Hydrate exploitation flow guarantee simulation experiment device and experiment method

Abstract

The invention belongs to the technical field of natural gas hydrate exploitation experiments, and discloses a hydrate exploitation flow guarantee simulation experiment device and an experiment method. The hydrate exploitation flow guarantee simulation experiment device comprises a horizontal well shaft, a three-phase single-substance input module, a three-phase separation measurement module used for three-phase separation, a hot water injection module used for blocking removal and secondary hydrate generation, a continuous oil pipe working condition simulation module used for driving an inner pipe to move and swing and performing sand washing operation, and a shaft monitoring module. The horizontal well shaft comprises an outer pipe and an inner pipe, and the outer pipe is provided with a three-phase injection port and a three-phase discharge port; the three-phase single-substance input module is used for providing simulation solid, simulation liquid and simulation gas, and the shaft monitoring module is used for collecting simulation experiment parameters and processing simulation experiment data. According to the invention, the simulation experiment can be carried out on the three-phase flow pattern, the sand carrying law, the generation of the secondary hydrate, the blockage removal and the like in the shaft of the horizontal well, and the change law is explored.

Description

Technical Field

[0001] The invention relates to the technical field of natural gas hydrate exploitation experiments, and in particular to a hydrate exploitation flow assurance simulation experimental device and an experimental method. Background Art

[0002] Since my country's natural gas hydrate reservoirs are mainly located in the muddy silt sand reservoirs on the seabed of the South China Sea, this type of reservoir is mainly muddy silt sand, with shallow burial depth, undiagenetic, high mud content, low permeability, low natural production capacity of single wells, easy sand production in the formation, and great difficulty in sand control. In view of the exploitation of muddy silt sand type natural gas hydrates, my country has proposed the sand control concept of "moderate porosity sand, prevention and drainage combined, drainage as the main method" to maintain the stability of the hydrate reservoir and maximize the release of formation production capacity. In the future large-scale commercial exploitation, long-term industrial exploitation will increase the risk of sand production, and the blockage of sand retaining media will inevitably occur. Therefore, the sand retaining particle size is moderately relaxed, only large-size formation sand is blocked, and most of the mud content or small-size formation sand is allowed to enter the wellbore with the fluid and be dredged to the bottom of the well. This can increase the effective working time of the sand retaining medium and is conducive to the effectiveness of subsequent unblocking measures.

[0003] Existing hydrate mining trials and simulation experiments have found that the decomposition process of hydrate mining is accompanied by the phenomenon of secondary hydrate crystallization. This is because hydrates need to absorb a large amount of heat during the decomposition process, which leads to a decrease in the temperature of local areas of the formation. According to the analysis of the Joule-Thomson effect, methane gas and formation water will form hydrate crystals again in the low-temperature and high-pressure area that meets the hydrate phase equilibrium conditions. This phenomenon is the secondary hydrate generation phenomenon. The secondary hydrates will block the circulation pipeline and affect the flow of fluids in the wellbore and the sand carrying effect.

[0004] Therefore, how to transport the mud content or small-particle formation sand brought into the production wellbore during the project to the platform by carrying sand in the wellbore to prevent sand sticking, sand plugging or sand burial in the production wellbore, and not affect the normal production operation of the artificial lift structure; and when secondary hydrate formation is discovered, when there are obstacles in the wellbore or diameter changes in the gas migration channel, the migration morphology and accumulation process of the three phases of gas, liquid and solid, the law of hydrate thermal injection and blockage removal, and other flow safety issues are of vital importance.

[0005] By using the simulation experimental device, the sand carrying law and sand carrying capacity in the horizontal wellbore in the hydrate extraction project can be simulated, which can realize the simulation analysis of the safety guarantee of hydrate flow, and thus provide strong guarantee for the wellbore sand carrying. Summary of the invention

[0006] The purpose of the present invention is to provide a hydrate mining flow assurance simulation experimental device and an experimental method to simulate the flow safety assurance in the hydrate mining project.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] A hydrate mining flow assurance simulation experimental device, comprising:

[0009] A horizontal wellbore, the horizontal wellbore comprising an outer pipe and an inner pipe arranged inside the outer pipe, the horizontal section of the outer pipe being provided with a three-phase injection port, and the vertical section of the outer pipe being provided with a three-phase discharge port;

[0010] A three-phase single-substance input module, which is used to provide simulated solid, simulated liquid and simulated gas and is selectively connected to the first inlet of the gas-liquid-solid mixer, and the outlet of the gas-liquid-solid mixer is connected to the three-phase injection port;

[0011] A three-phase separation measurement module, which is connected to the three-phase discharge port to perform three-phase separation on the three-phase mixture discharged from the horizontal wellbore and is connected to the second inlet of the gas-liquid-solid mixer;

[0012] A hot water injection module, the hot water injection module is connected to the inner tube to provide a constant temperature liquid, the constant temperature liquid is used to remove the blockage of the secondary generated hydrate;

[0013] A coiled tubing working condition simulation module is disposed at the top of the inner tube, and is used to drive the inner tube to move, swing and perform sand flushing operations;

[0014] The wellbore monitoring module is used to collect simulation experiment parameters and process simulation experiment data.

[0015] In some embodiments, the outer tube and the inner tube are both made of visible material, with a maximum pressure resistance of 30 MPa and a temperature tolerance range of -20°C to 40°C.

[0016] In some embodiments, the three-phase injection ports are provided in plurality, and the three-phase injection ports are provided in a plurality of groups along the axis direction of the outer tube, and the three-phase injection ports in each group are spaced apart around the axis of the outer tube.

[0017] In some embodiments, the three-phase single substance input module comprises:

[0018] A sand adding tank, in which the simulated solid is stored, the sand adding tank is connected to a mud pump through a sand outlet pipeline, and the discharge port of the mud pump is connected to the first inlet of the gas-liquid-solid mixer;

[0019] A liquid storage tank, in which the simulated liquid is stored, the liquid storage tank is connected to the mud pump via a liquid outlet pipeline, and the liquid storage tank is connected to the inner tube via a sand flushing pipeline;

[0020] A high-pressure gas cylinder, in which the simulated gas is stored, and the high-pressure gas cylinder is connected to the first inlet through a gas outlet pipeline.

[0021] In some embodiments, the three-phase separation measurement module includes a three-phase separator, a grit tank, a metering liquid tank and a metering gas cylinder. The mixture inlet of the three-phase separator is connected to the three-phase discharge outlet, and the solid phase outlet, liquid phase outlet and gas phase outlet of the three-phase separator are respectively connected to the grit tank, the metering liquid tank and the metering gas cylinder. The metering liquid tank and the metering gas cylinder are connected to the second inlet of the gas-liquid-solid mixer.

[0022] In some embodiments, the hot water injection module comprises:

[0023] A constant temperature liquid tank, in which the constant temperature liquid is stored, the constant temperature liquid tank is connected to the inner tube via a hot water pipe, a heat injection pump is provided on the hot water pipe, and the heat injection pump is used to inject the constant temperature liquid in the constant temperature liquid tank into the inner tube;

[0024] A heating motor is configured to heat and keep the constant temperature liquid in the constant temperature liquid tank.

[0025] In some embodiments, the coiled tubing operating condition simulation module includes:

[0026] A lifting platform, the top end of the inner tube is connected to the lifting platform, and the top end of the inner tube is selectively connected to the liquid storage tank and the constant temperature liquid tank;

[0027] A lifting drive member, wherein the output end of the lifting drive member is connected to the lifting platform to drive the inner tube to move upward and downward;

[0028] A rotating driving member, the rotating driving member is arranged on the lifting platform, and an output end of the rotating driving member is connected to the inner tube to drive the inner tube to swing in the outer tube;

[0029] An electric rotating head is arranged at the end of the inner tube.

[0030] In some embodiments, the wellbore monitoring module includes a data processing terminal and a high-speed camera, a temperature controller, a three-phase flow detector, a temperature and pressure sensor, a gas flow meter, a liquid flow meter and a gravity sensor communicatively connected to the data processing terminal.

[0031] The present invention also provides a hydrate production flow assurance simulation experiment method, using the hydrate production flow assurance simulation experiment device provided by the present invention, the hydrate production flow assurance simulation experiment method comprises a simulation experiment on the sand carrying law of the horizontal wellbore (1), and the specific steps are as follows:

[0032] S1, injecting simulated solid, simulated liquid and simulated gas into the three-phase single-substance input module according to the sand production, sand particle size and gas-liquid ratio during hydrate mining;

[0033] S2, starting the wellbore monitoring module, mixing the simulated solid and the simulated liquid to form a liquid-solid mixture, injecting the liquid-solid mixture and the simulated gas into a gas-liquid-solid mixer to form a gas-liquid-solid mixture, and injecting the gas-liquid-solid mixture into the outer pipe of the horizontal wellbore;

[0034] S3, the gas-liquid-solid mixture is discharged from the three-phase discharge port of the outer tube and enters the single-phase material at the separation place of the three-phase separation measurement module;

[0035] S4, start the coiled tubing working condition simulation module to drive the inner tube of the horizontal wellbore to move and swing, inject the simulated liquid into the inner tube for sand flushing, until no solid phase is discharged from the three-phase discharge port; the wellbore monitoring module collects simulation experiment parameters and processes simulation experiment data.

[0036] In some embodiments, the hydrate production flow assurance simulation experiment method further includes conducting a simulation experiment on the secondary generation of hydrates and sand carrying rules in the horizontal wellbore, and the specific steps are as follows:

[0037] SS1, execute step S1;

[0038] SS2, starting the wellbore monitoring module, controlling the temperature of the outer tube according to the generation degree of the secondary hydrate, injecting the simulated gas and the simulated liquid into the gas-liquid-solid mixer to form a gas-liquid mixture, injecting the gas-liquid mixture into the outer tube and forming the secondary hydrate in the outer tube;

[0039] SS3, execute steps S2-S4;

[0040] SS4, start the hot water injection module, inject the constant temperature liquid into the inner tube, the constant temperature liquid enters the outer tube through the end of the inner tube and passes through the three-phase separation measurement module and the gas-liquid-solid mixer from the three-phase outlet of the outer tube, and then enters the outer tube again to circulate and deblock the secondary generated hydrate; the wellbore monitoring module collects simulation experiment parameters and processes simulation experiment data.

[0041] Beneficial effects of the present invention:

[0042] The hydrate production flow assurance simulation experiment device provided by the present invention is provided with a horizontal wellbore, a three-phase single substance input module, a three-phase separation measurement module, a hot water injection module, a continuous oil pipe working condition simulation module and a wellbore monitoring module. By regulating and combining different module functions, it is possible to carry out simulation experiments on the three-phase flow pattern, sand carrying law, the generation of secondary hydrates and their unblocking in the horizontal wellbore under conditions of different gas-liquid-solid ratios and different flow rates, and can also carry out test data collection and experimental data processing, which is conducive to carrying out simulation experiments on possible situations in the natural gas hydrate production process, exploring their changing laws, and providing technical support for corresponding flow assurance measures. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a structural schematic diagram of a hydrate mining flow assurance simulation experimental device provided in an embodiment of the present invention.

[0044] In the figure:

[0045] 1. Horizontal wellbore; 11. Outer pipe; 111. Three-phase injection port; 112. Three-phase discharge port; 12. Inner pipe; 13. Temperature controller; 14. Three-phase flow detector; 15. High-speed camera;

[0046] 2. Three-phase single-substance input module; 21. Sand adding tank; 211. Sand outlet pipeline; 2111. Third one-way valve; 212. Mud pump; 213. First control valve; 22. Liquid storage tank; 221. Liquid outlet pipeline; 2211. Second one-way valve; 2212. First liquid flow meter; 2213. Second temperature and pressure sensor; 222. Sand flushing pipeline; 2221. Liquid injection pump; 2222. Fourth one-way valve; 2223. Third control valve; 2224. Third liquid flow meter; 23. High-pressure gas cylinder; 231. Gas outlet pipeline; 2311. First one-way valve; 2312. First gas flow meter; 2313. First temperature and pressure sensor;

[0047] 3. Three-phase separation measurement module; 31. Three-phase separator; 311. Fourth temperature and pressure sensor; 32. Sand settling tank; 321. Gravity sensor; 33. Measuring liquid tank; 331. Second liquid flow meter; 332. Sixth temperature and pressure sensor; 333. Sixth control valve; 34. Measuring gas cylinder; 341. Second gas flow meter; 342. Fifth temperature and pressure sensor; 343. Fifth control valve;

[0048] 4. Hot water injection module; 41. Constant temperature liquid tank; 42. Heating motor; 43. Hot water pipe; 44. Heat injection pump; 45. Fourth liquid flow meter; 46. Seventh temperature and pressure sensor; 47. Fifth one-way valve; 48. Fourth control valve;

[0049] 5. Coiled tubing working condition simulation module; 51. Lifting platform; 52. Lifting drive; 53. Electric rotating head;

[0050] 6. Wellbore monitoring module;

[0051] 7. Gas-liquid-solid mixer; 71. Second control valve; 72. Third temperature and pressure sensor. DETAILED DESCRIPTION

[0052] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0053] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0054] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0055] In the description of this embodiment, the terms "upper", "lower", "left", "right" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0056] The embodiment of the present invention provides a hydrate mining flow assurance simulation experimental device, such as Figure 1As shown, it includes a horizontal wellbore 1, a three-phase single substance input module 2, a three-phase separation measurement module 3, a hot water injection module 4, a coiled tubing working condition simulation module 5 and a wellbore monitoring module 6, wherein the horizontal wellbore 1 includes an outer tube 11 and an inner tube 12 arranged in the outer tube 11, the horizontal section of the outer tube 11 is provided with a three-phase injection port 111, and the vertical section of the outer tube 11 is provided with a three-phase discharge port 112; the three-phase single substance input module 2 is used to provide simulated solid, simulated liquid and simulated gas, and is selectively connected to the first inlet of the gas-liquid-solid mixer 7, the outlet of the gas-liquid-solid mixer 7 It is connected to the three-phase injection port 111; the three-phase separation measurement module 3 is connected to the three-phase discharge port 112 to perform three-phase separation on the three-phase mixture discharged from the horizontal wellbore 1 and is connected to the second inlet of the gas-liquid-solid mixer 7; the hot water injection module 4 is connected to the inner tube 12 to provide a constant temperature liquid, and the constant temperature liquid is used to unblock the secondary hydrate; the continuous tubing working condition simulation module 5 is arranged at the top of the inner tube 12, and the continuous tubing working condition simulation module 5 is used to drive the inner tube 12 to move, swing and sand flushing operations; the wellbore monitoring module 6 is used to collect simulation experiment parameters and process simulation experiment data.

[0057] The hydrate production flow assurance simulation experiment device provided by the present invention can conduct simulation experiments on the three-phase flow type, sand carrying law, generation of secondary hydrates and their unblocking in the horizontal wellbore 1 under the conditions of different gas-liquid-solid ratios and different flow rates by regulating and combining different module functions. The specific simulation experiment method is described in detail later, and test data collection and experimental data processing can be performed, which is conducive to conducting simulation experiments on possible situations in the natural gas hydrate production process, exploring its changing law, and providing technical support for corresponding flow assurance measures.

[0058] In some embodiments, both the outer tube 11 and the inner tube 12 are made of visual materials, with a maximum pressure resistance of 30 MPa and a temperature tolerance range of -20°C to 40°C. The visual material can be organic glass or plastic material that meets the pressure and stability requirements, which is conducive to monitoring the flow of the gas-liquid-solid mixture inside the inner tube 12 and the outer tube 11, as well as monitoring the generation and unblocking of secondary hydrates, and obtaining comprehensive simulation experiment parameters.

[0059] In some embodiments, a plurality of three-phase injection ports 111 are provided, and a plurality of groups of the three-phase injection ports 111 are provided along the axis direction of the outer tube 11 , and each group of the three-phase injection ports 111 are spaced apart around the axis of the outer tube 11 .

[0060] Specifically, Figure 1As shown, the three-phase injection port 111 is located at the end of the horizontal end of the outer tube 11, and is evenly distributed axially and circumferentially around the outer tube 11, realizing injection positions in multiple directions, which is used to simulate the three-phase flow and sand carrying process in the outer tube during hydrate production. The three-phase discharge port 112 is located near the top of the vertical section of the outer tube 11, and the three-phase mixture is discharged from the three-phase discharge port 112 with simulated solids under the action of simulated gas and simulated liquid, realizing the simulation of the sand carrying process. It should be noted that the wellbore monitoring module 6 includes a plurality of temperature controllers 13, a plurality of three-phase flow detectors 14 and a plurality of high-speed cameras 15, wherein the plurality of temperature controllers 13 are used to control the temperature of the outer tube 11, and the plurality of temperature controllers 13 are arranged at intervals on the periphery of the outer tube 11 and are evenly distributed, and the temperature change of the temperature controller 13 can be used to stably control the horizontal wellbore 1, which is used to simulate the generation temperature and unblocking temperature of secondary hydrate. A plurality of three-phase flow detectors 14 are fixedly mounted on the inner wall of the outer tube 11 along the axial direction of the outer tube 11, and at least one three-phase flow detector 14 is mounted on each of the upper, middle and lower sections of the outer tube 11. The three-phase flow detector 14 is used to measure in real time the ratio values ​​(such as flow ratio values) of the three phases of gas, liquid and solid flowing through each position of the wellbore. The high-speed camera 15 includes a mobile high-speed camera and three fixed high-speed cameras, wherein the three fixed high-speed cameras on the left are used to aim at a certain position in the outer tube 11 for shooting, and the mobile high-speed camera on the right can move along the axial direction of the outer tube 11 (as shown by the dotted line in the figure) to shoot to obtain simulation experiment parameters.

[0061] In some embodiments, the three-phase single-substance input module 2 includes a sand tank 21, a liquid storage tank 22 and a high-pressure gas cylinder 23. The sand tank 21 stores simulated solids, and the sand tank 21 is connected to the mud pump 212 through a sand outlet pipeline 211, and the discharge port of the mud pump 212 is connected to the first inlet of the gas-liquid-solid mixer 7; the liquid storage tank 22 stores simulated liquids, and the liquid storage tank 22 is connected to the mud pump 212 through a liquid outlet pipeline 221, and the liquid storage tank 22 is connected to the inner tube 12 through a sand flushing pipeline 222; the high-pressure gas cylinder 23 stores simulated gas, and the high-pressure gas cylinder 23 is connected to the first inlet of the gas-liquid-solid mixer 7 through a gas outlet pipeline 231.

[0062] In this embodiment, the three-phase single substance input module 2 can realize the injection of a fixed gas-liquid-solid three-phase ratio into the simulated horizontal wellbore 1 according to the experimental design requirements, and control the injection rate and wellbore pressure as needed. The simulated solid is used to simulate the formation sand entering the production wellbore during the hydrate exploitation process. A third one-way valve 2111 is provided on the sand outlet pipeline 211 to control the flow rate and flow velocity of the simulated solid. The simulated liquid is used to simulate the water generated by the decomposition of hydrates and the liquid substances existing in the formation entering the production wellbore during the hydrate exploitation process. A second one-way valve 2211 is provided on the liquid outlet pipeline 221 to control the flow rate and flow velocity of the simulated liquid. The simulated gas is used to simulate the decomposed gaseous hydrate in the production wellbore during the exploitation process. A first one-way valve 2311 is provided on the gas outlet pipeline 231 to control the flow rate and flow velocity of the high-pressure simulated gas. The mud pump 212 is used to fully mix the simulated solid and simulated liquid (sand and water) provided by the sand adding tank 21 and the liquid storage tank 22; the first control valve 213 is set at the outlet of the mud pump 212, which is used to conduct or cut off the pipeline between the mud pump 212 and the gas-liquid-solid mixer 7. Among them, the sand flushing pipeline 222 is also provided with a liquid injection pump 2221, a third control valve 2223 and a fourth check valve 2222. The liquid injection pump 2221 is used to inject the simulated liquid provided by the liquid storage tank 22 into the inner tube 12 for sand flushing. The third control valve 2223 is used to control the conduction or cutoff of the sand flushing pipeline 222; the fourth check valve 2222 controls the flow rate and flow rate of the simulated liquid used for sand flushing. It should be supplemented that the wellbore monitoring module 6 also includes multiple gas flow meters, multiple liquid flow meters and multiple temperature and pressure sensors, wherein the gas outlet pipeline 231 is provided with a first gas flow meter 2312 and a first temperature and pressure sensor 2313, which are used to detect the flow rate, temperature and pressure of the simulated gas in the gas outlet pipeline 231. The liquid outlet pipeline 221 is provided with a first liquid flow meter 2212 and a second temperature and pressure sensor 2213, which are used to detect the flow rate, temperature and pressure of the simulated liquid in the liquid outlet pipeline 221. The sand flushing pipeline 222 is provided with a third liquid flow meter 2224 for detecting the flow rate of the simulated liquid in the sand flushing pipeline 222. According to the needs of the simulation experiment, the gas-liquid-solid mixer 7 can mix the simulated solid and the simulated liquid to obtain a solid-liquid mixture, or mix the simulated liquid and the simulated gas to obtain a gas-liquid mixture, or mix the solid-liquid mixture with the simulated gas to obtain a gas-liquid-solid three-phase mixture. A second control valve 71 and a third temperature and pressure sensor 72 are provided between the gas-liquid-solid mixer 7 and the three-phase injection port 111 of the outer tube 11 for controlling the start and stop of injection and detecting temperature and pressure.

[0063] In some embodiments, the three-phase separation measurement module 3 includes a three-phase separator 31, a grit tank 32, a metering liquid tank 33 and a metering gas cylinder 34. The mixture inlet of the three-phase separator 31 is connected to the three-phase discharge outlet 112. The solid phase outlet, liquid phase outlet and gas phase outlet of the three-phase separator 31 are respectively connected to the grit tank 32, the metering liquid tank 33 and the metering gas cylinder 34. The metering liquid tank 33 and the metering gas cylinder 34 are connected to the second inlet of the gas-liquid-solid mixer 7.

[0064] The three-phase separation measurement module 3 can be used to separate the three-phase mixture of the horizontal wellbore 1 during the experiment, and accurately measure the three phases of gas, liquid and solid. Among them, the three-phase separator 31 is used to separate the three-phase mixture of gas, liquid and solid output from the outer pipe 11, and separate the gas, liquid and formation sand respectively; the sand settling tank 32 is used to store the separated formation sand, and the formation sand can be measured and extracted externally; the metering gas cylinder 34 is used to store the separated gas, and the gas can be measured and extracted externally; the metering liquid tank 33 is used to store the separated liquid, and the liquid can be measured and extracted externally. Accordingly, in order to collect data for the simulation experiment, the wellbore monitoring module 6 also includes a fourth temperature and pressure sensor 311 (for measuring the temperature and pressure of the discharged three-phase mixture) arranged between the three-phase discharge port 112 and the three-phase separator 31, a second liquid flowmeter 331 and a sixth temperature and pressure sensor 332 (for measuring the flow, pressure and temperature of the separated liquid) arranged between the three-phase separator 31 and the metering liquid tank 33, a second gas flowmeter 341 and a fifth temperature and pressure sensor 342 (for measuring the flow, pressure and temperature of the separated gas) arranged between the three-phase separator 31 and the metering gas cylinder 34, and a gravity sensor 321 arranged at the sand settling tank 32 for measuring the separated formation sand. During the simulation experiment, a sixth control valve 333 is arranged between the metering liquid tank 33 and the gas-liquid-solid mixer 7 for liquid conduction and cutoff control, and a fifth control valve 343 is arranged between the metering gas cylinder 34 and the gas-liquid-solid mixer 7 for gas conduction and cutoff control.

[0065] In some embodiments, the hot water injection module 4 includes a constant temperature liquid tank 41 and a heating motor 42. The constant temperature liquid tank 41 stores constant temperature liquid. The constant temperature liquid tank 41 is connected to the inner tube 12 through a hot water pipe 43. The hot water pipe 43 is provided with a heat injection pump 44. The heat injection pump 44 is used to inject the constant temperature liquid in the constant temperature liquid tank 41 into the inner tube 12; the heating motor 42 is configured to heat and keep the constant temperature liquid in the constant temperature liquid tank 41 warm.

[0066] It can be understood that the temperature controller 13 provided on the outer tube 11 is used to set the outer tube 11 to a constant temperature, and under a certain temperature and pressure, the environment in the wellbore can be made to meet the requirements of the secondary generation of hydrates. The heat injection of the hot water injection module 4 can be used to perform the decomposition function of the secondary generated hydrates, realize the unblocking effect in the wellbore, and can analyze the temperature and pressure conditions of the secondary generation of hydrates, the occurrence state of hydrate crystals and the flow characteristics, and can analyze the gas-liquid-solid three-phase flow pattern and sand carrying law in the wellbore annulus under the state where the flow size is changed due to the secondary generation of hydrates, and the gas-liquid-solid three-phase flow pattern and sand carrying law in the wellbore annulus under the process of heat injection unblocking hydrates. When conducting a simulation experiment, the heating motor 42 first heats the constant temperature liquid tank 41 so that the temperature of the constant temperature liquid meets the experimental requirements, and then injects the constant temperature liquid into the inner tube 12 through the heat injection pump 44, which is used to perform an unblocking experiment on the secondary generated hydrates in the horizontal wellbore 1. In order to obtain the parameters of the unblocking simulation experiment, the wellbore monitoring module 6 includes a fourth liquid flow meter 45 and a seventh temperature and pressure sensor 46 for detecting the flow, temperature and pressure of the constant temperature liquid. Further, the hot water pipe 43 is provided with a fifth check valve 47 and a fourth control valve 48 for controlling the constant temperature liquid in the hot water pipe 43.

[0067] In some embodiments, the continuous oil pipe working condition simulation module 5 includes a lifting platform 51, a lifting drive 52, a rotating drive and an electric rotating head 53. The top end of the inner tube 12 is connected to the lifting platform 51, and the top end of the inner tube 12 is selectively connected to the liquid storage tank 22 and the constant temperature liquid tank 41; the output end of the lifting drive 52 is connected to the lifting platform 51 to drive the inner tube 12 to move up and down; the rotating drive is arranged on the lifting platform 51, and the output end of the rotating drive is connected to the inner tube 12 to drive the inner tube 12 to swing in the outer tube 11; the electric rotating head 53 is arranged at the end of the inner tube 12.

[0068] In this embodiment, the coiled tubing working condition simulation module 5 is used to simulate the actual working conditions such as the lifting and lowering, rotation and sand flushing of the coiled tubing. Under the same conditions, the sand carrying capacity of the wellbore driven by the flow rate alone and the sand carrying capacity of the wellbore assisted by the coiled tubing can be compared and analyzed to obtain a sand carrying law analysis and flow safety guarantee scheme that is more in line with the working conditions of the hydrate test production. Figure 1The lifting platform 51 includes a telescopic rod and a cantilever beam. The telescopic rod can be an electric telescopic rod, or a lifting drive 52 can be used to drive the telescopic rod to move in a vertical direction, thereby driving the inner tube 12 to move up and down within a certain range; the top of the inner tube 12 is rotatably connected to the cantilever beam, and a rotating drive (not shown in the figure) is arranged on the cantilever beam. The output end of the rotating drive is connected to the inner tube 12 to drive the inner tube 12 to rotate back and forth within a certain range. The amplitude of the lifting and lowering movement and the swing of the inner tube 12 are limited by the diameter of the outer tube 11. In order to ensure the sealing of the three-phase mixture in the outer tube 11 during the movement of the inner tube 12, a sealing ring is arranged between the inner tube 12 and the outer tube 11 for sliding sealing. The electric rotating head 53 is arranged at the end of the inner tube 12 and is located in the outer tube 11. After the electric rotating head 53 is started, it can increase the outflow of the liquid in the inner tube 12 and the disturbance of the three-phase mixture in the outer tube 11, thereby improving the sand washing and sand carrying effects.

[0069] In some embodiments, the wellbore monitoring module 6 includes a data processing terminal and a plurality of high-speed cameras 15 (including three fixed high-speed cameras and one mobile high-speed camera) communicatively connected to the data processing terminal, a plurality of temperature controllers 13, a plurality of three-phase flow detectors 14, a plurality of temperature and pressure sensors (including seven from the first temperature and pressure sensor 2313 to the seventh temperature and pressure sensor 46), a gas flow meter (including a first gas flow meter 2312 and a second gas flow meter 341), a liquid flow meter (including four from the first liquid flow meter 2212 to the fourth liquid flow meter 45), and a gravity sensor 321. Figure 1 As shown in the dotted line connected to the wellbore monitoring module 6, the wellbore monitoring module 6 collects simulation experiment parameters and performs data processing, which can obtain the wellbore sand carrying law and the secondary production hydrate generation and unblocking law in the simulation experiment, can monitor the experimental process in real time, analyze the flow pattern changes in the wellbore, the sand migration situation and the secondary hydrate generation position; can conduct gas-liquid-solid three-phase flow patterns and wellbore sand carrying laws of horizontal wellbores 1 of different specifications under different gas-liquid ratios, different flow rates, and different degrees of secondary hydrate generation conditions, to guide practice.

[0070] The present invention also provides a hydrate exploitation flow assurance simulation experiment method, which can simulate the gas-liquid-solid three-phase flow pattern, wellbore sand carrying law and secondary hydrate blockage removal law of horizontal wellbores 1 of different specifications under conditions of different gas-liquid ratios, different flow velocities and different degrees of secondary hydrate generation.

[0071] The hydrate production flow assurance simulation experiment device provided by the present invention is used, and the hydrate production flow assurance simulation experiment method includes conducting a simulation experiment on the sand carrying law of the horizontal wellbore 1, and the specific steps are as follows:

[0072] S1, injecting simulated solid, simulated liquid and simulated gas into the three-phase single substance input module 2 according to the sand production, sand particle size and gas-liquid ratio in the hydrate mining process;

[0073] Specifically, by analyzing the actual sand production of the natural gas hydrate muddy silt sand reservoir during the mining process, the possible gas-liquid ratio range, sand particle size and sand amount of the wellbore are set according to the simulation of the gas and liquid production in the wellbore.

[0074] S2, start the wellbore monitoring module 6, mix the simulated solid and the simulated liquid to form a liquid-solid mixture, inject the liquid-solid mixture and the simulated gas into the gas-liquid-solid mixer 7 to form a gas-liquid-solid mixture, and inject the gas-liquid-solid mixture into the outer pipe 11 of the horizontal wellbore 1;

[0075] Among them, the simulated solid, simulated liquid and simulated gas are all required for the metering, mixing and injection process of a single experiment, and the flow rate and flow velocity are controlled by corresponding control valves or one-way valves.

[0076] S3, the gas-liquid-solid mixture is discharged from the three-phase discharge port 112 of the outer tube 11 and enters the three-phase separation measurement module 3 to separate the single-phase substances; the formation sand enters the sand settling tank 32, the gas enters the metering gas cylinder 34, and the liquid enters the metering liquid tank 33, and the quantity values ​​of the gas, liquid and solid single-phase substances are quantitatively measured respectively, and relevant experimental data are obtained.

[0077] The high-speed camera 15 and the three-phase flow detector 14 can be used to observe the changing law of the gas-liquid-solid three-phase flow pattern in the outer tube 11 and the amount of formation sand carried out of the wellbore during the circulation experiment of the outer tube 11. Furthermore, by setting different parameters such as the diameter of the outer tube 11, the diameter and amount of formation sand, the gas-liquid ratio in the wellbore, and the flow rate in the wellbore, the gas-liquid-solid three-phase flow pattern and the sand carrying law of the wellbore under different gas-liquid ratios, flow rates, sand diameters, and sand amounts of wellbores of different specifications can be simulated.

[0078] S4, start the coiled tubing working condition simulation module 5 to drive the inner tube 12 of the horizontal wellbore 1 to move and swing, and inject simulated liquid into the inner tube 12 for sand flushing until no solid phase is discharged from the three-phase discharge port 112; the wellbore monitoring module 6 collects simulation experiment parameters and processes simulation experiment data.

[0079] This step, with the assistance of the coiled tubing working condition simulation module 5, can obtain the gas-liquid-solid three-phase flow pattern and the sand-carrying law of the wellbore under different gas-liquid ratios and different flow rates of the outer tube 11 and the inner tube 12 of different specifications. During the sand flushing process, it is necessary to pay attention to controlling the lifting and lowering operation frequency, rotation operation frequency or sand flushing operation volume and flow rate of the inner tube 12 set in a single experiment, and repeat step S4 for a period of time until no formation sand is carried out from the three-phase discharge port 112 at the top of the outer tube 11.

[0080] In some embodiments, the hydrate production flow assurance simulation experiment device provided by the present invention is used, and the hydrate production flow assurance simulation experiment method includes conducting a simulation experiment on the secondary generation of hydrates and sand carrying rules of the horizontal wellbore 1, and the specific steps are as follows:

[0081] SS1, execute step S1;

[0082] SS2, start the wellbore monitoring module 6, control the temperature of the outer tube 11 according to the generation degree of the secondary hydrate, inject the simulated gas and the simulated liquid into the gas-liquid-solid mixer 7 to form a gas-liquid mixture, inject the gas-liquid mixture into the outer tube 11 and form the secondary hydrate in the outer tube 11;

[0083] This step requires setting the degree of secondary hydrate generation first, so as to determine the temperature, pressure, gas volume value and liquid volume value in the horizontal wellbore 1. The temperature of the outer tube 11 is controlled by the temperature controller 13. The simulated gas and simulated liquid are controlled by the corresponding one-way valve and control valve to the set gas volume value and set liquid volume value required for a single experiment. After the gas-liquid mixture is injected into the outer tube 11 through the three-phase injection port 111 at multiple points, it is discharged through the three-phase discharge port 112 and circulated through the three-phase separation measurement module 3 and the gas-liquid-solid mixer 7 until secondary hydrate crystals are formed in the outer tube 11. After the secondary hydrate generation of a single experiment is stabilized, the environmental parameters in the wellbore are stabilized by the corresponding control valve, and then a subsequent sand carrying experiment is carried out.

[0084] SS3, execute steps S2-S4; during the experiment, the high-speed camera 15 and the three-phase flow detector 14 of the wellbore monitoring module 6 can observe the changes in the secondary formation and crystallization of hydrates in the outer tube 11 during the circulation experiment of the outer tube 11, the gas-liquid-solid three-phase flow pattern and the change law of the amount of formation sand carried out of the wellbore.

[0085] SS4, start the hot water injection module 4, inject the constant temperature liquid into the inner tube 12, the constant temperature liquid enters the outer tube 11 through the end of the inner tube 12 and passes through the three-phase discharge port 112 of the outer tube 11 in turn through the three-phase separation measurement module 3 and the gas-liquid-solid mixer 7, and then enters the outer tube 11 again to circulate and unblock the secondary generated hydrate; the wellbore monitoring module 6 collects the simulation experiment parameters and processes the simulation experiment data.

[0086] In this step, the gas-liquid-solid mixture carried out of the outer tube 11 enters the three-phase separator 31, and after being separated into single-phase substances, the formation sand enters the sand settling tank 32, the gas enters the metering gas bottle 34, and the liquid enters the metering liquid tank 33, and the quantity values ​​of the gas, liquid, and solid single-phase substances are quantitatively measured respectively, and relevant experimental data are obtained. By setting different wellbore annular pressures, temperature controller 13 temperatures, gas-liquid ratios of secondary hydrate generation, different outer tube 11 diameters, formation sand diameters and sand volumes, gas-liquid ratios in the wellbore, flow rates in the wellbore and other parameter variables, the secondary hydrate generation positions and change laws of wellbores of different specifications under different degrees of secondary hydrate generation, different gas-liquid ratios, flow rates, sand diameters and sand volumes, as well as gas-liquid-solid three-phase flow patterns, wellbore sand carrying laws, and secondary hydrate blockage removal studies can be simulated.

[0087] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. Hydrate mining flow assurance simulation experimental device, characterized in that: include: A horizontal wellbore (1), the horizontal wellbore (1) comprising an outer pipe (11) and an inner pipe (12) arranged inside the outer pipe (11), the horizontal section of the outer pipe (11) being provided with a three-phase injection port (111), and the vertical section of the outer pipe (11) being provided with a three-phase discharge port (112); A three-phase single-substance input module (2), the three-phase single-substance input module (2) is used to provide simulated solid, simulated liquid and simulated gas, and is selectively connected to a first inlet of a gas-liquid-solid mixer (7), and the outlet of the gas-liquid-solid mixer (7) is connected to the three-phase injection port (111); A three-phase separation measurement module (3), the three-phase separation measurement module (3) being connected to the three-phase discharge port (112) to perform three-phase separation on the three-phase mixture discharged from the horizontal wellbore (1) and being connected to the second inlet of the gas-liquid-solid mixer (7); A hot water injection module (4), the hot water injection module (4) being connected to the inner tube (12) to provide a constant temperature liquid, the constant temperature liquid being used to remove the blockage of the secondary generated hydrate; A coiled tubing operating condition simulation module (5) is arranged at the top end of the inner tube (12), and the coiled tubing operating condition simulation module (5) is used to drive the inner tube (12) to move, swing and perform sand washing operations; The wellbore monitoring module (6) is used to collect simulation experiment parameters and process simulation experiment data.

2. The hydrate mining flow assurance simulation experimental device according to claim 1 is characterized in that: The outer tube (11) and the inner tube (12) are both made of visible material, with a maximum pressure resistance of 30 MPa and a temperature tolerance range of -20°C to 40°C.

3. The hydrate mining flow assurance simulation experimental device according to claim 1 is characterized in that: A plurality of three-phase injection ports (111) are provided, and a plurality of groups of the three-phase injection ports (111) are provided along the axis direction of the outer tube (11), and each group of the three-phase injection ports (111) are arranged at intervals around the axis of the outer tube (11).

4. The hydrate mining flow assurance simulation experimental device according to claim 1 is characterized in that: The three-phase single-substance input module (2) comprises: A sand adding tank (21), wherein the simulated solid is stored in the sand adding tank (21), the sand adding tank (21) is connected to a mud pump (212) via a sand outlet pipeline (211), and the discharge port of the mud pump (212) is connected to the first inlet of the gas-liquid-solid mixer (7); A liquid storage tank (22), wherein the simulated liquid is stored in the liquid storage tank (22), the liquid storage tank (22) is connected to the mud pump (212) via a liquid outlet pipeline (221), and the liquid storage tank (22) is connected to the inner tube (12) via a sand flushing pipeline (222); A high-pressure gas cylinder (23), wherein the simulated gas is stored in the high-pressure gas cylinder (23), and the high-pressure gas cylinder (23) is connected to the first inlet via a gas outlet pipeline (231).

5. The hydrate mining flow assurance simulation experimental device according to claim 1 is characterized in that: The three-phase separation measurement module (3) comprises a three-phase separator (31), a grit tank (32), a metering liquid tank (33) and a metering gas cylinder (34); the mixture inlet of the three-phase separator (31) is connected to the three-phase discharge outlet (112); the solid phase outlet, the liquid phase outlet and the gas phase outlet of the three-phase separator (31) are respectively connected to the grit tank (32), the metering liquid tank (33) and the metering gas cylinder (34); the metering liquid tank (33) and the metering gas cylinder (34) are connected to the second inlet of the gas-liquid-solid mixer (7).

6. The hydrate mining flow assurance simulation experimental device according to claim 4 is characterized in that: The hot water injection module (4) comprises: a constant temperature liquid tank (41), wherein the constant temperature liquid is stored in the constant temperature liquid tank (41), the constant temperature liquid tank (41) is connected to the inner tube (12) via a hot water pipe (43), and a heat injection pump (44) is provided on the hot water pipe (43), and the heat injection pump (44) is used to inject the constant temperature liquid in the constant temperature liquid tank (41) into the inner tube (12); A heating motor (42), wherein the heating motor (42) is configured to heat and keep the constant temperature liquid in the constant temperature liquid tank (41).

7. The hydrate mining flow assurance simulation experimental device according to claim 6 is characterized in that: The coiled tubing operating condition simulation module (5) comprises: A lifting platform (51), the top end of the inner tube (12) is connected to the lifting platform (51), and the top end of the inner tube (12) is selectively connected to the liquid storage tank (22) and the constant temperature liquid tank (41); A lifting drive member (52), wherein an output end of the lifting drive member (52) is connected to the lifting platform (51) to drive the inner tube (12) to move upward and downward; A rotating driving member, the rotating driving member being arranged on the lifting platform (51), the output end of the rotating driving member being connected to the inner tube (12) so as to drive the inner tube (12) to swing in the outer tube (11); An electric rotating head (53), wherein the electric rotating head (53) is arranged at the end of the inner tube (12).

8. The hydrate mining flow assurance simulation experimental device according to claim 1 is characterized in that: The wellbore monitoring module (6) comprises a data processing terminal and a high-speed camera (15) communicatively connected to the data processing terminal, a temperature controller (13), a three-phase flow detector (14), a temperature and pressure sensor, a gas flow meter, a liquid flow meter and a gravity sensor (321).

9. A hydrate mining flow assurance simulation experimental method, characterized in that: The hydrate production flow assurance simulation experiment device according to any one of claims 1 to 8 is used, and the hydrate production flow assurance simulation experiment method comprises conducting a simulation experiment on the sand carrying law of the horizontal wellbore (1), and the specific steps are as follows: S1, injecting simulated solid, simulated liquid and simulated gas into the three-phase single substance input module (2) according to the sand production, sand particle size and gas-liquid ratio in the hydrate mining process; S2, starting the wellbore monitoring module (6), mixing the simulated solid and the simulated liquid to form a liquid-solid mixture, injecting the liquid-solid mixture and the simulated gas into a gas-liquid-solid mixer (7) to form a gas-liquid-solid mixture, and injecting the gas-liquid-solid mixture into an outer pipe (11) of the horizontal wellbore (1); S3, the gas-liquid-solid mixture is discharged from the three-phase discharge port (112) of the outer tube (11) and enters the three-phase separation measurement module (3) to separate the single-phase material; S4, starting the continuous oil pipe working condition simulation module (5) to drive the inner tube (12) of the horizontal wellbore (1) to move and swing, injecting the simulated liquid into the inner tube (12) to flush the sand until no solid phase is discharged from the three-phase discharge port (112); the wellbore monitoring module (6) collects simulation experiment parameters and processes simulation experiment data.

10. The hydrate mining flow assurance simulation experimental method according to claim 9, characterized in that: The hydrate production flow assurance simulation experiment method further comprises conducting a simulation experiment on the secondary generation of hydrate and sand carrying law of the horizontal wellbore (1), and the specific steps are as follows: SS1, execute step S1; SS2, starting the wellbore monitoring module (6), controlling the temperature of the outer tube (11) according to the degree of formation of the secondary hydrate, injecting the simulated gas and the simulated liquid into the gas-liquid-solid mixer (7) to form a gas-liquid mixture, injecting the gas-liquid mixture into the outer tube (11) and forming the secondary hydrate in the outer tube (11); SS3, execute steps S2-S4; SS4, start the hot water injection module (4), inject the constant temperature liquid into the inner tube (12), the constant temperature liquid enters the outer tube (11) through the end of the inner tube (12) and passes through the three-phase discharge port (112) of the outer tube (11) and then passes through the three-phase separation measurement module (3) and the gas-liquid-solid mixer (7) in sequence, and then enters the outer tube (11) again to circulate and deblock the secondary generated hydrate; the wellbore monitoring module (6) collects simulation experiment parameters and processes simulation experiment data.

Images