Systems and methods for measuring parameters affecting the drainage capacity of gas storage facilities converted from aquifers.

Abstract

This invention discloses a system and method for measuring parameters affecting the drainage capacity of a gas storage facility undergoing aquatic redevelopment, comprising: a core holder for holding experimental cores; a water injection device for saturating the experimental cores with the held formation water; an outlet backpressure and measurement device for gradually reducing the pressure at the core outlet to a specified exhaustion lower limit pressure; a gas injection device for gas-driven operation on the cores whose outlet pressure has reached the exhaustion lower limit pressure; an inlet backpressure and measurement device for first injecting gas into the core inlet and then gradually reducing the pressure at the core inlet to measure the gas production and water production at each pressure point during the pressure reduction process when the inlet pressure drops to the specified exhaustion lower limit pressure; and a data processing device for calculating the dynamic recovery degree and dynamic expansion characteristics based on the water production and gas production at each pressure point.

Description

Technical Field

[0001] This invention relates to the field of physical modification technology for oil and gas reservoirs, and in particular to a system and method for measuring parameters affecting the drainage capacity of gas storage facilities modified from water-bearing layers. Background Technology

[0002] Currently, in the field of gas storage facility conversion both domestically and internationally, depleted oil and gas reservoirs have already established the necessary infrastructure and technical systems during the development phase, making conversion into gas storage facilities relatively more convenient and efficient. However, converting water-bearing reservoirs into gas storage facilities presents greater technical challenges, and its development in China started later; a complete and comprehensive set of evaluation and optimization standards has not yet been established. This type of conversion typically involves complex multi-round gas-water mutual drive and relative permeability lag phenomena, which limits the accuracy of traditional numerical simulation and dynamic intervention well testing methods. Experimental research is a relatively more accurate approach.

[0003] Existing experimental research on aquifers is limited. Existing findings mainly focus on water-flooded gas reservoirs, investigating changes in porosity and permeability under overburden pressure during reservoir construction and changes in gas-water phase permeability across multiple cycles. In actual aquifer-to-gas-storage conversion processes, key stages include depletion drainage, gas injection-pump pumping for expansion, and gas injection-blowing-drainage expansion. However, there is currently no complete experimental research covering all three stages.

[0004] Therefore, there is an urgent need for existing technologies to develop a scheme to analyze and evaluate the influencing factors on the drainage capacity of gas storage facilities converted from water layers. Summary of the Invention

[0005] The purpose of this invention is to provide a scheme for analyzing and evaluating the influencing factors in the drainage capacity of a gas storage facility converted from a water layer.

[0006] To address the aforementioned technical problems, this invention provides a system for measuring parameters affecting the drainage capacity of a gas storage facility undergoing aquatic redevelopment. The system includes: a core holder, an outlet backpressure and measuring device located at the outlet end of the holder, and a water injection device, a gas injection device, and an inlet backpressure and measuring device located at the inlet end of the holder. The core holder is used to hold experimental core samples; the water injection device is used to saturate the experimental core samples with the held formation water; the outlet backpressure and measuring device is used to gradually reduce the pressure at the core outlet end to a specified exhaustion lower limit pressure; the gas injection device is used to perform gas drive on the core samples whose outlet pressure has reached the exhaustion lower limit pressure; the inlet backpressure and measuring device is used to first inject gas into the core inlet end, then gradually reduce the pressure at the core inlet end, thereby measuring the gas production and water production at each pressure point during the pressure reduction process when the inlet pressure drops to the specified exhaustion lower limit pressure; and a data processing device is used to calculate the dynamic recovery rate and dynamic expansion characteristics based on the water production and gas production at each pressure point.

[0007] Preferably, the dynamic expansion characteristics include dynamic expansion capacity and dynamic expansion rate. The data processing device is further used to conduct measurement experiments by changing the specified lower limit pressure of decay, to obtain the dynamic extraction degree and dynamic expansion characteristics under different lower limit pressure conditions, and based on this, to determine the optimal lower limit pressure of decay.

[0008] Preferably, the gas injection device is further used to gas drive the core when the outlet pressure reaches the lower limit of decay pressure at a specified gas injection rate; the inlet back pressure and measuring device is further used to inject gas into the inlet end of the core at the specified gas injection rate; wherein, the data processing device is further used to conduct measurement experiments based on the optimal lower limit of decay pressure by changing the specified gas injection rate, to obtain the dynamic recovery degree and dynamic expansion characteristics under different gas injection rate conditions, and to determine the optimal gas injection rate based on this.

[0009] Preferably, the core holder forms a specified dip angle with the horizontal direction. The data processing device is further used to conduct measurement experiments by changing the specified dip angle based on the optimal attenuation lower limit pressure and the optimal gas injection rate, to obtain the dynamic production degree and dynamic expansion characteristics under different formation dip angle conditions, and to determine the optimal formation dip angle based on this.

[0010] Preferably, the experimental core is a long core, which is composed of at least one core sample with specified physical property parameters. The data processing device is further used to conduct measurement experiments based on the optimal attenuation lower limit pressure by replacing the experimental cores with different physical property parameters, to obtain the dynamic recovery degree and dynamic expansion characteristics under different physical property parameter conditions, and based on this, to determine the optimal physical property parameter, wherein the physical property parameter is permeability.

[0011] Preferably, the water injection device is further used to inject experimental formation water into the experimental core using a step-by-step pressurization method, so that the confining pressure is always kept greater than the confining pressure threshold, thereby determining the end of the saturated formation water stage when the core inlet pressure reaches the original formation pressure and the confining pressure reaches the original overlying pressure of the formation.

[0012] Preferably, the data processing device is further configured to calculate the dynamic gas-water ratio based on the gas production and water production at different times at the core outlet during the gas drive process, so as to determine the end of the gas drive stage when the dynamic gas-water ratio reaches the gas-water ratio threshold.

[0013] Preferably, the system further includes: a confining pressure device, which is connected to the side wall of the core holder, for providing the experimental confining pressure required for the experimental core to the measurement experimental system; and a temperature control device, which is used to simulate formation temperature conditions by providing the required experimental temperature to the measurement experimental system.

[0014] Preferably, the inlet / outlet backpressure and measuring device includes: an inlet / outlet backpressure valve disposed at the inlet / outlet end of the core holder; an inlet / outlet backpressure pump disposed at the first outlet of the inlet / outlet backpressure valve for adjusting the pressure at the inlet / outlet end of the core; an inlet / outlet backpressure pump switch disposed between the inlet / outlet backpressure valve and the inlet / outlet backpressure pump; an inlet / outlet measuring cylinder disposed at the second outlet of the inlet / outlet backpressure valve; and an inlet / outlet gas measuring instrument disposed at the rear end of the inlet / outlet measuring cylinder.

[0015] Preferably, the inlet / outlet back pressure and measuring device further includes: an inlet / outlet processor connected to the inlet / outlet gas measuring instrument, which is used to correct the measured gas flow data to convert the gas flow data under the experimental environment into gas flow data under the formation temperature and pressure conditions, so as to use the corrected gas flow to calculate the dynamic recovery degree and dynamic expansion characteristics under different experimental stages.

[0016] Preferably, the water injection device includes a first water valve, a water intermediate container, a second water valve, and a constant speed and constant pressure pump connected in sequence to the inlet end of the core holder, wherein the water intermediate container is used to contain experimental formation water configured according to the salinity conditions corresponding to the field water sample; the gas injection device includes a first gas sample valve, a gas sample intermediate container, a second gas sample valve, and a gas booster pump connected in sequence to the inlet end of the core holder.

[0017] On the other hand, embodiments of the present invention provide a method for measuring parameters affecting the drainage capacity of a gas storage facility undergoing aquatic redevelopment. This method utilizes the system described above, comprising: saturating the experimental core with a water injection device containing experimental formation water; the outlet backpressure and measuring device gradually reducing the pressure at the core outlet to a specified exhaustion lower limit pressure; the gas injection device performing gas drive on the core at the outlet pressure reaching the exhaustion lower limit pressure; the inlet backpressure and measuring device first injecting gas into the core inlet, then gradually reducing the pressure at the core inlet, thereby measuring the gas production and water production at each pressure point during the pressure reduction process when the inlet pressure drops to the specified exhaustion lower limit pressure; and a data processing device calculating the dynamic recovery degree and dynamic expansion characteristics based on the water production and gas production at each pressure point.

[0018] Compared with the prior art, one or more embodiments of the above solutions may have the following advantages or beneficial effects:

[0019] This invention proposes a system and method for measuring parameters affecting the drainage capacity of a water-reconstructed gas storage facility. The system and method provide experimental simulation of the drainage expansion capacity and working gas volume measurement of a water-reconstructed gas storage facility, as well as a multi-parameter optimization method and testing system. The testing system mainly includes a gas booster pump, a constant-speed and constant-pressure pump, a long core holder, a confining pressure pump, a backpressure pump, a processor, a waste gas recovery device, a high-temperature and high-pressure resistant visual container, a gas meter, and a temperature control device. Using this system, not only can the gas-water ratio of the gas storage facility be measured and the expansion rate curve of the gas storage facility be tested, but the same device can also accurately determine the drainage expansion capacity and recovery rate of a water-reconstructed gas storage facility. It can optimize the lower exhaustion limit pressure, gas injection rate, formation dip angle, and reservoir properties. By experimentally simulating the three processes of exhaustion drainage expansion, gas injection-pump drainage expansion, and gas injection-pump drainage expansion, it can better simulate the water-reconstructed drainage expansion process, enabling more rational and efficient utilization of the water-reconstructed gas storage facility.

[0020] Furthermore, this invention uses long core experiments to fully simulate three processes: depletion drainage expansion, gas injection-pump drainage expansion, and gas injection-pump-pump drainage expansion. It establishes the conditions for converting gas injection-pump drainage to pump-pump drainage. Through the equipment and experimental methods, it can measure the drainage expansion capacity (capacity utilization rate) and working gas volume ratio (recovery rate) of aquifer-converted gas storage facilities. It can simultaneously study the impact of different depletion lower limit pressures, injection rates, formation dip angles, and reservoir properties on the expansion of aquifer-converted gas storage facilities. This provides a basis for designing the capacity and working gas volume of aquifer-converted gas storage facilities, optimizing single-well injection-production systems, and formulating technical policies for drainage expansion technology. It enables the setting of control parameters for the transition from drainage to pump-pump during gas storage facility conversion, and allows for the optimization of depletion lower limit pressure, formation dip angle, injection rate, and reservoir property parameters. This allows us to utilize aquifer-converted gas storage facilities more rationally and efficiently.

[0021] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0022] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0023] Figure 1 This is a schematic diagram of the system for measuring parameters affecting the drainage capacity of a gas storage facility converted from a water layer, according to an embodiment of this application.

[0024] Figure 2This is a schematic diagram of the specific structure of the system for measuring parameters affecting the drainage capacity of a gas storage facility undergoing water layer reconstruction, as described in this application.

[0025] Figure 3 This is a schematic diagram illustrating the variation characteristics of the expansion recovery rate under different exhaustion lower limit pressure conditions in the system for measuring the drainage capacity parameters of a water-bearing gas storage facility, as described in this application embodiment.

[0026] Figure 4 This is a schematic diagram illustrating the variation characteristics of the expansion recovery rate under different gas injection rates in the system for measuring the drainage capacity parameters of a water-bearing gas storage facility, as described in this application embodiment.

[0027] Figure 5 This is a schematic diagram illustrating the variation characteristics of the expansion recovery rate under different formation dip angles in the system for measuring parameters affecting the drainage capacity of a water-bearing gas storage facility, as described in this application embodiment.

[0028] Figure 6 This is a schematic diagram illustrating the variation characteristics of expansion recovery rate under different reservoir properties in a system for measuring parameters affecting the drainage capacity of a water-reconstructed gas storage facility, as described in this application embodiment.

[0029] Figure 7 This is a schematic diagram illustrating the expansion rate variation characteristics under different exhaustion lower limit pressures in the system for measuring the drainage capacity parameters of a water-bearing gas storage facility, as described in this application embodiment.

[0030] Figure 8 This is a schematic diagram illustrating the expansion rate variation characteristics under different gas injection rates in a system for measuring the drainage capacity parameters of a water-bearing gas storage facility, as described in an embodiment of this application.

[0031] Figure 9 This is a schematic diagram illustrating the expansion rate variation characteristics under different formation dip angles in the system for measuring the drainage capacity parameters of a water-bearing gas storage facility, as described in this application embodiment.

[0032] Figure 10 This is a schematic diagram illustrating the expansion rate variation characteristics under different reservoir properties in the system for measuring the drainage capacity parameters of a water-reconstructed gas storage facility, as described in this application embodiment.

[0033] Figure 11 This is a flowchart illustrating the steps of a method for measuring parameters affecting the drainage capacity of a gas storage facility undergoing water layer reconstruction, as described in an embodiment of this application. Detailed Implementation

[0034] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples, so that the process of how the present invention uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly. It should be noted that, as long as there is no conflict, the various embodiments and features in the various embodiments of the present invention can be combined with each other, and the resulting technical solutions are all within the protection scope of the present invention.

[0035] Furthermore, the steps illustrated in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Also, although a logical order is shown in the flowcharts, in some cases the steps shown or described may be performed in a different order than that shown here.

[0036] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments. Unless the context clearly indicates otherwise, the singular forms “a” and “an” as used herein are also intended to include the plural. It should also be understood that the terms “comprising” and / or “including” as used herein specify the presence of the stated features, integers, steps, operations, units, and / or components, without excluding the presence or addition of one or more other features, integers, steps, operations, units, components, and / or combinations thereof.

[0037] The actual conversion of aquifers into gas storage facilities involves several key stages: depletion drainage, gas injection-pump-drainage expansion, and gas injection-pump-drainage expansion. However, there is currently no complete experimental study covering all three stages. Furthermore, for aquifer-converted gas storage facilities, considerations of the lower depletion limit pressure, injection rate, formation dip angle, and reservoir properties are crucial for designing efficient, safe, and economical facilities. These factors not only ensure maximum gas storage efficiency but also help reduce environmental risks and operating costs. Accurately determining the lower depletion limit pressure helps maintain the structural integrity and safety of the storage facility, avoiding reduced storage efficiency due to excessively low pressure. An appropriate injection rate ensures uniform gas distribution within the reservoir, preventing the formation of gas channels or premature breakthrough, thereby increasing effective gas storage capacity and extraction efficiency. Understanding the impact of different formation dip angles on gas storage and extraction is essential for optimizing storage facility design and operation strategies, and improving storage efficiency and safety. Simultaneously, reservoir properties (such as porosity and permeability) are key factors determining the performance of the gas storage facility. A deeper understanding and assessment of the physical properties of reservoirs can more accurately predict and optimize the performance of gas storage facilities, thereby improving their operational efficiency and economy.

[0038] To accurately simulate the actual conditions of aquatic redevelopment gas storage facilities during the depletion drainage and injection-production expansion stages, so as to construct aquatic redevelopment gas storage facilities efficiently and with high quality, and to determine key parameters in the process, such as drainage-to-injection control parameters, lower depletion limit pressure, gas injection rate, formation dip angle, and reservoir properties, this application of the present invention provides a system and method for measuring parameters affecting the drainage capacity of aquatic redevelopment gas storage facilities. This system and method fully simulates three processes—depletion drainage expansion, gas injection-pump drainage expansion, and gas injection-pump-pump drainage expansion—through long core experiments. It establishes the conditions for converting gas injection-pump drainage to pump-pump drainage. Through the equipment and experimental methods, it can measure the drainage expansion capacity (capacity utilization rate) and working gas volume ratio (recovery rate) of aquifer-converted gas storage facilities. It can simultaneously study the impact of different depletion lower limit pressures, injection rates, formation dip angles, and reservoir properties on the expansion of aquifer-converted gas storage facilities. This provides comprehensive data for the design of storage capacity and working gas volume in aquifer-converted gas storage facilities, optimization of single-well injection-production systems, and optimization of gas storage drainage expansion technology policies. It enables the setting of control parameters for the conversion from gas injection-pump to pump-pump during gas storage facility conversion, and the optimization of depletion lower limit pressure, formation dip angle, injection rate, and reservoir property parameters. This allows for more rational and efficient utilization of aquifer-converted gas storage facilities.

[0039] Example 1

[0040] Figure 1 This is a schematic diagram of the system for measuring parameters affecting the drainage capacity of a modified gas storage tank based on an embodiment of this application. See below for reference. Figure 1 The specific steps of the system (also called the "measurement experiment system") for measuring parameters affecting the drainage capacity of a gas storage tank undergoing water layer reconstruction, as described in the embodiments of the present invention, will be explained.

[0041] like Figure 1 As shown, the measurement experiment system described in this embodiment of the invention includes: a core holder, an outlet back pressure and measuring device, a water injection device, an air injection device, an inlet back pressure and measuring device, and a data processing device. The outlet back pressure and measuring device is located at the outlet end of the core holder, while the water injection device, air injection device, and inlet back pressure and measuring device are respectively located at the inlet end of the core holder. The data processing device is connected to both the outlet back pressure and measuring device and the inlet back pressure and measuring device.

[0042] The core holder is tilted at a specified angle to the horizontal. The core holder is used to hold the experimental core. The water injection device is used to saturate the experimental core with the formation water contained within it. The outlet backpressure and measurement device is used to gradually reduce the outlet pressure of the water-saturated experimental core to a specified exhaustion lower limit pressure.

[0043] The gas injection device is used to gas drive experimental cores whose outlet pressure has reached the lower limit of decay pressure at a specified gas injection rate.

[0044] The inlet backpressure and measuring device is used to first inject gas into the core inlet at a specified injection rate, and then gradually reduce the pressure at the core inlet. This allows for the measurement of gas production and water production at various pressure points during the depressurization process when the inlet pressure drops to a specified exhaustion lower limit pressure.

[0045] Finally, the data processing unit is used to calculate the (target) dynamic recovery degree and (target) dynamic expansion characteristics based on the water production and gas production at each pressure point (in the final stage).

[0046] Thus, after performing the following stages on the experimental core: saturation with formation water, core outlet backpressure regulation (gradually reducing the pressure at the core outlet), gas drive, gas injection after the inlet end was changed to a huff-and-puff stage, and core inlet backpressure regulation (gradually reducing the pressure at the core inlet), a complete single-scale measurement experiment was obtained. It should be noted that this embodiment of the invention uses the core outlet backpressure regulation stage to simulate the exhaust drainage expansion process, the gas drive stage to simulate the gas injection-pump drainage expansion stage, and the core inlet backpressure regulation stage to simulate the gas injection-huff-and-puff drainage expansion stage.

[0047] In addition, the inlet back pressure and measuring device and the outlet back pressure and measuring device are also used to collect the gas production and water production at different experimental stages in real time when connected to the core holder, so that the data processing device can calculate the dynamic recovery degree and dynamic expansion characteristics at different experimental stages based on the gas production and water production at different experimental stages.

[0048] In this embodiment of the invention, the dynamic expansion feature includes dynamic expansion capability and dynamic expansion rate. The data processing device is further used to conduct multiple rounds of single-complete measurement experiments by changing the specified lower limit pressure, to obtain the dynamic extraction degree under different lower limit pressure conditions (see...). Figure 3 ) and dynamic expansion characteristics (dynamic expansion rate characteristics, see Figure 7 This allows for the determination of the optimal lower limit pressure of exhaustion based on the dynamic extraction rate and dynamic expansion characteristics under different lower limit pressure conditions.

[0049] In one embodiment, the data processing device is further configured to conduct multiple rounds of single-complete measurement experiments based on the optimal attenuation lower limit pressure by changing a specified gas injection rate, to obtain the dynamic recovery rate under different gas injection rate conditions (see [reference]). Figure 4 ) and dynamic expansion characteristics (dynamic expansion rate characteristics, see Figure 8 The study investigated the dynamic recovery rate and dynamic expansion characteristics under different gas injection rate conditions to determine the optimal gas injection rate.

[0050] In one embodiment, the data processing device is also used to conduct multiple rounds of single-complete measurement experiments based on the optimal attenuation lower limit pressure and the optimal gas injection rate, by changing a specified dip angle, to obtain the dynamic recovery degree under different formation dip angle conditions (see [reference]). Figure 5 ) and dynamic expansion characteristics (dynamic expansion rate characteristics, see Figure 9 The optimal formation dip angle was determined by analyzing the dynamic extraction degree and dynamic expansion characteristics under different formation dip angles.

[0051] In this embodiment of the invention, the experimental core is a long core, the length of which is greater than the diameter of the core cross-section. The long core is composed of at least one core sample with specified physical properties.

[0052] Furthermore, the data processing device is also used to conduct multiple rounds of single-complete measurement experiments based on the optimal attenuation lower limit pressure by replacing experimental cores with different physical property parameters, in order to obtain the dynamic recovery degree under different reservoir physical property parameters (see [reference]). Figure 6 ) and dynamic expansion characteristics (dynamic expansion rate characteristics, see Figure 10 The study investigated the dynamic recovery rate and dynamic expansion characteristics under different reservoir physical property parameters, and determined the optimal reservoir physical property parameters.

[0053] In one embodiment, the data processing device is further configured to conduct multiple rounds of single-complete measurement experiments based on the optimal attenuation lower limit pressure, optimal gas injection rate, and optimal formation dip angle, by replacing experimental cores with different physical property parameters, to obtain the dynamic recovery degree under different reservoir physical property parameter conditions (see [reference]). Figure 6 ) and dynamic expansion characteristics (dynamic expansion rate characteristics, see Figure 10 The study investigated the dynamic recovery rate and dynamic expansion characteristics under different reservoir physical property parameters, and determined the optimal reservoir physical property parameters.

[0054] In one embodiment, the physical property parameter is permeability.

[0055] Furthermore, the aforementioned water injection device is also used to inject experimental formation water into the experimental core using a step-by-step pressurization method, so that the confining pressure is always kept greater than the confining pressure threshold (e.g., the confining pressure threshold is 3 MPa). Thus, when the core inlet pressure reaches the original formation pressure and the confining pressure reaches the original overlying pressure of the formation, the saturated formation water stage is determined to end, so as to start the core outlet backpressure regulation stage.

[0056] Furthermore, the data processing device is also used to calculate the dynamic gas-water ratio based on the gas production and water production at the core outlet at different times during the gas drive process, so that the gas-water ratio at a certain moment in the dynamic gas-water ratio reaches the gas-water ratio threshold (e.g., 500m). 3 / m 3 When the gas drive phase ends, the gas injection phase can begin.

[0057] Furthermore, the data processing device is also used to determine the end of the current single complete measurement experiment when the water production at each pressure point during the core inlet backpressure adjustment stage is detected to be almost zero.

[0058] Figure 2 This is a schematic diagram of the system for measuring parameters affecting the drainage capacity of a modified gas storage tank based on an embodiment of this application. See below for reference. Figure 2 The specific structure of the measurement experimental system described in the embodiments of the present invention will be explained.

[0059] In this embodiment of the invention, the core holder 11 is a long core holder that can accommodate experimental cores ranging from 0 to 100 cm. The core holder 11 has a maximum pressure resistance of 70 MPa and a temperature resistance of 200°C.

[0060] The measurement experiment system described in this embodiment of the invention further includes a confining pressure device and a temperature control device. The sidewall of the core holder 11 is connected to the confining pressure device. The confining pressure device is used to provide the measurement experiment system with the required confining pressure for the experimental core. The experimental confining pressure is set according to the experimental core.

[0061] like Figure 2 As shown, the confining pressure device includes a confining pressure pump 9 and a confining pressure valve 10. The confining pressure pump 9 is connected to the side wall of the core holder 11, and the confining pressure valve 10 is located between the confining pressure pump 9 and the core holder 11.

[0062] The temperature control device 20 is used to simulate formation temperature conditions by providing the required experimental temperature to the measurement experimental system. The temperature control device 20 can provide different experimental temperatures, and different experimental temperatures can be set according to experimental requirements, thereby more realistically simulating actual reservoir conditions.

[0063] Furthermore, the inlet backpressure and measuring device includes: an inlet backpressure valve 27, an inlet backpressure pump 29, an inlet backpressure pump switch 28, an inlet measuring cylinder 26, and an inlet gas measuring instrument 25.

[0064] An inlet backpressure valve 27 is located at the inlet end of the core holder 11. An inlet backpressure pump 29 is connected to the first outlet of the inlet backpressure valve 29. The inlet backpressure pump 29 is used to regulate the inlet pressure of the experimental core. An inlet backpressure pump switch 28 is located between the inlet backpressure valve 27 and the inlet backpressure pump 29. An inlet measuring cylinder 26 is connected to the second outlet of the inlet backpressure valve 29. An inlet gas measuring instrument 25 is located at the rear end of the inlet measuring cylinder 26.

[0065] In addition, the inlet back pressure and measuring device also includes an inlet processor 24 connected to the inlet gas measuring instrument 25.

[0066] The inlet processor 24 is used to correct the measured gas flow data to convert the gas flow data under the experimental environment into gas flow data under the formation temperature and pressure conditions, so as to use the corrected gas flow to calculate the dynamic recovery degree and dynamic expansion characteristics under different experimental stages.

[0067] In addition, the inlet back pressure and measuring device also includes an inlet exhaust gas recovery module 30 connected to the inlet gas measuring instrument 25. The inlet exhaust gas recovery module 30 is located at the rear end of the inlet gas measuring instrument 25.

[0068] Therefore, the inlet end measuring cylinder 26 and the inlet end gas measuring instrument 25 in the inlet back pressure and measuring device can measure the real-time gas (flow) and real-time water (flow) at the inlet end of the core produced at different experimental stages.

[0069] Furthermore, the outlet back pressure and measuring device includes: an outlet back pressure valve 15, an outlet back pressure pump 14, an outlet back pressure pump switch 13, an outlet measuring cylinder 18, and an outlet gas measuring instrument 19.

[0070] An outlet backpressure valve 15 is located at the outlet end of the core holder 11. An outlet backpressure pump 14 is connected to the first outlet of the outlet backpressure valve 15. The outlet backpressure valve 15 is used to regulate the outlet pressure of the experimental core. An outlet backpressure pump switch 13 is located between the outlet backpressure valve 15 and the outlet backpressure pump 14. An outlet measuring cylinder 18 is connected to the second outlet of the outlet backpressure valve 15. An outlet gas measuring instrument 19 is located at the rear end of the outlet measuring cylinder 18.

[0071] In addition, the outlet back pressure and measuring device also includes an outlet processor 16 connected to the outlet gas measuring instrument 19.

[0072] The output processor 16 is used to correct the measured gas flow data to convert the gas flow data under the experimental environment into gas flow data under the formation temperature and pressure conditions, so as to use the corrected gas flow to calculate the dynamic recovery degree and dynamic expansion characteristics under different experimental stages.

[0073] In addition, the outlet back pressure and measuring device also includes an outlet exhaust gas recovery module 17 connected to the outlet gas measuring instrument 19. The outlet exhaust gas recovery module 17 is located at the rear end of the outlet gas measuring instrument 19.

[0074] Therefore, the outlet end measuring cylinder 18 and the outlet end gas measuring instrument 19 in the outlet back pressure and measuring device can measure the real-time gas (flow) and real-time water (flow) at the outlet end of the core produced at different experimental stages.

[0075] Furthermore, such as Figure 2As shown, the water injection device includes: a first water valve 5, a water intermediate container 23, a second water valve 7, and a constant speed and pressure pump 6, all sequentially connected to the inlet end of the core holder 11. The inlet end of the core holder 11 is connected to the first water valve 11; both ends of the water intermediate container 23 are connected to the first water valve 5 and the second water valve 7, respectively; the second water valve 7 is connected to the constant speed and pressure pump 6. The water intermediate container 23 is used to contain experimental formation water, which is configured according to the salinity conditions corresponding to the field water samples.

[0076] The constant speed and constant pressure pump 6 can inject the experimental formation water contained in the intermediate water container 23 into the experimental core, so that the core is saturated with formation water.

[0077] Furthermore, such as Figure 2 As shown, the gas injection device includes: a first gas sample valve 4, a gas sample intermediate container 3, a second gas sample valve 2, and a gas booster pump 1, which are sequentially connected to the inlet end of the core holder 11. Specifically, the inlet end of the core holder 11 is connected to the first gas sample valve 4; both ends of the gas sample intermediate container 3 are connected to the first gas sample valve 4 and the second gas sample valve 2, respectively; and the second gas sample valve 2 is connected to the gas booster pump 1.

[0078] The gas booster pump 1 can inject the experimental gas contained in the intermediate gas sample container 3 into the experimental core, thereby pressurizing the core to the target pressure and thus realistically simulating the formation gas pressure.

[0079] Furthermore, the measurement experimental system described in this embodiment of the invention also includes: an input valve 8 disposed adjacent to the inlet end of the core holder 11 and an output valve 12 disposed adjacent to the outlet end of the core holder 11. The input valve 8 controls the on / off state of all devices (water injection device, air injection device, and inlet back pressure and measuring device) connected to the inlet end of the core holder 11 relative to the inlet end of the core holder 11. The output valve 12 controls the on / off state of all devices (outlet back pressure and measuring device) connected to the outlet end of the core holder 11 relative to the outlet end of the core holder 11.

[0080] Furthermore, the measurement experimental system described in this embodiment of the invention further includes: a first pressure gauge 21 for measuring the core inlet pressure and a second pressure gauge 22 for measuring the core outlet pressure. The first pressure gauge 21 is positioned between the inlet end of the core holder 11 and the input valve 8; the second pressure gauge 22 is positioned between the outlet end of the core holder 11 and the output valve 12.

[0081] Representative core samples were selected, and the samples were extracted, cleaned, and dried according to relevant standards. After processing, the length L, diameter d, and porosity of the core samples were measured. Permeability K, mass m.

[0082] Specifically, for water-bearing reservoirs, in the initial stage of reservoir reconstruction, it is necessary to achieve reservoir capacity by injecting gas into the upper layer and draining the lower layer. To this end, the optimal lower exhaustion limit pressure during the drainage and capacity expansion period can be determined through the following single complete measurement experiment. The specific operation procedure is as follows:

[0083] 1. Optimization experimental study on the lower limit pressure of exhaustion:

[0084] (1) Place four core samples in the long core holder in order from the inlet end to the outlet end, apply confining pressure to 3MPa, and adjust the test temperature to the formation temperature; select representative core samples, extract, clean and dry the core samples according to the corresponding standards, and measure the length L, diameter d, core porosity φ, permeability K and mass m of the core samples after processing. After splicing all the core samples in the length direction, the experimental core is obtained and placed in the core holder 11.

[0085] (2) Keep valves 5, 7, 12, 13, 15, 28, and 27 closed, and open valves 2, 4, 8, and 10 to use the gas injection device to vacuum the inside of the core holder 11 and the experimental core before a single complete measurement experiment.

[0086] (3) After the vacuuming is completed, close valves 2 and 4, open valves 5 and 7, and use the water injection device to gradually increase the pressure to saturate the core with formation water, keeping the confining pressure always greater than the fluid pressure by 3 MPa, so that the core fluid pressure rises to the original formation pressure and the confining pressure rises to the original overlying pressure of the formation, thus completing the saturated core treatment.

[0087] (4) Close valves 5, 7, and 8, and open valves 12, 13, and 15. Use the backpressure pump 14 in the outlet backpressure and measuring device to adjust the pressure at the core outlet, gradually reducing the fluid pressure. Record a point every 2 MPa, for example, until the fluid pressure drops to the lower limit pressure. Record the water production at each pressure point using the measuring cylinder 18 in the outlet backpressure and measuring device. The data processing device then uses the recorded data to calculate the water volume factor B. w By measuring the water production at each pressure point during the depletion stage, the recovery rate and expansion characteristics at the corresponding points are calculated.

[0088] (5) Open valves 2, 4, and 8. Under the lower limit pressure of exhaustion, use the gas injection device to perform gas-driven operation at a constant gas injection rate until the gas-to-water ratio is approximately 500 m³ / s. 3 / m 3 At this time, the gas production, water production and core inlet pressure changes at different times are measured using the measuring cylinder 18 and gas meter 19 in the outlet back pressure and measuring device, and the production degree and expansion characteristics at the corresponding time are calculated.

[0089] (6) Close valves 2, 4, 12, 13, and 15, and open outlet valves 27 and 28. At this time, change the gas injection end to the spit test state. Use the back pressure pump 29 in the inlet back pressure and measuring device to adjust the core inlet pressure. Inject gas at the same gas injection rate as in (5) to raise the core fluid pressure to the original formation pressure. Then, continue to use the back pressure pump 29 in the inlet back pressure and measuring device to adjust the core inlet pressure step by step. Record a point every 2 MPa, for example, until the pressure drops to the lower limit pressure of formation exhaustion. Use the measuring cylinder 26 and gas meter 25 in the inlet back pressure and measuring device to record the gas production and water production at each spit pressure point. Calculate the recovery degree, expansion characteristics, and recovery rate at different pressure points until the discharged water volume is almost zero and stop spitting.

[0090] (7) Change the lower limit pressure of water layer depletion in steps (4) and (6), repeat the above experiment, analyze the impact of different lower limit pressures of water layer depletion on the expansion drainage, and select the optimal working lower limit pressure.

[0091] During gas storage facility renovation, excessively rapid gas injection rates can alter the physical structure of the aquifer, such as causing fractures or expanding existing fractures, leading to a reduced service life of the gas storage facility. Simultaneously, the injection rate affects the properties of fluids within the oil and gas reservoir. Only an appropriate injection rate can facilitate the uniform advancement of the gas-water interface within the aquifer. If the injection rate is too high, it may result in uneven internal fluid flow during the renovation process, preventing the effective removal of formation water. Therefore, determining a reasonable injection rate is crucial. The following are the optimization steps for the injection rate:

[0092] 2. Experimental study on the optimization of gas injection rate:

[0093] The above experiments can optimize the lower limit pressure of exhaustion. Using the same experimental methods and steps as Experiment 1, only the gas injection rate is changed. Based on the dynamic water production and dynamic gas production at different pressure points, the target dynamic recovery degree and target dynamic expansion characteristics can be calculated, and the optimal gas injection rate can be optimized.

[0094] 3. Experimental study on the optimization of formation dip angle:

[0095] With the optimal velocity and the optimal lower limit pressure of exhaustion, by using the same experimental methods and steps as in Experiment 1 and only changing the formation dip angle, we can calculate the target dynamic recovery degree and the target dynamic expansion characteristics based on the dynamic water production and dynamic gas production at different pressure points, and optimize the optimal formation dip angle.

[0096] 4. Experimental study on the optimization of reservoir properties:

[0097] Similarly, by using the same experimental methods and steps as in Experiment 1, but changing only the formation properties, the influence of reservoir properties on water layer drainage and expansion can be determined.

[0098] In this embodiment of the invention, the gas flow rate measured under experimental conditions is corrected using the gas state equation to obtain the gas flow rate under the corresponding formation temperature and pressure conditions. The gas flow rate correction formula is as follows:

[0099]

[0100] Where q1 represents the gas flow rate under formation temperature and pressure conditions, in cm³. 3 / s; Z1 represents the gas deviation coefficient under formation temperature and pressure conditions (obtained by the DAK method); P3 represents the fluid pressure in MPa; P atm Z2 represents atmospheric pressure, in MPa; Z2 represents the gas deviation coefficient under atmospheric pressure conditions; q2 represents the gas flow rate under laboratory conditions, in cm³. 3 / s.

[0101] Furthermore, in this embodiment of the invention, after the core sample is dried, it is placed sequentially into the long core holder 11, saturated after vacuuming, and the pore volume of the long core and the pipeline volumes at the inlet and outlet ends are measured to calculate the total pore volume. The total pore volume is expressed using the following expression:

[0102] N = V p +V1+V2

[0103] Where N represents the total pore volume, in ml; V p V1 represents the measured pore volume of the core sample, in ml; V2 represents the pipeline volume at the core inlet, in ml; V3 represents the pipeline volume at the core outlet, in ml.

[0104] Furthermore, in this embodiment of the invention, the expansion capacity refers to the ratio of the cumulative water volume discharged from the core to the total pore volume under original conditions. The expansion capacity is expressed by the following expression:

[0105]

[0106] Among them, V w Indicates cumulative water output in ml; η represents expansion capacity in %; B w This represents the volume coefficient of water.

[0107] Furthermore, in this embodiment of the invention, the capacity expansion rate is the difference between the capacity expansion capabilities measured in two consecutive measurements, and is expressed by the following expression:

[0108] △η=η2-η1

[0109] Where △η represents the expansion rate, %; η1 and η2 represent the expansion capacity of two adjacent measurement points, respectively, %.

[0110] Furthermore, in this embodiment of the invention, the air-to-water ratio R gw This can be represented by the following expression:

[0111]

[0112] Among them, V g This represents the cumulative gas production, in cubic meters (m³). 3 .

[0113] Furthermore, in this embodiment of the invention, the recovery rate R is represented by the following expression:

[0114]

[0115] Among them, I inj This indicates the gas injection volume, in meters (m³). 3 .

[0116] Example 2

[0117] Based on the test apparatus described in Embodiment 1 above, the following section uses a water-layer modified gas storage project as an example to illustrate the measurement process of parameters affecting the drainage capacity of the water-layer modified gas storage facility:

[0118] The original formation pressure of the water layer was 25 MPa, and the formation temperature was 95℃. After the reservoir was built, the pressure operating range was 13-25 MPa. See Table 1 for the basic parameters of the core sample.

[0119] Table 1 Basic physical properties of core samples

[0120]

[0121] (1) Optimization experimental study on the lower limit pressure of exhaustion:

[0122] Four core samples were placed into the long core holder in sequence from the inlet to the outlet. A confining pressure of 3 MPa was applied, and the system temperature was adjusted to the formation temperature. Valves 5, 7, 12, 13, 15, 28, and 27 were kept closed, while valves 2, 4, 8, and 10 were opened to evacuate the system. After evacuation, valves 2 and 4 were closed, and valves 5 and 7 were opened to gradually increase the pressure to saturate the core with formation water, maintaining a confining pressure always greater than the fluid pressure by 3 MPa. Ultimately, the fluid pressure in the core was raised to the original formation pressure, and the confining pressure was raised to the original overlying pressure. Valves 5, 7, and 8 were closed, and valves 12, 13, and 15 were opened to gradually decrease the fluid pressure, recording a point every 2 MPa. Finally, the fluid pressure was reduced to the exhaustion lower limit pressure, and the water volume factor B was calculated.w Meter the water production at each pressure point during the depletion stage, and calculate the recovery rate and capacity expansion. Open valves 2, 4, and 8, and perform gas-driven treatment at a constant injection rate under the lower limit pressure of depletion until the gas-water ratio is approximately 500 m³ / s. 3 / m 3 The gas and water production, as well as pressure changes at different times, were measured to calculate the recovery rate and expansion. Valves 2, 4, 12, 13, and 15 were closed, while outlet valves 27 and 28 were opened. The gas injection end was switched to a huff-and-puff configuration, and gas was injected at the same rate to raise the core fluid pressure to the original formation pressure. The pressure was then gradually reduced, with a record taken every 2 MPa, until the pressure was finally reduced to the lower formation pressure limit. The gas and water production at each huff-and-puff pressure point were measured, and the recovery rate, expansion, and recovery rate were calculated. Huff-and-puff was stopped when the discharged water volume was almost zero. The lower water depletion limit pressure in step four was changed, and the above experiment was repeated to analyze the impact of different lower water depletion limit pressures on expansion and drainage, and to select the optimal working lower limit pressure.

[0123] Figure 3 The changes in pressure expansion recovery rate are shown at exhaustion lower limit pressures of 13 MPa and 19 MPa. Figure 7 The study demonstrates the impact of exhaustion lower limit pressures of 13 MPa and 19 MPa on the injection-production drainage capacity expansion.

[0124] (2) Experimental study on the optimization of gas injection rate:

[0125] Based on the optimal exhaustion lower limit pressure of 13MPa, the gas injection rate was changed to three different rates of 0.3ml / min, 0.6ml / min and 0.9ml / min respectively. The same experimental method and steps as experiment (1) were used, only the injection and extraction rates were changed. After three experiments, the optimal gas injection rate can be optimized.

[0126] Figure 4 The changes in pressure expansion recovery rate are shown at gas injection rates of 0.3 ml / min, 0.6 ml / min, and 0.9 ml / min. Figure 8 The effects of gas injection rates of 0.3 ml / min, 0.6 ml / min, and 0.9 ml / min on injection-production-drainage expansion were shown.

[0127] (3) Experimental study on the optimization of formation dip angle:

[0128] Based on the optimal velocity of 0.3 ml / min and the optimal lower limit pressure of 13 MPa, the dip angle of the formation was changed, and experiments were carried out at three different dip angles of 0°, 30° and 60°. The same experimental methods and steps as in experiment (1) were used, but the dip angle of the formation was changed. The three experiments were completed to optimize the optimal dip angle of the formation.

[0129] Figure 5 The changes in pressure expansion recovery rate are shown at formation dip angles of 0°, 30°, and 60°. Figure 9 The study demonstrates the impact of formation dip angles of 0°, 30°, and 60° on injection-production-drainage capacity expansion.

[0130] (4) Experimental study on the optimization of reservoir properties:

[0131] Based on the optimal velocity of 0.3 ml / min, the optimal lower limit pressure of 13 MPa, and the preferred formation dip angle of 60°, the formation properties were changed, and experiments were carried out with three different core combinations of 107 md, 58 md, and 25 md. The same experimental methods and steps as in experiment (1) were used, but the formation properties were changed. After completing three experiments, the influence of reservoir properties on water layer drainage expansion can be obtained.

[0132] Figure 5 The changes in pressure expansion recovery rate are shown under reservoir properties of 107md, 58md, and 25md. Figure 9 The study demonstrates the impact of reservoir properties of 107md, 58md, and 25md on injection-production-drainage expansion.

[0133] Example 3

[0134] Based on the systems described in Embodiments 1 and 2 above for measuring parameters affecting the drainage capacity of a gas storage facility undergoing aquatic layer reconstruction, this invention also provides a method (also referred to as a "measurement experiment method") for measuring parameters affecting the drainage capacity of a gas storage facility undergoing aquatic layer reconstruction. This measurement experiment method utilizes the aforementioned measurement experiment system.

[0135] Figure 11 This is a flowchart illustrating the steps of a method for measuring parameters affecting the drainage capacity of a modified gas storage tank based on an embodiment of this application. Figure 11 As shown, the measurement experiment method described in this embodiment of the invention includes at least the following steps:

[0136] Step S1101: Saturate the experimental core using a water injection device that contains experimental formation water;

[0137] Step S1102: The outlet back pressure and measuring device reduces the pressure at the core outlet end in stages to bring the outlet pressure down to the specified exhaustion lower limit pressure.

[0138] Step S1103: The gas injection device performs gas drive on the core when the outlet pressure reaches the lower limit of the decay pressure;

[0139] Step S1104: The inlet back pressure and measuring device first injects gas into the core inlet end, and then gradually reduces the pressure at the core inlet end, so that when the inlet pressure drops to the specified exhaustion lower limit pressure, the gas production and water production at each pressure point during the pressure reduction process are measured.

[0140] In step S1105, the data processing device calculates the dynamic extraction degree and dynamic expansion characteristics based on the water production and gas production at each pressure point.

[0141] This invention discloses a system and method for measuring parameters affecting the drainage capacity of a water-reconstructed gas storage facility. The system and method provide experimental simulation of the drainage expansion capacity and working gas volume measurement of a water-reconstructed gas storage facility, as well as a multi-parameter optimization method and testing system. The testing system mainly includes a gas booster pump, a constant-speed and constant-pressure pump, a long core holder, a confining pressure pump, a backpressure pump, a processor, a waste gas recovery device, a high-temperature and high-pressure resistant visual container, a gas meter, and a temperature control device. Using this system, not only can the gas-water ratio of the gas storage facility be measured and the expansion rate curve of the gas storage facility be tested, but the same device can also accurately determine the drainage expansion capacity and recovery rate of a water-reconstructed gas storage facility. It can optimize the lower exhaustion limit pressure, gas injection rate, formation dip angle, and reservoir properties. By experimentally simulating the three processes of exhaustion drainage expansion, gas injection-pump drainage expansion, and gas injection-pump drainage expansion, it can better simulate the water-reconstructed drainage expansion process, enabling more rational and efficient utilization of the water-reconstructed gas storage facility.

[0142] Furthermore, this invention uses long core experiments to fully simulate three processes: depletion drainage expansion, gas injection-pump drainage expansion, and gas injection-pump-pump drainage expansion. It establishes the conditions for converting gas injection-pump drainage to pump-pump drainage. Through the equipment and experimental methods, it can measure the drainage expansion capacity (capacity utilization rate) and working gas volume ratio (recovery rate) of aquifer-converted gas storage facilities. It can simultaneously study the impact of different depletion lower limit pressures, injection rates, formation dip angles, and reservoir properties on the expansion of aquifer-converted gas storage facilities. This provides a basis for designing the capacity and working gas volume of aquifer-converted gas storage facilities, optimizing single-well injection-production systems, and formulating technical policies for drainage expansion technology. It enables the setting of control parameters for the transition from drainage to pump-pump during gas storage facility conversion, and allows for the optimization of depletion lower limit pressure, formation dip angle, injection rate, and reservoir property parameters. This allows us to utilize aquifer-converted gas storage facilities more rationally and efficiently.

[0143] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

[0144] In the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0145] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0146] It should be understood that the embodiments disclosed herein are not limited to the specific structures, processing steps, or materials disclosed herein, but should be extended to equivalent substitutions of these features as understood by those skilled in the art. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0147] The phrase "an embodiment" or "an embodiment" used in this specification means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Therefore, the phrase "an embodiment" or "an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0148] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and changes in form and detail of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection of this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A system for measuring parameters affecting the drainage capacity of a gas storage facility undergoing water layer modification, characterized in that, include: The core holder includes an outlet back pressure and measuring device located at the outlet end of the holder, and a water injection device, an air injection device, and an inlet back pressure and measuring device located at the inlet end of the holder. The core holder is used to hold the experimental core. The water injection device is used to saturate the experimental core with the experimental formation water contained therein. The outlet back pressure and measuring device is used to reduce the outlet pressure to a specified exhaustion lower limit pressure by gradually reducing the pressure at the core outlet end. The gas injection device is used to perform gas driving on core samples whose outlet pressure has reached the lower limit of attenuation. The inlet back pressure and measuring device is used to first inject gas into the core inlet end, and then gradually reduce the pressure at the core inlet end, so as to measure the gas production and water production at each pressure point during the depressurization process when the inlet pressure drops to the specified exhaustion lower limit pressure. The data processing device is used to calculate the dynamic recovery rate and dynamic expansion characteristics based on the water production and gas production at each pressure point.

2. The system according to claim 1, characterized in that, The dynamic expansion features include dynamic expansion capability and dynamic expansion rate, wherein... The data processing device is also used to conduct measurement experiments by changing the specified lower limit pressure of decay, to obtain the dynamic extraction degree and dynamic expansion characteristics under different lower limit pressure conditions, and based on this, to determine the optimal lower limit pressure of decay.

3. The system according to claim 2, characterized in that, The gas injection device is also used to perform gas driving on core samples whose outlet pressure has reached the lower limit of decay pressure at a specified gas injection rate. The inlet back pressure and measuring device is also used to inject gas into the core inlet end according to the specified gas injection rate, wherein... The data processing device is further configured to conduct measurement experiments based on the optimal attenuation lower limit pressure by changing the specified gas injection rate, to obtain the dynamic recovery degree and dynamic expansion characteristics under different gas injection rate conditions, and to determine the optimal gas injection rate based on this.

4. The system according to claim 3, characterized in that, The core holder forms a specified angle with the horizontal direction, wherein... The data processing device is further configured to conduct measurement experiments by changing the specified dip angle based on the optimal attenuation lower limit pressure and the optimal gas injection rate, to obtain the dynamic recovery degree and dynamic expansion characteristics under different formation dip angle conditions, and to determine the optimal formation dip angle based on this.

5. The system according to any one of claims 2 to 4, characterized in that, The experimental core is a long core, which is composed of at least one core sample with specified physical properties. The data processing device is also used to conduct measurement experiments based on the optimal attenuation lower limit pressure by replacing experimental cores with different physical property parameters, to obtain the dynamic extraction degree and dynamic expansion characteristics under different physical property parameter conditions, and based on this, to determine the optimal physical property parameter, wherein the physical property parameter is permeability.

6. The system according to any one of claims 1 to 5, characterized in that, The water injection device is also used to inject experimental formation water into the experimental core in a step-by-step pressurization manner, so that the confining pressure is always kept greater than the confining pressure threshold, thereby determining the end of the saturated formation water stage when the core inlet pressure reaches the original formation pressure and the confining pressure reaches the original overlying pressure of the formation.

7. The system according to any one of claims 1 to 6, characterized in that, The data processing device is also used to calculate the dynamic gas-water ratio based on the gas production and water production at different times at the core outlet during the gas drive process, so as to determine the end of the gas drive stage when the dynamic gas-water ratio reaches the gas-water ratio threshold.

8. The system according to any one of claims 1 to 7, characterized in that, The system also includes: A confining pressure device, which is connected to the side wall of the core holder, is used to provide the experimental confining pressure required for the experimental core to the measurement experimental system; A temperature control device is used to simulate formation temperature conditions by providing the required experimental temperature to the measurement experimental system.

9. The system according to any one of claims 1 to 8, characterized in that, Inlet / outlet back pressure and measuring device includes: Back pressure valves are installed at the inlet / outlet ends of the core holder; A back pressure pump is installed at the first outlet of the back pressure valve at the inlet / outlet end, which is used to regulate the pressure at the inlet / outlet end of the core sample. An inlet / outlet back pressure pump switch is installed between the inlet / outlet back pressure valve and the inlet / outlet back pressure pump. Measuring cylinders installed at the inlet / outlet ends of the second outlet of the back pressure valve at the inlet / outlet end; A gas measuring instrument located at the rear end of the measuring cylinder at the inlet / outlet.

10. The system according to claim 9, characterized in that, The inlet / outlet back pressure and measuring device also includes: The inlet / outlet processor, connected to the gas meter at the inlet / outlet, is used to correct the measured gas flow data to convert the gas flow data under the experimental environment into gas flow data under the formation temperature and pressure conditions. The corrected gas flow is then used to calculate the dynamic recovery degree and dynamic expansion characteristics under different experimental stages.

11. The system according to any one of claims 1 to 10, characterized in that, The water injection device includes a first water valve, a water intermediate container, a second water valve, and a constant speed and constant pressure pump that are sequentially connected to the inlet end of the core holder. The water intermediate container is used to hold experimental formation water configured according to the mineralization conditions corresponding to the field water sample. The gas injection device includes a first gas sample valve, a gas sample intermediate container, a second gas sample valve, and a gas booster pump, which are sequentially connected to the inlet end of the core holder.

12. A method for measuring parameters affecting the drainage capacity of a gas storage facility undergoing water layer modification, characterized in that, The method is implemented using the system as described in any one of claims 1 to 11, wherein the method comprises: The experimental core was saturated using a water injection device that contains formation water. The outlet back pressure and measuring device reduces the pressure at the core outlet in stages until the outlet pressure drops to a specified exhaustion lower limit pressure. The gas injection device performs gas driving on core samples whose outlet pressure has reached the lower limit of attenuation. The inlet back pressure and measuring device first injects gas into the core inlet end, and then gradually reduces the pressure at the core inlet end, so as to measure the gas production and water production at each pressure point during the depressurization process when the inlet pressure drops to the specified exhaustion lower limit pressure. The data processing device calculates the dynamic extraction degree and dynamic expansion characteristics based on the water production and gas production at each pressure point.

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