Hydrate reservoir deformation measuring device and method

Abstract

The invention relates to a hydrate reservoir deformation measuring device and method.The device comprises a hydrate reservoir simulation system which comprises a sand-filled box body, and the sand-filled box body can rotate so that hydrate can be evenly generated in a porous medium to form a hydrate reservoir; a vertical mining shaft is arranged in the sand filling box body, a pressure control structure used for controlling axial pressure and confining pressure of a hydrate reservoir is connected to the vertical mining shaft, and at least one row of foil type strain gauges with temperature sensors are arranged in the sand filling box body; a low temperature control system; a gas-liquid supply system; a produced gas and produced liquid recovery system; a data processing system. According to the invention, the sand filling box body is rotated to ensure that water molecules are uniformly distributed in a porous medium, a gas / water-passing hydrate homogeneous reservoir is generated, multiple parameters such as temperature, pressure and stress can be measured, and the integrity of an experimental result is ensured.

Description

Technical Field

[0001] The present invention relates to the technical fields of hydrate exploitation and carbon dioxide sequestration, and particularly relates to a device and method for measuring the deformation of a hydrate reservoir. Background Art

[0002] Existing research on reservoir deformation during hydrate exploitation and carbon dioxide sequestration is mainly carried out through experiments. Chinese Patent CN104155188B discloses a visualization test device for the mechanical properties of natural gas hydrate sediments. With a low-temperature and high-pressure hydrate triaxial apparatus and an X-ray CT imaging system as the main equipment, by controlling the confining pressure and axial pressure of the simulated reservoir, etc., it is possible to synchronously test the macroscopic and microscopic mechanical properties of natural gas hydrate sediments and obtain mechanical property test data. Chinese Patent CN113958292A discloses a simulation test device for the instability mechanism of combustible ice exploitation strata and its use method. By combining a deep-sea natural gas hydrate exploitation strata instability mechanism simulation test device with a supply part and a discharge part, it effectively simulates the process of deep-sea natural gas hydrate exploitation, and clearly records the process of hydrate reservoir deformation and instability through a data acquisition and processing component.

[0003] Existing experimental devices for studying reservoir deformation during hydrate exploitation and carbon dioxide sequestration have not ensured the uniform distribution state of hydrates in porous media, and there are few measurable parameters, which is not conducive to observing the propagation changes of the hydrate decomposition front during the application of different exploitation methods, significantly limiting the exploration of relevant response characteristics.

[0004] Therefore, based on the experience and practice of being engaged in the relevant industry for many years, the inventor of the present invention proposes a device and method for measuring the deformation of a hydrate reservoir to overcome the defects of the prior art. Summary of the Invention

[0005] The purpose of the present invention is to provide a device and method for measuring the deformation of a hydrate reservoir, which can ensure the uniform distribution of water molecules in porous media by rotating a sand-filled box body, and generate a gas / liquid-permeable homogeneous hydrate reservoir, in which multiple parameters such as temperature, pressure, and stress can be measured, ensuring the integrity of experimental results.

[0006] The purpose of the present invention is achieved as follows. A device for measuring the deformation of a hydrate reservoir includes a hydrate reservoir simulation system, which includes a sand-filled box body that can be closed or opened. The sand-filled box body is filled with porous media, and the sand-filled box body can rotate to uniformly generate hydrates in the porous media to form a hydrate reservoir; a vertical production wellbore and a vertical injection wellbore are arranged in the sand-filled box body. A pressure control structure for controlling the axial pressure and confining pressure of the hydrate reservoir is connected to the vertical production wellbore, and the vertical injection wellbore is used for injecting a thermal stimulation fluid and CO 2 gas; at least one row of foil strain gauges with temperature sensors is arranged in the sand-filled box body.

[0007] A low-temperature control system for controlling the temperature of the sand-filled box body;

[0008] A gas-liquid supply system, communicating with the sand-filled box body, for injecting gas and water into the sand-filled box body;

[0009] A gas and liquid production recovery system, communicating with the top end of the vertical production wellbore, for recovering the produced gas and liquid from the hydrate reservoir;

[0010] A data processing system, electrically connected to the hydrate reservoir simulation system, the low-temperature control system, the gas-liquid supply system, and the gas and liquid production recovery system, for collecting and processing the temperature, pressure, and stress parameters of the processing device.

[0011] In a preferred embodiment of the present invention, a driven rotating shaft and a driving rotating shaft are respectively arranged on the horizontal two sides of the sand-filled box body, and the driven rotating shaft and the driving rotating shaft are hinged on a sand-filled box rotating bracket; the driving rotating shaft is connected to a driving motor.

[0012] In a preferred embodiment of the present invention, an upper end cover is hermetically arranged at the top end of the sand-filled box body, and the upper end cover is connected to the vertical production wellbore and the vertical injection wellbore; the pressure control structure includes a hydraulic cylinder connected to the top end of the upper end cover, and the hydraulic cylinder can abut and push the upper end cover to control the axial pressure and confining pressure of the hydrate reservoir in the sand-filled box body; the sand-filled box body, the upper end cover, the driven rotating shaft, the driving rotating shaft, the driving motor, and the sand-filled box rotating bracket are all within the action range of the low-temperature control system.

[0013] In a preferred embodiment of the present invention, a first injection hole and a second injection hole are arranged at the bottom end of the sand-filled box body, and the gas-liquid supply system communicates with the first injection hole and the second injection hole.

[0014] In a preferred embodiment of the present invention, the low-temperature control system includes a circulation pump, an electric heater, a refrigeration unit, and a low-temperature control module, and the temperature accuracy of the low-temperature control system is ±0.1 °C.

[0015] In a preferred embodiment of the present invention, the gas-liquid supply system includes a gas supply part and a liquid supply part, the gas supply part includes a CO 2 gas cylinder, a CH 4 gas cylinder, a gas booster pump, and a gas storage tank. A CO 2 pressure reducing valve is arranged between the CO 2 gas cylinder and the gas booster pump, and a CH 4 pressure reducing valve is arranged between the CH 4A pressure reducing valve, a first stop valve and a first pressure sensor are arranged between the gas booster pump and the gas storage tank. The output end of the gas storage tank is connected to the sand filling box body through an injection gas pipeline, and a PID stop valve, a second pressure sensor and a second stop valve are arranged on the injection gas pipeline; the liquid supply part includes an injection pump, and the injection pump is connected to the sand filling box body through an injection liquid pipeline, and a third stop valve is arranged on the injection liquid pipeline.

[0016] In a preferred embodiment of the present invention, the gas and liquid production recovery system includes a gas-liquid separation tank and a gas recovery tank. The top end of the vertical production wellbore is communicated with the gas-liquid separation tank through a gas and liquid production pipeline. A third pressure sensor, a fifth stop valve and a back pressure valve are arranged on the gas and liquid production pipeline. The gas and liquid production pipeline is also communicated with a fourth stop valve and a vacuum pump; the output end of the gas-liquid separation tank is connected to a drying tank, and the output end of the drying tank is connected to the gas recovery tank through an adjustable mass flowmeter and an integrator and a laser methane sensor. An electronic balance is arranged at the bottom outlet of the gas-liquid separation tank.

[0017] In a preferred embodiment of the present invention, the data processing system includes a data acquisition card and an acquisition conversion box, a real-time monitoring software and an electronic computer, and a data acquisition line; the input end of the data acquisition card and the acquisition conversion box is electrically connected to the hydrate reservoir simulation system, the gas-liquid supply system and the gas and liquid production recovery system through the data acquisition line, and the output end of the data acquisition card and the acquisition conversion box is electrically connected to the real-time monitoring software and the electronic computer.

[0018] In a preferred embodiment of the present invention, a first row of foil strain gauges with temperature sensors, a second row of foil strain gauges with temperature sensors, and a third row of foil strain gauges with temperature sensors are arranged in the sand filling box body. The first row of foil strain gauges with temperature sensors, the second row of foil strain gauges with temperature sensors, and the third row of foil strain gauges with temperature sensors transmit strain and temperature data to the data acquisition card and the acquisition conversion box and the real-time monitoring software and the electronic computer through the data acquisition line.

[0019] The object of the present invention can also be achieved in this way. A method for measuring the deformation of a hydrate reservoir includes the following steps:

[0020] S1. Assemble and connect the aforementioned hydrate reservoir deformation measuring device, clean the inside of the sand filling box body, and check all pipelines and valves;

[0021] S2. Fill the sand filling box body with a porous medium, measure the porosity of the simulated reservoir, seal the sand filling box body, and the low-temperature control system stabilizes the temperature of the sand filling box body to room temperature;

[0022] S3. The gas-liquid supply system injects water and injects CH 4 gas into the sand filling box body;

[0023] S4. Lower the sand-filled box body to the experimental temperature through the low-temperature control system. Hydrates start to form inside the sand-filled box body. Rotate the sand-filled box body, and record the temperature and pressure data through the foil strain gauges with temperature sensors in each column and the third pressure sensor during the hydrate formation process.

[0024] S5. When the three-phase saturation set value is reached inside the sand-filled box body, stop rotating the sand-filled box body, and start the hydraulic cylinder to apply the set axial pressure and confining pressure to the porous medium containing hydrates.

[0025] S6. Open the gas and liquid production recovery system, and inject the thermal stimulation fluid through the vertical injection wellbore. The hydrates in the reservoir start to decompose, and the produced gas and liquid flow towards the gas and liquid production recovery system; monitor the experimental data in real time.

[0026] S7. Monitor the gas production rate of the reservoir. When the absolute value of the gas production rate is lower than the set threshold, inject CO 2 gas into the vertical injection wellbore. At this time, there are two reactions inside the reservoir: the replacement between CH 4 and CO 2 and the sequestration of CO 2 .

[0027] S8. Continuously monitor the production ratio of CO 2 and CH 4 in the reservoir. When this ratio is higher than the set threshold and the reservoir temperature is stable for a long time, stop injecting carbon dioxide, and the hydrate production experiment ends.

[0028] As described above, the hydrate reservoir deformation measurement device and method of the present invention have the following beneficial effects:

[0029] The present invention ensures the uniform distribution of water molecules in the porous medium by rotating the sand-filled box body, and generates a homogeneous hydrate reservoir with gas / water passing through. The data processing system collects and processes multiple parameters such as the temperature, pressure, and stress of the device, ensuring the integrity of the experimental results; by monitoring the temperature and deformation characteristics of the reservoir around the wellbore during the exploitation of natural gas hydrates and the sequestration of carbon dioxide, it reveals the corresponding relationship between the microscopic distribution pattern of hydrates and the deformation characteristics of the reservoir during the hydrate decomposition process, and clarifies the microscopic deformation mechanism of the reservoir during the hydrate decomposition and carbon dioxide sequestration processes. Description of the Drawings

[0030] The following drawings are only intended to illustrate and explain the present invention, and do not limit the scope of the present invention.

[0031] Among them:

[0032] Figure 1 : is a schematic diagram of the hydrate reservoir deformation measurement device of the present invention.

[0033] Figure 2 : Schematic diagram of the sand-filled box of the present invention.

[0034] In the figure:

[0035] 1. CO 2 gas cylinder; 2. CH 4 gas cylinder; 3. CO 2 pressure reducing valve; 4. CH 4 pressure reducing valve; 5. gas booster pump; 6. first stop valve; 7. first pressure sensor; 8. gas storage tank; 9. PID stop valve; 10. second pressure sensor; 11. second stop valve; 12. liquid injection pump; 13. third stop valve; 14. first injection hole; 15. second injection hole; 16. first row of foil strain gauges with temperature sensors; 17. second row of foil strain gauges with temperature sensors; 18. third row of foil strain gauges with temperature sensors; 19. sand-filled box; 20. upper end cover; 21. driven rotating shaft; 22. driving rotating shaft; 23. driving motor; 24. sand-filled box rotating bracket; 25. hydraulic cylinder; 26. circulation pump; 27. electric heater; 28. refrigeration unit; 29. vertical mining shaft; 30. sealing ring; 31. low temperature control module; 32. third pressure sensor; 33. fourth stop valve; 34. vacuum pump; 35. fifth stop valve; 36. back pressure valve; 37. gas-liquid separation tank; 38. electronic balance; 39. drying tank; 40. sixth stop valve; 41. adjustable mass flowmeter and integrator; 42. laser methane sensor; 43. seventh stop valve; 44. gas recovery tank; 45. data acquisition card and acquisition conversion box; 46. real-time monitoring software and electronic computer; 47. data acquisition line; 48. gas injection pipeline; 49. liquid injection pipeline; 50. gas and liquid production pipeline; 51. vertical injection shaft. Detailed implementation manners

[0036] For a clearer understanding of the technical features, objectives, and effects of the present invention, the specific implementation manners of the present invention will now be described with reference to the accompanying drawings.

[0037] The specific embodiments of the present invention described herein are for the purpose of explaining the present invention only and should not be construed in any way as limiting the present invention. Under the teachings of the present invention, those skilled in the art can conceive of any possible variations based on the present invention, and all of these should be considered as falling within the scope of the present invention. It should be noted that when an element is referred to as being "disposed on" another element, it can be directly on the other element or there can also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "mounted", "connected", and "coupled" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the communication inside two elements. It can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are only for the purpose of illustration and do not represent the only embodiments.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0039] As Figure 1 、 Figure 2 shown, the present invention provides a hydrate reservoir deformation measurement device (an experimental device for measuring the deformation of a reservoir during hydrate production and carbon dioxide sequestration), including,

[0040] A hydrate reservoir simulation system, including a sand-filled box body 19 that can be closed or opened. The sand-filled box body 19 is filled with a porous medium (this porous medium can use quartz sand). The sand-filled box body 19 can rotate to uniformly generate hydrates in the porous medium to form a hydrate reservoir; a vertical production wellbore 29 and a vertical injection wellbore 51 are arranged in the sand-filled box body 19. A pressure control structure for controlling the axial pressure and confining pressure of the hydrate reservoir is connected to the vertical production wellbore 29; the vertical injection wellbore 51 is used for injecting a thermal stimulation fluid and CO 2 gas; at least one row of foil strain gauges with temperature sensors is arranged in the sand-filled box body 19 to monitor the temperature and deformation characteristics of the reservoir around the wellbore;

[0041] A low-temperature control system for controlling the temperature of the sand-filled box body 19;

[0042] A gas-liquid supply system, which is communicated with the sand-filled box body 19 and is used for injecting gas and water into the sand-filled box body;

[0043] A gas and liquid production recovery system, which is connected to the top end of the vertical production wellbore 29 and is used to recover the gas and liquid produced from the hydrate reservoir;

[0044] A data processing system, which is electrically connected to the hydrate reservoir simulation system, the cryogenic control system, the gas-liquid supply system, and the gas and liquid production recovery system, and is used to collect the temperature, pressure, and stress parameters of the processing device.

[0045] In the present invention, by rotating the sand-filled box body, it is ensured that water molecules are evenly distributed in the porous medium, and a homogeneous hydrate reservoir with gas / water passing through is generated. The data processing system collects and processes multiple parameters such as the temperature, pressure, and stress of the device, ensuring the integrity of the experimental results; by monitoring the temperature and deformation characteristics of the reservoir around the wellbore during the exploitation of natural gas hydrates and the sequestration of carbon dioxide, the corresponding relationship between the microscopic distribution pattern of hydrates and the deformation characteristics of the reservoir during the hydrate decomposition process is revealed, and the microscopic deformation mechanism of the reservoir during the hydrate decomposition and carbon dioxide sequestration processes is clarified.

[0046] Furthermore, as Figure 1 shown, a driven rotating shaft 21 and a driving rotating shaft 22 are respectively arranged on the horizontal two sides of the sand-filled box body 19, and the driven rotating shaft 21 and the driving rotating shaft 22 are hinged on the sand-filled box rotating bracket 24; the driving rotating shaft 22 is connected to a driving motor 23, and the driving motor 23 is a stepless speed regulation motor.

[0047] The sand-filled box body 19 is placed on the sand-filled box rotating bracket 24 through the driven rotating shaft 21 and the driving rotating shaft 22, and the sand-filled box body 19 is rotated at a uniform speed by means of the driving motor 23 (stepless speed regulation motor), so as to realize the uniform generation of hydrates in the porous medium.

[0048] Furthermore, as Figure 1 、 Figure 2 shown, an upper end cover 20 is hermetically arranged at the top end of the sand-filled box body 19, and a sealing ring 30 is arranged between the inner wall of the upper end cover 20 and the sand-filled box body 19. The sand-filled box body 19 is mainly sealed by means of the upper end cover 20 and the sealing ring 30 to create a high-pressure gas environment.

[0049] The upper end cover 20 is connected to the vertical production wellbore 29 and the vertical injection wellbore 51; in one embodiment, as Figure 2 shown, there are two vertical wellbores, one is located at the central position of the sand-filled box body 19 as the vertical production wellbore 29, and the other is located on one side of the sand-filled box body 19 as the vertical injection wellbore 51.

[0050] The pressure control structure includes a hydraulic cylinder 25 connected to the top end of the upper end cover. The hydraulic cylinder 25 can abut and push the upper end cover 20 to control the axial pressure and confining pressure of the hydrate reservoir in the sand filling box body. The sand filling box body 19, the upper end cover 20, the driven rotating shaft 21, the driving rotating shaft 22, the driving motor 23, and the sand filling box rotating bracket 24 are all within the scope of the action of the low-temperature control system. The hydraulic oil of the hydraulic cylinder 25 applies a certain pressure to the upper end cover 20 through the piston rod, thereby realizing the control of the axial pressure and confining pressure of the hydrate reservoir in the sand filling box body 19. The maximum axial pressure that can be applied reaches 4 MPa.

[0051] Furthermore, as Figure 1 shown, a first injection hole 14 and a second injection hole 15 are provided at the bottom end of the sand filling box body 19. The gas-liquid supply system is connected to the first injection hole 14 and the second injection hole 15. The first injection hole 14 and the second injection hole 15 are used for injecting gas or liquid into the sand filling box body 19.

[0052] Furthermore, as Figure 1 shown, the low-temperature control system includes a circulation pump 26, an electric heater 27, a refrigeration unit 28, and a low-temperature control module 31. The temperature accuracy of the low-temperature control system is ±0.1 °C. The low-temperature control system stabilizes the temperature of the sand filling box body 19 to the required temperature.

[0053] Furthermore, as Figure 1 shown, the gas-liquid supply system includes a gas supply part and a liquid supply part. The gas supply part includes a CO 2 gas cylinder 1, a CH 4 gas cylinder 2, a gas booster pump 5, and a gas storage tank 8. A CO 2 pressure reducing valve 3 is provided between the CO 2 gas cylinder 1 and the gas booster pump 5. A CH 4 pressure reducing valve 4 is provided between the CH 4 gas cylinder 2 and the gas booster pump 5. A first stop valve 6 and a first pressure sensor 7 are provided between the gas booster pump 5 and the gas storage tank 8. The output end of the gas storage tank 8 is connected to the sand filling box body 19 through an injection gas pipeline 48. A PID stop valve 9, a second pressure sensor 10, and a second stop valve 11 are provided on the injection gas pipeline. The liquid supply part includes an injection liquid pump 12. The injection liquid pump 12 is connected to the sand filling box body 19 through an injection liquid pipeline 49. A third stop valve 13 is provided on the injection liquid pipeline.

[0054] Furthermore, as Figure 1As shown in the figure, the gas and liquid production recovery system includes a gas-liquid separation tank 37 and a gas recovery tank 44. The top of the vertical production wellbore 29 is connected to the gas-liquid separation tank 37 through a gas and liquid production pipeline 50. A third pressure sensor 32, a fifth stop valve 35, and a back pressure valve 36 are provided on the gas and liquid production pipeline 50. The gas and liquid production pipeline 50 is also connected to a fourth stop valve 33 and a vacuum pump 34. The output end of the gas-liquid separation tank 37 is connected to a drying tank 39. The output end of the drying tank 39 is connected to the gas recovery tank 44 through a sixth stop valve 40, an adjustable mass flowmeter and integrator 41, and a laser methane sensor 42 via a seventh stop valve 43. An electronic balance 38 is provided at the bottom outlet of the gas-liquid separation tank 37.

[0055] Further, as Figure 1 shown in the figure, the data processing system includes a data acquisition card and acquisition conversion box 45, a real-time monitoring software and an electronic computer 46, and a data acquisition line 47. The input end of the data acquisition card and acquisition conversion box 45 is electrically connected to the hydrate reservoir simulation system, the gas and liquid supply system, and the gas and liquid production recovery system through the data acquisition line 47. The output end of the data acquisition card and acquisition conversion box 45 is electrically connected to the real-time monitoring software and the electronic computer 46.

[0056] Further, as Figure 1 shown in the figure, a first column of foil strain gauges with temperature sensors 16, a second column of foil strain gauges with temperature sensors 17, and a third column of foil strain gauges with temperature sensors 18 are arranged in the sand-filled box body 19. The first column of foil strain gauges with temperature sensors 16, the second column of foil strain gauges with temperature sensors 17, and the third column of foil strain gauges with temperature sensors 18 transmit strain and temperature data to the data acquisition card and acquisition conversion box 45, the real-time monitoring software, and the electronic computer 46 through the data acquisition line 47.

[0057] The above-mentioned first column of foil strain gauges with temperature sensors 16, the second column of foil strain gauges with temperature sensors 17, and the third column of foil strain gauges with temperature sensors 18 are spaced step by step on both sides of the vertical production wellbore 29, and each contains 6 strain gauge units, for a total of 18 strain gauge units.

[0058] Further, the wiring of the first column of foil strain gauges with temperature sensors 16, the second column of foil strain gauges with temperature sensors 17, and the third column of foil strain gauges with temperature sensors 18 is led out from the central position of the driven rotating shaft 21 to prevent damage to the wiring caused by the rotation of the sand-filled box body 19 during hydrate formation.

[0059] The input end of the data acquisition card and acquisition conversion box 45 is connected to the electronic balance 38, the adjustable mass flowmeter and integrator 41, the laser methane sensor 42, the first pressure sensor 7, the second pressure sensor 10, and the third pressure sensor 32 through the data acquisition line 47.

[0060] The present invention also provides a method for measuring the deformation of a hydrate reservoir (an experimental method that can measure the deformation of the reservoir during the exploitation of hydrates and the sequestration of carbon dioxide), including the following processes:

[0061] S1. Assemble and connect the device for measuring the deformation of the hydrate reservoir, clean the inside of the sand-filled box 19, and check all pipelines and valves;

[0062] S2. Fill the sand-filled box 19 with a porous medium, measure the porosity of the simulated reservoir, seal the sand-filled box 19, and the low-temperature control system stabilizes the temperature of the sand-filled box 19 to room temperature;

[0063] Specifically, turn on the low-temperature control module 31, fill the internal cavity of the sand-filled box 19 with quartz sand, measure the porosity of the simulated reservoir, install the upper end cover 20, seal the hydrate reservoir simulation system, turn on the vacuum pump 34 to evacuate, and turn on the low-temperature control system to stabilize the temperature of the sand-filled box 19 to room temperature;

[0064] S3. The gas-liquid supply system injects water and CH 4 gas into the sand-filled box;

[0065] Specifically, with the aid of the liquid injection pump 12 and the first injection hole 14 and the second injection hole 15, inject a certain amount of deionized water into the inside of the sand-filled box 19; through the PID cut-off valve 9, the first injection hole 14, and the second injection hole 15, inject CH 4 gas from the gas storage tank 8 into the sand-filled box 19, and the simulated reservoir pressure is 10 - 15 MPa;

[0066] S4. Use the low-temperature control system to lower the temperature of the sand-filled box to the experimental temperature, hydrates start to form inside the sand-filled box, rotate the sand-filled box, and record the temperature and pressure data through the foil strain gauges with temperature sensors in each column and the third pressure sensor during the hydrate formation process;

[0067] Specifically, use the low-temperature control system to lower the temperature of the sand-filled box 19 from room temperature to 0 - 10 °C. At this time, hydrates start to form inside the sand-filled box 19, then turn on the drive motor 23 (a stepless speed regulation motor), and rotate the sand-filled box 19 at a lower speed with the aid of the driven rotating shaft 21 and the driving rotating shaft 22. Record the temperature and pressure data through the first column of foil strain gauges 16 with temperature sensors, the second column of foil strain gauges 17 with temperature sensors, the third column of foil strain gauges 18 with temperature sensors, and the third pressure sensor 32 during the hydrate formation process;

[0068] S5. According to the hydrates, water, CH 4Calculate the target pressure of the sand-filled box 19 for the three-phase saturation of the gas. When the three-phase saturation set value is reached in the sand-filled box 19, turn off the drive motor 23 to stop the rotation of the sand-filled box 19, and then start the hydraulic cylinder 25 to apply the set axial pressure and confining pressure to the porous medium containing hydrate;

[0069] S6. Open the gas and liquid production recovery system, inject the thermal stimulation fluid through the vertical injection wellbore. The hydrate in the reservoir starts to decompose, and the produced gas and liquid flow towards the gas and liquid production recovery system; Monitor the experimental data in real time;

[0070] Specifically, open the fifth shut-off valve 35 and the back-pressure valve 36, start to reduce the pressure of the hydrate reservoir (below the hydrate phase equilibrium pressure) / or increase the temperature of the hydrate reservoir (above the hydrate phase equilibrium temperature) through the low-temperature control system / inject the thermal stimulation fluid into the vertical injection wellbore 51. At this time, the hydrate in the reservoir starts to decompose, and the free gas and decomposed gas will be produced through the vertical production wellbore 29 and the gas and liquid production pipeline 50. At the same time, monitor the data of the foil strain gauge with a temperature sensor, the pressure sensor, the back-pressure valve 36, the electronic balance 38, the adjustable mass flowmeter and the integrator 41, and the laser methane sensor 42;

[0071] S7. Monitor the gas production rate of the reservoir. When the absolute value of the gas production rate is lower than the set threshold, inject CO 2 gas into the vertical injection wellbore. At this time, there are CH 4 and CO 2 replacement and CO 2 storage reactions in the reservoir;

[0072] Specifically, monitor the gas production rate of the reservoir at all times through the adjustable mass flowmeter and the integrator 41. When the absolute value of the gas production rate is lower than a certain threshold, inject CO 2 gas into the vertical injection wellbore 51. At this time, there are CH 4 and CO 2 replacement and CO 2 storage reactions in the reservoir;

[0073] S8. Monitor the production ratio of CO 2 and CH 4 in the reservoir at all times through the laser methane sensor 42. When this ratio is higher than the set threshold and the reservoir temperature is stable for a long time, stop injecting carbon dioxide, and the hydrate production experiment ends.

[0074] As described above, the hydrate reservoir deformation measurement device and method of the present invention have the following beneficial effects:

[0075] The present invention ensures the uniform distribution of water molecules in a porous medium by rotating a sand-filled box and generates a homogeneous reservoir of gas / hydrate-water, and a data processing system collects and processes multiple parameters such as the temperature, pressure, and stress of the device, ensuring the integrity of the experimental results; by monitoring the temperature and deformation characteristics of the reservoir around the wellbore during the exploitation of natural gas hydrates and the sequestration of carbon dioxide, the corresponding relationship between the microscopic distribution pattern of hydrates and the deformation characteristics of the reservoir during the decomposition of hydrates is revealed, and the microscopic deformation mechanism of the reservoir during the decomposition of hydrates and the sequestration of carbon dioxide is clarified.

[0076] The above are only illustrative specific embodiments of the present invention and are not intended to limit the scope of the present invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A hydrate reservoir deformation measurement device, characterized in that, Including a hydrate reservoir simulation system, which includes a sand-filled box that can be closed or opened. The sand-filled box is filled with a porous medium, and the sand-filled box can rotate to uniformly generate hydrates in the porous medium to form a hydrate reservoir. A vertical production wellbore and a vertical injection wellbore are arranged in the sand-filled box. A pressure control structure for controlling the axial pressure and confining pressure of the hydrate reservoir is connected to the vertical production wellbore, and the vertical injection wellbore is used to inject a thermal stimulation fluid and CO 2 gas; At least one column of foil strain gauges with temperature sensors is arranged in the sand-filled box; a low-temperature control system for controlling the temperature of the sand-filled box; a gas-liquid supply system communicating with the sand-filled box for injecting gas and water into the sand-filled box; a gas and liquid production recovery system communicating with the top end of the vertical production wellbore for recovering the gas and liquid produced from the hydrate reservoir; a data processing system electrically connected to the hydrate reservoir simulation system, the low-temperature control system, the gas-liquid supply system, and the gas and liquid production recovery system for collecting and processing the temperature, pressure, and stress parameters of the device.

2. The hydrate reservoir deformation measurement device according to claim 1, characterized in that, a driven rotating shaft and a driving rotating shaft are respectively arranged on the horizontal two sides of the sand-filled box, and the driven rotating shaft and the driving rotating shaft are hinged on a sand-filled box rotating bracket; the driving rotating shaft is connected to a driving motor.

3. The hydrate reservoir deformation measurement device according to claim 2, characterized in that, an upper end cover is hermetically arranged at the top end of the sand-filled box, and the upper end cover is connected to the vertical production wellbore and the vertical injection wellbore; the pressure control structure includes a hydraulic cylinder connected to the top end of the upper end cover, and the hydraulic cylinder can push against and advance the upper end cover to control the axial pressure and confining pressure of the hydrate reservoir in the sand-filled box; the sand-filled box, the upper end cover, the driven rotating shaft, the driving rotating shaft, the driving motor, and the sand-filled box rotating bracket are all within the action range of the low-temperature control system.

4. The hydrate reservoir deformation measurement device according to claim 3, characterized in that, a first injection hole and a second injection hole are arranged at the bottom end of the sand-filled box, and the gas-liquid supply system communicates with the first injection hole and the second injection hole.

5. The hydrate reservoir deformation measurement device according to claim 3, characterized in that, the low-temperature control system includes a circulation pump, an electric heater, a refrigeration unit, and a low-temperature control module, and the temperature accuracy of the low-temperature control system is ±0.1°C.

6. The hydrate reservoir deformation measurement device according to claim 1, characterized in that, The gas-liquid supply system includes a gas supply part and a liquid supply part. The gas supply part includes a CO 2 gas cylinder, a CH 4 gas cylinder, a gas booster pump, and a gas storage tank. A CO 2 pressure reducing valve is provided between the CO 2 gas cylinder and the gas booster pump. A CH 4 pressure reducing valve is provided between the CH 4 gas cylinder and the gas booster pump. A first stop valve and a first pressure sensor are arranged between the gas booster pump and the gas storage tank. The output end of the gas storage tank is connected to the sand filling box body through an injection gas pipeline. A PID stop valve, a second pressure sensor, and a second stop valve are arranged on the injection gas pipeline; the liquid supply part includes a liquid injection pump. The liquid injection pump is connected to the sand filling box body through a liquid injection pipeline. A third stop valve is arranged on the liquid injection pipeline.

7. The hydrate reservoir deformation measurement device according to claim 1, characterized in that, the gas and liquid production recovery system includes a gas-liquid separation tank and a gas recovery tank, the top end of the vertical production wellbore is communicated with the gas-liquid separation tank through a gas and liquid production pipeline, a third pressure sensor, a fifth stop valve, and a back pressure valve are arranged on the gas and liquid production pipeline, and the gas and liquid production pipeline is also communicated with a fourth stop valve and a vacuum pump; the output end of the gas-liquid separation tank is connected to a drying tank, the output end of the drying tank is connected to the gas recovery tank through an adjustable mass flowmeter and an integrator, and a laser methane sensor, and an electronic balance is arranged at the bottom outlet of the gas-liquid separation tank.

8. The hydrate reservoir deformation measurement device according to claim 1, characterized in that, The data processing system includes a data acquisition card and an acquisition conversion box, real-time monitoring software, a computer, and a data acquisition line; the input end of the data acquisition card and the acquisition conversion box is electrically connected to the hydrate reservoir simulation system, the gas-liquid supply system, and the gas and liquid production recovery system through the data acquisition line, and the output end of the data acquisition card and the acquisition conversion box is electrically connected to the real-time monitoring software and the computer.

9. The hydrate reservoir deformation measurement device according to claim 8, characterized in that in the sand-filled box body, a first column of foil strain gauges with temperature sensors, a second column of foil strain gauges with temperature sensors, and a third column of foil strain gauges with temperature sensors are arranged. The first column of foil strain gauges with temperature sensors, the second column of foil strain gauges with temperature sensors, and the third column of foil strain gauges with temperature sensors transmit strain and temperature data to the data acquisition card and the acquisition conversion box, and the real-time monitoring software and the computer through the data acquisition line.

10. A method for measuring the deformation of a hydrate reservoir, characterized in that it includes the following steps: S1. Assemble and connect the hydrate reservoir deformation measurement device according to any one of claims 1-9, clean the inside of the sand-filled box body, and check all pipelines and valves; S2. Fill the sand-filled box body with a porous medium, measure the porosity of the simulated reservoir, seal the sand-filled box body, and the low-temperature control system stabilizes the temperature of the sand-filled box body to room temperature; S3. The gas-liquid supply system injects water and CH 4 gas into the sand filling box 4 gas; S4. Lower the temperature of the sand-filled box body to the experimental temperature through the low-temperature control system. Hydrates start to form in the sand-filled box body. Rotate the sand-filled box body. During the hydrate formation process, record the temperature and pressure data through the foil strain gauges with temperature sensors in each column and the third pressure sensor; S5. When the three-phase saturation set value is reached in the sand-filled box body, stop the rotation of the sand-filled box body, and start the hydraulic cylinder to apply a set axial pressure and confining pressure to the porous medium containing hydrates; S6. Open the gas and liquid production recovery system, inject a thermal stimulation fluid through the vertical injection wellbore, the hydrates in the reservoir start to decompose, and the produced gas and liquid flow to the gas and liquid production recovery system; Monitor the experimental data in real time; S7. Monitor the gas production rate of the reservoir. When the absolute value of the gas production rate is lower than the set threshold, inject CO into the vertical injection wellbore. 2 At this time, there are two reactions in the reservoir: the displacement between CH 4 and CO 2 and the storage of CO. 2 ​ S8. Continuously monitor the production ratio of CO 2 and CH 4 in the reservoir. When this ratio is higher than the set threshold and the reservoir temperature remains stable for a long time, stop injecting carbon dioxide and end the hydrate production experiment.

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