A physical simulation experimental system for gas-liquid multiphase seepage in gas reservoir type gas storage

Abstract

The present application discloses a gas-liquid multiphase seepage physical simulation experimental system for a gas reservoir type gas storage, comprising a rock sample sealing and heating insulation system, a triaxial stress and confining pressure loading system, an oil-gas-water injection and pore pressure replenishment system, a gas-liquid-solid three-phase separation and metering system, an optical fiber gas sensing monitoring system, a distributed optical fiber displacement monitoring system and a gas supply and leakage alarm system. The rock sample sealing and heating insulation system comprises a rock sample sealing unit for loading rock samples and a heating insulation unit for heating rock samples; the triaxial stress and confining pressure loading system comprises a triaxial stress loading unit for providing triaxial stress to the rock samples and a confining pressure loading unit for providing confining pressure to the rock samples; the oil-gas-water injection and pore pressure replenishment system comprises a gas phase injection unit and a liquid phase injection unit for performing oil-gas-water three-phase injection into the rock samples; the present application is used to solve the bottleneck problem of dynamic sealing evaluation of gas reservoir type gas storage under strong injection-production alternating loads, and guide the scientific site selection and scheme design of gas storage.

Description

Technical Field

[0001] The present application relates to the technical field of gas reservoir type gas storage, and in particular to a gas-liquid multiphase seepage physical simulation experimental system for gas reservoir type gas storage. Background Art

[0002] Natural gas underground storage is an important infrastructure to ensure national energy security, and gas reservoir type storage is the main type of underground gas storage in my country. my country's gas reservoir storage generally has a complex edge and bottom water system, and the complex fluid distribution caused by gas-liquid mutual drive directly affects the storage capacity, injection and production efficiency, and gas injection safety.

[0003] The geological structure of gas storage is complex, and the sealing performance and dynamic evolution of the gas storage have a huge impact on the site selection, construction, and safe operation and maintenance of the gas storage. The sealing performance of the gas storage trap is an important factor in the safe operation of the gas storage. The strong injection and strong production of the gas storage cause periodic disturbances in the ground stress, resulting in large changes in the force of the trap, which is easy to cause dynamic changes in the sealing performance. The main reason for the tension and shear failure of the gas storage trap (including the cap rock and fault) is the rapid change in the formation pressure during the injection and production process and the resulting changes in the underground stress field in the reservoir area.

[0004] In addition, the injection and production process of gas storage wells is very different from that of conventional oil and gas reservoir development wells. The injection and production pipes have to bear alternating loads for a long time during the injection and production process. The high-intensity injection and production of natural gas causes the gas storage injection and production pipes to be subjected to additional loads such as swelling, temperature, formation expansion and contraction. Under complex injection and production conditions, the sealing and safety of the reservoir wellbore and its cement ring will be seriously threatened. At the same time, complex conditions in the reservoir wellbore may also cause safety issues such as wellbore deformation, collapse, sanding in the wellbore, and fluid channeling, which is crucial to the construction and operation of the reservoir.

[0005] However, effective prediction theories and methods for the sealing of gas storage faults, caprocks, wellbores and reservoirs have not yet been established at home and abroad. Therefore, it is urgent to overcome the bottleneck problem of dynamic sealing evaluation of gas reservoir-type gas storage under strong injection and production alternating loads, so as to guide the scientific site selection and scheme design of gas storage. Summary of the invention

[0006] In order to solve the above problems, the present application provides a gas-liquid multiphase seepage physical simulation experimental system and experimental method for gas reservoir type gas storage, so as to solve the bottleneck problem of dynamic sealing evaluation of gas reservoir type gas storage under strong injection and production alternating load, and guide the scientific site selection and scheme design of gas storage. The technical scheme is as follows:

[0007] The present application provides a gas-liquid multiphase seepage physical simulation experiment system for a gas reservoir type gas storage, including a rock sample sealing and heating and insulation system, a triaxial stress and confining pressure loading system, an oil-gas-water injection and pore pressure replenishment system, a gas-liquid-solid three-phase separation and metering system, an optical fiber gas sensor monitoring system, a distributed optical fiber displacement monitoring system, and a gas supply and leakage alarm system. The rock sample sealing and heating and insulation system includes a rock sample sealing unit for loading rock samples and a heating and insulation unit for heating rock samples; the triaxial stress and confining pressure loading system includes a triaxial stress loading unit for providing triaxial stress to the rock sample and a confining pressure loading unit for providing confining pressure to the rock sample; The oil, gas and water injection and pore pressure replenishment system is connected to the inlet end of the rock sample through a pipeline, including a gas phase injection unit and a liquid phase injection unit, so as to perform three-phase injection of oil, gas and water into the rock sample; the gas-liquid-solid three-phase separation and metering system is connected to the outlet end of the rock sample through a pipeline, including a back pressure unit, a solid separation and metering unit and a gas-liquid separation and metering unit; the optical fiber gas sensing monitoring system is used to detect and sense the leakage of the specified gas; the distributed optical fiber displacement monitoring system is used to monitor and record the internal deformation and crack distribution of the rock sample during the loading process; the gas supply and leakage alarm system is used to provide a safe and reliable centralized gas supply point.

[0008] For example, in the gas-liquid multiphase seepage physical simulation experimental system of the gas reservoir type gas storage provided in one embodiment, the rock sample sealing unit includes a main pressure chamber, a rock sample rubber sleeve and a loading plate, and a chamber for loading the rock sample is provided at the center of the main pressure chamber, and a confining pressure environment is provided for the rock sample; the rock sample rubber sleeve is provided on the outside of the rock sample to seal the rock sample; the loading plates are respectively provided around the rock sample and abut against the rock sample rubber sleeve on the outer wall of the rock sample.

[0009] For example, in the gas-liquid multiphase seepage physical simulation experimental system of the gas reservoir type gas storage provided in one embodiment, the heating and insulation unit includes a heating rod and a flexible insulation sleeve, the heating rod is embedded in the main pressure chamber around the inside to heat the main pressure chamber and transfer heat to the rock sample; the flexible insulation sleeve is wrapped around the outside of the main pressure chamber to insulate the main pressure chamber and perform temperature compensation.

[0010] For example, in the gas reservoir type gas storage reservoir gas-liquid multiphase seepage physical simulation experimental system provided in one embodiment, the triaxial stress loading unit includes loading cylinders respectively located around the rock sample, a servo loading pump providing a power source for the loading cylinder, a servo oil source providing a pre-pressurization function for axial loading, a servo valve controlling the hydraulic pressure of the loading cylinder, a reversing valve controlling the movement direction of the loading cylinder piston, a displacement sensor controlling the displacement loading of the loading cylinder, and an air compressor providing low-pressure power to the loading cylinder for resetting the loading cylinder piston, and the pressure head of the loading cylinder is respectively in contact with the loading plates around the rock sample; the confining pressure loading unit includes a high-precision constant speed and constant pressure pump, which is connected to the main pressure bin through a pipeline to provide a constant pressure in the main pressure bin and provide confining pressure for the rock sample.

[0011] For example, in the gas-liquid multiphase seepage physical simulation experimental system of the gas reservoir type gas storage provided in one embodiment, the gas phase injection unit is connected to the rock sample through a pipeline, including a gas booster pump group connected by a pipeline for providing high-pressure gas at the input end, a high-pressure gas storage container for storing high-pressure gas, an air compressor for providing power for the gas booster pump group, a pneumatic pressure controller for controlling the gas pressure, and a gas flow controller for controlling the gas flow.

[0012] For example, in the gas-liquid multiphase seepage physical simulation experimental system of the gas reservoir type gas storage provided in one embodiment, the liquid phase injection unit is connected to the rock sample through a pipeline, including a liquid constant flow and pressure pump and a piston container connected by a pipeline, and the piston container is used to isolate the working fluid from the injected fluid.

[0013] For example, in the gas-liquid multiphase seepage physical simulation experimental system of the gas reservoir type gas storage provided in one embodiment, the back pressure unit includes a back pressure pump, a back pressure container and a back pressure valve connected by pipelines; the solid separation and metering unit is located between the rock sample outlet and the back pressure valve, and includes a solid collection and metering container for separating solids; the gas-liquid separation and metering unit is connected to the back pressure valve, and includes a gas-liquid separator for gas-liquid separation of the fluid at the rock sample outlet, wherein the separated gas is discharged through the top outlet of the gas-liquid separator and enters a high-speed gas flowmeter or a low-speed gas flowmeter for gas phase flow metering via a drying tank, and the separated liquid is discharged through the bottom outlet of the gas-liquid separator and enters an oil phase metering pump for oil phase flow metering or a water phase metering pump for water phase flow metering via an oil-water separation pipe, and an oil-water interface detector is provided on the oil-water separation pipe.

[0014] For example, in the gas reservoir type gas storage reservoir gas-liquid multiphase seepage physical simulation experimental system provided in one embodiment, the optical fiber gas sensing monitoring system includes a gas probe disposed inside the rock sample and a signal conditioner electrically connected to the gas probe.

[0015] For example, in the gas-liquid multiphase seepage physical simulation experimental system of the gas reservoir type gas storage provided in one embodiment, the distributed optical fiber displacement monitoring system includes a light source, a coupler, a detector and an optical fiber electrically connected, and the optical fiber is buried inside the rock sample.

[0016] For example, in the gas-liquid multiphase seepage physical simulation experimental system of the gas reservoir type gas storage provided in one embodiment, the gas supply and leakage alarm system includes a gas cylinder placement rack for holding gas cylinders, a solenoid valve arranged on the gas cylinder outlet pipeline and a gas monitor connected to the solenoid valve through a line, a temperature / pressure sensor, a video monitor, a central monitoring server, an alarm, ventilation equipment and fire-fighting equipment, and an electrostatic protection device is provided in the gas cylinder placement room.

[0017] The beneficial effects brought by a gas-liquid multiphase seepage physical simulation experiment system for a gas reservoir type gas storage provided by some embodiments of the present application are as follows: the present application fills the gap that there is no relatively complete large-scale triaxial multiphase multicomponent complex multi-field coupling experiment system for gas storage development in China at present, and solves the technical problem that the current physical simulation experiment requirements for the operating conditions of complex geological structures under multi-cycle intensive injection and production conditions of gas reservoirs cannot be met. The present application is used to carry out various experiments such as multiphase fluid injection / detection and stress deformation monitoring of large-scale rock samples under triaxial stress conditions, revealing the migration, miscibility, displacement and distribution of multiphase fluids, mixing and leakage of gas components in heterogeneous and non-continuous formations during the injection and production process of underground gas storages, the dynamic stability and yielding of geological bodies with complex internal structures, the sudden change of seepage characteristics, and the deformation, collapse, sand production in the wellbore, fluid crossflow and other safety issues of key nodes of the wellbore such as casing, perforation holes, and cement rings, which have great scientific significance and value. It is not only a key scientific issue at the forefront of the development of deep rock mechanics and a major topic that needs to be solved urgently, but also has important significance for improving the construction and operation level of gas storage facilities and the development of disciplines in my country. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a schematic diagram of the structure of the gas-liquid multiphase seepage physical simulation experimental system of the gas reservoir type gas storage of the present application;

[0020] Figure 2 It is a front view of the sample sealing and heating and heat preservation unit structure of the present application;

[0021] Figure 3 It is a side view of the sample sealing and heating and heat preservation unit structure of the present application;

[0022] Figure 4 It is a schematic diagram of the structure of the triaxial stress and confining pressure loading system of the present application;

[0023] Figure 5 It is a schematic diagram of the structure of the gas supply and leakage alarm system of the present application. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0025] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0026] The present application provides a gas reservoir type gas storage gas-liquid multiphase seepage physical simulation experimental system, such as Figure 1As shown, it includes a rock sample sealing and heating and insulation system 100, a triaxial stress and confining pressure loading system 200, an oil, gas and water injection and pore pressure replenishment system 300, a gas-liquid-solid three-phase separation and metering system 400, an optical fiber gas sensor monitoring system 500, a distributed optical fiber displacement monitoring system 600 and a gas supply and leakage alarm system 700. The rock sample sealing and heating and insulation system 100 includes a rock sample sealing unit 110 for loading rock samples and a heating and insulation unit 120 for heating rock samples. The triaxial stress and confining pressure loading system 200 includes a triaxial stress loading unit 210 for providing triaxial stress for rock samples and a confining pressure loading unit 220 for providing confining pressure for rock samples. The water injection and pore pressure replenishment system 300 is connected to the inlet end of the rock sample through a pipeline, including a gas phase injection unit 310 and a liquid phase injection unit 320, so as to perform three-phase injection of oil, gas and water into the rock sample. The gas-liquid-solid three-phase separation and metering system 400 is connected to the outlet end of the rock sample through a pipeline, including a back pressure unit 410, a solid separation and metering unit 420 and a gas-liquid separation and metering unit 430. The optical fiber gas sensor monitoring system 500 is used to detect and sense the leakage of the specified gas. The distributed optical fiber displacement monitoring system 600 is used to monitor and record the internal deformation and crack distribution of the rock sample during the loading process. The gas supply and leakage alarm system 700 is used to provide a centralized gas supply point.

[0027] The rock sample sealing and heating and heat preservation unit 100 is intended to provide sealing conditions for the pore pressure loading of the rock sample, prevent the pore fluid from overflowing from the rock sample boundary, and provide a heating and constant temperature environment for the rock sample. The rock sample sealing and heating and heat preservation system 100 is composed of two groups of parts: a rock sample sealing unit 110 and a heating and heat preservation unit 120.

[0028] For example, in the gas-liquid multiphase seepage physical simulation experimental system of the gas reservoir type gas storage provided in one embodiment, Figure 1-3 As shown, the rock sample sealing unit 110 includes a main pressure chamber 111, a rock sample rubber sleeve 112 and a loading plate 113. A chamber for loading the rock sample is provided at the center of the main pressure chamber 111, and a confining pressure environment is provided for the rock sample; the rock sample rubber sleeve 112 is sleeved on the outside of the rock sample to seal the rock sample; the loading plate 113 is respectively arranged around the rock sample and abuts against the rock sample rubber sleeve 112 on the outer wall of the rock sample.

[0029] Among them, gas, fluid injection and testing instrument interfaces are reserved on the loading plate 113 to meet the experimental pore pressure loading and testing requirements. By setting the main pressure chamber 111 outside the rock sample, a confining pressure environment is provided for the rock sample, and the rupture of the rock sample rubber sleeve 112 is also avoided.

[0030] Specifically, the main pressure chamber 111 is made of high-strength alloy 42CrMo, and is mainly used to place rock samples, providing guarantees for multiphase seepage tests and confining pressure loading of rock samples. After mechanical verification and analysis, when the overall pressure is 70MPa, the components fully meet the material yield strength conditions. The rock sample rubber sleeve 112 is mainly used to seal the rock sample to provide guarantees for subsequent seepage experiments. The rock sample rubber sleeve 112 adopts a square five-sided structure, which is easy to install and has reliable sealing performance. The rubber sleeve material is fluororubber, and the working temperature is less than 200°C. The loading plate 113 is made of 2Cr13 and is connected to the corresponding pressure head 2111. During the experiment, the loading plate 113 is directly in contact with the rock sample rubber sleeve 112. An injection port is designed in the middle of the two oppositely arranged front and rear loading plates 113 to realize oil, gas and water multiphase injection seepage experiments.

[0031] For example, in the gas-liquid multiphase seepage physical simulation experimental system of the gas reservoir type gas storage provided in one embodiment, Figure 1-3 As shown, the heating and insulation unit 120 includes a heating rod 121 and a flexible insulation sleeve 122. The heating rod 121 is embedded around the inside of the main pressure chamber 111 to heat the main pressure chamber 111 and transfer heat to the rock sample; the flexible insulation sleeve 122 is wrapped around the outside of the main pressure chamber 111 to insulate the main pressure chamber 111 and perform temperature compensation.

[0032] Specifically, heating rod mounting holes are provided near the four corners of the main pressure chamber 111, and heating rods 121 are embedded in the heating rod mounting holes. During the experiment, the rock sample is subjected to confining pressure loading by means of an oil bath, and the main pressure chamber 111 is heated by the heating rods 121 provided on the main pressure chamber 111, thereby heating the oil and transferring the heat to the rock sample. The main pressure chamber 111 is wrapped with a flexible insulation sleeve 122 to insulate and temperature compensate the entire main pressure chamber 111, and can provide a maximum test temperature of 200°C. It is equipped with a temperature compensation and control system to achieve good heating and constant temperature performance.

[0033] The triaxial stress and confining pressure loading system 200 is designed to provide triaxial stress and main pressure chamber pressure (rock sample confining pressure) for rock samples. It can load rock samples with a maximum size of 300mm×300mm×300mm. The triaxial stress and confining pressure loading system 200 can perform triaxial five-sided loading with a maximum loading stress of 80MPa, and provide confining pressure power for the rock sample sealing and heating and insulation system with a maximum confining pressure of 65MPa. Figure 4 As shown, the triaxial stress and confining pressure loading system 200 is composed of two groups of parts: a triaxial stress loading unit 210 and a confining pressure loading unit 220 .

[0034] For example, in the gas-liquid multiphase seepage physical simulation experimental system of the gas reservoir type gas storage provided in one embodiment, Figure 1 ,4 As shown, the triaxial stress loading unit 210 includes a loading cylinder 211 located around the rock sample, a servo loading pump 212 providing a power source for the loading cylinder 211, a servo oil source 213 providing a pre-pressurization function for axial loading, a servo valve 214 controlling the hydraulic pressure of the loading cylinder 211, a reversing valve 215 controlling the movement direction of the piston of the loading cylinder 211, a displacement sensor 216 controlling the displacement loading of the loading cylinder 211, and a servo ... low-pressure power for the loading cylinder 211. The air compressor 217 resets the piston of the cylinder 211, and the pressure head 2111 of the loading cylinder 211 abuts against the loading plates 113 around the rock sample respectively, and the rock sample cross section fits the loading and docks with the pressure head 2111 of the loading cylinder 211 of the external triaxial stress loading unit 210; the confining pressure loading unit 220 includes a high-precision constant speed and constant pressure pump 221, and the high-precision constant speed and constant pressure pump 221 is connected to the main pressure chamber 111 through a pipeline to provide a constant pressure in the main pressure chamber 111 and provide confining pressure for the rock sample.

[0035] Specifically, the triaxial stress loading unit 210 mainly satisfies the system triaxial stress loading, such as Figure 2-3As shown, the loading cylinder 211 mainly provides pressure loading on three axes and five surfaces (X axis, -X axis, -Y axis, Z axis, -Z axis) for the whole machine. The Y axis direction is a fixed axis, and the top plate 218 is used to apply reverse force. This application uses a bidirectional servo loading cylinder 211 with a maximum loading tonnage of 800T, a cylinder diameter of 360mm, and a working pressure of 80MPa. The loading cylinder 211 is installed on a U-shaped high-strength loading frame. The high-strength loading frame adopts a combined integral door frame structure to provide a maximum test force of 8000kN. The loading cylinder 211 uses a servo oil source 213 (servo hydraulic source) for pre-pressurization, and a high-pressure servo loading pump 212 performs pressure loading control; the servo loading pump 212 mainly provides a power source for the three-axis loading cylinder 211. This application uses a KDHB-500D servo loading pump with a single cylinder capacity of 500mL, a working pressure of 80MPa, a pressure accuracy of 0.1%FS, a flow range of 0.1~150mL / min, and a flow rate accuracy of ±1% of the set value; the servo oil source 21 3 mainly provides pre-pressurization function for axial loading to ensure the stability of subsequent servo loading pump pressure loading. Its main functional components include: hydraulic pump, motor, accumulator, level gauge, oil filter, air filter, oil source control cabinet, pressure control system, various valves and valve group modules. The maximum flow rate of the oil source is 300L / min, the maximum oil supply pressure is 31.5MPa, and the pressure adjustment range is 0-25MPa; the servo valve 214 mainly controls the hydraulic pressure of the loading cylinder 211. This application uses the Moog D633-308B direct-acting servo valve with a flow range of 3.8-100L / min, a maximum working pressure of 35MPa, and a response time of 5ms; the reversing valve 215 mainly controls the movement direction of the piston of the loading cylinder 211 to realize the bidirectional work of the loading cylinder 211. Rexroth's 4WE is used 10 E33 / CG24N9K4 / V-type reversing valve; the displacement sensor 216 is mainly used for displacement loading control of the loading cylinder 211, providing high-precision (0.01% FS) direct or absolute position detection feedback, and adopts a magnetostrictive displacement sensor, which has the advantages of high response frequency, fast refresh, anti-interference, small hysteresis, high precision, etc.; the air compressor 217 mainly provides low-pressure power for the loading cylinder 211, which is used for resetting the piston of the loading cylinder 211; the confining pressure loading unit 220 mainly adopts a high-precision constant speed and constant pressure pump 221, which is connected to the main pressure chamber 111 through a pipeline to provide a constant pressure in the pressure chamber, that is, to provide confining pressure for the rock sample. Its single cylinder volume is 100mL, the flow range is 0.01-100mL / min, the working pressure is 70MPa, and the pressure measurement resolution is 0.001MPa.

[0036] The oil, gas and water injection and pore pressure replenishment system 300 is designed to provide oil, gas and water three-phase injection for rock samples, especially constant pressure / constant flow injection of combustible gas, simulate reservoir well injection and production, oil and gas well development and transformation, etc.; and provide oil, gas and water three-phase pore pressure supply, simulate in-situ formation pore pressure and finite / infinite boundary formation fluid (edge ​​and bottom water, residual oil and gas) supply. The oil, gas and water injection and pore pressure replenishment system 300 consists of a gas phase injection unit 310 and a liquid phase injection unit 320.

[0037] For example, in the gas-liquid multiphase seepage physical simulation experimental system of the gas reservoir type gas storage provided in one embodiment, Figure 1 As shown, the gas injection unit 310 is connected to the rock sample through a pipeline, including a gas booster pump group 311 connected through a pipeline for providing high-pressure gas at the input end, a high-pressure gas storage container 312 for storing high-pressure gas, an air compressor 313 for providing power to the gas booster pump group 311, a pneumatic pressure controller 314 for controlling the gas pressure, and a gas flow controller 315 for controlling the gas flow.

[0038] Specifically, a gas booster pump group 311 is used to provide high-pressure gas at the input end, and the gas is stored in a high-pressure gas storage container 312. The gas booster pump group 311 is powered by an air compressor 313. The gas pressure is controlled by a pneumatic pressure controller 314, and a TESCOM ER5000 electronic pressure controller is selected. It can be controlled by a computer or PLC to achieve integrated management and control; the gas flow is controlled by a gas flow controller 315, and an AST10-HBC digital mass flow meter is selected, which consists of a mass flow sensor, a laminar stratification component, a flow controller regulating valve and an amplification control circuit, and can perform digital signal input and output and flow control.

[0039] For example, in the gas-liquid multiphase seepage physical simulation experimental system of the gas reservoir type gas storage provided in one embodiment, Figure 1 As shown, the liquid phase injection unit 320 is connected to the rock sample through a pipeline, and includes a liquid constant flow and pressure pump 321 and a piston container 322 connected through the pipeline. The piston container 322 is used to isolate the working fluid from the injection fluid.

[0040] Specifically, liquid phase injection is achieved by a liquid constant flow and constant pressure pump 321, and a piston container 322 is added to isolate the working fluid from the injected fluid and protect the liquid constant flow and constant pressure pump 321. A KDHB-200 high-precision injection pump is used, with a single cylinder capacity of 200mL, a working pressure of 60MPa, a pressure accuracy of 0.1%FS, a flow range of 0.01~80mL / min, and a flow rate accuracy of ±1% of the set value.

[0041] The gas-liquid-solid three-phase separation and metering system 400 is designed to separate and meter the key data such as the gas, liquid and solid three-phase discharge rate and cumulative discharge volume in physical simulation experiments such as formation fluid migration and displacement and wellbore sand production. It consists of a back pressure unit 410, a solid separation and metering unit 420 and a gas-liquid separation and metering unit 430.

[0042] For example, in the gas-liquid multiphase seepage physical simulation experimental system of the gas reservoir type gas storage provided in one embodiment, Figure 1 As shown, the back pressure unit 410 includes a back pressure pump 411, a back pressure container 412 and a back pressure valve 413 connected by pipelines; the solid separation and metering unit 420 is located between the rock sample outlet and the back pressure valve 413, and includes a solid collection and metering container 421 for separating solids; the gas-liquid separation and metering unit 430 is connected to the back pressure valve 413, and includes a gas-liquid separator 431 for gas-liquid separation of the fluid at the rock sample outlet, wherein the separated gas is discharged through the top outlet of the gas-liquid separator 431 and enters a high-speed gas flowmeter 433 or a low-speed gas flowmeter 434 for gas phase flow metering via a drying tank 432, and the separated liquid is discharged through the bottom outlet of the gas-liquid separator 431 and enters an oil phase metering pump 436 for oil phase flow metering or a water phase metering pump 437 for water phase flow metering via an oil-water separation pipe 435, and an oil-water interface detector 438 is provided on the oil-water separation pipe 435.

[0043] Specifically, the back pressure unit 410 is a pressure regulating device used to load a pressure higher than the atmospheric pressure up to the simulated formation pressure at the rock sample outlet, which is mainly used to make the outflow liquid stable, prevent evaporation, and improve the metering accuracy; the solid collection and metering container 421 is used to separate and meter the solids to prevent sand from clogging the metering pipeline, and is installed between the rock sample outlet and the back pressure valve 413; the gas-liquid separator 431 is mainly used to separate the gas and liquid of the fluid at the rock sample outlet, the fluid is separated by an umbrella-shaped spiral, the gas is metered by the gas metering device through the upper outlet, and the liquid flows out from the bottom to the oil-water metering device ; The drying tank 432 is used to dry the liquid components carried in the gas to ensure the accuracy of gas metering, and also plays a role in protecting the gas flowmeter. It is made of stainless steel, stores desiccant inside, and has an effective volume of 500mL; the oil-water automatic metering device uses the principle of gravity separation to separate the oil and water in the liquid phase through the oil-water separator 431, and measures the oil phase and water phase flow rates respectively through the oil phase metering pump 436 and the water phase metering pump 437; the gas flowmeter is used for gas phase flow measurement, and can be divided into a high-speed gas flowmeter 433 and a low-speed gas flowmeter 434 according to the flow rate.

[0044] The fiber optic gas sensing monitoring system 500 is designed to detect and quickly sense the loss of a specified gas, so as to evaluate the time efficiency of fluid migration between wells in a physical model, analyze the dominant migration path, etc.

[0045] For example, in the gas-liquid multiphase seepage physical simulation experimental system of the gas reservoir type gas storage provided in one embodiment, Figure 1 As shown, the optical fiber gas sensing monitoring system 500 includes a gas probe 510 disposed inside the rock sample and a signal conditioner 520 electrically connected to the gas probe 510 .

[0046] Specifically, the optical fiber gas sensing monitoring system 500 is composed of an optical fiber photothermal spectroscopy CH4 sensor based on an all-optical fiber system and a stimulated Raman spectroscopy H2 sensor based on an all-optical fiber system.

[0047] The distributed optical fiber displacement monitoring system 600 is designed to monitor and record the internal deformation and crack distribution of the rock sample during loading. The distributed optical fiber displacement monitoring system 600 is composed of OSI-C type ultra-high precision distributed optical fiber sensing equipment.

[0048] For example, in the gas-liquid multiphase seepage physical simulation experimental system of the gas reservoir type gas storage provided in one embodiment, Figure 1 As shown, the distributed optical fiber displacement monitoring system 600 includes a light source 610, a coupler 620, a detector 630 and an optical fiber 640 which are electrically connected, and the optical fiber 640 is buried inside the rock sample.

[0049] Specifically, the distributed optical fiber displacement monitoring system 600 is based on OFDR technology and uses single-mode optical fiber as a sensor. By measuring the changes in the position and intensity of the Rayleigh scattering signal, it can invert the strain distribution at each position of the entire optical fiber. It can achieve a spatial resolution of up to 1mm within a sensing range of 50m, a strain test range of -12000~+12000με, and a strain test accuracy of ±0.1℃ / 1.0με.

[0050] The gas supply and leak alarm system 700 is designed to provide a centralized gas supply point for experimental devices and ensure their safe and reliable operation.

[0051] For example, in the gas-liquid multiphase seepage physical simulation experimental system of the gas reservoir type gas storage provided in one embodiment, Figure 5 As shown, the gas supply and leakage alarm system 700 includes a gas cylinder placement rack 710 for holding gas cylinders, a solenoid valve 720 arranged on the gas cylinder outlet pipeline, a gas monitor 721 connected to the solenoid valve 720 through a line, a temperature / pressure sensor 722, a video monitor 723, a central monitoring server 724, an alarm 725, ventilation equipment 726 and fire extinguishing equipment 727, and an electrostatic protection device 730 is provided in the gas cylinder placement room.

[0052] Specifically, the gas supply and leakage alarm system 700 can centrally place the gas source cylinder 710 to isolate the fire source and physical collision and fall damage, and the electrostatic protection device 730 provides static elimination and protection to prevent static sparks. At the same time, the gas supply and leakage alarm system 700 is equipped with a variety of sensors for abnormal monitoring. When the gas monitor 721 detects that the gas cylinder has a gas leak, the concentration of the gas (especially flammable and explosive gases such as CH4 and H2) exceeds the gas warning value, the temperature / pressure sensor 722 detects that the pressure of the gas cylinder is abnormal, the temperature or pressure of the gas cylinder placement room is abnormal, and the video monitor 723 detects that the gas cylinder placement room is abnormal, the central monitoring server 724 automatically monitors and processes, the alarm 725 alarms, and sends a message to the emergency personnel. According to the dangerous situation, the system controls the solenoid valve 720 to close the gas source channel, actively opens the ventilation equipment 726 ventilation, and the fire extinguishing equipment 727 fire extinguishing function, so as to control the dangerous situation in the first time and ensure the safety of equipment and personnel.

[0053] The gas-liquid multiphase seepage physical simulation experimental system of the gas reservoir type gas storage in the present application is mainly aimed at the physical simulation experimental research on the migration, miscibility, displacement and distribution of multiphase fluids in heterogeneous and non-continuous formations, gas component mixing and leakage problems in the injection and production process of underground gas storage, the dynamic stability and yielding of geological bodies with complex internal structures, the sudden change of seepage characteristics, the deformation, collapse, sand production in the wellbore, fluid crossflow and other safety issues of key nodes of the wellbore such as casing, perforation holes, cement ring, etc. It is helpful to overcome the bottleneck problem of dynamic sealing evaluation of gas reservoir type gas storage under strong injection and production alternating loads, guide the scientific site selection and scheme design of gas storage, and is of great significance to improving the construction and operation level of gas storage in my country and the development of disciplines.

[0054] Although the implementation scheme of the present application has been disclosed as above, it is not limited to the applications listed in the specification and implementation modes, and it can be fully applicable to various fields suitable for the present application. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present application is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A gas-liquid multiphase seepage physical simulation experimental system for gas reservoir type gas storage, characterized in that: include: A rock sample sealing and heating and heat preservation system, comprising a rock sample sealing unit for loading rock samples and a heating and heat preservation unit for heating rock samples; the rock sample sealing unit comprises a main pressure chamber, a rock sample rubber sleeve and a loading plate, a chamber for loading rock samples is provided at the center of the main pressure chamber, and a confining pressure environment is provided for the rock samples; the rock sample rubber sleeve is sleeved on the outside of the rock sample to seal the rock sample; the loading plates are respectively arranged around the rock sample and abut against the rock sample rubber sleeve on the outer wall of the rock sample; The triaxial stress and confining pressure loading system comprises a triaxial stress loading unit for providing triaxial stress for a rock sample and a confining pressure loading unit for providing confining pressure for a rock sample; the triaxial stress loading unit comprises loading cylinders respectively located around the rock sample, a servo loading pump providing a power source for the loading cylinders, a servo oil source providing a pre-pressurization function for axial loading, a servo valve for controlling the hydraulic pressure of the loading cylinders, a reversing valve for controlling the movement direction of the loading cylinder piston, a displacement sensor for controlling the displacement loading of the loading cylinder, and an air compressor for providing low-pressure power for the loading cylinder for resetting the loading cylinder piston, the pressure head of the loading cylinder is respectively in contact with the loading plates around the rock sample; the confining pressure loading unit comprises a high-precision constant speed and constant pressure pump, which is connected to the main pressure chamber through a pipeline to provide a constant pressure in the main pressure chamber and provide confining pressure for the rock sample; The oil, gas and water injection and pore pressure replenishment system is connected to the inlet of the rock sample through a pipeline, and includes a gas phase injection unit and a liquid phase injection unit to perform three-phase injection of oil, gas and water into the rock sample; A gas-liquid-solid three-phase separation and metering system is connected to the rock sample outlet through a pipeline, and includes a back pressure unit, a solid separation and metering unit, and a gas-liquid separation and metering unit; Fiber optic gas sensing monitoring system for detecting and sensing the loss of specified gases; Distributed fiber optic displacement monitoring system, used to monitor and record the internal deformation and crack distribution of rock samples during loading; Gas supply and leakage alarm system is used to provide a safe and reliable centralized gas supply point.

2. According to claim 1, the gas-liquid multiphase seepage physical simulation experimental system of gas reservoir type gas storage is characterized in that: The heating and heat preservation unit comprises: Heating rods are embedded around the main pressure chamber to heat the main pressure chamber and transfer heat to the rock sample; A flexible insulation sleeve is wrapped around the outside of the main pressure chamber to insulate and temperature compensate the main pressure chamber.

3. According to claim 1, the gas-liquid multiphase seepage physical simulation experimental system of gas reservoir type gas storage is characterized in that: The gas phase injection unit is connected to the rock sample through a pipeline, and includes a gas booster pump group connected through the pipeline for providing high-pressure gas at the input end, a high-pressure gas storage container for storing high-pressure gas, an air compressor for providing power to the gas booster pump group, a pneumatic pressure controller for controlling the gas pressure, and a gas flow controller for controlling the gas flow.

4. According to claim 3, the gas-liquid multiphase seepage physical simulation experimental system of gas reservoir type gas storage is characterized in that: The liquid phase injection unit is connected to the rock sample through a pipeline, and comprises a liquid constant flow and pressure pump and a piston container connected through the pipeline. The piston container is used to isolate the working fluid from the injection fluid.

5. According to claim 1, the gas-liquid multiphase seepage physical simulation experimental system of gas reservoir type gas storage is characterized in that: The back-pressure unit includes a back-pressure pump, a back-pressure container and a back-pressure valve connected by pipelines; the solid separation and metering unit is located between the rock sample outlet and the back-pressure valve, and includes a solid collection and metering container for separating solids; the gas-liquid separation and metering unit is connected to the back-pressure valve, and includes a gas-liquid separator for performing gas-liquid separation on the fluid at the rock sample outlet, wherein the separated gas is discharged through the top outlet of the gas-liquid separator and enters a high-speed gas flowmeter or a low-speed gas flowmeter for gas phase flow metering via a drying tank, and the separated liquid is discharged through the bottom outlet of the gas-liquid separator and enters an oil phase metering pump for oil phase flow metering or a water phase metering pump for water phase flow metering via an oil-water separation pipe, and an oil-water interface detector is provided on the oil-water separation pipe.

6. According to claim 1, the gas-liquid multiphase seepage physical simulation experimental system of gas reservoir type gas storage is characterized in that: The optical fiber gas sensing monitoring system comprises a gas probe arranged inside a rock sample and a signal conditioner electrically connected to the gas probe.

7. The gas-liquid multiphase seepage physical simulation experimental system of gas reservoir type gas storage according to claim 1 is characterized in that: The distributed optical fiber displacement monitoring system comprises an electrically connected light source, a coupler, a detector and an optical fiber, and the optical fiber is buried inside a rock sample.

8. The gas-liquid multiphase seepage physical simulation experimental system of gas reservoir type gas storage according to claim 1 is characterized in that: The gas supply and leakage alarm system includes a gas cylinder placement rack for holding gas cylinders, a solenoid valve installed on the gas cylinder outlet pipeline, and a gas monitor connected to the solenoid valve through a line, a temperature and pressure sensor, a video monitor, a central monitoring server, an alarm, ventilation equipment and fire-fighting equipment. An electrostatic protection device is provided in the gas cylinder placement room.

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