A gas-soluble imbibition oil displacement agent solution, a preparation method and application thereof

Abstract

The present application relates to the technical field of oil exploitation, and particularly relates to a gas-soluble imbibition oil displacement agent solution, a preparation method and application thereof, the solution comprising an anionic surfactant, a non-ionic surfactant and water, the mass ratio of the anionic surfactant and the non-ionic surfactant being (1-2):1; the gas-soluble imbibition oil displacement agent solution can dissolve 15.4%-23.6% of CO2; after the gas-soluble imbibition oil displacement agent solution dissolves CO2, the oil-water interfacial tension under the condition of 90 DEG C and 10 MPa is 0.08-0.016 mN / m, and the lipophilic contact angle is 50 DEG -60 DEG. The gas-soluble imbibition oil displacement agent compounded in the present application has the best imbibition oil displacement effect in the oil-water interfacial tension and wettability range, and after being fully dissolved with CO2, the imbibition recovery rate is higher compared with the anionic / non-ionic imbibition oil displacement agent solution before compounding.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil exploitation, in particular to a gas-soluble imbibition oil displacement agent solution and a preparation method and application thereof. BACKGROUND

[0002] With the increase of global energy demand, low-permeability oil reservoirs have gradually become the focus of oil exploration and development. The low-permeability oil reservoirs have low permeability and low porosity, which brings difficulties to oil production. The low-permeability oil reservoirs have poor properties such as low permeability, low porosity and low pressure. In the process of water injection, the oil displacement efficiency and injectivity are limited due to the poor reservoir properties. It is difficult to exploit the crude oil in the small pores of the rock by using the previous water injection and gas injection oil displacement methods for low-permeability reservoirs. Moreover, in the middle and late stages of development, problems such as high injection pressure, water channeling, gas channeling and clay swelling often occur. After traditional primary and secondary recovery, a large amount of remaining oil is still not recovered.

[0003] Spontaneous imbibition has attracted much attention due to its simple operation, low cost and high running efficiency. Imbibition refers to the process in which the wetting phase fluid enters the rock pore and displaces the non-wetting phase fluid under the action of capillary force / gravity without external pressure. This process usually occurs between the fractures formed by fracturing and the rock matrix. Imbibition is affected by many factors, such as rock reservoir pore structure, fluid properties, boundary conditions, etc. The most important influence is capillary pressure and gravity.

[0004] In the tertiary oil recovery dominated by surfactant flooding, the surfactant has the ability to emulsify crude oil, reduce the capillary force and starting pressure of the oil-wet reservoir, and can enter smaller pore throats, thereby improving the recovery efficiency.

[0005] At present, the imbibition oil displacement agent solution used in oilfields is mostly an imbibition oil displacement agent solution with ultra-low oil-water interfacial tension, i.e. the oil-water interfacial tension of the solution is less than 10 -3 mN / m, and good enhanced oil recovery effect has been achieved. However, for imbibition oil recovery, too low oil-water interfacial tension will result in extremely low capillary force, which is not conducive to the imbibition effect in the oil displacement process. Moreover, when the temperature is too high, the wetting reversal ability of the surfactant with ultra-low oil-water interfacial tension is poor, and the exploitation degree of the strong oil-wet reservoir is low. In addition, the imbibition effects of surfactants with different oil-water interfacial tensions are different after dissolving CO2 gas, so it is necessary to develop a new surfactant system which has a specific range of oil-water interfacial tension and oil-wet contact angle and can achieve better imbibition effect after dissolving CO2 gas. SUMMARY

[0006] The present application aims to overcome the deficiencies of the prior art, and provides a gas-soluble imbibition oil displacement agent solution, a preparation method and application thereof.

[0007] To achieve the above technical effects, the present application adopts the following technical solutions:

[0008] The gas-soluble imbibition oil displacement agent solution comprises anionic surfactant, non-ionic surfactant and water, the anionic surfactant is alkyl fatty alcohol sulfonate, the non-ionic surfactant is selected from one of polyethylene glycol and polyoxyethylene ether; the mass ratio of the anionic surfactant and the non-ionic surfactant is (1-2):1.

[0009] The gas-soluble imbibition oil displacement agent solution can dissolve 15.4%-23.6% of CO2 by mass; after dissolving CO2, the oil-water interfacial tension of the gas-soluble imbibition oil displacement agent solution under the condition of 90 DEG C and 10 MPa is 0.08-0.1054 mN / m, and the lipophilic contact angle is 50 DEG -60 DEG.

[0010] The gas-soluble imbibition oil displacement agent solution provided by the present application has an oil-water interfacial tension of 0.08-0.1054 mN / m and a lipophilic contact angle of 50-60 DEG under the condition of 90 DEG C and 10 MPa after dissolving CO2 by using anionic surfactant and non-ionic surfactant in a proportion, has good imbibition oil displacement effect, and has good temperature resistance and stability, and can be applied to high-temperature formation conditions. The non-ionic surfactants polyethylene glycol and polyoxyethylene ether used in the present application have high stability in the solution and are not easily affected by strong electrolytes, and can play a synergistic effect of reducing oil-water interfacial tension and changing wettability by combining with the hydrophilic monomers on the anionic surfactant alkyl fatty alcohol sulfonate.

[0011] Preferably, the salinity of the water ranges from 20000 mg / L to 30000 mg / L. The gas-soluble surfactant provided by the present application has a certain salt tolerance and can be effectively applied to an oil reservoir environment with a salinity of less than 30000 mg / L.

[0012] Preferably, the mass concentration of the anionic surfactant is 0.1wt%-0.2wt%. The mass ratio of the anionic surfactant and the non-ionic surfactant is 2:1.

[0013] Preferably, the non-ionic surfactant is polyethylene glycol.

[0014] The application provides a preparation method of the gas-soluble imbibition oil displacement agent solution.

[0015] Preferably, the mass concentration of the anionic surfactant in the gas-soluble imbibition oil displacement agent solution is 0.1wt%-0.2wt%, and the mass concentration of the nonionic surfactant is 0.05wt%-0.1wt%. Further preferably, the mass concentration of the anionic surfactant in the gas-soluble imbibition oil displacement agent solution is 0.2wt%, and the mass concentration of the nonionic surfactant is 0.1wt%.

[0016] The application also provides the application of the gas-soluble imbibition oil displacement agent solution or the gas-soluble imbibition oil displacement agent solution prepared by the above method, wherein the gas-soluble imbibition oil displacement agent solution is fully dissolved with gaseous CO2 and then injected into a low-permeability oil reservoir for imbibition oil recovery.

[0017] Preferably, in the application, the gaseous CO2 accounts for 15.4%-23.6% of the mass of the gas-soluble imbibition oil displacement agent solution; further preferably, the gaseous CO2 accounts for 18.8% of the mass of the gas-soluble imbibition oil displacement agent solution.

[0018] Preferably, the permeability of the low-permeability oil reservoir is less than 50 mD.

[0019] The application has the following beneficial effects:

[0020] 1. The gas-soluble imbibition oil displacement agent solution provided by the application has an oil-water interfacial tension of 0.08-0.1054 mN / m and an oil-wet contact angle of 50-60° under the condition of 90℃ and 10MPa after the CO2 is dissolved, and the imbibition oil displacement effect is good in the oil-water interfacial tension and wettability range; when fully dissolved with CO2, the whole system is in a liquid phase, and the mass transfer of CO2 from the water phase to the oil phase can make the oil swell, and the imbibition recovery rate is higher compared with the anionic and nonionic imbibition oil displacement agent solution before compounding.

[0021] 2. The application compounds a kind of anionic surfactant with good wettability and a kind of nonionic surfactant with low oil-water interfacial tension to form a kind of gas-soluble imbibition oil displacement agent, which is injected into the formation after fully dissolved with gaseous CO2, which can make the gas-soluble imbibition oil displacement agent fully contact with crude oil, and in addition, CO2 will be precipitated due to the decrease of formation pressure, and the precipitated nonionic surfactant will be taken away, and when the precipitated nonionic surfactant contacts with formation water, it will form gas-soluble imbibition oil displacement agent again, which can avoid the problem that the gas-soluble imbibition oil displacement agent and gaseous CO2 cannot be fully dissolved due to the change of formation pressure.

[0022] 3. The gas-soluble imbibition oil displacement agent provided by the application has good temperature resistance and is more stable. The imbibition oil displacement agent is colorless and clear after being dissolved in water, which proves that the surfactant is stable and can resist temperatures up to 90 DEG C. DETAILED DESCRIPTION

[0023] The application will be further described below in combination with examples and comparative examples.

[0024] Raw material sources:

[0025] The surfactants used in the application are all commercially available surfactants. The alkyl fatty alcohol sulfonate is purchased from Qingdao Changxing Chemical Co., Ltd. and has a purity of greater than or equal to 98.5%, and has the following structural formula:

[0026] ;

[0027] In the structural formula, R can be selected from alkyl groups in the range of C10-C15.

[0028] The polyethylene glycol is purchased from Qingdao Changxing Chemical Co., Ltd. and has a purity of greater than or equal to 98.5%, and has the following structural formula:

[0029] .

[0030] Experimental Example 1:

[0031] Surfactant oil-water interfacial tension measurement experiment

[0032] I. Experimental purpose: measuring the oil-water interfacial tension of anionic / non-ionic imbibition oil displacement agent solution and gas-soluble imbibition oil displacement agent solution after compounding in different proportions

[0033] II. Experimental conditions:

[0034] (1) Experimental temperature: 90 DEG C;

[0035] (2) Experimental surfactant:

[0036] The anionic imbibition oil displacement agent solution is alkyl fatty alcohol sulfonate;

[0037] The non-ionic imbibition oil displacement agent solution is a polyethylene glycol aqueous solution containing a CO2-philic group;

[0038] The anionic surfactant and the non-ionic surfactant are mixed in water to obtain a gas-soluble imbibition oil displacement agent, which is colorless and clear.

[0039] (3) Experimental oil: a certain low-permeability block crude oil; core permeability is 25 mD;

[0040] (4) Experimental instrument: TX-500C rotating drop oil-water interfacial tension instrument. The oil-water interfacial tension measurement range of the equipment is 10 -6-10 2 mN / m, temperature range 0-100℃, temperature accuracy ±0.1℃, reading accuracy 0.1%.

[0041] III. Experimental steps:

[0042] (1) Prepare simulated formation water with salinity of 24570 mg / L, add surfactant to the formation water and stir thoroughly to form a solution of imbibition oil displacement agent;

[0043] (2) Inject the solution of imbibition oil displacement agent into the sample tube through a micro-needle and drop a certain volume of oil droplets into the solution, then place the sample tube into a heating tank until the temperature is stable;

[0044] (3) Rotate the sample tube at a speed of 7000 r / min, and take a photo of the oil droplets every 10 s, and input the crude oil density into the computer interface when the oil droplets are stable for 30 min and the aspect ratio of the oil droplets is >4:1 to calculate the IFT (interfacial tension between oil and water); measure three times and take the average value.

[0045] IV. Experimental results and analysis:

[0046] The interfacial tension between oil and water of anionic / non-ionic imbibition oil displacement agent solution and gas-soluble imbibition oil displacement agent solution is shown in Table 1.

[0047] Table 1 Interfacial tension between oil and water of different solutions

[0048]

[0049] From the data in Table 1, it can be seen that polyethylene glycol has high stability in the solution and is not easily affected by strong electrolytes, and can be mixed with other types of surfactants with good compatibility. The combination of the hydrophilic monomer on the alkyl fatty alcohol sulfonate and the polyethylene glycol can exert the synergistic effect of reducing the interfacial tension between oil and water and changing the wettability. The non-ionic surfactant has a lower interfacial tension between oil and water, and after compounding with anionic surfactant, the interfacial tension between oil and water of the compounded surfactant can be reduced. The hydrophilic group of anionic surfactant forms a monomolecular adsorption layer with non-ionic surfactant, and a mixed micelle is formed inside the solution, which increases the hydrophilicity of the compounded surfactant, and the gas-soluble imbibition oil displacement agent solution prepared has good interfacial tension between oil and water.

[0050] Experimental Example 2

[0051] Imbibition oil displacement agent solution-crude oil-rock contact angle experiment

[0052] The measurement of contact angle conforms to the People's Republic of China Petroleum and Natural Gas Industry Standard SY / T5153-2017.

[0053] I. Experimental purpose: measure the contact angle of anion / non-ion imbibition oil displacement agent solution, gas-soluble imbibition oil displacement agent solution after compounding in different proportions, crude oil and rock

[0054] II. Experimental conditions:

[0055] (1) Experimental temperature: 90°C;

[0056] (2) Experimental surfactant:

[0057] The anion imbibition oil displacement agent solution is alkyl fatty alcohol sulfonate;

[0058] The non-ion imbibition oil displacement agent solution is a polyethylene glycol aqueous solution containing a CO2-philic group;

[0059] The anion surfactant and non-ion surfactant are mixed in water to obtain a gas-soluble imbibition oil displacement agent, which is colorless and clear.

[0060] (3) Experimental oil: crude oil from a certain low-permeability block; core permeability is 25 mD;

[0061] (4) Experimental instrument: Tracker-H instrument (France) contact angle module, the upper limit of the pressure of the equipment is 20 MPa, the upper limit of the temperature is 200°C, the error is <±0.5°, the reading accuracy is 0.1%.

[0062] III. Experimental steps:

[0063] (1) Prepare simulated formation water with a salinity of 21735 mg / L, add surfactant to the formation water and stir thoroughly to form an imbibition oil displacement agent solution;

[0064] (2) First, clean the core slices with carbon tetrachloride solvent, then clean them with toluene:alcohol:acetone=0.7:0.15:0.15 solvent, and finally rinse them with deionized water;

[0065] (3) Put the cleaned core slices into an aging tank saturated with oil and age them at 90°C for one week to make the core slices oil-wet, and immerse all the core slices in the surfactant solution for 7 days for standby use;

[0066] (4) Pour the surfactant solution into the contact angle measurement sample pool, and then fix the core slices on the contact angle module;

[0067] (5) Control the motor to make the needle drop a 10 μL oil droplet and slowly drop the oil droplet on the slice surface, and record the contact angle data after the oil droplet stabilizes (error <±0.5°). Measure three times and take the average value.

[0068] IV. Experimental results and analysis:

[0069] The contact angle of the solution of the anionic / nonionic imbibition oil displacement agent after compounding is shown in Table 2.

[0070] Table 2 Contact angle of different solutions

[0071]

[0072] The polyethylene glycol has high stability in the solution and is not easily affected by strong electrolyte, can be mixed with other types of surfactants, has good compatibility, and can play the synergistic effect of reducing the oil-water interfacial tension and changing the wettability by combining with the hydrophilic monomer on the alkyl fatty alcohol sulfonate. The anion has a hydrophilic monomer, and the hydrophilicity of the compounded solution can be increased after mixing with the non-ion. The hydrophilic group of the anionic surfactant forms a monomolecular adsorption layer with the nonionic surfactant, and a mixed micelle is formed in the solution, so that the hydrophilicity of the surfactant after compounding is increased, and the gas-soluble imbibition oil displacement agent solution prepared has a good oil contact angle. Only the wettability is changed from oil-wet state to water-wet state, the capillary driving force can be effectively increased, and the imbibition effect is increased.

[0073] Experimental Example 3

[0074] Spontaneous imbibition experiment

[0075] I. Experimental purpose: comparison of imbibition oil recovery of anionic / nonionic, different proportion compounded imbibition oil displacement agent solutions.

[0076] II. Experimental conditions:

[0077] (1) Temperature 90℃, pressure 0.101 MPa;

[0078] (2) Experimental surfactant:

[0079] The anionic imbibition oil displacement agent solution is alkyl fatty alcohol sulfonate;

[0080] The nonionic imbibition oil displacement agent solution is a polyethylene glycol aqueous solution containing a CO2 group;

[0081] The anionic surfactant and the nonionic surfactant are mixed in water to obtain a gas-soluble imbibition oil displacement agent, which is colorless and clear;

[0082] (3) Experimental oil: a low-permeability block crude oil;

[0083] (4) Experimental core: a low-permeability block core with a permeability of 26x10 -3 μm 2 and a porosity of 15.7%;

[0084] (5) Experimental instrument: Amott imbibition bottle, maximum range 2 mL, accuracy 0.01 mL.

[0085] III. Experimental procedure:

[0086] (1) Dry the core in the oven at 105℃ for 12 h to measure the dry weight, then put it into the intermediate container and vacuumize for 24 h with vacuum pump;

[0087] (2) Apply 20 MPa pressure to the core and saturate for a week to simulate the reservoir environment. Finally take out the core, wipe off the floating oil and measure the wet weight to calculate the volume of saturated oil;

[0088] (3) Put the core into the Amott imbibition bottle, and inject the anionic, nonionic imbibition oil displacement agent solution, and the compounded gas-soluble imbibition oil displacement agent solution into the imbibition bottle respectively.

[0089] (4) Put the imbibition bottle into the water bath, adjust the temperature to 90℃, and record the imbibition recovery rate.

[0090] IV. Experimental results and analysis:

[0091] The imbibition recovery rates of the anionic / nonionic imbibition oil displacement agent solution and the compounded gas-soluble imbibition oil displacement agent solution are shown in Table 3. The imbibition recovery rate of the gas-soluble surfactant compounded according to the mass ratio of 2:1 is the highest.

[0092] Table 3. Imbibition recovery rates of different solutions

[0093]

[0094] Polyethylene glycol has high stability in solution and is not easily affected by strong electrolytes. It can be mixed with other types of surfactants and has good compatibility. Its combination with the hydrophilic monomer on the alkyl fatty alcohol sulfonate can exert the synergistic effect of reducing the oil-water interfacial tension and changing the wettability of both. The anion has a hydrophilic monomer, and after mixing with the nonion, the hydrophilicity of the compounded solution can be increased. The oil-water interfacial tension of the nonion is lower, and after compounding with the anion, the oil-water interfacial tension of the compounded surfactant can be reduced. The hydrophilic group of the ionic surfactant forms a monomolecular adsorption layer with the nonionic surfactant, and a mixed micelle is formed inside the solution, which increases the hydrophilicity of the compounded surfactant, and the gas-soluble imbibition oil displacement agent solution prepared has good oil-water interfacial tension and oil-wet contact angle. In the range of the oil-water interfacial tension and contact angle obtained by the present application, the capillary force reaches the highest, the oil-water interfacial tension is too high, the resistance of the oil droplet through the pore throat is too large, and too low will produce very low capillary force, which hinders imbibition, and the intermediate value is the best.

[0095] Experimental Example 4

[0096] Contact angle and oil-water interfacial tension experiment of gas-soluble imbibition oil displacement agent solution-crude oil-rock after dissolving CO2

[0097] The contact angle measurement conforms to the People's Republic of China Petroleum and Natural Gas Industry Standard SY / T5153-2017.

[0098] I. Experimental Objective: To measure the interfacial tension and contact angle of an aerosolized displacement agent solution after CO2 dissolution, in relation to oil and water.

[0099] II. Experimental conditions:

[0100] (1) Experimental temperature: 90℃;

[0101] (2) Surfactant used in the experiment:

[0102] The compounded aerosol-soluble percolation displacement agent dissolves in water to form a colorless and clear solution.

[0103] (3) Experimental oil: crude oil from a low-permeability block; core permeability was 25 mD;

[0104] (4) Experimental instruments: Tracker-H oil-water interfacial tension instrument (France) was used. The upper limit of pressure of this instrument is 20 MPa, the upper limit of temperature is 200℃, the error is <±0.5°, and the reading accuracy is 0.1%.

[0105] III. Experimental Procedure:

[0106] (1) Prepare simulated formation water with a salinity of 29482 mg / L, add surfactant to the formation water and stir thoroughly to form an adsorption displacement agent solution;

[0107] (2) First, clean the core slices with carbon tetrachloride solvent, then clean them with toluene: alcohol: acetone = 0.7: 0.15: 0.15 solvent, and finally rinse them with deionized water.

[0108] (3) Place the cleaned core slices into an aging tank saturated with oil and age them at 90°C for one week to make the core slices oleophilic. Soak all the core slices in a surfactant solution for 7 days for later use.

[0109] (4) Fix the core slices onto the contact angle module, and then pass the dissolved CO2 aerosol percolation displacement agent solution into the contact angle measurement sample cell;

[0110] (5) Control the motor to dispense a 10 μL oil droplet from the needle and slowly drip the oil droplet onto the slice surface. After the oil droplet stabilizes (error < ±0.5°), record the contact angle data. Take the average of three measurements.

[0111] (6) Install the syringe and needle tube filled with crude oil on the drive system, adjust the temperature of the high-pressure reactor to 90°C, and introduce the gas-soluble percolation displacement agent solution after dissolving CO2 into the high-pressure sealed container.

[0112] (7) Adjust the temperature of the high-pressure reactor to 90℃, and inject the gas-soluble imbibition oil displacement agent solution into the high-temperature and high-pressure reactor after dissolving CO2 in the closed container;

[0113] (8) Adjust the base to make the needle appear in the visual window, drive the motor, and make the oil droplets form a suspended oil droplet on the syringe needle tip;

[0114] (9) Input CO2 and oil droplet density in the control system, and measure the oil droplet volume and oil-water interfacial tension through the data image acquisition system.

[0115] Four, experimental results and analysis:

[0116] The oil-water interfacial tension and contact angle of the gas-soluble imbibition oil displacement agent solution after dissolving CO2 and crude oil are shown in Table 4.

[0117] Table 4 Oil-water interfacial tension and contact angle of gas-soluble imbibition oil displacement agent solution with different proportions

[0118]

[0119] After dissolving CO2, the solution is acidic, and CO2 diffuses more from the water phase to the oil phase in the core, causing the volume of crude oil to expand. CO2 dissolves in contact with crude oil in the pore, which can further reduce the viscosity of crude oil. Due to the mass transfer effect, CO2 diffuses from the water phase to the oil phase, causing the oil to swell, thereby reducing the oil-wet contact angle and the oil-water interfacial tension

[0120] Experimental Example 5

[0121] I. Experimental purpose: To compare the imbibition recovery rate of the gas-soluble imbibition oil displacement agent solution after dissolving CO2 with different proportions.

[0122] II. Experimental conditions:

[0123] (1) Temperature 90℃, pressure 10 MPa;

[0124] (2) Experimental surfactant: gas-soluble imbibition oil displacement agent after compounding, colorless and clear after dissolving in water;

[0125] (3) Experimental oil: a certain low-permeability block crude oil;

[0126] (4) Experimental core: a certain low-permeability block core, permeability 26x10 -3 μm 2 , porosity 15.7%;

[0127] (5) Experimental instrument: high-temperature and high-pressure imbibition device, maximum pressure 15 MPa.

[0128] (6) CO2: purity 99.9%, produced by Qingdao Tianyuan Gas Manufacturing Co., Ltd.

[0129] III. Experimental procedure:

[0130] (1) Dry the core in an oven at 105°C for 12 h to measure the dry weight, then put it into the intermediate container and vacuum pump for 24 h;

[0131] (2) Apply a pressure of 20 MPa to the core and saturate for a week to simulate the reservoir environment. Finally, take out the core and wipe off the floating oil and measure the wet weight to calculate the volume of saturated oil;

[0132] (3) Put the core into the high-temperature and high-pressure infiltration device, and after the compounded gas-soluble surfactant and CO2 are fully dissolved, the solution is injected into the high-temperature and high-pressure infiltration device.

[0133] (4) Put the high-temperature and high-pressure infiltration device into a water bath, adjust the temperature to 90°C, and record the infiltration recovery rate.

[0134] IV. Experimental results and analysis:

[0135] The infiltration recovery rate of the compounded CO2-dissolved gas-soluble oil displacement agent solution is shown in Table 5. The infiltration recovery rate of the compounded CO2-dissolved gas-soluble surfactant is the highest, which is 32.61% when the mass ratio is 2:1. This indicates that during the spontaneous infiltration process, when the wettability of the gas-soluble oil displacement agent and the oil-water interfacial tension are between 50-60° and 0.1-0.2 mN / m, the synergistic effect produced by dissolving CO2 can achieve better infiltration effect.

[0136] Table 5 Infiltration recovery rate of CO2-dissolved gas-soluble oil displacement agent solution

[0137]

[0138] From the table data, under the condition of 1:1, with the increase of CO2 proportion, the oil-water interfacial tension decreases, which reduces the capillary driving force in the infiltration process. Although the contact angle decreases slightly, the influence of oil-water interfacial tension on capillary force is greater. Thus, the infiltration recovery rate decreases. This also proves that the infiltration recovery rate is high when the oil-water interfacial tension is in the range of 0.1-0.2 mN / m.

Claims

1. A solution of a gas-soluble imbibition oil displacement agent, characterized by, The solution comprises an anionic surfactant, a non-ionic surfactant and water, the non-ionic surfactant is selected from one of polyethylene glycol and polyoxyethylene ether; the mass ratio of the anionic surfactant and the non-ionic surfactant is (1-2):1; After the solution of the gas-soluble imbibition oil displacement agent dissolves CO2, the oil-water interfacial tension under the condition of 90℃ and 10MPa is 0.08-0.1054mN / m, and the lipophilic contact angle is 50°-60°. The structural formula of the anionic surfactant is as follows: ； In the structural formula, R can be selected from alkyl in the range of C10-C15.

2. The solution of the gas-dissolved imbibition oil displacement agent as claimed in claim 1, wherein The salinity of the water ranges from 20000mg / L to 30000mg / L.

3. The solution of the gas-dissolved imbibition oil displacement agent as claimed in claim 1, wherein The mass concentration of the anionic surfactant is 0.1wt%-0.2wt%, and the mass ratio of the anionic surfactant and the non-ionic surfactant is 2:

1.

4. The solution of the gas-dissolved imbibition oil displacement agent as claimed in claim 1, wherein The non-ionic surfactant is polyethylene glycol.

5. A process for the preparation of a solution of a gas soluble imbibition oil displacement agent as claimed in any one of claims 1 to 4, characterised in that, The anionic surfactant and the non-ionic surfactant are dissolved in water according to different mass ratios, thereby obtaining the solution of the gas-soluble imbibition oil displacement agent.

6. The production method according to claim 5, wherein In the solution of the gas-soluble imbibition oil displacement agent, the mass concentration of the anionic surfactant is 0.1wt%-0.2wt%, and the mass concentration of the non-ionic surfactant is 0.05wt%-0.1wt%.

7. The production method according to claim 6, wherein In the solution of the gas-soluble imbibition oil displacement agent, the mass concentration of the anionic surfactant is 0.2wt%, and the mass concentration of the non-ionic surfactant is 0.1wt%.

8. Application of the solution of the gas-soluble imbibition oil displacement agent according to any one of claims 1-4 or prepared by the method according to any one of claims 5-7, wherein the solution of the gas-soluble imbibition oil displacement agent is fully dissolved with gaseous CO2 and then injected into a low-permeability oil reservoir for imbibition oil production.

9. Use according to claim 8, wherein the compound is ###0002### The permeability of the low-permeability oil reservoir is less than 50mD.

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