Experimental device and method for simulating injection-production seepage hysteresis effect of fracture-vug type gas storage

Abstract

The invention discloses an experimental device and method for simulating the injection-production seepage hysteresis effect of a fracture-vug type gas storage, belongs to the technical field of oil and gas resource development, and aims to research the injection-production seepage hysteresis effect of the fracture-vug type carbonate rock gas storage. The experimental device for simulating the injection-production seepage hysteresis effect of the fracture-cavity type gas storage comprises a production system, an injection-production system, a monitoring system and a temperature control system, wherein the production system comprises a cavity model (1), a fracture model and a core holder which are connected in sequence; and the injection and production system can inject gas into the production system or extract the gas in the production system. According to the experimental device and method for simulating the injection-production seepage hysteresis effect of the fracture-vug type gas storage, the injection-production seepage process of the fracture-vug type gas storage under the high-temperature and high-pressure conditions can be simulated, optimization of storage capacity parameter design during gas storage construction is facilitated, and scientific and efficient construction of a strong heterogeneous fracture-vug type carbonate rock gas storage is supported.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas resource development, and in particular to an experimental device for simulating the injection and production seepage hysteresis effect of a fracture-cavity gas storage reservoir, and also to an experimental method for simulating the injection and production seepage hysteresis effect of a fracture-cavity gas storage reservoir. Background Art

[0002] With the continuous advancement of gas storage construction, new storage areas are further extended to strongly heterogeneous carbonate gas reservoirs. The storage and permeability characteristics are more complex and the existing site selection and parameter design experience cannot be directly borrowed. The scientific and efficient construction of gas storage faces new problems in understanding the non-equilibrium special seepage characteristics and influences of fracture-cavity bodies: 1. How to quantitatively characterize the seepage lag effect between low-permeability matrix and high-permeability fracture-cavity bodies caused by permeability differences; 2. How to evaluate and implement the storage capacity utilization mechanism of two types of systems, low-permeability matrix and high-permeability fracture-cavity systems under high-speed injection and production conditions; 3. How to clarify the requirements of strongly heterogeneous fracture-cavity bodies for the injection-production balance period under high-speed injection and production; 4. How to evaluate the changes in the injection-production capacity of injection-production wells in strongly heterogeneous fracture-cavity reservoirs and the influencing factors. Summary of the invention

[0003] In order to study the injection and production seepage hysteresis effect of fracture-cavity carbonate gas storage, the present invention provides an experimental device and method for simulating the injection and production seepage hysteresis effect of fracture-cavity gas storage, which can simulate the injection and production seepage process of fracture-cavity gas storage under high temperature and high pressure conditions, and quantitatively characterize the pressure changes of low-permeability matrix and high-permeability fracture-cavity body in the high-intensity injection and production seepage process and the influence on the recovery rate in order to study the seepage hysteresis effect of fracture-cavity gas storage in the high-intensity injection and production process.

[0004] The technical solution adopted by the present invention to solve its technical problem is:

[0005] An experimental device for simulating the injection and production hysteresis effect of a fracture-cavity gas storage reservoir, comprising:

[0006] A production system, including a hole model, a seam model and a core holder connected in sequence;

[0007] An injection and production system capable of injecting gas into the production system or producing gas from the production system;

[0008] A monitoring system capable of detecting the pressure and temperature of the production system, and the monitoring system can also perform timing;

[0009] A temperature control system is capable of controlling the temperature of the production system.

[0010] An experimental method for simulating the hysteresis effect of injection and production of a fracture-cavity gas storage reservoir, wherein the experimental method for simulating the hysteresis effect of injection and production of a fracture-cavity gas storage reservoir adopts the experimental device for simulating the hysteresis effect of injection and production of a fracture-cavity gas storage reservoir;

[0011] The experimental method for simulating the injection and production seepage hysteresis effect of the fracture-cavity type gas storage includes an experimental process of simulating the seepage hysteresis effect of the fracture-cavity type carbonate rock gas storage during gas injection and an experimental process of simulating the seepage hysteresis effect of the fracture-cavity type carbonate rock gas storage during gas production;

[0012] The experimental process of simulating the seepage hysteresis effect of the fracture-cavity carbonate gas storage during gas injection comprises the following steps:

[0013] Step 1a, the production system simulates an underground reservoir environment;

[0014] Step 2a, the injection and production system injects high-pressure gas into the core holder, observes the pressure change outside the two axial pressure ends of the core holder, records the time for the pressure outside the two axial pressure ends of the core holder to reach a first set value from an initial value, and obtains the pressure lag time during gas injection;

[0015] The experimental process of simulating the seepage hysteresis effect of the fracture-cavity carbonate gas storage during gas production comprises the following steps:

[0016] Step 1b, the production system simulates an underground reservoir environment;

[0017] Step 2b, the injection and production system produces the high-pressure gas in the core holder, observes the pressure changes outside the two axial pressure ends of the core holder, records the time for the pressure outside the two axial pressure ends of the core holder to reach the second set value from the initial value, and obtains the pressure lag time during gas production.

[0018] The beneficial effects of the present invention are:

[0019] 1. The core holder can be disassembled and assembled at will as needed to simulate the different hole-crack matching patterns and volume sizes of fracture-cavity gas storage. The experimental method simulates the injection and production seepage process of a single well in a strongly heterogeneous gas storage. Gas injection and production can also be performed from two core holder ports to simulate the injection and production process of a multi-well system. In short, the model uses real cores on the one hand, and adds models of large caves and cracks in the formation that cannot be simulated on the other hand, which more realistically reflects the fracture-cavity reservoir of carbonate rocks. By adding multiple valves and high-precision pressure gauges, a method is provided for studying the pressure and seepage hysteresis effect of fracture-cavity reservoirs during high-intensity injection and production.

[0020] 2. The seepage characteristics of strongly heterogeneous fracture-cavity carbonate rocks and the seepage equilibrium time between high-permeability fracture-cavity bodies and low-permeability matrix under high-speed injection and production conditions can be obtained, which helps to optimize the design of storage capacity parameters during the construction of gas storage facilities, such as the optimization of injection and production volume, injection and production pressure, injection and production cycle, injection and production time and other parameters, and supports the scientific and efficient construction of strongly heterogeneous fracture-cavity carbonate rock gas storage facilities. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings in the specification, which constitute a part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0022] Figure 1 It is a schematic diagram of the experimental device for simulating the injection and production seepage hysteresis effect of the fracture-cavity gas storage reservoir according to the present invention.

[0023] Figure 2 It is a schematic diagram of the production system and monitoring system.

[0024] Figure 3 It is a schematic diagram of the injection-production system.

[0025] Figure 4 It is a schematic diagram of the hole model.

[0026] Figure 5 is a schematic diagram of the second core holder.

[0027] The following are the descriptions of the reference numerals:

[0028] 1. Hole model; 2. First core holder; 3. Second core holder; 4. Third core holder; 5. Fourth core holder; 6. First control valve; 7. First pressure gauge; 8. Second control valve; 9. Third control valve; 10. Second pressure gauge; 11. Fourth control valve; 12. Fifth control valve; 13. Third pressure gauge; 14. Sixth control valve; 15. Fourth pressure gauge; 16. Seventh control valve; 17. First confining pressure pump; 18. Fifth pressure gauge; 19. Second confining pressure pump ; 20. Sixth pressure gauge; 21. Seventh pressure gauge; 22. Vacuum pump; 23. Eighth control valve; 24. Eighth pressure gauge; 25. Ninth control valve; 26. Tenth control valve; 27. Ninth pressure gauge; 28. Eleventh control valve; 29. ​​Inlet and outlet interface; 30. Tenth pressure gauge; 31. Twelfth control valve; 32. Thirteenth control valve; 33. Mass flow meter; 34. Gas source; 35. Flow pressure pump; 36. Back pressure valve; 37. Fluid collection device; 38. Eleventh pressure gauge.

[0029] 101. partition; 102. spiral rod; 103. closed cavity; 104. outer shell. DETAILED DESCRIPTION

[0030] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0031] An experimental device for simulating the injection and production hysteresis effect of a fracture-cavity gas storage reservoir, comprising:

[0032] A production system, including a hole model 1, a seam model and a core holder connected in sequence;

[0033] The injection and production system can inject high-pressure gas into the production system or produce high-pressure gas in the production system, such as Figures 1 to 3 As shown;

[0034] A monitoring system capable of detecting the pressure and temperature of the production system, and the monitoring system can also perform timing;

[0035] A temperature control system capable of controlling the temperature of the production system;

[0036] A control unit, the monitoring system and the temperature control system are both connected to the control unit.

[0037] In this embodiment, the structure of the hole model 1 is substantially the same as that of the cylinder. The hole model 1 contains a closed cavity 103, the volume of which can be adjusted. The seam model is a pipeline connecting the closed cavity 103 and the first axial pressure end of the core holder. The closed cavity 103, the seam model and the core holder are connected in sequence. Figure 1 and Figure 4 shown.

[0038] The hole model 1 includes an outer shell 104, which is a cylindrical structure with both ends closed. A partition 101 is arranged in the outer shell 104, and the partition 101 is sealed and connected to the outer shell 104. The partition 101 is connected to a spiral rod 102. A rod cavity and a rodless cavity are formed in the outer shell 104. The spiral rod 102 is located in the rod cavity, and the rodless cavity is a closed cavity 103. By moving the spiral rod 102, the partition 101 can be driven to move axially along the outer shell 104, thereby adjusting and changing the volume of the closed cavity 103.

[0039] The core clamp can adopt existing technology products. The core clamp comprises a confining pressure end and two axial pressure ends. High-pressure fluid is injected into the core clamp through the confining pressure end to provide confining pressure to the core in the core clamp. High-pressure fluid is injected into the core clamp through the axial pressure end to provide axial pressure to the core in the core clamp.

[0040] In this embodiment, the core holder includes a first core holder 2, and the fracture model includes a first pipeline connecting the closed cavity 103 and the first axial pressure end of the first core holder 2. Along the direction from the first core holder 2 to the hole model 1, the first pipeline is sequentially provided with a first control valve 6, a first pressure gauge 7, and a second control valve 8. The second axial pressure end of the first core holder 2 is connected to the inlet and outlet interface 29 of the injection and production system through a first pipeline, and along the direction from the injection and production system to the first core holder 2, the first pipeline is sequentially provided with a tenth pressure gauge 30 and a twelfth control valve 31.

[0041] In this embodiment, the core holder further comprises a second core holder 3, such as Figure 5 As shown, the fracture model also includes a second pipeline connecting the closed cavity 103 and the first axial pressure end of the second core holder 3. Along the direction from the hole model 1 to the second core holder 3, the second pipeline is sequentially provided with a third control valve 9, a second pressure gauge 10 and a fourth control valve 11. The production system also includes a vacuum pump 22. The second axial pressure end of the second core holder 3 is connected to the inlet of the vacuum pump 22 through a second pipeline. Along the direction from the second core holder 3 to the vacuum pump 22, the second pipeline is sequentially provided with an eighth control valve 23, an eighth pressure gauge 24 and a ninth control valve 25.

[0042] In this embodiment, the core holder further includes a third core holder 4, and the fracture model further includes a third pipeline connecting the closed cavity 103 and the first axial pressure end of the third core holder 4. A fifth control valve 12 and a third pressure gauge 13 are sequentially arranged on the third pipeline along the direction from the hole model 1 to the third core holder 4. The second axial pressure end of the third core holder 4 is connected to the inlet of the vacuum pump 22 through a third pipeline, and a tenth control valve 26, a ninth pressure gauge 27 and an eleventh control valve 28 are sequentially arranged on the third pipeline along the direction from the third core holder 4 to the vacuum pump 22.

[0043] In this embodiment, the core holder further includes a fourth core holder 5, and the fracture model further includes a fourth pipeline connecting the closed cavity 103 and the first axial pressure end of the fourth core holder 5. Along the direction from the fourth core holder 5 to the hole model 1, the fourth pipeline is provided with a sixth control valve 14, a fourth pressure gauge 15 and a seventh control valve 16 in sequence. The second axial pressure end of the fourth core holder 5 is connected to the inlet and outlet interface 29 of the injection and production system through a fourth pipeline. Along the direction from the injection and production system to the fourth core holder 5, the fourth pipeline is provided with an eleventh pressure gauge 38 and a thirteenth control valve 32 in sequence. The eleventh pressure gauge 38 may or may not be provided.

[0044] In this embodiment, the production system further includes a first confining pressure pump 17 and a second confining pressure pump 19. The confining pressure end of the first core holder 2 and the confining pressure end of the fourth core holder 5 are both connected to the first confining pressure pump 17, and the confining pressure end of the second core holder 3 and the confining pressure end of the third core holder 4 are both connected to the second confining pressure pump 19. Figure 1 and Figure 2 shown.

[0045] A fifth pressure gauge 18 is provided between the first core holder 2 and the first confining pressure pump 17, a sixth pressure gauge 20 is provided between the second core holder 3 and the second confining pressure pump 19, and a seventh pressure gauge 21 is provided between the third core holder 4 and the second confining pressure pump 19. All components and devices in the experimental device for simulating the injection and production seepage hysteresis effect of fracture-cavity gas storage can adopt existing technical products.

[0046] In the production system, the core holder includes at least a first core holder 2, and the specific number of the core holders can be determined as needed. The core in the core holder is used to simulate the rock in the actual formation, the fracture model is used to simulate the fracture in the actual formation, and the cave model 1 is used to simulate the cave in the actual formation.

[0047] The monitoring system can detect the pressure and temperature in the closed cavity 103 of the hole model 1, each of the fracture models and each of the core holders in the production system, and the monitoring system contains all the above-mentioned pressure gauges. The temperature control system can control the temperature in the closed cavity 103 of the hole model 1, each of the fracture models and each of the core holders in the production system so that the temperature is the same as the temperature in the actual bottom layer. The control unit can be a computer, and the control unit can record the above-mentioned pressure and temperature and their corresponding time.

[0048] In this embodiment, the injection and production system includes a gas source 34, a fluid pressure pump 35, a fluid collection device 37 and an inlet and outlet interface 29. The inlet and outlet interface 29 is a six-way valve. The outlet of the gas source 34 is connected to the six-way valve through a first delivery pipeline. A mass flow meter 33 is provided on the first delivery pipeline. The inlet of the fluid collection device 37 is connected to the six-way valve through a second delivery pipeline. A back pressure valve 36 is provided on the second delivery pipeline. The pressure control interface of the back pressure valve 36 and the inlet of the gas source 34 are both connected to the output end of the fluid pressure pump 35.

[0049] The six-way valve has six interfaces, such as Figure 1As shown, six interfaces are located at the six corners of the hexagon, and the six interfaces are respectively the left interface, the upper left interface, the upper right interface, the right interface, the lower right interface and the lower left interface. Each interface is provided with a valve, and the six-way valve contains a valve cavity. If the valve on any interface is opened, the interface is connected to the valve cavity; if the valve on any interface is closed, the interface is not connected to the valve cavity. When in use, the corresponding valve of the pipeline to be connected is opened, and all other valves are closed.

[0050] The second axial pressure end of the first core holder 2 is connected to the upper left interface of the six-way valve through the first pipeline, and the second axial pressure end of the fourth core holder 5 is connected to the upper right interface of the six-way valve through the fourth pipeline. The outlet of the gas source 34 is connected to the left interface of the six-way valve through the first delivery pipeline, and the inlet of the fluid collection device 37 is connected to the right interface of the six-way valve through the second delivery pipeline. Figure 1 and Figure 3 shown.

[0051] When the injection and production system injects gas into the production system, the gas in the gas source 34 enters the production system (such as the first core holder 2 and / or the fourth core holder 5) through the first delivery pipeline and the inlet and outlet interface 29 in sequence, and the flow pressure pump 35 pressurizes the gas source 34 (i.e., the gas cylinder) to supply gas to the production system, and the flow pressure pump 35 can control the injection pressure. When the injection and production system produces the high-pressure gas in the core holder, the high-pressure gas in the production system enters the fluid collection device 37 (gas collection device) through the inlet and outlet interface 29, the second delivery pipeline and the back pressure valve 36 in sequence, and the flow pressure pump 35 can control the gas production pressure. The flow pressure pump 35 can be a single-cylinder pump or a double-cylinder pump. When the flow pressure pump 35 is a double-cylinder pump, the inlet of the gas source 34 is connected to the output end of one pump cylinder of the flow pressure pump 35, and the pressure control interface of the back pressure valve 36 is connected to the output end of the other pump cylinder of the flow pressure pump 35.

[0052] An experimental method for simulating the injection and production seepage hysteresis effect of a fracture-cavity gas storage is introduced below. The experimental method for simulating the injection and production seepage hysteresis effect of a fracture-cavity gas storage adopts the above-mentioned experimental device for simulating the injection and production seepage hysteresis effect of a fracture-cavity gas storage; the experimental method for simulating the injection and production seepage hysteresis effect of a fracture-cavity gas storage includes an experimental process of simulating the seepage hysteresis effect of a fracture-cavity carbonate rock gas storage during gas injection and an experimental process of simulating the seepage hysteresis effect of a fracture-cavity carbonate rock gas storage during gas production.

[0053] The experimental process of simulating the seepage hysteresis effect of the fracture-cavity carbonate gas storage during gas injection comprises the following steps:

[0054] Step 1a, the production system simulates an underground reservoir environment;

[0055] Step 2a, the injection and production system injects high-pressure gas into the core holder, observes the pressure changes outside the two axial pressure ends of the core holder, records the time for the pressure outside the two axial pressure ends of the core holder to reach a first set value from an initial value, and obtains the pressure lag time during gas injection.

[0056] The experimental process of simulating the seepage hysteresis effect of the fracture-cavity carbonate gas storage during gas production comprises the following steps:

[0057] Step 1b, the production system simulates an underground reservoir environment;

[0058] Step 2b, the injection and production system produces the high-pressure gas in the core holder, observes the pressure changes outside the two axial pressure ends of the core holder, records the time for the pressure outside the two axial pressure ends of the core holder to reach the second set value from the initial value, and obtains the pressure lag time during gas production.

[0059] The following describes in detail an experimental method for simulating the injection and production seepage hysteresis effect of a fracture-cavity gas storage by taking a core holder including a first core holder 2, a second core holder 3, a third core holder 4 and a fourth core holder 5 as an example.

[0060] The experimental process of simulating the seepage hysteresis effect of the fracture-cavity carbonate gas storage during gas injection comprises the following steps:

[0061] Preparation before the experiment: Build the experimental device for simulating the injection and production seepage hysteresis effect of the fracture-cavity gas storage, wash and dry the real reservoir core (clean the core according to the national standard of "Core Analysis Method") and put it into the core holder (the core holder has no requirements on the core size, full-diameter plunger cores are all OK, and the present invention is not limited to the core shape, size, permeability, any artificial core, and artificially carved core); adjust the volume of the closed cavity 103 of the cave model 1 according to the volume of the cave in the actual reservoir, for example, the volume ratio of the cave volume to the closed cavity 103 is 100:1-1000:1. Connect the cave model 1 and each core holder by the corresponding fracture model.

[0062] Step 1a: The production system simulates an underground reservoir environment.

[0063] The vacuum pump 22 is started to evacuate the hole model 1, each core holder and each fracture model (the pressure gauge of the vacuum pump 22 shows -0.1 MPa), the first core holder 2, the second core holder 3, the third core holder 4, and the fourth core holder 5 are pressurized to the required high pressure (the confining pressure pump can pressurize to 100 MPa) by the first confining pressure pump 17 and the second confining pressure pump 19, and the temperature control system is set to the underground reservoir temperature. The temperature control system controls the temperature in the closed cavity 103 of the hole model 1, each fracture model and each core holder in the production system so that the temperature is the same as the temperature in the actual bottom layer.

[0064] Step 2a, the injection and production system injects high-pressure gas into the core holder, observes the pressure changes outside the two axial pressure ends of the core holder, records the time for the pressure outside the two axial pressure ends of the core holder to reach a first set value from an initial value, and obtains the pressure lag time during gas injection.

[0065] The ninth control valve 25, the eleventh control valve 28 and the valve at the upper left interface of the six-way valve are all closed, and the other control valves are all in the open state. The gas in the gas source 34 is injected into the fourth core clamp 5 at a constant pressure through the inlet and outlet interface 29 by the flow pressure pump 35. The pressure (or pressure intensity) of the constant pressure injection of the injection and production system is P. The first set value can be the injection pressure of the injection and production system. The real-time changes of the pressure at both ends of the core clamp are observed and recorded. All pressure gauges are high-precision pressure gauges, and the control unit (computer or computer) collects and records data.

[0066] After the flow pressure pump 35 injects gas into the fourth core clamp 5, the value of the fourth pressure gauge 15 first changes to P, and timing is performed at the same time, recording the time when the fourth pressure gauge 15 reaches the P value as t1, the time when the first pressure gauge 7, the second pressure gauge 10 and the third pressure gauge 13 reach the P value are t2, t3 and t4 respectively, the time when the tenth pressure gauge 30, the eighth pressure gauge 24 and the ninth pressure gauge 27 reach the P value are t5, t6 and t7 respectively, and four cores with different permeability and porosity are placed in the first core clamp 2, the second core clamp 3, the third core clamp 4 and the fourth core clamp 5. Theoretically, the values ​​of t2, t3, and t4 are basically the same and can be used to calibrate each other. The value of t2-t1 is the time for pressure propagation in the fracture-cavity system, t1 is the time for the pressure to be fully transmitted to the matrix core in the fourth core holder 5, t5 is the time for the pressure to be transmitted from the injection end (second axial pressure end) of the fourth core holder 5 to the discharge end (second axial pressure end) of the first core holder 2, t6 is the time for the pressure to be transmitted from the injection end (second axial pressure end) of the fourth core holder 5 to the discharge end (second axial pressure end) of the second core holder 3, and t7 is the time for the pressure to be transmitted from the injection end (second axial pressure end) of the fourth core holder 5 to the discharge end (second axial pressure end) of the third core holder 4.

[0067] The first core is placed in the first core holder 2, the second core is placed in the second core holder 3, the third core is placed in the third core holder 4, and the fourth core is placed in the fourth core holder 5. t1 is the pressure transmission time in the fourth core, t5-t1 is the pressure transmission time in the first core, t6-t1 is the pressure transmission time in the second core, and t7-t1 is the pressure transmission time in the third core. The pressure transmission time is the pressure lag time and the pressure balance time. Therefore, the pressure balance time of cores with different permeabilities can be obtained. By changing the injection pressure P, the pressure balance time of matrices with different permeabilities in the pore-fracture system can be obtained. The pressure balance time is proportional to the seepage lag, so it can be used to quantitatively study the seepage lag effect, such as obtaining a relationship chart of different injection and production pressures, fracture-cavity matching modes and pressure balance time.

[0068] In addition, constant-speed gas injection can also be performed. After a certain amount of gas is injected into the fourth core clamp 5, the twelfth control valve 31 is closed, and the pressure changes of the hole-fracture-cavity system are monitored in real time to obtain the pressure balance time of the entire system. The present invention is not limited to four core clamps, and the core clamps, the hole model 1 and the fracture model can be arbitrarily matched as needed to obtain the pressure balance time of different hole-fracture matching modes, thereby providing an experimental device and method for studying the pressure change law and seepage characteristics of different hole-fracture systems under high-speed injection and production conditions.

[0069] Preferably, the experimental process of simulating the seepage hysteresis effect of the fracture-cavity carbonate gas storage during gas production comprises the following steps after the experimental process of simulating the seepage hysteresis effect of the fracture-cavity carbonate gas storage during gas injection:

[0070] Step 1b: The production system simulates an underground reservoir environment.

[0071] The first core holder 2, the second core holder 3, the third core holder 4, and the fourth core holder 5 are pressurized to the required high pressure (the confining pressure pump can pressurize to 100MPa) by the first confining pressure pump 17 and the second confining pressure pump 19, and the temperature control system is set to the underground reservoir temperature. The temperature control system controls the temperature in the closed cavity 103 of the hole model 1, each of the fracture models, and each of the core holders in the production system so that the temperature is the same as the temperature in the actual bottom layer. After the pressure of the entire system of the first core holder 2, the second core holder 3, the third core holder 4, the fourth core holder 5, the fracture model, and the hole model 1 is balanced, the outlet valve of the gas source 34 is closed.

[0072] Step 2b, the injection and production system produces the high-pressure gas in the core holder, observes the pressure changes outside the two axial pressure ends of the core holder, records the time for the pressure outside the two axial pressure ends of the core holder to reach the second set value from the initial value, and obtains the pressure lag time during gas production.

[0073] Keep the ninth control valve 25, the eleventh control valve 28 and the valves of the upper left interface of the six-way valve closed, the flow pressure pump 35 is connected to the back pressure valve 36, and the back pressure valve 36 is connected to the injection end (the second axial pressure end) of the fourth core clamp 5 through the inlet and outlet interface 29. The gas production pressure can be controlled by setting the pressure of the flow pressure pump 35, that is, the flow pressure pump 35 can control the gas production pressure. The second set value can be the production pressure of the injection and production system (that is, the gas production pressure). The gas production pressure is lower than the injection pressure and also lower than the pressure of the entire fracture system. The lower the gas production pressure, the greater the pressure difference of the entire system and the faster the gas production speed. The pressure balance characteristics of the entire hole fracture system under different gas production pressures can be studied, and the back pressure valve 36 can also be replaced with a mass flowmeter 33 to control the gas production speed and obtain the pressure balance time and characteristics of the hole fracture under different gas production speeds.

[0074] The above connection is a control mode of simultaneous injection and simultaneous production, and the injection and production mode of one injection and one production, one injection and multiple production, and multiple injections and multiple production can also be realized by controlling the valve. For example, when multiple production is achieved with one injection, the valve on the upper left interface of the twelfth control valve 31, the six-way valve is opened, and connected to the gas collection device 37 through the inlet and outlet interface 29 and the back pressure valve 36. The high-precision pressure gauges distributed at both ends of the first core holder 2, the second core holder 3, the third core holder 4 and the fourth core holder 5 collect pressure data in real time and upload it to the computer (to achieve multi-point pressure measurement, in order to facilitate the subsequent calculation of the pressure balance time of any hole and cave, all pipeline pressures need to be collected, and the calculation of the pressure balance time and the seepage lag time between the high-permeability fracture and cave body and the low-permeability matrix is ​​similar to the gas injection process), and the pressure lag time between the low-permeability matrix and the high-permeability fracture and cave body during the gas production process is obtained, and the seepage lag effect during the gas production process is studied.

[0075] The above is only a specific embodiment of the present invention, and cannot be used to limit the scope of the invention. Therefore, the replacement of equivalent components, or equivalent changes and modifications made according to the scope of protection of the patent of the present invention, should still fall within the scope of this patent. In addition, the technical features of the present invention can be freely combined with each other, with technical features and technical solutions, with technical solutions and embodiments.

Claims

1. An experimental device for simulating the seepage hysteresis effect of fracture-cavity gas storage, characterized in that: The experimental device for simulating the injection and production seepage hysteresis effect of the fracture-cavity gas storage includes: A production system, comprising a hole model (1), a seam model and a core holder connected in sequence; An injection and production system capable of injecting gas into the production system or producing gas from the production system; A monitoring system capable of detecting the pressure and temperature of the production system, and the monitoring system can also perform timing; A temperature control system is capable of controlling the temperature of the production system.

2. The experimental device for simulating the injection and production hysteresis effect of fracture-cavity gas storage according to claim 1 is characterized in that: The hole model (1) contains a closed cavity (103), the volume of which can be adjusted, the seam model is a pipeline connecting the closed cavity (103) and the first axial pressure end of the core holder, and the closed cavity (103), the seam model and the core holder are connected in sequence.

3. The experimental device for simulating the injection and production hysteresis effect of fracture-cavity gas storage according to claim 2 is characterized in that: The core holder comprises a first core holder (2), the fracture model comprises a first pipeline connecting the closed cavity (103) and the first axial pressure end of the first core holder (2), and a first control valve (6), a first pressure gauge (7) and a second control valve (8) are sequentially arranged on the first pipeline in a direction from the first core holder (2) to the cave model (1).

4. The experimental device for simulating the injection and production hysteresis effect of fracture-cavity gas storage according to claim 3 is characterized in that: The second axial pressure end of the first core holder (2) is connected to the inlet and outlet interface (29) of the injection and production system through a first pipeline, and a tenth pressure gauge (30) and a twelfth control valve (31) are sequentially arranged on the first pipeline in the direction from the injection and production system to the first core holder (2).

5. The experimental device for simulating the injection and production hysteresis effect of fracture-cavity gas storage according to claim 3 is characterized in that: The core holder further comprises a second core holder (3), and the fracture model further comprises a second pipeline connecting the closed cavity (103) and the first axial pressure end of the second core holder (3), and a third control valve (9), a second pressure gauge (10) and a fourth control valve (11) are sequentially arranged on the second pipeline in a direction from the hole model (1) to the second core holder (3).

6. The experimental device for simulating the injection and production hysteresis effect of fracture-cavity gas storage according to claim 5 is characterized in that: The production system further comprises a vacuum pump (22); the second axial pressure end of the second core holder (3) is connected to the inlet of the vacuum pump (22) via a second pipeline; and an eighth control valve (23), an eighth pressure gauge (24) and a ninth control valve (25) are sequentially arranged on the second pipeline in a direction from the second core holder (3) to the vacuum pump (22).

7. The experimental device for simulating the injection and production hysteresis effect of fracture-cavity gas storage according to claim 5 is characterized in that: The core holder further comprises a third core holder (4), and the fracture model further comprises a third pipeline connecting the closed cavity (103) and the first axial pressure end of the third core holder (4), and a fifth control valve (12) and a third pressure gauge (13) are sequentially arranged on the third pipeline in a direction from the hole model (1) to the third core holder (4).

8. The experimental device for simulating the injection and production hysteresis effect of fracture-cavity gas storage according to claim 7 is characterized in that: The production system further comprises a vacuum pump (22); the second axial pressure end of the third core holder (4) is connected to the inlet of the vacuum pump (22) via a third pipeline; and in a direction from the third core holder (4) to the vacuum pump (22), a tenth control valve (26), a ninth pressure gauge (27) and an eleventh control valve (28) are sequentially arranged on the third pipeline.

9. The experimental device for simulating the injection and production hysteresis effect of fracture-cavity gas storage according to claim 7 is characterized in that: The core holder further comprises a fourth core holder (5), and the fracture model further comprises a fourth pipeline connecting the closed cavity (103) and the first axial pressure end of the fourth core holder (5), and a sixth control valve (14), a fourth pressure gauge (15) and a seventh control valve (16) are sequentially arranged on the fourth pipeline in a direction from the fourth core holder (5) to the cave model (1).

10. The experimental device for simulating the injection and production hysteresis effect of fracture-cavity gas storage according to claim 9, characterized in that: The second axial pressure end of the fourth core clamp (5) is connected to the inlet and outlet interface (29) of the injection and production system through a fourth pipeline, and a thirteenth control valve (32) is arranged on the fourth pipeline.

11. The experimental device for simulating the injection and production hysteresis effect of fracture-cavity gas storage according to claim 9, characterized in that: The production system further comprises a first confining pressure pump (17) and a second confining pressure pump (19); the confining pressure end of the first core holder (2) and the confining pressure end of the fourth core holder (5) are both connected to the first confining pressure pump (17); and the confining pressure end of the second core holder (3) and the confining pressure end of the third core holder (4) are both connected to the second confining pressure pump (19).

12. The experimental device for simulating the injection and production hysteresis effect of fracture-cavity gas storage according to claim 1, characterized in that: The injection and production system comprises a gas source (34), a fluid pressure pump (35), a fluid collection device (37) and an inlet and outlet interface (29), wherein the inlet and outlet interface (29) is a six-way valve, the outlet of the gas source (34) is connected to the six-way valve via a first delivery pipeline, a mass flow meter (33) is provided on the first delivery pipeline, the inlet of the fluid collection device (37) is connected to the six-way valve via a second delivery pipeline, a back pressure valve (36) is provided on the second delivery pipeline, and the pressure control interface of the back pressure valve (36) and the inlet of the gas source (34) are both connected to the output end of the fluid pressure pump (35).

13. An experimental method for simulating the hysteresis effect of injection and production of fracture-cavity gas storage, characterized in that: The experimental method for simulating the injection and production seepage hysteresis effect of a fracture-cavity gas storage reservoir adopts the experimental device for simulating the injection and production seepage hysteresis effect of a fracture-cavity gas storage reservoir as described in claim 1; The experimental method for simulating the injection and production seepage hysteresis effect of the fracture-cavity type gas storage includes an experimental process of simulating the seepage hysteresis effect of the fracture-cavity type carbonate rock gas storage during gas injection and an experimental process of simulating the seepage hysteresis effect of the fracture-cavity type carbonate rock gas storage during gas production; The experimental process of simulating the seepage hysteresis effect of the fracture-cavity carbonate gas storage during gas injection comprises the following steps: Step 1a, the production system simulates an underground reservoir environment; Step 2a, the injection and production system injects high-pressure gas into the core holder, observes the pressure change outside the two axial pressure ends of the core holder, records the time for the pressure outside the two axial pressure ends of the core holder to reach a first set value from an initial value, and obtains the pressure lag time during gas injection; The experimental process of simulating the seepage hysteresis effect of the fracture-cavity carbonate gas storage during gas production comprises the following steps: Step 1b, the production system simulates an underground reservoir environment; Step 2b, the injection and production system produces the high-pressure gas in the core holder, observes the pressure changes outside the two axial pressure ends of the core holder, records the time for the pressure outside the two axial pressure ends of the core holder to reach the second set value from the initial value, and obtains the pressure lag time during gas production.

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