CN111706308A - Simulation device and method for monitoring gas-water flow in porous media containing methane hydrate - Google Patents

Abstract

The invention discloses a gas-water flow monitoring simulation device and method in a porous medium containing methane hydrate, comprising a water injection unit, a gas injection unit, a monitoring simulation device, a gas-liquid separation unit and a signal acquisition unit; the detection simulation device is installed in a water bath Inside the incubator; the detection simulation device includes a cylindrical shell, the upper end of the shell is open and is provided with a top cover to seal; a vertical wellbore is set on the central axis of the shell, a square perforation is set on the vertical wellbore, and the outer wall of the wellbore is evenly wrapped for electric heating coils; a plurality of vertical integrated test heads and a plurality of lateral integrated test heads are arranged in the annular space between the casing and the vertical wellbore; the annular space between the casing and the wellbore is filled with porous media. The top cover is provided with a water injection port, and the bottom surface of the shell is provided with an air injection port; the water injection port is connected to the water injection unit, and the air injection port is connected to the air injection unit. The simulation device of the present invention studies the gas-water flow in the production process under the combined action of depressurization and auxiliary heat.

Description

Simulation device and method for monitoring gas-water flow in porous media containing methane hydrate

technical field

The invention relates to the technical field of methane hydrate exploitation, in particular to a gas-water flow monitoring simulation device and an experimental method in a porous medium containing methane hydrate under the combined action of depressurization and auxiliary heat.

Background technique

For hydrate reservoirs, although depressurization mining has been regarded as the most efficient method of production, it faces challenges such as low hydrate recovery rate and long mining time. The combined use of heat shock method, chemical injection method, etc.) has gradually become a trend, and depressurization + auxiliary heat is a typical representative. The auxiliary heat can be electromagnetic heating, resistance heating, hot water injection and steam injection, etc. A method to increase the hydrate recovery rate by the input of external energy. During the production process, with the melting of hydrate, the effective permeability of the reservoir is greatly improved, which makes the methane produced by melting and the flow of water in the reservoir change. The seepage mechanism, well layout parameters, and productivity prediction all have important influences, but the current research in this part is mainly explained from the perspective of numerical simulation, and the actual reservoir cannot meet the ideal conditions used in numerical simulation, so it is necessary to It is corrected from an experimental point of view to improve its prediction accuracy.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a kind of gas-water in porous medium containing methane hydrate in view of the problem that the existing research is mainly explained from the perspective of numerical simulation, but the actual reservoir cannot reach the ideal conditions used in the numerical simulation. The flow monitoring simulation device and the corresponding experimental method are used for the simulation experimental research on the gas-water flow in the production process under the combined action of depressurization and auxiliary heat.

The gas-water flow monitoring simulation device in the porous medium containing methane hydrate provided by the present invention mainly includes a water injection unit, a gas injection unit, a monitoring simulation unit, a gas-liquid separation unit and a signal acquisition unit.

The detection simulation unit is installed in a water bath incubator. The detection and simulation unit includes a cylindrical shell, the upper end of which is open and is provided with a top cover to seal. A sealing ring is arranged between the casing and the top cover and is connected by threads. A vertical wellbore is installed on the central axis of the casing, square perforations at different heights are set on the vertical wellbore, and sand control nets are arranged on the perforations. The outer wall of the diameter wellbore is evenly wrapped with an electric heating coil, and the electric heating coil is connected to the DC power supply outside the casing. Differential pressure test heads are installed at the perforation positions corresponding to different heights in the wellbore. In the annular space between the casing and the wellbore of the vertical well, a plurality of longitudinally integrated test heads and a plurality of laterally integrated test heads are installed on the horizontal plane where the perforations at different heights are located. A plurality of longitudinally integrated test heads are arranged around the wellbore to form a first ring with the wellbore as the center, and the plurality of longitudinally integrated test heads are equally spaced on the first ring. A plurality of laterally integrated test heads are distributed on the outside of the first ring to form a second ring with the wellbore as the center of the circle, and the plurality of laterally integrated test heads are distributed at equal intervals on the second ring. The horizontally integrated test head and the longitudinally integrated test head are both integrated test heads that integrate a resistivity test head, a differential pressure test head and a temperature probe. The annular space between the casing and the vertical wellbore is filled with dry porous media, such as quartz sand.

A pressure gauge is arranged on the top cover, a filter head is arranged in the casing near the pressure gauge, and the filter head is communicated with the pressure gauge through a pressure test pipeline. The top cover is also provided with a water injection port, and the bottom surface of the shell is provided with an air injection port. The water injection port is connected to the water injection unit, and the air injection port is connected to the air injection unit. The top outlet of the vertical well bore is connected to the gas-liquid separation unit, and a back pressure valve is installed on the connecting pipeline between the top outlet of the vertical well bore and the gas-liquid separation unit.

The signal acquisition unit is used for collecting resistivity signal, differential pressure signal, temperature signal, pressure gauge signal and back pressure valve signal in the casing.

The water injection unit includes a deionized water tank and a water injection pump, the inlet of the injection pump is connected to the deionized water tank, and the outlet is connected to the water injection port of the detection simulation unit.

The gas injection unit includes a methane gas cylinder, a gas booster pump, an air compressor, and a gas storage tank. The gas booster pump inlet is connected to the methane gas cylinder, the gas outlet is connected to the gas storage tank, and the gas storage tank is connected to the detection simulation unit. Air injection port. The gas booster pump is connected to the air compressor at the same time.

The gas-liquid separation unit includes a gas-liquid separator, the wellbore outlet of the vertical well is connected to the gas-liquid separator, and a back pressure valve is arranged on the connecting pipeline between the two, and the gas outlet of the gas-liquid separator is connected to a gas flow meter, and the gas-liquid separator is connected to the gas-liquid separator. A weighing balance is set below the liquid separator for weighing the liquid.

Preferably, the top cover is provided with at least two integrated boards, the integrated boards are provided with a plurality of installation openings, each installation opening is installed with a longitudinal outer joint, and the longitudinal outer joint is connected to the longitudinally integrated test head. External joints corresponding to each laterally integrated test head are installed on the outer wall surface of the casing, and each external joint is connected to a laterally integrated test head. All external connectors are connected to the signal acquisition unit.

A method for experimenting with the above-mentioned gas-water flow monitoring simulation device, the steps are as follows:

S1. Fill the dry porous medium in the monitoring simulation unit, compact it, and install the top cover to seal;

S2, put the monitoring simulation unit into the constant temperature water bath, turn it on and adjust it to the temperature required by the experiment and keep it constant;

S3. Inject methane into the monitoring and simulation unit to 20MPa through the gas injection unit, test the tightness of the monitoring and simulation unit to ensure no gas leakage, and continue the experiment;

S4. Inject the water in the deionized water tank into the monitoring simulation unit until the pressure of the pressure gauge reaches the pressure of the actual reservoir;

S5, inject gas into the monitoring and simulation unit through the gas injection unit to the pressure of 25MPa, adjust the temperature of the constant temperature water bath to the actual temperature of the reservoir, and start the synthesis of hydrate;

S6. Open the wellbore outlet of the vertical well, adjust the back pressure valve, release the methane without hydrate in the monitoring simulation unit, and reduce the pressure to the equilibrium pressure corresponding to the water bath temperature;

S7. Turn on the electric heating coil for heating, so that the hydrate begins to decompose during the depressurization process; during this process, the differential pressure, temperature and resistivity signals are monitored and transmitted to the signal acquisition unit;

S8. The gas generated from the wellbore outlet of the vertical well enters the gas-liquid separator, the gas is measured by a gas flow meter and then discharged, and the separated water is weighed by a balance.

Compared with the prior art, the advantages of the present invention are:

(1) In the monitoring simulation device of the present invention, the wellbore perforation position and the differential pressure test point are located at the same position, which is convenient for comparison of test data.

(2) By winding the electric heating coil on the outer wall of the vertical wellbore to realize the combined action of depressurization and auxiliary heat, the simulation experiment was carried out to study the flow of gas and water in the porous medium. It overcomes the defect that the existing numerical simulation method cannot reach the ideal conditions used in numerical simulation in actual reservoirs, and corrects it from the perspective of experiments to improve its prediction accuracy and lay a foundation for improving related research. Furthermore, resistivity, differential pressure, and temperature are used to monitor the flow of gas and water in porous media.

Other advantages, objects, and features of the present invention will appear in part from the description that follows, and in part will be appreciated by those skilled in the art from the study and practice of the invention.

Description of drawings

Fig. 1 is a process flow diagram of the gas-water flow monitoring simulation device in a porous medium containing methane hydrate of the present invention.

Figure 2. The cross-sectional structure diagram of the monitoring simulation unit.

Figure 3 is a schematic diagram of the three-dimensional distribution of the test points of the monitoring simulation unit.

Labels in the figure:

1. Deionized water tank; 2. Inlet gate valve of injection pump; 3. Constant speed and constant pressure pump; 4. Outlet gate valve of injection pump; 5. Gas cylinder; 6. Gas cylinder outlet valve; 7. Inlet gate valve of methane booster pump; 8. Methane booster pump; 9. Methane booster pump outlet gate valve; 10. Air compressor control gate valve; 11. Air compressor; 12. Gas storage tank inlet gate valve; 13. Gas storage tank; 14. Pressure gauge; 15 , outlet gate valve of gas storage tank; 16, control gate valve; 17, installation inlet gate valve; 18, installation water inlet gate valve; 19, constant temperature water bath; 20, monitoring simulation unit; 21, lateral resistivity test point; 22, lateral difference Pressure test point; 23. Transverse temperature test point; 24. Differential pressure monitor; 25. Vertical wellbore; 26. Electric heating coil; 27. Square perforation; 28. Pressure gauge; 29. Outlet valve at the outlet of vertical wellbore; 30 31, DC power supply; 32, back pressure valve inlet control gate valve; 33, back pressure valve; 34, back pressure valve outlet control gate valve; 35, temperature signal acquisition line; 36, resistivity signal acquisition line; 37, differential Pressure signal acquisition line; 38, pressure signal acquisition line; 39, back pressure valve signal acquisition line; 40, gas-liquid separator; 41, gas flow meter; 42, gas outlet; 43, balance; 44, signal acquisition instrument ;45, computer; 46, differential pressure test point in wellbore; 47, longitudinal resistivity test point; 48, longitudinal differential pressure test point; 49, longitudinal temperature test point; 50, shell; 51, top cover; 52, seal Ring; 53, thread; 54, sand control net; 55, upper differential pressure test head; 56, middle layer differential pressure test head; 57, lower differential pressure test head; 58, longitudinally integrated test head; 59, horizontally integrated test head ;60, resistivity test head; 61, differential pressure test head; 62, temperature probe; 63, filter head; 64, test pipeline; 65, water injection port; 66, gas injection port; 67, integrated board; 68, installation port ; 69, the longitudinal outer joint; 70, the lateral outer joint; 71, the outer interface of the electric heating coil; 72, the fastener; 73, the installation site.

Detailed ways

The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, but not to limit the present invention.

As shown in Figures 1-3, the gas-water flow monitoring simulation device in a porous medium containing methane hydrate provided by the present invention mainly includes a water injection unit, a gas injection unit, a monitoring simulation unit 20, a gas-liquid separation unit and a signal acquisition unit.

The water injection unit includes a deionized water tank 1 and an injection pump 3. The inlet of the injection pump 3 is connected to the deionized water tank 1, and the outlet is connected to the detection simulation unit. The inlet gate valve 2 and the outlet gate valve 4 are respectively set on the water injection pipeline near the water inlet and outlet of the water injection pump. After the outlet of the injection pump 3 is connected to the outlet gate valve 4, it is connected to the detection simulation unit 20 via the device inlet gate valve 18, and the detection simulation Unit 20 is injected with deionized water.

The gas injection unit includes a methane gas cylinder 5 , a gas booster pump 8 , an air compressor 11 , and a gas storage tank 13 . The methane gas cylinder is equipped with a cylinder outlet valve 6 . The air inlet of the gas booster pump 8 is connected to the methane cylinder 5 , and the air outlet is connected to the gas storage tank 13 . The gas storage tank 13 is connected to the detection simulation unit 20 to inject methane gas into the detection simulation unit. The gas booster pump 8 is simultaneously connected to the air compressor 11 . The gas booster pump 8 is simultaneously connected to the air compressor 11 . In the specific connection structure, the booster pump inlet gate valve 7 and the booster pump outlet gate valve 9 are respectively installed on the pipeline near the gas booster pump 8 inlet and outlet ends. The gas tank inlet gate valve 12 is installed at the air inlet end of the gas storage tank 13, and the pressure gauge 14, the gas storage tank outlet gate valve 15, the control gate valve 16, and the device inlet gate valve 17 are installed in sequence at the gas outlet end of the gas storage tank 13. The air gate valve 17 is installed near the detection simulation unit 20 . An air compressor control gate valve 10 is installed between the air compressor 11 and the gas booster pump 8 .

The detection simulation unit 20 is installed in the water bath incubator 19 . The detection and simulation unit 20 includes a cylindrical sealed casing, and a vertical well bore 25 is installed on the central axis of the casing. Square perforations 27 at different heights are arranged on the vertical well bore. The outer wall of the diameter wellbore is evenly wound with the electric heating coil 26 , and the electric heating coil is connected to the DC power supply 31 outside the casing through the wire 30 . Differential pressure test points 46 are set in the wellbore corresponding to the perforation positions at different heights. In the annular space between the casing and the vertical well bore 25 , resistivity test points, differential pressure test points, and temperature test points are set at height positions corresponding to the perforations 27 at different height positions. A plurality of longitudinal resistivity test points 47 , a plurality of longitudinal differential pressure test points 48 and a plurality of longitudinal temperature test points 49 are correspondingly installed in the perforations at different heights. Multiple longitudinal resistivity test points at the same height are arranged at equal intervals around the wellbore to form an annular shape. Likewise, multiple longitudinal differential pressure test points at the same height are arranged at equal intervals around the wellbore to form an annular shape. Multiple longitudinal resistivity test points at the same height are arranged at equal intervals around the wellbore to form an annular shape. A plurality of transverse resistivity test points 21 are also arranged on the same horizontal height outside the ring formed by each longitudinal resistivity test point. A plurality of lateral resistivity test points 21 are equally spaced to form another concentric annular ring. A plurality of transverse differential pressure test points 22 are also provided at the same level outside the ring formed by each longitudinal differential pressure test point. A plurality of lateral differential pressure test points 22 are equally spaced to form another concentric annular ring. A plurality of transverse temperature test points 23 are also provided at the same level outside the ring formed by each longitudinal temperature test point. A plurality of transverse temperature test points are equally spaced to form another concentric annular ring. Install the corresponding resistivity test head, differential pressure test head or temperature probe on each test point to test signals such as resistivity, differential pressure and temperature. A differential pressure monitor 24 is also installed at the height positions corresponding to the perforations 27 at different height positions. For differential pressure measurements, two differential pressure test heads are required, one in the resistivity, differential pressure and temperature probes laterally integrated test head and the resistivity, differential pressure and temperature probes longitudinally integrated test head, and the other One is located in a vertical well bore. The annular space between the casing and the vertical wellbore is filled with dry porous media, such as quartz sand.

The top of the cylindrical sealed casing is provided with a pressure gauge 28 for testing its internal pressure. An outlet valve 29 is installed at the top outlet of the vertical well bore, and the outlet valve 29 is connected to the gas-liquid separation unit. The gas-liquid separation unit includes a gas-liquid separator 40 . The outlet valve 29 is connected to the gas-liquid separator 40, and a back pressure valve inlet control gate valve, a back pressure valve 33, and a back pressure valve outlet control gate valve 34 are arranged on the connecting pipeline between the outlet valve 29 and the gas-liquid separator 40. The gas outlet of the gas-liquid separator 40 is connected to a gas flow meter 41 , and the gas passing through the gas flow meter is discharged from the gas outflow 42 . A weighing balance 43 is arranged below the gas-liquid separator for weighing the liquid.

The signal acquisition unit includes a signal acquisition instrument 44 and a computer 45 . The signal acquisition instrument is used to collect and detect the resistivity signal, differential pressure signal, temperature signal, pressure gauge signal and back pressure valve signal in the analog unit, and transmit it to the computer. The resistivity test point passes through the resistivity signal acquisition line 36 , the differential pressure test point passes through the differential pressure signal acquisition line 37 , and the temperature test point passes through the temperature signal acquisition line 35 , and is transmitted to the signal acquisition instrument 44 and displayed on the computer 45 .

As shown in FIGS. 2 and 3 , in a preferred embodiment, the detection and simulation unit 20 includes a cylindrical casing 50 , the upper end of which is open and is provided with a top cover 51 for sealing. A sealing ring 52 is provided between the casing and the top cover and is connected by threads 53 to seal the fluid in the casing. A vertical wellbore 25 is installed on the central axis of the casing, and square perforations 27 at different heights are arranged on the vertical wellbore, for example, three square perforations at different heights shown in FIGS. 2 and 3 . Sand control nets 54 are provided on each square perforation. The outer wall of the diameter wellbore 25 is evenly wound with an electric heating coil 26, and the electric heating coil is connected to the DC power supply 31 outside the casing. Increase the direct current to provide heat to the simulated hydrate reservoir. Differential pressure test heads are installed in the perforation positions corresponding to different height positions in the vertical well bore 25 . For example, the upper-layer differential pressure test head 55 , the middle-layer differential pressure test head 56 , and the lower-layer differential pressure test head 57 in FIG. 2 . In the differential pressure test of each layer, the longitudinal and transverse test heads are located on the same radial direction, so the same pressure test port is used to facilitate the differential pressure comparison in the radial direction. At the same time, in order to ensure the success of the test, the perforation The radial direction is consistent with the position of the test head. In the annular space between the perforation casing and the vertical wellbore, 8 longitudinally integrated test heads 58 and 8 transversely integrated test heads 59 are installed on the horizontal plane where the perforations at three different heights are located. The 8 longitudinally integrated test heads 59 The type test head is arranged around the wellbore to form a first ring with the wellbore as the center; 8 longitudinally integrated test heads are equally spaced on the first ring. Eight laterally integrated test heads are distributed on the outside of the first ring to form a second ring with the wellbore as the center of the circle, and the eight laterally integrated test heads are equally spaced on the second ring. The distribution of mounting sites for all integrated test heads is shown in Figure 3. The installation sites 73 are evenly distributed symmetrically in two directions of the circumference and the radius, and are divided into three layers. The horizontally integrated test head and the longitudinally integrated test head are both integrated test heads that integrate the resistivity test head 60 , the differential pressure test head 61 and the temperature probe 62 . The annular space between the casing and the vertical wellbore is filled with dry porous media, such as quartz sand.

The top cover 51 is provided with a pressure gauge 28 , and a filter head 63 is arranged in the housing near the pressure gauge, and the filter head communicates with the pressure gauge 28 through a pressure test line 64 . A water injection port 65 is also provided on the top cover, and an air injection port 66 is provided on the bottom surface of the casing. The water injection port 65 is connected to the water injection unit, and the air injection port 66 is connected to the air injection unit. Used to supply water and gas to generate hydrate.

The top cover 51 is provided with two circular integrated boards 67, and three evenly spaced mounting ports 68 are provided on the integrated board. Each mounting port is installed with a longitudinal outer joint 69, which is connected to a longitudinally integrated test head. connect. A lateral outer joint 70 corresponding to each laterally integrated test head is installed on the outer wall of the casing, and each laterally integrated test head is connected to each laterally integrated test head. All lateral external connectors and vertical external connectors are connected to the signal acquisition unit. The top cover is also provided with an external interface 71 for the electric heating coil. The center of the top cover is provided with a sealing fastener 72 for installing and fixing the wellbore of the vertical well. In a single section ( FIG. 2 ), six lateral outer joints 70 are equally spaced on the outer wall of the cylindrical shell 3 , and six longitudinal outer joints 69 are mounted on two circular integrated plates 67 located on the top cover 51 superior. Realize flow monitoring of resistivity, differential pressure and temperature changes of hydrate reservoirs under the combined action of depressurization and auxiliary heat.

A method for experimenting with the above-mentioned gas-water flow monitoring simulation device, the steps are as follows:

(1) The monitoring simulation unit 20 is filled with dried quartz sand as a simulated porous medium, compacted, and a top cover is installed to seal.

(2) Put the monitoring simulation unit 20 into the constant temperature water bath box 19, open and adjust the temperature to the constant temperature required by the experiment.

(3) Open the intake gate valve 17 and the control gate valve 16, open the air compressor control gate valve 10 and the methane booster pump 8, pressurize and store the methane in the gas cylinder 5, pass the gas storage tank 13 to the monitoring simulation unit 20, inject methane to 20MPa, test and monitor the airtightness in the simulation unit 20, and continue the experiment until there is no gas leakage.

(4) Open the water inlet gate valve 18, the water injection pump inlet gate valve 2 and the water injection pump outlet gate valve 4, open the water injection pump 3, and inject the water in the deionized water tank 1 into the monitoring simulation unit 20 until the pressure of the pressure gauge 28 reaches the actual reservoir pressure.

(5) Open the inlet gate valve 17, release methane from the gas storage tank 13, continue to increase the pressure of the monitoring simulation unit 20 to 25 MPa, and adjust the temperature of the constant temperature water bath 19 to the actual temperature of the reservoir, and the hydrate begins to synthesize.

(6) Open the wellbore outlet valve 29 of the vertical well, control the gate valve 32 at the inlet of the back pressure valve, adjust the back pressure valve 33 to a certain value, open the outlet control gate valve 34 of the back pressure valve, and release the methane that has not yet generated hydrate in the monitoring simulation unit 20 , down to near the equilibrium pressure corresponding to the temperature of the water bath.

(7) Turn on the DC power supply 31, and supply heat to the heating coil 26 through the heating coil wire 30, so that the hydrate begins to decompose during the depressurization process. In this process, the differential pressure, temperature and resistivity signals of the whole process are monitored, transmitted to the signal acquisition instrument 44, and displayed on the computer 45.

(8) The gas produced by the vertical wellbore enters the gas-liquid separator 40 , the gas is measured by the gas wet flow meter 41 and discharged from the gas outlet 42 , and the separated water is weighed by the balance 43 .

The above are only preferred embodiments of the present invention, and do not limit the present invention in any form. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Technical personnel, within the scope of the technical solution of the present invention, can make some changes or modifications to equivalent embodiments of equivalent changes by using the technical content disclosed above, but any content that does not depart from the technical solution of the present invention, according to the present invention Any simple modifications, equivalent changes and modifications made to the above embodiments still fall within the scope of the technical solutions of the present invention.

Claims (9)

1. A gas-water flow monitoring simulation device in a porous medium containing methane hydrate, characterized in that it comprises a water injection unit, a gas injection unit, a monitoring simulation unit, a gas-liquid separation unit and a signal acquisition unit; The detection and simulation unit is installed in a water-bath incubator; the detection and simulation unit comprises a cylindrical casing, the upper end of which is open and is provided with a top cover to seal; a vertical well shaft is arranged on the central axis of the casing, and square wells with different heights are arranged on the vertical well shaft. Perforation, sand control net is installed on the perforation, the outer wall of the diameter wellbore is evenly wrapped with electric heating coils, and the electric heating coils are connected to the DC power supply outside the casing; the perforation positions corresponding to different heights in the wellbore are installed with differential pressure test In the annular space between the casing and the vertical wellbore, multiple longitudinally integrated test heads and multiple horizontally integrated test heads are installed on the horizontal plane where the perforations at different heights are located; multiple longitudinally integrated test heads surround the The wellbore is arranged to form a first ring with the wellbore as the center, and a plurality of vertical integrated test heads are distributed at equal intervals on the first ring; a second ring at the center of the circle, and a plurality of horizontally integrated test heads are equally spaced on the second ring; the horizontally integrated test heads and the longitudinally integrated test heads are set resistivity test heads, differential pressure test heads and An integrated test head with a temperature probe; the annular space between the casing and the vertical wellbore is filled with porous media; A pressure gauge is arranged on the top cover, a filter head is arranged in the casing near the pressure gauge, and the filter head is communicated with the pressure gauge through a pressure test pipeline; a water injection port is also arranged on the top cover, and an air injection port is arranged on the bottom surface of the casing; the water injection port is connected to the water injection unit , the gas injection port is connected to the gas injection unit; the top outlet of the vertical well bore is connected to the gas-liquid separation unit, and a back pressure valve is provided on the connecting pipeline between the top outlet of the vertical well bore and the gas-liquid separation unit; The signal acquisition unit is used for collecting resistivity signal, differential pressure signal, temperature signal, pressure gauge signal and back pressure valve signal in the casing. 2 . The gas-water flow monitoring simulation device in a porous medium containing methane hydrate according to claim 1 , wherein a sealing ring is provided between the casing and the top cover and is connected by threads. 3 . 3. The gas-water flow monitoring simulation device in a porous medium containing methane hydrate according to claim 2, wherein at least two integrated plates are arranged on the top cover, and a plurality of installation openings are arranged on the integrated plates, A longitudinal outer joint is installed in each installation port, and the longitudinal outer joint is connected to the longitudinal integrated test head. 4. The gas-water flow monitoring simulation device in a porous medium containing methane hydrate as claimed in claim 3, wherein an external joint corresponding to each laterally integrated test head is installed on the outer wall of the casing, All external connectors are connected to the signal acquisition unit. 5. The gas-water flow monitoring simulation device in a porous medium containing methane hydrate according to claim 1, wherein the water injection unit comprises a deionized water tank and an injection pump, and the inlet of the injection pump is connected to the deionized water tank, The outlet is connected to the water injection port of the detection simulation unit. 6 . The gas-water flow monitoring simulation device in porous media containing methane hydrate according to claim 1 , wherein the gas injection unit comprises a methane gas cylinder, a gas booster pump, an air compressor, and a gas storage tank. 7 . , The air inlet of the gas booster pump is connected to the methane cylinder, the gas outlet is connected to the gas storage tank, and the gas storage tank is connected to the gas injection port of the detection simulation unit; the gas booster pump is connected to the air compressor at the same time. 7. The gas-water flow monitoring simulation device in a porous medium containing methane hydrate according to claim 1, wherein the gas-liquid separation unit comprises a gas-liquid separator, and the wellbore outlet of the vertical well is connected to the gas-liquid separator, And a back pressure valve is set on the connecting pipeline between the two, the gas outlet of the gas-liquid separator is connected to a gas flow meter, and a weighing balance is set below the gas-liquid separator for weighing the liquid. 8 . The gas-water flow monitoring simulation device in a porous medium containing methane hydrate according to claim 1 , wherein the porous medium is quartz sand. 9 . 9. a method that adopts the gas-water flow monitoring simulation device described in any one of claims 1-8 to carry out experiment, it is characterized in that, step is as follows: S1. Fill the dry porous medium in the monitoring simulation unit, compact it, and install the top cover to seal; S2, put the monitoring simulation unit into the constant temperature water bath, turn it on and adjust it to the temperature required by the experiment and keep it constant; S3. Inject methane into the monitoring and simulation unit to 20MPa through the gas injection unit, test the tightness of the monitoring and simulation unit to ensure no gas leakage, and continue the experiment; S4. Inject the water in the deionized water tank into the monitoring simulation unit until the pressure of the pressure gauge reaches the pressure of the actual reservoir; S5, inject gas into the monitoring and simulation unit through the gas injection unit to the pressure of 25MPa, adjust the temperature of the constant temperature water bath to the actual temperature of the reservoir, and start the synthesis of hydrate; S6. Open the wellbore outlet of the vertical well, adjust the back pressure valve, release the methane without hydrate in the monitoring simulation unit, and reduce the pressure to the equilibrium pressure corresponding to the water bath temperature; S7. Turn on the electric heating coil for heating, so that the hydrate begins to decompose during the depressurization process; during this process, the differential pressure, temperature and resistivity signals are monitored and transmitted to the signal acquisition unit; S8. The gas generated from the wellbore outlet of the vertical well enters the gas-liquid separator, the gas is measured by a gas flow meter and then discharged, and the separated water is weighed by a balance.

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