Method and system for testing gas energized refracturing performance of old well

Abstract

The invention discloses a method and a system for testing the gas energized refracturing performance of an old well, and belongs to the field of low-permeability reservoir development. After an oil well produces for a period of time, stratum energy is lost, and the yield is reduced, so that liquid carbon dioxide is injected to supplement energy before re-fracturing; liquid carbon dioxide is injected, under the formation condition, carbon dioxide and crude oil components form a mixed-phase front edge, heavy hydrocarbon is extracted from crude oil through supercritical fluid, and gas at the displacement front edge is continuously concentrated. Carbon dioxide and crude oil are changed into mixed-phase liquid to form a single liquid phase, so that the in-situ crude oil can be effectively displaced to a production well, and the recovery efficiency is improved. Liquid carbon dioxide is used for supplementing formation energy before fracturing, the carbon dioxide liquid energizing injection opportunity and injection mode are optimized according to the site construction condition, the optimal carbon dioxide energizing dosage is calculated according to the formation pressure of a target well and the area of an old crack, and a theoretical basis is provided for research on improvement of single well yield through re-fracturing.

Description

Technical Field

[0001] The invention belongs to the technical field of low-permeability oil reservoir development, and relates to a method and system for testing the performance of gas-enhanced repeated fracturing of old wells. Background Art

[0002] With the development of oil and gas field, low permeability reservoirs have become the main strategic resources. Due to the low permeability of the reservoir, it is difficult to establish an effective displacement pressure system by injecting water under the economic limit well network, resulting in a significant decline in production after a period of exploitation. At present, repeated fracturing is performed on oil wells with low exploitation to restore the single well production. Before repeated fracturing, energy is supplemented to the production layer to restore the formation pressure to maintain the level, maintain high and stable production of the oil well, and extend the effectiveness of the measures.

[0003] At present, the main way to replenish formation energy before repeated fracturing is to mechanically seal the old perforated section of the oil well and inject oil-displacing fracturing fluid. The energy of the formation deficit is calculated based on the amount of produced fluid during the development period of the oil well, so as to obtain the amount of oil-displacing fracturing fluid required for repeated fracturing. In view of the current shortage of water resources in some areas, the repeated fracturing energy replenishment method has limited contribution to the production increase effect, resulting in low recovery rate and difficulty in meeting fracturing needs. Summary of the invention

[0004] The purpose of the present invention is to solve the problem that the repeated fracturing energy replenishment method in the prior art has limited contribution to the production improvement effect, resulting in low recovery rate, and to provide a method and system for testing the performance of old well gas-enhanced repeated fracturing.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention provides a method for testing the performance of gas-enhanced repeated fracturing in old wells, comprising the following steps:

[0007] Liquid carbon dioxide is injected into the old perforation section of the gas well, and liquid carbon dioxide is injected into the pre-fluid stage of repeated fracturing in the selected perforation section to obtain the production fracture area and production fracture volume of the oil well;

[0008] The amount of carbon dioxide adsorbed in the matrix and the amount of carbon dioxide used to restore formation pressure are obtained according to the production fracture area and the production fracture volume of the oil well;

[0009] The amount of carbon dioxide gas crossover and the amount of carbon dioxide injected are obtained based on the amount of carbon dioxide adsorbed in the matrix and the amount of carbon dioxide used to restore formation pressure, thereby achieving repeated fracturing tests.

[0010] Preferably, liquid carbon dioxide is injected into each old perforation section, odd-numbered old perforation sections, or even-numbered old perforation sections.

[0011] Preferably, a reduction in displacement friction test is performed when liquid carbon dioxide is injected into the first perforation section.

[0012] Preferably, the method for obtaining the production fracture volume of an oil well is as follows:

[0013]

[0014] Among them, W p is the volume of the flowback fracturing fluid, ΔP is the change in formation pressure during the flowback stage, d max is the maximum average fracture width before flowback, K is the matrix permeability under reservoir conditions, φ is the matrix porosity, t2 is the flowback time, and B w is the formation water volume coefficient, μ w is the formation water viscosity, C F is the crack volume compression coefficient, C t is the comprehensive compression factor, V cc is the volume of produced fluid during the production process, and t is the sum of the equilibrium pressure time and the flowback time after fracturing.

[0015] Preferably, the method for obtaining the production fracture volume of an oil well is as follows:

[0016]

[0017] Among them, V fi is the initial fracture volume after fracturing, W p is the volume of the flowback fracturing fluid, ΔP is the change in formation pressure during the flowback stage, d max is the maximum average fracture width before flowback, K is the matrix permeability under reservoir conditions, φ is the matrix porosity, t2 is the flowback time, and B w is the formation water volume coefficient, μ w is the formation water viscosity, C F is the crack volume compression coefficient, C t is the comprehensive compression coefficient, and t is the sum of the equilibrium pressure time and the flowback time after fracturing.

[0018] Preferably, the comprehensive compression coefficient C t The acquisition method is as follows:

[0019]

[0020] Among them, C o is the crude oil compressibility coefficient, C w is the formation water compressibility coefficient, S wc is the bound water saturation, C f is the rock pore compressibility coefficient.

[0021] Preferably, the method for obtaining the amount of carbon dioxide adsorbed on the substrate is as follows:

[0022] V ab=[-0.2521+0.179×exp(P / 14.731)]×A f

[0023] Where P is the equilibrium pressure after injection of carbon dioxide, A f Produce fracture volume for oil wells.

[0024] Preferably, the method for obtaining the amount of carbon dioxide used to restore formation pressure is as follows:

[0025] V re =1.2V fi

[0026] Among them, V fi is the initial fracture volume after fracturing.

[0027] Preferably, the carbon dioxide gas cross-flow amount V is obtained ch and CO2 injection volume V to The method is as follows:

[0028] V ch =0.3V to

[0029] V to =V ab +V re +V ch

[0030] Among them, V ab is the amount of carbon dioxide adsorbed on the matrix, V re is the amount of carbon dioxide used to restore formation pressure.

[0031] The present invention provides a gas-enhanced repeated fracturing performance testing system for old wells, comprising:

[0032] A carbon dioxide injection module, which is used to inject liquid carbon dioxide into the old perforation section of the gas well, and inject liquid carbon dioxide into the pre-fluid stage of repeated fracturing in the selected perforation section to obtain the production fracture area and production fracture volume of the oil well;

[0033] A parameter acquisition module, wherein the carbon dioxide parameter acquisition module is used to acquire the amount of carbon dioxide adsorbed in the matrix and the amount of carbon dioxide used to restore formation pressure according to the production fracture area and the production fracture volume of the oil well;

[0034] A parameter processing module is used to obtain the amount of carbon dioxide gas crossover and the amount of carbon dioxide injection according to the amount of carbon dioxide adsorbed in the matrix and the amount of carbon dioxide used to restore the formation pressure, so as to realize repeated fracturing tests.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The present invention proposes a method for testing the performance of gas-enhanced repeated fracturing of old wells. Since the formation energy is depleted and the production decreases after the oil well has been produced for a period of time, liquid carbon dioxide is first injected before repeated fracturing to supplement energy. By injecting liquid carbon dioxide, under formation conditions, carbon dioxide and crude oil components form a miscible front, and the supercritical fluid extracts heavier hydrocarbons from the crude oil, and continuously concentrates the gas at the displacement front. Carbon dioxide and crude oil become miscible liquids, forming a single liquid phase, so that the formation crude oil can be effectively displaced to the production well to improve the recovery rate. Liquid carbon dioxide is used to supplement the formation energy before fracturing, and the timing and injection method of liquid carbon dioxide energy enhancement injection are optimized according to the on-site construction conditions, and the optimal amount of carbon dioxide energy enhancement is calculated according to the formation pressure of the target well and the area of ​​the old fracture. Therefore, the method proposed by the present invention overcomes the shortcomings of water shortage in some areas and the limited contribution of existing repeated fracturing energy supplement methods to the production improvement effect, and provides a theoretical basis for the research on repeated fracturing to increase the production of single wells.

[0037] The present invention proposes a gas-assisted re-fracturing performance test system for old wells, which realizes re-fracturing test by dividing the system into a carbon dioxide injection module, a parameter acquisition module and a parameter processing module. The modular concept is adopted to make each module independent of each other, which is convenient for unified management of each module. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 This is a flow chart of the gas energized repeated fracturing performance testing method for old wells of the present invention.

[0040] Figure 2 This is a diagram of the old well gas energization repeated fracturing performance test system of the present invention. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0042] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0044] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0045] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0046] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0048] The present invention proposes a method for testing the performance of old well gas-enhanced repeated fracturing. Figure 1 As shown, the following steps are included:

[0049] S1. Injecting liquid carbon dioxide into the old perforation section of the gas well, and injecting liquid carbon dioxide into the pre-fluid stage of repeated fracturing in the selected perforation section to obtain the production fracture area and production fracture volume of the oil well;

[0050] Liquid carbon dioxide is injected into each old perforation section, odd-numbered old perforation sections, or even-numbered old perforation sections.

[0051] When injecting liquid CO2 in the first perforation section, a friction test was performed to reduce the displacement.

[0052] The method for obtaining the production fracture volume of an oil well is as follows:

[0053]

[0054] Among them, W p is the volume of the flowback fracturing fluid, ΔP is the change in formation pressure during the flowback stage, d max is the maximum average fracture width before flowback, K is the matrix permeability under reservoir conditions, φ is the matrix porosity, t2 is the flowback time, and B w is the formation water volume coefficient, μ w is the formation water viscosity, C F is the crack volume compression coefficient, C t is the comprehensive compression factor, V cc is the volume of produced fluid during the production process, and t is the sum of the equilibrium pressure time and the flowback time after fracturing.

[0055] The method for obtaining the production fracture volume of an oil well is as follows:

[0056]

[0057] Among them, V fi is the initial fracture volume after fracturing, W p is the volume of the flowback fracturing fluid, ΔP is the change in formation pressure during the flowback stage, d max is the maximum average fracture width before flowback, K is the matrix permeability under reservoir conditions, φ is the matrix porosity, t2 is the flowback time, and B w is the formation water volume coefficient, μ w is the formation water viscosity, C F is the crack volume compression coefficient, C t is the comprehensive compression coefficient, and t is the sum of the equilibrium pressure time and the flowback time after fracturing.

[0058] Comprehensive compression coefficient C t The acquisition method is as follows:

[0059]

[0060] Among them, C o is the crude oil compressibility coefficient, C w is the formation water compressibility coefficient, S wc is the bound water saturation, C f is the rock pore compressibility coefficient.

[0061] S2. Obtaining the amount of carbon dioxide adsorbed in the matrix and the amount of carbon dioxide used to restore formation pressure according to the production fracture area and the production fracture volume of the oil well;

[0062] The method for obtaining the amount of carbon dioxide adsorbed on the matrix is ​​as follows:

[0063] V ab =[-0.2521+0.179×exp(P / 14.731)]×A f

[0064] Where P is the equilibrium pressure after injection of carbon dioxide, A f Produce fracture volume for oil wells.

[0065] The method for obtaining the amount of carbon dioxide used to restore formation pressure is as follows:

[0066] V re =1.2V fi

[0067] Among them, V fi is the initial fracture volume after fracturing.

[0068] S3. The carbon dioxide gas crossover amount and the carbon dioxide injection amount are obtained according to the amount of carbon dioxide adsorbed in the matrix and the amount of carbon dioxide used to restore the formation pressure, so as to realize repeated fracturing tests.

[0069] Get the CO2 gas cross-flow volume V ch and CO2 injection volume V to The method is as follows:

[0070] V ch =0.3V to

[0071] V to =V ab +V re +V ch

[0072] Among them, V ab is the amount of carbon dioxide adsorbed on the matrix, V re is the amount of carbon dioxide used to restore formation pressure.

[0073] The present invention is that after a period of oil well production, the formation energy is deficient and the output decreases. Liquid carbon dioxide is injected to supplement energy before repeated fracturing. By injecting liquid gas, under formation conditions, carbon dioxide and crude oil components form a miscible front, and supercritical fluid extracts heavier hydrocarbons from the crude oil, and continuously concentrates the gas at the displacement front. Carbon dioxide and crude oil become miscible liquids, forming a single liquid phase, so that the formation crude oil can be effectively displaced to the production well, thereby improving the recovery rate. The specific process is as follows:

[0074] Step 1: Gas-liquid energized repeated fracturing section selection method:

[0075] Before repeated fracturing, inject liquid CO2 into each old perforation section; or inject CO2 only into odd-numbered old perforation sections; or inject CO2 only into even-numbered old perforation sections. The selection of injection sections is determined based on the economic budget. If the economic budget is limited, it is preferred to inject CO2 only into some of the old perforation sections (with the same spacing between perforation sections).

[0076] Step 2: Gas energized repeated fracturing injection method:

[0077] Liquid carbon dioxide is injected in the pre-fluid stage of repeated fracturing in the selected perforated section. The injection rate is 2 cubic meters per minute. When injecting in the first perforated section, a friction test of reduced displacement is required. The specific method is to reduce the displacement to 1 cubic meter per minute when there are 2 cubic meters of liquid carbon dioxide left.

[0078] Step 3: Calculation of gas energization repeated fracturing injection volume:

[0079] The calculation of gas energized repeated fracturing injection volume includes: the volume of the fracture after the oil well has been produced for a period of time, the area of ​​the fracture after the oil well has been produced for a period of time, the amount of carbon dioxide adsorbed in the matrix, the amount of carbon dioxide used to restore the formation pressure, the estimation of carbon dioxide gas crosstalk and the amount of carbon dioxide injected.

[0080] The meanings and units of the parameters in the above formula are as follows: P is the equilibrium pressure after carbon dioxide injection, MPa; V fi is the initial fracture volume after fracturing, m 3 ; W i is the volume of the underground fracturing fluid, m 3 ; W q is the volume of fracturing fluid entering the matrix after the pump is stopped during fracturing, m 3 ; ΔV f is the crack deformation volume, m 3 ; W p is the volume of flowback fracturing fluid, m 3 ; W d is the volume of fracturing fluid entering the fracture from the matrix during the flowback process, m 3 ; ΔP is the change in formation pressure during the flowback stage (change in wellhead oil pressure during the flowback stage), MPa; d max is the maximum average seam width before flowback, m; μ o is the viscosity of crude oil, mPa·s; K is the matrix permeability under reservoir conditions, mD; φ is the matrix porosity, %; t1 is the equilibrium pressure time after fracturing, d; t2 is the flowback time, d; B w is the volume coefficient of formation water (fracturing fluid), which is generally 1.01-1.03; μ wis the formation water viscosity, mPa·s; C F is the crack volume compression coefficient, 1 / MPa; C t is the comprehensive compression coefficient, 1 / MPa; C f is the rock pore compression coefficient, 1 / MPa; C o is the crude oil compression coefficient, 1 / MPa; C w : Formation water compressibility, 1 / MPa; S wc V is bound water saturation, a decimal; cc B is the amount of liquid produced during the production process; w The value is 1.02, C F The value is 3×10-2 1 / MPa (empirical value).

[0081] The present invention proposes a gas-enhanced repeated fracturing performance testing system for old wells. Figure 2 As shown, it includes a carbon dioxide injection module, a parameter acquisition module and a parameter processing module;

[0082] The carbon dioxide injection module is used to inject liquid carbon dioxide into the old perforation section of the gas well, and inject liquid carbon dioxide into the pre-fluid stage of repeated fracturing in the selected perforation section to obtain the production fracture area and production fracture volume of the oil well;

[0083] The carbon dioxide parameter acquisition module is used to acquire the amount of carbon dioxide adsorbed in the matrix and the amount of carbon dioxide used to restore formation pressure according to the production fracture area and the production fracture volume of the oil well;

[0084] The parameter processing module is used to obtain the carbon dioxide gas cross-flow amount and the carbon dioxide injection amount according to the amount of carbon dioxide adsorbed in the matrix and the amount of carbon dioxide used to restore the formation pressure, so as to realize repeated fracturing tests.

[0085] Therefore, the present invention proposes a method for testing the performance of gas-enhanced repeated fracturing of old wells. In view of the current water shortage in some areas, the need for repeated fracturing to further improve the recovery rate, the need for carbon sequestration, etc., liquid carbon dioxide is injected before repeated fracturing to supplement the formation energy. Under the formation conditions, carbon dioxide and crude oil components form a miscible front, and the supercritical fluid extracts heavier hydrocarbons from the crude oil, and continuously concentrates the gas at the displacement front. Carbon dioxide and crude oil become miscible liquids, forming a single liquid phase, so that the formation crude oil can be effectively displaced to the production well. According to the on-site construction situation, the timing and method of injection of liquid carbon dioxide for energy enhancement are optimized, and the amount of carbon dioxide required for energy enhancement is calculated according to the formation pressure of the target well and the area of ​​the old fractures.

[0086] The gas-enhanced repeated fracturing performance testing method for old wells proposed in the present invention has the following advantages: 1) Before repeated fracturing, the oil-displacing fracturing fluid is injected into the formation at a low displacement to replenish the formation energy, so that the formation energy is restored to more than 100% before mining. The amount of oil-displacing fracturing fluid required for energy replenishment before repeated fracturing is large, the on-site liquid supply cycle is long, and there is a problem of insufficient liquid supply capacity. 2) The oil-displacing fracturing fluid mainly acts to increase the formation pressure to maintain the level. 3) This method overcomes the shortcomings of water scarcity in some areas and the limited effect of the existing repeated fracturing using oil-displacing fracturing fluid to replenish energy and increase production, and provides a theoretical basis for research on repeated fracturing to increase single well production.

[0087] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for testing the performance of gas-enhanced repeated fracturing in old wells, characterized in that: The steps include: Liquid carbon dioxide is injected into the old perforation section of the gas well, and liquid carbon dioxide is injected into the pre-fluid stage of repeated fracturing in the selected perforation section to obtain the production fracture area and production fracture volume of the oil well; The amount of carbon dioxide adsorbed in the matrix and the amount of carbon dioxide used to restore formation pressure are obtained according to the production fracture area and the production fracture volume of the oil well; The amount of carbon dioxide gas crossover and the amount of carbon dioxide injected are obtained based on the amount of carbon dioxide adsorbed in the matrix and the amount of carbon dioxide used to restore formation pressure, thereby achieving repeated fracturing tests.

2. The method for testing the performance of old well gas energized repeated fracturing according to claim 1, characterized in that: Liquid carbon dioxide is injected into each old perforation section, odd-numbered old perforation sections, or even-numbered old perforation sections.

3. The method for testing the performance of old well gas-enhanced repeated fracturing according to claim 1, characterized in that: When injecting liquid carbon dioxide in the first perforation section, a reduction rate friction test was performed.

4. The method for testing the performance of old well gas energized repeated fracturing according to claim 1, characterized in that: The method for obtaining the production fracture volume of an oil well is as follows: Among them, W p is the volume of the flowback fracturing fluid, ΔP is the change in formation pressure during the flowback stage, d max is the maximum average fracture width before flowback, K is the matrix permeability under reservoir conditions, φ is the matrix porosity, t2 is the flowback time, and B w is the formation water volume coefficient, μ w is the formation water viscosity, C F is the crack volume compression coefficient, C t is the comprehensive compression factor, V cc is the volume of produced fluid during the production process, and t is the sum of the equilibrium pressure time and the flowback time after fracturing.

5. The method for testing the performance of old well gas energized repeated fracturing according to claim 1, characterized in that: The method for obtaining the production fracture volume of an oil well is as follows: Among them, V fi is the initial fracture volume after fracturing, W p is the volume of the flowback fracturing fluid, ΔP is the change in formation pressure during the flowback stage, d max is the maximum average fracture width before flowback, K is the matrix permeability under reservoir conditions, φ is the matrix porosity, t2 is the flowback time, and B w is the formation water volume coefficient, μ w is the formation water viscosity, C F is the crack volume compression coefficient, C t is the comprehensive compression coefficient, and t is the sum of the equilibrium pressure time and the flowback time after fracturing.

6. The method for testing the performance of old well gas energized repeated fracturing according to claim 4 or 5, characterized in that: Comprehensive compression coefficient C t The acquisition method is as follows: Among them, C o is the crude oil compressibility coefficient, C w is the formation water compressibility coefficient, S wc is the bound water saturation, C f is the rock pore compressibility coefficient.

7. The method for testing the performance of old well gas energized repeated fracturing according to claim 1, characterized in that: The method for obtaining the amount of carbon dioxide adsorbed on the matrix is ​​as follows: In ab =[-0.2521+0.179×exp(P / 14.731)]×A f Where P is the equilibrium pressure after injection of carbon dioxide, A f Produce fracture volume for oil wells.

8. The method for testing the performance of old well gas-enhanced repeated fracturing according to claim 1, characterized in that: The method for obtaining the amount of carbon dioxide used to restore formation pressure is as follows: V re =1.2V fi Among them, V fi is the initial fracture volume after fracturing.

9. The method for testing the performance of old well gas-enhanced repeated fracturing according to claim 1, characterized in that: Get the CO2 gas cross-flow volume V ch and CO2 injection volume V to The method is as follows: V ch =0.3V to V to =V ab +V re +V ch Among them, V ab is the amount of carbon dioxide adsorbed on the matrix, V re is the amount of carbon dioxide used to restore formation pressure.

10. A gas-enhanced repeated fracturing performance testing system for old wells, characterized in that: include: A carbon dioxide injection module, which is used to inject liquid carbon dioxide into the old perforation section of the gas well, and inject liquid carbon dioxide into the pre-fluid stage of repeated fracturing in the selected perforation section to obtain the production fracture area and production fracture volume of the oil well; A parameter acquisition module, wherein the carbon dioxide parameter acquisition module is used to acquire the amount of carbon dioxide adsorbed in the matrix and the amount of carbon dioxide used to restore formation pressure according to the production fracture area and the production fracture volume of the oil well; A parameter processing module is used to obtain the amount of carbon dioxide gas cross-flow and the amount of carbon dioxide injection according to the amount of carbon dioxide adsorbed in the matrix and the amount of carbon dioxide used to restore the formation pressure, so as to realize repeated fracturing tests.

Images