkylbenzene sulfonate, and the molecular formula of the fatty alcohol polyoxyethylene ether is RO-(CH2CH2O)nH, where R is an alkyl group with 8 carbons and n is 9. Amino-terminated polyurethane modified TiO2 was prepared by the following method: Polyethylene glycol, cashew phenol diol, nano-titanium dioxide, and 1,3-phenyl diisocyanate were thoroughly mixed and reacted to obtain an isocyanate-terminated prepolymer. γ-aminopropyltriethoxysilane was reacted with the prepolymer to obtain an aminosilane-terminated polyurethane prepolymer. Diethanolamine was added to the prepolymer, and after mixing and reacting, amino-terminated polyurethane modified TiO2 was obtained. The components, by weight, included: 40 parts polyethylene glycol, 10 parts cashew phenol diol, 30 parts nano-titanium dioxide, 10 parts 1,3-phenyl diisocyanate, 3 parts γ-aminopropyltriethoxysilane, and 10 parts diethanolamine.

[0029] Example 2 The difference from Example 1 is that the high-temperature oil displacement agent contains the following raw materials in parts by weight: 40 parts of linear alkylbenzene sulfonate, 15 parts of fatty alcohol polyoxyethylene ether, 3 parts of lignin, and 25 parts of amino-terminated polyurethane modified TiO2. The high-temperature oil displacement agent is prepared into a 0.3% oil displacement agent solution before use.

[0030] Among them, the linear alkylbenzene sulfonate is C24 sodium alkylbenzene sulfonate, and the molecular formula of fatty alcohol polyoxyethylene ether is RO-(CH2CH2O)nH, where R is an alkyl group with 10 carbons and n is 20. Amino-terminated polyurethane modified TiO2 was prepared by the following method: Polypropylene glycol, cashew phenol diol, nano-titanium dioxide, and 2,4-toluene diisocyanate were thoroughly mixed and reacted to obtain an isocyanate-terminated prepolymer. γ-aminopropyltrimethoxysilane was reacted with the prepolymer to obtain an aminosilane-terminated polyurethane prepolymer. Diethylene glycol amine was added to the prepolymer, and after mixing and reacting, amino-terminated polyurethane modified TiO2 was obtained. The components, by weight, included: 48 parts polypropylene glycol, 12 parts cashew phenol diol, 35 parts nano-titanium dioxide, 16 parts 2,4-toluene diisocyanate, 4 parts γ-aminopropyltrimethoxysilane, and 13 parts diethylene glycol amine.

[0031] Example 3 The difference from Example 1 is that the high-temperature oil displacement agent contains the following raw materials in parts by weight: 50 parts of linear alkylbenzene sulfonate, 10 parts of fatty alcohol polyoxyethylene ether, 5 parts of lignin, and 3 parts of amino-terminated polyurethane modified TiO2. The high-temperature oil displacement agent is prepared into a 0.3% oil displacement agent solution before use.

[0032] Among them, the linear alkylbenzene sulfonate is C24 sodium alkylbenzene sulfonate, and the molecular formula of fatty alcohol polyoxyethylene ether is RO-(CH2CH2O)nH, where R is an alkyl group with 10 carbons and n is 20. Amino-terminated polyurethane modified TiO2 was prepared by the following method: Polypropylene glycol, cashew phenol diol, nano-titanium dioxide, and 2,4-toluene diisocyanate were thoroughly mixed and reacted to obtain an isocyanate-terminated prepolymer. γ-aminopropyltrimethoxysilane was reacted with the prepolymer to obtain an aminosilane-terminated polyurethane prepolymer. Diethylene glycol amine was added to the prepolymer, and after mixing and reacting, amino-terminated polyurethane modified TiO2 was obtained. The components, by weight, included: 55 parts polypropylene glycol, 15 parts cashew phenol diol, 40 parts nano-titanium dioxide, 20 parts 2,4-toluene diisocyanate, 5 parts γ-aminopropyltrimethoxysilane, and 20 parts diethylene glycol amine.

[0033] Example 4 The difference from Example 2 is that the lignin is replaced with an equal amount of diisocyanate-modified lignin. The preparation method of diisocyanate-modified lignin is as follows: Lignin was dispersed in 3 times its mass of toluene, and 15% of the mass of 2,4-toluene diisocyanate was added. The mixture was reacted at 80°C for 3 hours. After the reaction was complete, the mixture was centrifuged and dried to obtain isocyanate-modified lignin. The amount of terephthalic diisothiocyanate used was 15% of the mass of lignin.

[0034] Example 5 The difference from Example 2 is that the lignin is replaced with an equal amount of isocyanate-modified lignin. The preparation method of isocyanate-modified lignin is as follows: Lignin was dispersed in 3 times its mass of N,N-dimethylformamide, and 25% of the mass of lignin was added to 1,3-phenyl diisocyanate. The mixture was reacted at 95°C for 5 hours. After the reaction was complete, the mixture was centrifuged and dried to obtain isocyanate-modified lignin. The amount of 1,3-phenyl diisocyanate used was 25% of the mass of lignin.

[0035] Example 6 The difference from Example 5 is that in the preparation of isocyanate modified lignin, the amount of 2,4-toluene diisocyanate used is 40% of the lignin quality.

[0036] Comparative Example 1 The difference from Example 2 is that unmodified TiO2 is used instead of amino-terminated polyurethane modified TiO2.

[0037] Comparative Example 2 The difference from Example 2 is that the amount of amino-terminated polyurethane modified TiO2 added is 10 parts, which is an excess.

[0038] Comparative Example 3 The difference from Example 2 is that amino-terminated polyurethane modified TiO2 was not added.

[0039] Comparative Example 4 The difference from Example 2 is that cashew phenol diol was not added during the amino-terminated polyurethane modification of TiO2.

[0040] Comparative Example 5 The difference from Example 2 is that the amino-terminated polyurethane modified TiO2 is replaced by an equal amount of aminosilane coupling agent modified TiO2. The aminosilane coupling agent modified TiO2 is prepared by the following method: TiO2 is ultrasonically dispersed in a sufficient amount of 75% aqueous ethanol solution, and γ-aminopropyltrimethoxysilane is added according to the mass ratio of TiO2 to γ-aminopropyltrimethoxysilane 35:93. The mixture is stirred at 60°C for 6 hours. After the reaction is complete, the mixture is filtered and dried to obtain the final product.

[0041] Experimental Example 1 Interfacial tension test: After the high-temperature oil displacement agent was prepared into a 0.3% mass concentration solution with tap water, it was tested using a TX500C rotating drop interfacial tension meter. The crude oil viscosity was 19220 mPa·s, and the test conditions were: temperature 60°C.

[0042] Viscosity reduction test: The high-temperature oil displacement agent was mixed with tap water to prepare a 0.3% (w / w) solution, and the test was conducted in accordance with Q / SH10202193-2018.

[0043] Salt resistance test: The high-temperature oil displacement agent was mixed with water with a calcium and magnesium ion concentration of 2000 mg / L to prepare a 0.3% solution by mass, and its viscosity reduction rate was tested.

[0044] Temperature resistance test: The high-temperature oil displacement agent was mixed with tap water to prepare a 0.3% solution by mass, dried at 300℃ for 24 hours, and then cooled to obtain a high-temperature treated sample. The viscosity reduction rate was then tested.

[0045] Static and dynamic adsorption tests: After the oil displacement agent is injected into the formation, the effective content of the injected oil displacement agent decreases due to adsorption loss from formation minerals, thus affecting the oil displacement effect in the oilfield. The static and dynamic adsorption capacities of the high-temperature resistant oil displacement agents prepared in the respective examples and comparative examples were tested at 75°C.

[0046] The results are shown in Table 1 below. It can be seen that the oil-water interfacial tension between the high-temperature resistant oil displacement agent provided in this application and heavy oil is ≤6.0×10⁻⁶. -3 The viscosity reduction rate reaches over 93%, and even after treatment at 300℃, the viscosity reduction rate remains above 90%, fully leveraging the displacement effect of steam chemical flooding on heavy oil, thus improving crude oil recovery. Furthermore, the viscosity reduction rate is above 90% even at 2000 mg / L of calcium and magnesium ions, and it exhibits good salt resistance. In addition, the high-temperature resistant oil displacement agent of this application has a low adsorption capacity, reducing adsorption of the oil displacement agent on the rock surface and minimizing waste.

[0047] Table 1. Performance test results of high-temperature oil displacement agents

[0048] Experimental Example 2 Several adjacent wells (reservoir parameters: crude oil viscosity 1800-2000 mP.s, reservoir depth 1000-1100 m, reservoir thickness 9-10 m) were used for the following construction method: The high-temperature resistant oil displacement agents prepared in Examples 2, 5, and the comparative example were mixed with tap water to form a 0.3% (w / w) solution. Steam and the high-temperature resistant oil displacement agent were simultaneously injected at a mass ratio of 0.3:1. The steam injection temperature was 300°C, the injection rate was 100 t / (d·ha·m), the production-injection ratio was 1.5, and the steam dryness reaching the bottom of the well was controlled to be greater than 40%. After 30 days of continuous injection, the oil recovery rate was compared with that of conventional steam drive, as shown in Table 2 below.

[0049] Table 2. Oil Displacement Effect

[0050] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, this application is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of this application without departing from the scope of this application should be within the protection scope of this application.

Claims

1. A method for assisting steam development of heavy oil reservoirs with a high-temperature resistant oil-displacing agent, characterized in that, The method comprises: preparing a high-temperature resistant oil displacement agent solution by adding water to the high-temperature resistant oil displacement agent, and continuously injecting the high-temperature resistant oil displacement agent solution into a steam injection well during steam flooding of a heavy oil reservoir. The high-temperature resistant oil displacement agent comprises the following raw materials in parts by weight: 35-50 parts of linear alkyl benzene sulfonate, 10-15 parts of fatty alcohol polyoxyethylene ether, 2-5 parts of lignin, and 3-8 parts of amino-terminated polyurethane modified TiO2.

2. The method of claim 1, wherein, The amino-terminated polyurethane modified TiO2 is prepared by first reacting polymeric diol, cardanol diol, nano-TiO2 and polyisocyanate to obtain isocyanate group terminated pre-polymer modified TiO2, then adding amino silane to modify the isocyanate group terminated pre-polymer, and finally adding a molecular chain regulator to react.

3. The method of claim 2, wherein, In the preparation process of the amino-terminated polyurethane modified TiO2, the raw materials include, in parts by weight: 40-55 parts of polymeric diol, 10-15 parts of cardanol diol, 30-40 parts of nano-TiO2, 10-20 parts of polyisocyanate, 3-5 parts of amino silane, and 10-20 parts of molecular chain regulator.

4. The method according to claim 2 or 3, characterized in that, The polymeric diol is selected from any one or a combination of several of polyethylene glycol, polypropylene glycol, and polytetrahydrofuran diol; and / or The polyisocyanate is selected from a polyisocyanate monomer containing at least two polyisocyanate groups; and / or The amino silane is selected from any one or a combination of several of γ-aminopropyl triethoxysilane, γ-aminopropyl trimethoxysilane, and γ-(β-aminoethyl) aminopropyl trimethoxysilane; and / or The molecular chain regulator is selected from at least one of diethanolamine, monoisopropanolamine, diisopropanolamine, diglycolamine, and triglycolamine.

5. The method of claim 1, wherein, The linear alkyl benzene sulfonate is C20-C24 alkyl benzene sulfonate sodium; and the fatty alcohol polyoxyethylene ether has a molecular formula of R-O-(CH2CH2O)n-H, wherein R is an alkyl group of 8-14 carbons, and n is a positive integer of 9-20.

6. The method of claim 1, wherein, The lignin is also modified by diisocyanate, and the diisocyanate modified lignin is prepared by: The lignin is dispersed in a solvent, diisocyanate is added, and the mixture is reacted at 80-95°C for 3-5 hours, after which the reaction product is centrifuged and dried to obtain the diisocyanate modified lignin; the amount of diisocyanate used is 15-25% of the mass of the lignin.

7. The method of claim 1, wherein, The mass concentration of the high-temperature resistant oil displacement agent solution is 0.3-1%.

8. The method of claim 1, wherein, During the steam flooding process, the steam injection temperature is 250-300°C, the single well steam injection rate is 100-150 t / d, the production injection ratio is 1-1.5, and the dryness of the steam reaching the bottom of the well is controlled to be greater than 40%.

9. The method of claim 8, wherein, The steam and the high-temperature resistant oil displacement agent are injected simultaneously, and the mass ratio of the steam to the high-temperature resistant oil displacement agent is (0.001-0.3):

1.

10. The method of claim 1, wherein, The conditions of the heavy oil reservoir are as follows: the oil layer burial depth is 900-1500 m, the oil layer thickness is ≥8 m, and the crude oil viscosity is >100 mPa·s.

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