Optimal selection method and experimental device for oil reservoir gas injection modes for CO2 yield increase and storage

Abstract

The invention relates to the technical field of oil reservoir gas injection development, and discloses an oil reservoir gas injection mode optimization method and experiment device for CO2 yield increase and storage, and the optimization method comprises the following steps: S1, building an optimization experiment device; s2, constructing a geologic model after fracturing of the target oil reservoir and configuring a fluid sample; s3, carrying out multi-scheme physical simulation experiments under different gas injection modes of the oil reservoir; s4, the crude oil recovery rate, the CO2 oil change rate, the CO2 storage amount and the CO2 storage rate under different gas injection modes are calculated; s5, establishing a hierarchical structure model by using an analytic hierarchy process and constructing a judgment matrix of evaluation indexes; and S6, calculating the weight vector of each evaluation index, performing consistency check, calculating the comprehensive score of CO2 yield increase and storage performance under different gas injection modes, and screening out the optimal gas injection mode of the oil reservoir. Physical simulation of different types of oil reservoirs under multiple gas injection modes of continuous gas injection, pulse gas injection, advanced gas injection, gas injection huff and puff and gas-water alternation is achieved, and the problem that gas injection mode optimization cannot be conducted in existing oil reservoir CO2 injection scheme optimization is solved.

Description

Technical Field

[0001] The invention relates to the technical field of reservoir gas injection development, and in particular to a method and an experimental device for optimizing a reservoir gas injection mode for increasing CO2 production and sealing. Background Art

[0002] Conventional oil reservoirs can achieve considerable oil recovery by natural depletion or water injection development. However, the unconventional resources such as tight oil reservoirs, heavy oil reservoirs and shale oil reservoirs that are currently being developed are affected by reservoir physical properties or crude oil properties, and the recovery rate of depletion development is extremely low and water injection development is extremely difficult. Therefore, gas injection development has become an important way to improve the oil recovery of unconventional oil reservoirs. There are various gas injection media in oil reservoirs, among which the interaction between CO2 and crude oil can achieve various production increase mechanisms such as swelling, viscosity reduction, extraction, miscibility and competitive adsorption. In addition, as the main component of greenhouse gases, CO2 can be injected into oil reservoirs to achieve various forms of geological storage such as construction, binding, dissolution, mineralization and adsorption, which can effectively alleviate the greenhouse effect. Therefore, CO2 is the most ideal gas injection medium for oil reservoirs at this stage.

[0003] However, my country is short of natural CO2 gas sources, and industrial CO2 separation and purification technology is still immature. The development of CO2 injection in oil reservoirs should be based on the realization of considerable economic benefits (increased crude oil production) and social benefits (CO2 storage). In addition, there are various ways of injecting gas into oil reservoirs, including continuous gas injection, pulse gas injection, gas injection huff and puff, advanced gas injection, and gas-water alternation. Different gas injection methods are suitable for different types of oil reservoirs, and the economic and social benefits they bring are also different. Therefore, before carrying out gas injection development in oil reservoirs, it is necessary to screen out the optimal gas injection method based on CO2 production increase and storage performance.

[0004] Among the existing related studies, there is a Chinese patent with publication number CN118586210A, which discloses a method and device for coordinated optimization of carbon dioxide throughput, oil production and storage. The method includes: based on the numerical simulation model of single-well carbon dioxide throughput development in the target block, a first sample set and a second sample set are generated by sampling using a multi-dimensional biased Latin sampling method; segmented processing of the dynamic data of carbon dioxide throughput and oil production in the reservoir is performed to establish a third sample set; based on the second sample set and the third sample set, a process parameter optimization proxy model is established; based on the process parameter optimization proxy model and constraints, a multi-objective optimization algorithm is used to solve the optimal Pareto frontier of the objective function; based on the optimal Pareto frontier of the objective function, the optimal process parameters of CO2 throughput are determined.

[0005] The existing Chinese patent with publication number CN116641688A discloses a method, system, equipment and storage medium for improving the recovery rate of gas reservoirs and its storage by CO2. The method includes: S100, obtaining the dynamic parameters of the developed target gas reservoir in the current state and analyzing the key factors; S200, constructing a potential prediction model for improving the recovery rate of CO2 in the target gas reservoir and generating the improvement range of CO2 recovery rate in the target gas reservoir; S300, analyzing whether the improvement range of CO2 recovery rate in the target gas reservoir is greater than the economic recovery range; S400, constructing a basic numerical simulation model of the actual development well group of the target gas reservoir and generating the economic net present value and CO2 geological storage volume; S500, using the Bayesian adaptive direct search algorithm to generate the conversion timing and the corresponding simulation engineering parameters, and calculate the objective function; S600, generating the optimal engineering parameters. The adoption of this scheme can simultaneously achieve the improvement of CO2 recovery rate and the maximization of its effective storage volume, reduce the optimization cost, and improve the optimization efficiency.

[0006] The existing Chinese patent with publication number CN119004836A discloses a method and system for optimizing injection schemes for geological storage of CO2 in abandoned oil reservoirs. The method includes: establishing a geological model for storing CO2 in abandoned oil reservoirs and setting initial conditions; setting different CO2 injection schemes according to field experience and actual conditions; simulating each injection scheme to obtain the CO2 front position, maximum bottom hole pressure and CO2 safe storage ratio within a certain storage period as evaluation indicators for the next step; performing data standardization on each evaluation indicator; using the analytic hierarchy process (AHP) to establish a hierarchical structure model, construct a judgment matrix of the evaluation indicators, and perform a consistency test. If the test passes, the weight of the analytic hierarchy process is obtained, otherwise the judgment matrix is ​​reconstructed; according to the processed results, the entropy weight method (EWM) is used to determine the information entropy weight; according to the results of the analytic hierarchy process and the entropy weight method, a comprehensive weight is established, and the results of each scheme are weighted and summed to select the best injection scheme.

[0007] The existing Chinese patent with publication number CN118468603B discloses a method for optimizing saline CO2 geological storage injection schemes based on AHP-EWM-TOPSIS, including: establishing a geological model for storing CO2 in saline layers; setting a CO2 injection scheme; simulating the minimum reservoir safety factor, the maximum surface uplift and the safe capture ratio of CO2 storage during the storage process of each scheme as evaluation indicators; performing data standardization on the evaluation indicators; using the hierarchical analysis method to construct a judgment matrix of the evaluation indicators to obtain a single-layer weight vector; using the entropy weight method to determine the information entropy weight and obtain the comprehensive weight; based on the superior and inferior solution distance method and the comprehensive weight, calculating and sorting the TOPSIS score to obtain the optimal CO2 injection scheme.

[0008] The above four reservoir CO2 injection scheme optimization methods are all aimed at optimizing the injection parameters under a certain injection method. There are certain differences in the injection methods used in different types of reservoirs. The optimization of the injection method is the basis and prerequisite for the subsequent optimization of the injection parameters. Moreover, most of these existing reservoir CO2 injection scheme optimization methods conduct numerical simulation of gas injection development by establishing a target reservoir geological model, but this requires accurate and systematic geological, fluid, engineering and development data, which makes it unsuitable for the initial stage of reservoir exploration and development where various data are scarce. In addition, most of the existing reservoir CO2 injection scheme optimization methods choose crude oil recovery rate or CO2 storage capacity as the evaluation index of CO2 production increase or storage performance, but these two parameters can only evaluate the effectiveness of the reservoir gas injection scheme, while ignoring the economic evaluation of the gas injection scheme, so it is difficult to apply to the actual situation of CO2 gas source shortage at this stage. Therefore, it is necessary to develop a method and experimental device for optimizing gas injection methods in oil reservoirs based on CO2 production increase and storage performance, to realize physical simulation of different gas injection methods in various types of oil reservoirs, and to combine the effectiveness and economy of CO2 production increase and storage performance to reasonably optimize the gas injection development method in the early stage of oil reservoir exploration and development. Summary of the invention

[0009] In order to overcome or alleviate one or more of the above technical problems, the purpose of the present invention is to provide a method and experimental device for optimizing gas injection methods for CO2 production increase and storage in oil reservoirs. By building an experimental device for physical simulation of optimal gas injection methods for oil reservoirs, physical simulation experiments under different gas injection methods for oil reservoirs are carried out, and combined with four evaluation indicators such as crude oil recovery rate, CO2 oil exchange rate, CO2 storage volume and CO2 storage rate, a comprehensive evaluation is made on the effectiveness and economy of CO2 production increase and storage, so as to achieve the optimization of gas injection development methods in the early stage of oil reservoir exploration and development.

[0010] The present invention provides the following technical solutions:

[0011] An experimental device for optimizing the gas injection method of CO2 production enhancement and storage in oil reservoirs, comprising a fluid injection and production system, a geological model system and a fluid collection system connected in sequence, all of which are electrically connected to the data acquisition system;

[0012] The fluid injection and production system comprises three high-pressure piston containers containing crude oil, CO2 and deuterated water, respectively injecting oil samples, CO2 and deuterated water into the geological model system through a double-cylinder displacement pump to respectively simulate formation oil, target reservoir injection gas and target reservoir formation water. The fluid injection and production system performs gas injection experiments of multiple gas injection methods and multiple gas injection schemes with different parameters on the geological model system, and the multiple gas injection methods are selected from continuous gas injection, pulse gas injection, alternating gas and water injection, advanced gas injection or gas injection huff and puff;

[0013] The geological model system is used to simulate the overlying formation pressure and the formation temperature of the geological model after the target reservoir is fractured;

[0014] The fluid collection system is used to cool and separate the gas and liquid of the mixed fluid passing through the geological model system, separate the CO2 in the fluid at the production end of the geological model system from the liquid oil and water and the gaseous light hydrocarbons, collect data on the total amount of CO2 produced, and recover the waste gas of the separated gaseous light hydrocarbons;

[0015] The data acquisition system is used to collect in real time the volume of fluid injected by the dual-cylinder displacement pump and the pressure and temperature of the geological model of the target oil reservoir after fracturing; to collect in real time the T2 spectrum hydrogen signal of the crude oil in the geological model of the target oil reservoir after fracturing; and to collect the total amount of CO2 produced at the production end of the fluid collection system.

[0016] According to some embodiments, the fluid injection and production system includes a double-cylinder displacement pump for controlling oil and gas injection connected by a high-pressure fluid pipeline, a first high-pressure piston container, a second high-pressure piston container and a third high-pressure piston container for storing crude oil, CO2 and deuterated water respectively, and a first multi-way valve and a second multi-way valve for adjusting the gas injection mode of the geological model system, wherein the first multi-way valve includes at least five valves, three of which are respectively connected to the output ends of the first, second and third high-pressure piston containers, the fourth valve is connected to the input end of the geological model system, and the second multi-way valve is arranged at the high-pressure fluid of the rear end of the geological model system. On the body pipeline, another valve of the second multi-way valve except the inlet valve and the outlet valve is connected to the fifth valve of the first multi-way valve; the geological model system includes a non-magnetic clamp for clamping the geological model of the target reservoir after fracturing, the non-magnetic clamp is provided with a confining pressure pump simulating the overlying formation pressure, and an oil bath simulating the formation temperature, and the second multi-way valve is arranged at the production end of the non-magnetic clamp; the fluid collection system is connected to the condenser, the gas-liquid separator, the CO2 membrane separator and the waste gas recovery container in sequence through the high-pressure fluid pipeline, and the front end of the condenser is provided with a back pressure valve and a back pressure pump for controlling the oil and gas production;

[0017] The data acquisition system includes a nuclear magnetic resonance analyzer for collecting crude oil T2 spectrum hydrogen signals, which is arranged at the periphery of the non-magnetic clamp and the oil bath; a mass flowmeter for measuring the CO2 production volume is arranged at the rear end of the CO2 membrane separator; a temperature sensor is arranged at the oil bath for respectively collecting the temperature of the geological model of the target reservoir after fracturing; pressure sensors are arranged at both sides of the injection end and the production end of the non-magnetic clamp for collecting the front and rear end pressures of the geological model of the target reservoir after fracturing; and a data recording device for recording all collected data; the dual-cylinder displacement pump has its own fluid injection volume measurement, and the measurement data is transmitted to the data recording device.

[0018] According to some embodiments, the CO2 membrane separator uses a double-layer polyethylene amine membrane.

[0019] On the other hand, the present invention also provides a method for optimizing the experimental device for optimizing the gas injection method for increasing CO2 production and storing oil reservoirs, which comprises the following steps:

[0020] S1, constructing an experimental device for optimizing the gas injection method for increasing CO2 production and storing oil reservoirs;

[0021] S2, constructing the geological model of the target reservoir after fracturing and configuring fluid samples:

[0022] Drill multiple full-diameter cores in different areas of the target reservoir, and then drill multiple standard plunger cores from the full-diameter cores; grind the end faces of the plunger cores flat, wash the oil and dry them; number the cores and measure the basic physical parameters, including porosity φ and permeability K, to establish a core library for the target reservoir; select cores with similar physical properties to the reservoir from the core library and splice them into long cores as the initial geological model between the injection and production wells according to the geological data of the target reservoir; carry out fracture-making experiments on the long cores according to the fracturing construction parameters of the target reservoir to simulate the geological model after fracturing between the injection and production wells; configure oil samples with the same components to simulate formation crude oil according to the chromatographic analysis data of the target reservoir; prepare deuterated water to simulate the formation water of the target reservoir to shield the influence of hydrogen signals in the water on hydrogen signals in the crude oil; use high-purity CO2 to simulate the injection gas of the target reservoir;

[0023] S3, conduct multi-scheme physical simulation experiments under different gas injection methods in oil reservoirs:

[0024] The core is placed in a vacuum pressurization saturation device, and the core is evacuated and pressurized to the actual formation pressure to completely saturate the deuterated water; the saturated core is placed in a non-magnetic clamp in sequence according to the splicing order, and fluorinated oil is used instead of water to increase the confining pressure and temperature of the geological model system to the overlying formation pressure and formation temperature through a confining pressure pump and an oil bath respectively; the deuterated water in the third high-pressure piston container is injected into the geological model system by a double-cylinder displacement pump to increase the system flow pressure to the original formation pressure; the first high-pressure piston container is injected into the geological model system by a double-cylinder displacement pump. The oil sample in the pressure piston container is injected into the geological model system to carry out the oil-water displacement process to simulate the filling and accumulation process of the oil reservoir; by adjusting the two multi-way valves, a multi-scheme physical simulation experiment under different gas injection modes of the oil reservoir is carried out; the gas injection modes include continuous gas injection, pulse gas injection, gas injection huff and puff, gas-water alternating injection and advanced gas injection; by adjusting the injection gas flow rate and gas injection pressure value of the double-cylinder displacement pump, as well as the duration and frequency of the opening and closing of the first and second multi-way valves, a multi-scheme physical simulation experiment under different gas injection modes is carried out respectively;

[0025] S4, calculate the crude oil recovery factor, CO2 oil exchange rate, CO2 storage volume and CO2 storage rate under different gas injection methods as the effectiveness and economic evaluation indicators of CO2 production increase and storage performance;

[0026] The T2 spectrum hydrogen signal of the crude oil in the long core during the physical simulation experiment was collected in real time by the nuclear magnetic resonance instrument of the data acquisition system, and the experiment was stopped after the total amount of hydrogen signal was stable; the total amount of hydrogen signal N at the beginning of the physical simulation experiment was counted. i and the total amount of hydrogen signal N at the end time f ; The total CO2 injection volume V is calculated by the dual-cylinder displacement pump of the fluid injection and production system and the mass flow meter of the data acquisition system i and the total CO2 output V p ; Using formula R o =(N i -N f ) / N i Calculate the oil recovery factor as the effectiveness evaluation index of CO2 production enhancement performance; use the formula H = (N i -N f ) / V i Calculate the CO2 oil exchange rate as the economic evaluation index of CO2 production increase performance; use the formula V s =V i -V p Calculate the CO2 storage capacity as the effectiveness evaluation index of CO2 storage performance; use the formula R g =(V i -V p ) / V i Calculate the CO2 storage rate as an economic evaluation index of CO2 storage performance; calculate the crude oil recovery rate, CO2 oil exchange rate, CO2 storage volume and CO2 storage rate of each scheme under different gas injection methods;

[0027] S5, performing data standardization processing on the evaluation indicators, using the hierarchical analysis method to establish a hierarchical structure model and construct a judgment matrix of the evaluation indicators, including the following steps:

[0028] S51: Data standardization processing is performed on the crude oil recovery factor, CO2 oil exchange rate, CO2 storage volume and CO2 storage rate of each scheme under different gas injection methods. The processing formula is:

[0029] y ij =[x ij -min(x ij )] / [max(x ij )-min(x ij )]

[0030] Where x ij is the value before data standardization, y ijis the value after data standardization, max(x ij ) is the maximum value under a certain indicator, min(x ij ) is the minimum value under a certain indicator;

[0031] S52: Use the analytic hierarchy process to establish a hierarchical model consisting of a target layer, a criterion layer, and a scheme layer, where the target layer is the optimal gas injection method for the reservoir based on CO2 production increase and storage performance, the criterion layer is the four evaluation indicators of crude oil recovery rate, CO2 oil exchange rate, CO2 storage capacity, and CO2 storage rate, and the scheme layer is a number of schemes available under different gas injection methods; use the analytic hierarchy process to construct a 4×4 judgment matrix A of the four evaluation indicators of crude oil recovery rate, CO2 oil exchange rate, CO2 storage capacity, and CO2 storage rate, and define the importance of indicator i compared with indicator j as a ij , as the corresponding element in matrix A, determine a by judging the matrix element scaling method ij Numeric value;

[0032] S6, calculate the weight vector of each evaluation index and perform consistency test, calculate the comprehensive score of CO2 production increase and storage performance under different gas injection methods according to the weight vector, and select the optimal gas injection method for the reservoir, including the following steps:

[0033] S61: Normalize the judgment matrix A by column, then sum the normalized columns by row, and then divide each element of the summed vector by the order n of the judgment matrix A to obtain the weight vector w of the evaluation index. j ;

[0034] S62: Combine the formulas CR = CI / RI and CI = (λ max -n) / (n-1) calculates the consistency ratio CR for consistency check. If the consistency check passes, the weight vector w is used. j , otherwise, return to the construction of the judgment matrix in S52 until the consistency check is passed, where λ max is the maximum characteristic root, RI is the random consistency index;

[0035] S63: Through the weight vector w j After the standardized data y ij The weighted summation is performed to obtain the comprehensive scores of CO2 production increase and storage performance of each scheme under different gas injection methods;

[0036] S64: Filter out the three highest-scoring solutions among the various gas injection methods and calculate the average value to represent the final score of the gas injection method, based on which the optimal gas injection method is selected.

[0037] According to some embodiments, in the physical simulation experiment described in S3, the five valves of the first multi-way valve are respectively #1 to #5, #1 to #3 are respectively connected to the output ends of the first, second and third high-pressure piston containers, #5 is used for the input of the geological model system, and the three valves of the second multi-way valve are respectively #6 to #8, wherein #6 is connected to the output of the geological model system, #8 is used as the input of the fluid collection system, and #7 is connected to #4;

[0038] Keep valves #2, #5, #6 and #8 open, valves #1, #3, #4 and #7 closed, and set the dual-cylinder displacement pump to constant speed displacement mode to simulate continuous gas injection;

[0039] Keep valves #2, #5, #6 and #8 open, valves #1, #3, #4 and #7 closed, and set the dual-cylinder displacement pump to variable speed displacement mode to simulate pulse gas injection;

[0040] Keep valves #5, #6 and #8 open, valves #1, #4 and #7 closed, valves #2 and #3 open alternately, and set the dual-cylinder displacement pump to constant speed displacement mode to simulate the alternating gas-water injection method;

[0041] Keep #2 and #5 valves open, #1, #3, #4, #6, #7 and #8 valves closed, set the double-cylinder displacement pump to constant pressure displacement mode, keep all valves of the first and second multi-way valves closed for a period of time, then open #2, #5, #6 and #8 valves, and set the double-cylinder displacement pump to constant speed displacement mode to simulate the advanced gas injection method;

[0042] Keep valves #2, #4, #6 and #7 open, valves #1, #3, #5 and #8 closed, set the dual-cylinder displacement pump to constant pressure displacement mode, keep all valves of the first and second multi-way valves closed for a period of time, and then open valves #6 and #8 to simulate the gas injection throughput mode.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] (1) The present invention provides a method and experimental device for optimizing the gas injection method for increasing CO2 production and storing in oil reservoirs, thereby realizing physical simulation of different types of oil reservoirs under various gas injection methods such as continuous gas injection, pulse gas injection, advanced gas injection, gas injection throughput, and gas-water alternation, thereby solving the problem that the existing method for optimizing the CO2 injection scheme for oil reservoirs cannot optimize the gas injection method.

[0045] (2) The present invention utilizes cores with similar physical properties in oil reservoirs to splice into long cores and conduct fracture-making experiments, thereby achieving accurate characterization of geological models after fracturing of different types of oil reservoirs. It then conducts multi-scheme physical simulation experiments under different gas injection methods, thus getting rid of the reliance of model building and simulation processes on reservoir data in existing methods for optimizing CO2 injection schemes in oil reservoirs, and is therefore suitable for the early stages of oil reservoir exploration and development.

[0046] (3) The present invention selects four indicators, namely, crude oil recovery rate, CO2 oil exchange rate, CO2 storage volume and CO2 storage rate, to comprehensively evaluate the effectiveness and economy of CO2 production increase and storage under different gas injection methods in the reservoir, and the physical simulation experimental device for optimizing the reservoir gas injection method can accurately obtain the above four evaluation indicators, which makes up for the defect that the existing reservoir CO2 injection scheme optimization method only considers the effectiveness of the gas injection scheme but ignores the economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A flow chart of a method for optimizing the reservoir gas injection method for CO2 production increase and storage provided in an embodiment of the present invention.

[0048] Figure 2 The reservoir gas injection method provided in the embodiment of the present invention is preferably a physical simulation experimental device.

[0049] Figure 3 A hierarchical structure model established by using the hierarchical analysis method provided in the embodiment of the present invention.

[0050] In the figure:

[0051] A double-cylinder displacement pump 101; a first high-pressure piston container 102; a second high-pressure piston container 103; a third high-pressure piston container 104; a first multi-way valve 105; a second multi-way valve 106; a back-pressure valve 107; a back-pressure pump 108; a non-magnetic clamp 201; a confining pressure pump 202; an oil bath 203; a condenser 301; a gas-liquid separator 302; a CO2 membrane separator 303; a waste gas recovery container 304; a nuclear magnetic resonance analyzer 401; a mass flow meter 402; a data recording device 403; a temperature sensor 404; and a pressure sensor 405. DETAILED DESCRIPTION

[0052] The present invention is described in detail below in conjunction with the embodiments and drawings, but it should be understood that the embodiments and drawings are only used to exemplify the present invention and do not constitute any limitation on the protection scope of the present invention. All reasonable changes and combinations within the scope of the inventive concept of the present invention fall within the protection scope of the present invention.

[0053] Example 1

[0054] This embodiment provides a specific implementation of the method for optimizing the gas injection method for CO2 production and storage. In step 1, an experimental device for physical simulation of the optimization of the gas injection method for the reservoir is constructed, such as Figure 1 , including the following steps:

[0055] Step 1.1, the experimental device for physical simulation of reservoir gas injection method includes a fluid injection and production system, a geological model system and a fluid collection system connected in sequence, which are respectively connected to a data acquisition system for data acquisition, such as Figure 2 .

[0056] Step 1.2, the fluid injection and production system includes a dual-cylinder displacement pump 101 for controlling oil and gas injection. The dual-cylinder displacement pump 101 has a metering function for collecting the injected volume of CO2, and corresponds to the first high-pressure piston container 102, the second high-pressure piston container 103 and the third high-pressure piston container 104 for storing crude oil, CO2 and deuterated water (D2O), respectively, and the first multi-way valve 105 for adjusting the gas injection method, including #1~#5 interfaces in the figure; wherein #1~#3 are connected to the first, second and third high-pressure piston containers respectively. It also includes a second multi-way valve 106 on the high-pressure fluid pipeline between the geological model system and the fluid collection system, including #6~#8 interfaces in the figure. The first multi-way valve 105 controls fluid injection, and the second multi-way valve 106 controls fluid extraction. A back pressure valve 107 and a back pressure pump 108 are provided at the rear end of the second multi-way valve 106.

[0057] The geological model system includes a non-magnetic holder 201 for loading a long core, a confining pressure pump 202 for providing overburden pressure, and an oil bath 203 for simulating formation temperature.

[0058] The fluid collection system includes a condenser 301 for cooling the produced fluid, a gas-liquid separator 302 for separating gas and liquid in the produced fluid, a CO2 membrane separator 303 for separating CO2 and light hydrocarbons (C2-C5) in the gas, and a waste gas recovery container 304, wherein the CO2 membrane separator 303 uses a double-layer polyethylene amine membrane;

[0059] The data acquisition system includes a nuclear magnetic resonance analyzer 401 for collecting crude oil T2 spectrum hydrogen signals, which is arranged outside the non-magnetic clamp 201 and the oil bath 203, a mass flow meter 402 for measuring the CO2 production volume, which is arranged at the rear end of the CO2 membrane separator 303, a temperature sensor 404 for respectively collecting temperatures, which is arranged on the oil bath 203, and two pressure sensors 405 are arranged on both sides of the injection end and the production end of the non-magnetic clamp 201, which are respectively used to collect the pressure at the input end and the production end of the non-magnetic clamp, and a data recording device 403 for recording the above data. The data recording device 403 can be selected from a high-performance computer, such as Figure 2 shown.

[0060] Step 1.3, the geological model system connects the high-pressure fluid pipelines derived from the injection end and the production end of the non-magnetic clamp 201 to the first multi-way valve 105 and the second multi-way valve 106 respectively. Figure 2 The #5 interface of the first multi-way valve 105 is connected to the injection end of the non-magnetic clamp 201, the extraction end of the non-magnetic clamp 201 is connected to the #6 of the second multi-way valve 106, the #7 of the second multi-way valve 106 is connected to the #4 of the first multi-way valve, and the #8 of the second multi-way valve 106 is connected to the inlet end of the back pressure valve 107; in the fluid collection system, the outlet end of the back pressure valve 107 is connected to the high-pressure fluid pipeline derived from the inlet end of the condenser 301; the temperature sensor 404 and the pressure sensor 404 of the data acquisition system 5 are respectively connected to the oil bath 203 and the non-magnetic holder 201 of the geological model system, the nuclear magnetic resonance analyzer 401 is arranged around the non-magnetic holder 201 of the geological model system, and the mass flow meter 402 is connected to the outlet end of the CO2 membrane separator 303 of the fluid collection system through a high-pressure fluid pipeline; the temperature sensor 404, the pressure sensor 405, the double-cylinder displacement pump 101, the back pressure pump 108, the nuclear magnetic resonance analyzer 401 and the mass flow meter 402 are connected to the computer through a data acquisition line.

[0061] In step 2, a post-fracture geological model of the target reservoir is constructed and fluid samples are configured, including the following steps:

[0062] Step 2.1, taking a certain oil reservoir in Jimsar Sag, Xinjiang as an example, multiple full-diameter cores are drilled in different areas of the target oil reservoir, and then multiple standard plunger cores are drilled from the full-diameter cores. The core drilling process complies with the Petroleum and Natural Gas Industry Standard SY / T 5366-2021 "Technical Specifications for Coring Data Acquisition of Oilfield Development Wells" of the People's Republic of China.

[0063] Step 2.2: Grind the two end faces of the plunger core drilled in step 2.1, wash with oil and dry, then number the cores and measure the porosity. The core library of the target reservoir was established based on basic physical property parameters such as permeability K. The core processing and physical property testing process followed the National Standard of the People's Republic of China GB / T 29172-2012 "Core Analysis Method".

[0064] Step 2.3, according to the physical property distribution data in the geological data of the target oil reservoir, 6 cores with similar physical properties are selected from the core library and spliced ​​into a long core as the initial geological model between the injection and production wells. The long cores are numbered 1 to 6 from the injection end to the production end. Among them, cores 1, 2, 5 and 6 have developed natural microcracks and good physical properties, while cores 3 and 4 do not develop natural microcracks and have poor physical properties.

[0065] In step 2.4, before the target oil reservoir was put into production, fracturing construction measures were carried out on the reservoir in the area near the production wells. According to the fracturing construction parameters, fracture creation experiments were carried out on cores 5 and 6 to simulate the geological model after fracturing between injection and production wells. The cores after fracture creation had physical property distribution and fracture development similar to those of the reservoir after fracturing.

[0066] Step 2.5, collect formation oil obtained during the oil testing phase of the target reservoir, determine the proportion of saturated hydrocarbons, aromatic hydrocarbons, colloids and asphaltene components in the formation oil by gas chromatography, and prepare oil samples with the same components in the laboratory to simulate formation crude oil. If conditions permit, the formation oil can be directly used for physical simulation experiments.

[0067] Step 2.6, deuterated water is prepared by electrolysis to simulate the formation water of the target oil reservoir to shield the influence of the hydrogen signal in the water on the hydrogen signal in the crude oil, and high-purity CO2 is used to simulate the injection gas of the target oil reservoir.

[0068] In step 3, a multi-scheme physical simulation experiment under different gas injection modes in the reservoir is carried out, including the following steps:

[0069] Step 3.1, place the core in a vacuum pressurization saturation device and evacuate for 24 hours, then set a saturation pressure of 35 MPa according to the actual formation pressure of the reservoir and continue the deuterated water pressurization saturation process for 24 hours until the core is completely saturated with deuterated water.

[0070] In step 3.2, the saturated cores are placed in the non-magnetic clamp in the order of splicing, and fluorinated oil is used instead of water to increase the confining pressure and temperature of the geological model system to the overlying formation pressure of 42 MPa and the formation temperature of 110 °C through the confining pressure pump and oil bath, respectively.

[0071] Step 3.3, keep the multi-way valves #3 and #5 open, keep the valves #1, #2, #4, #6, #7 and #8 closed, and use the double-cylinder displacement pump 101 to inject the deuterated water in the third high-pressure piston container 104 into the geological model system until the flow pressure of the geological model system is increased to the original formation pressure of 35MPa, and stabilize for 30 minutes under the formation temperature and pressure conditions.

[0072] Step 3.4, keep the multi-way valves #1, #5, #6 and #8 open, and keep the valves #2, #3, #4 and #7 closed, and use the double-cylinder displacement pump 101 to inject the oil sample in the first high-pressure piston container 102 into the geological model system to perform the oil-to-water process, simulating the oil reservoir filling process, until no water is produced at the production end of the geological model.

[0073] Step 3.5, keep the multi-way valves #2, #5, #6 and #8 open, keep the valves #1, #3, #4 and #7 closed, set the dual-cylinder displacement pump 101 to the constant speed displacement mode, simulate the continuous gas injection mode, and adjust the displacement flow rate to perform physical simulation experiments of 5 gas injection schemes under the continuous gas injection mode. These 5 schemes refer to each gas injection mode. Different gas injection schemes can be designed under the gas injection mode by adjusting the gas injection parameters. They do not specifically refer to specific gas injection schemes. In actual operation, the scheme design can be carried out according to your own needs. There are existing technologies for gas injection scheme design, which will not be repeated here. After the experiment, the core is taken out for oil washing and drying.

[0074] Step 3.6, repeat steps 3.1 to 3.4, keep the multi-way valves #2, #5, #6 and #8 open, keep the valves #1, #3, #4 and #7 closed, set the dual-cylinder displacement pump 101 to the variable speed displacement mode, simulate the pulse gas injection mode, and conduct physical simulation experiments of 5 gas injection schemes under the pulse gas injection mode by adjusting the displacement flow rate and pulse frequency. After the experiment, take out the core for oil washing and drying.

[0075] Step 3.7, repeat steps 3.1 to 3.4, keep multi-way valves #5, #6 and #8 open, keep #1, #4 and #7 closed, open #2 and #3 alternately, set the dual-cylinder displacement pump 101 to constant speed displacement mode, and simulate the alternating gas-water injection method. However, due to the poor physical properties of the target reservoir, water is difficult to inject into the geological model, so the alternating gas-water injection method is not suitable for this reservoir. After the experiment, the core is taken out for oil washing and drying.

[0076] Step 3.8, repeat steps 3.1 to 3.4, first keep the multi-way valves #2 and #5 open, and the valves #1, #3, #4, #6, #7 and #8 closed, and the double-cylinder displacement pump 101 is set to the constant pressure displacement mode, and then keep all the valves of the first and second multi-way valves closed for a period of time, and then open the multi-way valves #2, #5, #6 and #8, and set the double-cylinder displacement pump 101 to the constant speed displacement mode to simulate the advance gas injection mode, and by adjusting the displacement pressure and flow rate as well as the valve opening and closing time, conduct physical simulation experiments of 5 gas injection schemes under the advance gas injection mode. After the experiment, take out the core for oil washing and drying.

[0077] Step 3.9, repeat steps 3.1 to 3.4, first keep the multi-way valves #2, #4, #6 and #7 open, and the valves #1, #3, #5 and #8 closed, set the dual-cylinder displacement pump 101 to the constant pressure displacement mode, then keep all the valves of the first and second multi-way valves closed for a period of time, and then open the multi-way valves #6 and #8 to simulate the gas injection throughput mode, and conduct physical simulation experiments of 5 gas injection schemes under the gas injection throughput mode by adjusting the displacement pressure and the duration and frequency of valve opening and closing.

[0078] In step 4, the crude oil recovery factor, CO2 oil exchange rate, CO2 storage volume and CO2 storage rate under different gas injection methods are calculated as the effectiveness and economic evaluation indicators of CO2 production increase and storage performance, including the following steps:

[0079] Step 4.1, the nuclear magnetic resonance instrument of the data acquisition system is used to collect the T2 spectrum hydrogen signal of the crude oil in the long core in real time during the physical simulation experiment, and the experiment is stopped after the total amount of hydrogen signal is stable, and the total amount of hydrogen signal N at the start of the physical simulation experiment is counted. i and the total amount of hydrogen signal N at the end time f .

[0080] Step 4.2: The total amount of CO2 V injected into the geological model system is adjusted by the dual-cylinder displacement pump 101 of the fluid injection and production system. i Statistics are performed to separate the CO2 in the fluid at the production end of the geological model system from liquid oil and water and gaseous light hydrocarbons through the fluid collection system, and the total amount of CO2 produced V is measured by the mass flow meter 402. p Conduct statistics.

[0081] Step 4,3, using formula R o =(N i -N f ) / N i The oil recovery factor is calculated as the effectiveness evaluation index of CO2 production enhancement performance, using the formula H = (N i -N f ) / V i The CO2 oil exchange rate is calculated as the economic evaluation index of CO2 production increase performance, using the formula V s =V i -V p The CO2 storage capacity is calculated as the effectiveness evaluation index of CO2 storage performance, using the formula R g =(V i -V p ) / V i The CO2 storage rate is calculated as an economic evaluation index of CO2 storage performance.

[0082] In step 4.4, the values ​​of crude oil recovery factor, CO2 oil exchange rate, CO2 storage volume and CO2 storage rate of a total of 20 gas injection schemes under the four gas injection methods are counted. The results are shown in Table 1.

[0083] Table 1

[0084]

[0085]

[0086] In step 5, the evaluation index is subjected to data standardization, and a hierarchical structure model is established using the hierarchical analysis method to construct a judgment matrix of the evaluation index, including the following steps:

[0087] Step 5.1, the data of crude oil recovery, CO2 oil exchange rate, CO2 storage volume and CO2 storage rate of 20 gas injection schemes under four gas injection methods are standardized. The processing formula is: ij =[x ij -min(x ij )] / [max(x ij )-min(x ij )], where x ij is the value before data standardization, y ij is the value after data standardization, max(x ij ) is the maximum value under a certain indicator, min(x ij ) is the minimum value under a certain indicator, and the processing results are shown in Table 2.

[0088] Table 2

[0089]

[0090]

[0091] Step 5.2, use the analytic hierarchy process to establish a hierarchical model consisting of a target layer, a criterion layer, and a scheme layer. The target layer is the optimal gas injection method for the reservoir based on CO2 production and storage performance. The criterion layer is the four evaluation indicators of crude oil recovery rate, CO2 oil exchange rate, CO2 storage volume, and CO2 storage rate. The scheme layer is 20 schemes under the four available gas injection methods, such as Figure 3 shown.

[0092] Step 5.3, use the analytic hierarchy process to construct a 4×4 judgment matrix of the four evaluation indicators: crude oil recovery rate, CO2 oil exchange rate, CO2 storage capacity and CO2 storage rate Define the importance of indicator i compared with indicator j as a ij , as the corresponding element in matrix A, a is determined by the judgment matrix element scaling method shown in Table 3 ij The values ​​are shown in Table 4, and the final judgment matrix is

[0093] Table 3

[0094]

[0095] Table 4

[0096]

[0097] In step 6, the weight vectors of various evaluation indicators are calculated and consistency tests are performed. The comprehensive scores of CO2 production increase and storage performance under different gas injection methods are calculated based on the weight vectors, and the optimal gas injection method for the reservoir is selected based on this, including the following steps:

[0098] Step 6.1, the judgment matrix Normalize by column, then sum the normalized columns by row, and then divide each element of the summed vector by the order 4 of the judgment matrix A to obtain the weight vector w of the evaluation index j =[0.250.550.10.1].

[0099] Step 6.2, combine the formula CR = CI / RI and CI = (λ max -n) / (n-1) calculates the consistency ratio CR for consistency test, where λ max is the maximum characteristic root, RI is the random consistency index, which can be determined by looking up Table 5. The calculation results show that CR = 0.0148 < 0.1. Through the consistency test, the weight vector w j =[0.250.550.10.1] can be used for subsequent calculations.

[0100] Table 5

[0101]

[0102] Step 6.3, through the weight vector w j =[0.250.550.10.1] for the standardized data y in Table 2 ij By weighted summation, the comprehensive scores of CO2 production increase and storage performance effectiveness and economy of 20 schemes under four gas injection methods are obtained, as shown in Table 6.

[0103] Table 6

[0104]

[0105] In step 6.4, the three highest scoring schemes among the four gas injection methods are screened out and the average value is taken to represent the final score of the gas injection method. The results show that the final scores of continuous gas injection, pulse gas injection, advanced gas injection and gas injection throughput are 0.47, 0.26, 0.60 and 0.65 respectively. Therefore, gas injection throughput is the optimal gas injection method for the target reservoir in this embodiment.

[0106] The above embodiments are only preferred implementations of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. An experimental device for optimizing the gas injection method for CO2 production increase and storage in oil reservoirs, characterized by: It includes a fluid injection and production system, a geological model system and a fluid collection system which are connected in sequence, and all three are electrically connected to the data acquisition system; The fluid injection and production system comprises three high-pressure piston containers containing crude oil, CO2 and deuterated water, respectively injecting oil samples, CO2 and deuterated water into the geological model system through a double-cylinder displacement pump to respectively simulate formation oil, target reservoir injection gas and target reservoir formation water. The fluid injection and production system performs gas injection experiments of multiple gas injection methods and multiple gas injection schemes with different parameters on the geological model system, and the multiple gas injection methods are selected from continuous gas injection, pulse gas injection, alternating gas and water injection, advanced gas injection or gas injection huff and puff; The geological model system is used to simulate the overlying formation pressure and the formation temperature of the geological model after the target reservoir is fractured; The fluid collection system is used to cool and separate the gas and liquid of the mixed fluid passing through the geological model system, separate the CO2 in the fluid at the production end of the geological model system from the liquid oil and water and the gaseous light hydrocarbons, collect data on the total amount of CO2 produced, and recover the waste gas of the separated gaseous light hydrocarbons; The data acquisition system is used to collect in real time the volume of fluid injected by the dual-cylinder displacement pump and the pressure and temperature of the geological model of the target oil reservoir after fracturing; to collect in real time the T2 spectrum hydrogen signal of the crude oil in the geological model of the target oil reservoir after fracturing; and to collect the total amount of CO2 produced at the production end of the fluid collection system.

2. According to claim 1, the experimental device for optimizing the gas injection method for increasing CO2 production and storing in oil reservoirs is characterized by: The fluid injection and production system includes a double-cylinder displacement pump for controlling oil and gas injection connected by a high-pressure fluid pipeline, a first high-pressure piston container, a second high-pressure piston container and a third high-pressure piston container for storing crude oil, CO2 and deuterated water respectively, and a first multi-way valve and a second multi-way valve for adjusting the gas injection mode of the geological model system. The first multi-way valve includes at least five valves, three of which are respectively connected to the output ends of the first, second and third high-pressure piston containers, and the fourth valve is connected to the input end of the geological model system. The second multi-way valve is arranged on the high-pressure fluid pipeline at the rear end of the geological model system. , another valve of the second multi-way valve except the inlet valve and the outlet valve is connected to the fifth valve of the first multi-way valve; the geological model system includes a non-magnetic clamp for clamping the geological model of the target reservoir after fracturing, the non-magnetic clamp is provided with a confining pressure pump simulating the overlying formation pressure, and an oil bath simulating the formation temperature, and the second multi-way valve is arranged at the production end of the non-magnetic clamp; the fluid collection system is connected to the condenser, the gas-liquid separator, the CO2 membrane separator and the waste gas recovery container in sequence through the high-pressure fluid pipeline, and the front end of the condenser is provided with a back pressure valve and a back pressure pump for controlling the oil and gas production; The data acquisition system includes a nuclear magnetic resonance analyzer for collecting crude oil T2 spectrum hydrogen signals, which is arranged at the periphery of the non-magnetic clamp and the oil bath; a mass flowmeter for measuring the CO2 production volume is arranged at the rear end of the CO2 membrane separator; a temperature sensor is arranged at the oil bath for respectively collecting the temperature of the geological model of the target reservoir after fracturing; pressure sensors are arranged at both sides of the injection end and the production end of the non-magnetic clamp for collecting the front and rear end pressures of the geological model of the target reservoir after fracturing; and a data recording device for recording all collected data; the dual-cylinder displacement pump has its own fluid injection volume measurement, and the measurement data is transmitted to the data recording device.

3. The experimental device for optimizing the gas injection method for increasing CO2 production and storing in oil reservoirs according to claim 2 is characterized by: The CO2 membrane separator adopts a double-layer polyethylene amine membrane.

4. A method for optimizing the experimental device for optimizing the gas injection method for increasing CO2 production and storing in oil reservoirs according to claims 2 and 3, characterized in that: The following steps are involved: S1, constructing the experimental device for optimizing the gas injection method for increasing CO2 production and storing oil reservoirs: S2, constructing the geological model of the target reservoir after fracturing and configuring fluid samples: Drill multiple full-diameter cores in different areas of the target reservoir, and then drill multiple standard plunger cores from the full-diameter cores; grind the end faces of the plunger cores flat, wash the oil and dry them; number the cores and measure the basic physical parameters, including porosity φ and permeability K, to establish a core library for the target reservoir; select cores with similar physical properties to the reservoir from the core library and splice them into long cores as the initial geological model between the injection and production wells according to the geological data of the target reservoir; carry out fracture-making experiments on the long cores according to the fracturing construction parameters of the target reservoir to simulate the geological model after fracturing between the injection and production wells; configure oil samples with the same components to simulate formation crude oil according to the chromatographic analysis data of the target reservoir; prepare deuterated water to simulate the formation water of the target reservoir to shield the influence of hydrogen signals in the water on hydrogen signals in the crude oil; use high-purity CO2 to simulate the injection gas of the target reservoir; S3, conduct multi-scheme physical simulation experiments under different gas injection methods in oil reservoirs: The core is placed in a vacuum pressurization saturation device, and the core is evacuated and pressurized to the actual formation pressure to completely saturate the deuterated water; the saturated core is placed in a non-magnetic clamp in sequence according to the splicing order, and fluorinated oil is used instead of water to increase the confining pressure and temperature of the geological model system to the overlying formation pressure and formation temperature through a confining pressure pump and an oil bath respectively; the deuterated water in the third high-pressure piston container is injected into the geological model system by a double-cylinder displacement pump to increase the system flow pressure to the original formation pressure; the first high-pressure piston container is injected into the geological model system by a double-cylinder displacement pump. The oil sample in the pressure piston container is injected into the geological model system to carry out the oil-water displacement process to simulate the filling and accumulation process of the oil reservoir; by adjusting the two multi-way valves, a multi-scheme physical simulation experiment under different gas injection modes of the oil reservoir is carried out; the gas injection modes include continuous gas injection, pulse gas injection, gas injection huff and puff, gas-water alternating injection and advanced gas injection; by adjusting the injection gas flow rate and gas injection pressure value of the double-cylinder displacement pump, as well as the duration and frequency of the opening and closing of the first and second multi-way valves, a multi-scheme physical simulation experiment under different gas injection modes is carried out respectively; S4, calculate the crude oil recovery factor, CO2 oil exchange rate, CO2 storage volume and CO2 storage rate under different gas injection methods as the effectiveness and economic evaluation indicators of CO2 production increase and storage performance; The T2 spectrum hydrogen signal of the crude oil in the long core during the physical simulation experiment was collected in real time by the nuclear magnetic resonance instrument of the data acquisition system, and the experiment was stopped after the total amount of hydrogen signal was stable; the total amount of hydrogen signal N at the beginning of the physical simulation experiment was counted. i and the total amount of hydrogen signal N at the end time f ; The total CO2 injection volume V is calculated by the dual-cylinder displacement pump of the fluid injection and production system and the mass flow meter of the data acquisition system i and the total CO2 output V p ; Using formula R o =(N i -N f ) / N i Calculate the oil recovery factor as the effectiveness evaluation index of CO2 production enhancement performance; use the formula H = (N i -N f ) / V i Calculate the CO2 oil exchange rate as the economic evaluation index of CO2 production increase performance; use the formula V s =V i -V p Calculate the CO2 storage capacity as the effectiveness evaluation index of CO2 storage performance; use the formula R g =(V i -V p ) / V i Calculate the CO2 storage rate as an economic evaluation index of CO2 storage performance; calculate the crude oil recovery rate, CO2 oil exchange rate, CO2 storage volume and CO2 storage rate of each scheme under different gas injection methods; S5, performing data standardization processing on the evaluation indicators, using the hierarchical analysis method to establish a hierarchical structure model and construct a judgment matrix of the evaluation indicators, including the following steps: S51: Data standardization processing is performed on the crude oil recovery factor, CO2 oil exchange rate, CO2 storage volume and CO2 storage rate of each scheme under different gas injection methods. The processing formula is: y ij =[x ij -min(x ij )] / [max(x ij )-min(x ij )] Where x ij is the value before data standardization, y ij is the value after data standardization, max(x ij ) is the maximum value under a certain indicator, min(x ij ) is the minimum value under a certain indicator; S52: Use the analytic hierarchy process to establish a hierarchical model consisting of a target layer, a criterion layer, and a scheme layer, where the target layer is the optimal gas injection method for the reservoir based on CO2 production increase and storage performance, the criterion layer is the four evaluation indicators of crude oil recovery rate, CO2 oil exchange rate, CO2 storage capacity, and CO2 storage rate, and the scheme layer is a number of schemes available under different gas injection methods; use the analytic hierarchy process to construct a 4×4 judgment matrix A of the four evaluation indicators of crude oil recovery rate, CO2 oil exchange rate, CO2 storage capacity, and CO2 storage rate, and define the importance of indicator i compared with indicator j as a ij , as the corresponding element in matrix A, determine a by judging the matrix element scaling method ij Numeric value; S6, calculate the weight vector of each evaluation index and perform consistency test, calculate the comprehensive score of CO2 production increase and storage performance under different gas injection methods according to the weight vector, and select the optimal gas injection method for the reservoir, including the following steps: S61: Normalize the judgment matrix A by column, then sum the normalized columns by row, and then divide each element of the summed vector by the order n of the judgment matrix A to obtain the weight vector w of the evaluation index. j ; S62: Combine the formulas CR = CI / RI and CI = (λ max -n) / (n-1) calculates the consistency ratio CR for consistency check. If the consistency check passes, the weight vector w is used. j , otherwise, return to the construction of the judgment matrix in S52 until the consistency check is passed, where λ max is the maximum characteristic root, RI is the random consistency index; S63: through the weight vector w j After the standardized data y ij The weighted summation is performed to obtain the comprehensive scores of CO2 production increase and storage performance of each scheme under different gas injection methods; S64: Filter out the three highest-scoring solutions among the various gas injection methods and calculate the average value to represent the final score of the gas injection method, based on which the optimal gas injection method is selected.

5. The preferred method according to claim 4, characterized in that: In the physical simulation experiment described in S3, the five valves of the first multi-way valve are #1 to #5, #1 to #3 are connected to the output ends of the first, second and third high-pressure piston containers respectively, #5 is used for the input of the geological model system, the three valves of the second multi-way valve are #6 to #8, #6 is connected to the output of the geological model system, #8 is used as the input of the fluid collection system, and #7 is connected to #4; Keep valves #2, #5, #6 and #8 open, valves #1, #3, #4 and #7 closed, and set the dual-cylinder displacement pump to constant speed displacement mode to simulate continuous gas injection; Keep valves #2, #5, #6 and #8 open, valves #1, #3, #4 and #7 closed, and set the dual-cylinder displacement pump to variable speed displacement mode to simulate pulse gas injection; Keep valves #5, #6 and #8 open, valves #1, #4 and #7 closed, valves #2 and #3 open alternately, and set the dual-cylinder displacement pump to constant speed displacement mode to simulate the alternating gas-water injection method; Keep #2 and #5 valves open, #1, #3, #4, #6, #7 and #8 valves closed, set the double-cylinder displacement pump to constant pressure displacement mode, keep all valves of the first and second multi-way valves closed for a period of time, then open #2, #5, #6 and #8 valves, and set the double-cylinder displacement pump to constant speed displacement mode to simulate the advanced gas injection method; Keep valves #2, #4, #6 and #7 open, valves #1, #3, #5 and #8 closed, set the dual-cylinder displacement pump to constant pressure displacement mode, keep all valves of the first and second multi-way valves closed for a period of time, and then open valves #6 and #8 to simulate the gas injection throughput mode.

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