CN210442219U - Sand-containing shale gas gathering and transportation pipeline erosion experiment loop platform - Google Patents

Abstract

The utility model relates to a contain sand shale gas gathering and transportation pipeline erosion experiment loop platform, it mainly comprises nitrogen gas jar, gas flowmeter, manometer, water pitcher, pump, heating furnace, fluidflowmeter, gate valve, manifold, movable feeding device, heat exchanger, erosion chamber, three-phase separator, reducing pipe, elbow, tee bend, reducer. Seven links of air compression, air transmission, sand adding, sand discharging, erosion and measurement are integrated into an integrated process. The radius of the circular path with different pipe diameters at a 90-degree corner is optimized to obtain the radius when the erosion wear is minimum. The erosion cavity is made into a movable type and can be replaced by a reducer pipe, a reducer, a tee joint and elbows at other corners after being disassembled so as to research the erosion influence degree of the collecting and conveying pipeline on each pipe fitting under different operating conditions. The bacterial corrosion condition of the gathering and transportation pipeline is considered to research the synergistic effect of the bacterial corrosion and the erosion on the gathering and transportation pipeline. The utility model discloses convenient to use is swift, labour saving and time saving, and it is simple to dismantle, low in cost.

Description

Sand-containing shale gas gathering and transportation pipeline erosion experiment loop platform

Technical Field

The utility model belongs to the technical field of gas-liquid-solid (gas-water-sand) three-phase erosion experiments, in particular to an erosion experiment loop platform for a sand-containing shale gas gathering and transportation pipeline.

Background

Shale gas wells usually adopt a sand fracturing yield increase mode, sand particles are discharged to the ground along with exhaust gas of a shaft in a blowout test process to erode ground flow equipment and pipes such as a reducer pipe, an elbow, a tee joint, a large head and a small head, the flow rate of the shale gas after passing through a throttling device is greatly increased compared with the flow rate before throttling, and the erosion phenomenon formed on the equipment is serious, such as drill pipe fracture, erosion perforation fracture of a gas conveying pipeline elbow, erosion failure of a reducer section of a sand discharge pipeline and the like caused by a gas drilling shaft sand-carrying airflow erosion drilling tool.

The commonly used desanders are of two types, a double-barrel tubular desander and a cyclone desander. The mesh and the slot of the filter screen of the double-cylinder tubular column type desander are easily blocked in the backflow process of high-viscosity fracturing liquid systems such as glue solution and the like, so that the filter screen is damaged due to overlarge pressure difference. The cyclone desander can only be used for replacing the cyclone pipe after closing the well, and the sealing cover on the cyclone pipe is in flange connection without a manual/pneumatic guide chain, so that the cyclone pipe is inconvenient to replace. Both of the conventional sand removers have respective defects in operational performance, and cannot fully meet the actual requirements of field engineering. Consequently, sand cannot be efficiently drained at the wellhead during the blowout test, and a large amount of sand inevitably exists inside the surface gathering and transportation pipeline.

The theoretical formula for describing the movement and erosion of the solid particles is deduced by the predecessor according to the Euler-Lagrange method, but parameters such as an erosion angle, a contact area, a collision coefficient and the like in the formula cannot be determined. The numerical simulation can calculate the movement speed of the air flow and sand grains, but cannot calculate the erosion rate of the wall surface of the pipeline, and the empirical parameters obtained by experiments need to be substituted into the calculation. And through the experimental method, the area which is easy to generate erosion and abrasion can be identified, so that measures such as thickening the pipe wall or periodic detection can be adopted in time, and the safety of the pipeline system is further ensured. And the erosion of the gas-liquid-solid three-phase flow to the gathering and transportation pipeline is more serious and complex than that of all single-phase flow and two-phase flow. At present, no mature theory is provided for deducing a formula reflecting the gas-liquid-solid three-phase erosion effect. Therefore, the smooth completion of the erosion research requires the design of a set of gas-liquid-solid three-phase erosion experiment loop platform.

The erosion abrasion of the elbow at the 90-degree corner of the ground gathering and transportation pipeline is the most serious, the discrete quantity is intensively distributed from the elbow to the outlet of the straight pipe, and the erosion abrasion rate of the straight pipe section is very small; the maximum erosion wear rate and the average erosion wear rate of the gathering and transportation pipeline are reduced along with the increase of the diameter of the inner wall of the gathering and transportation pipeline, the curvature radius of the elbow and the curvature of the elbow section; the maximum erosive wear rate and the average erosive wear rate of the pipeline increase with the increase of the flow velocity of shale gas in the gathering and transportation pipeline. Under the conditions of the same sand outlet speed and consistent sand carrying amount, the erosion effect of sand grains with different diameters on the gathering and transportation pipeline is increased along with the increase of the diameter of the sand grains; with the same diameter of sand, the erosive effect of the sand on the gathering and transportation pipe increases with increasing velocity.

Therefore, the optimal radius of the 90-degree corner of the circular track with different pipe diameters, namely the radius when the erosion wear is minimum, is optimized, and the smaller the radius is, the more serious the erosion wear is; however, the radius of the 90-degree corner cannot be infinite, otherwise a large circular loop is formed, and the implementation in engineering application cannot be realized. The design of a device for accurately controlling and adjusting the sand content ratio, the control of the grain size of sand and the control of the density of sand are the key points of the research at present and in the future.

Disclosure of Invention

The utility model aims at providing a feasible, technically reliable sand-containing shale gas gathering and transportation pipeline experiment loop platform in economy to prior art's not enough.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

the utility model relates to an experimental loop platform for a sand-containing shale gas gathering and transportation pipeline, which mainly comprises a nitrogen tank (containing an air injection valve), a gas flowmeter (type: vortex flowmeter), a pressure gauge, a water tank (containing an air injection valve), a pump, a heating furnace, a liquid flowmeter (type: mass flowmeter), a gate valve, a gathering pipe, a movable feeding device (containing a solid densimeter and a centrifugal filter), a heat exchanger (containing a thermometer and a temperature control instrument), an erosion cavity (containing a sample and a sample holder), a three-phase separator, a reducer pipe, an elbow, a tee joint, a big end and a small end and the like. The nitrogen tank is a device for providing an air source, and can provide power for the injected gas due to higher pressure in the tank, so that the mechanical energy of the motive power is converted into gas pressure energy. Therefore, the nitrogen tank is also a pressure generating device of the compressed gas. The right end of an air injection valve in the nitrogen tank is connected with a horizontal pipe, and a gate valve, a gas flowmeter and a pressure gauge are arranged in the horizontal pipe. The right end of the water tank air injection valve is connected with a horizontal pipe, and a gate valve, a pump, a heating furnace and a liquid flowmeter are arranged in the horizontal pipe. The gas flowing out of the nitrogen tank and the liquid flowing out of the water tank are mixed with each other in the manifold, the gas-liquid phase flowing out of the manifold is connected with a sand outlet at the bottom of the movable feeding device through a three-way pipe in the middle section of the horizontal pipe, and the horizontal height of the gas injection valve is ensured to be larger than that of the sand outlet, so that sand is prevented from flowing back to the movable material lifting device. The flow of gas entering the gathering and transportation pipeline can be controlled by adjusting the opening of the gas injection valve at the bottom of the nitrogen tank, and a gas flowmeter (vortex flowmeter) is arranged on a horizontal pipe at the outlet of the nitrogen tank to play a role in measuring the gas flow. The nitrogen tank, the vortex flowmeter, the gate valve and the pressure gauge jointly form a gas phase supply unit. Disposed in parallel with the gas phase supply unit is an aqueous phase supply unit. The water phase supply unit consists of a water tank, a pump, a gate valve, a heating furnace, a liquid flowmeter (mass flowmeter) and the like. The heating furnace is used for removing oxygen components in water in the water tank to create an anaerobic environment in which bacteria can survive, so that a certain coupling effect of bacterial corrosion and erosion corrosion in the shale gas gathering and transportation process is considered, and a precondition is provided for researching erosion influence on gathering and transportation pipelines and pipe fittings in the environment in which subsequent bacteria exist. The gas phase and the aqueous phase are collected at a manifold after passing through respective supply units. And the gas-water phases enter the movable feeding device after passing through the manifold, and then are subjected to heat exchange through the heat exchanger to be heated to a preset temperature. The movable feeding device is a closed structure with a cylindrical upper part and a cone lower part, so that bacteria carried in sand can survive, and research conditions are provided for the influence on the gathering and transportation pipeline and the pipe fitting under the coordination of bacterial corrosion and erosion. The top of the movable feeding device is provided with filter screens of different shapes, the filter screens can be taken out and replaced, and the clamp can be fixed after replacement to adapt to the experimental requirements of sand grains of different shapes, so that the influence of the sand grains of different shapes on the erosion strength and the speed can be analyzed, and a spiral stirrer which can stretch into the bottom of the movable lifting device is arranged at the axis of the filter screens. The bottom of the movable feeding device is provided with a hopper which can play a role in screening sand grains with different diameters, so that the influence characteristics of the sand grains with different particle size ranges on the erosion process of the gathering and transportation pipeline can be analyzed, the sand amount can be measured by combining a scale which is tightly attached to the outer wall surface of the device and is marked with volume scales, the sand amount can be used as a basis for accurately controlling the sand content ratio, and the bottom of the movable feeding device is provided with a sand discharge port for emptying the sand grains in the movable feeding device, so that the sand grains can be recycled and periodically used. A solid density meter is additionally arranged in the movable feeding device so as to achieve the aim of controlling the sand density, thereby analyzing the erosion intensity and speed of the collecting and conveying pipeline by different solid densities. The movable feeding device is connected with the erosion cavity through the horizontal pipe, the erosion cavity is a closed combined three-dimensional space, the middle section of the erosion cavity is a cuboid, two hemispheres are arranged at two ends of the erosion cavity, a sample with an adjustable placing inclination angle is mounted in the middle section of the erosion cavity, the sample is made of a rectangular composite material with a certain thickness, the relative position of the sample on the clamp is adjusted through the clamp, the erosion angle can be adjusted, and the influence of the impact angle on the erosion wear performance of the material is examined. The heat exchanger is arranged at the inlet of the erosion cavity, the heating power of the thermocouple connected with the test piece table is controlled through the heat exchanger (a temperature control instrument), and the surface temperature of the test piece is controlled, so that the erosion rate of the material under different temperature conditions is researched. The temperature of the gas-water-sand three-phase flow can be controlled through the heat exchanger, so that the erosion effect of the multiphase flow on the gathering and transportation pipeline and the pipe fitting under different temperature working conditions can be researched. The erosion cavity is designed into a detachable device, and horizontal straight pipes with different pipe diameters and 90-degree corner elbows can be replaced, so that the diameter of the gathering and transportation pipeline at the 90-degree corner is optimized. The erosion cavity can be replaced by pipe fittings such as reducing pipes, reducer heads, tee joints and elbows at corners except 90 degrees after being disassembled so as to research the erosion influence degree of different running conditions of the gathering and transportation pipeline on each pipe fitting. The pipe fitting mainly comprises a reducer with different geometric dimensions, installation positions and structural materials, an elbow, a three-way pipe, a reducer pipe and the like, wherein the elbow, the three-way pipe and the reducer pipe are composed of different pipe diameters, various flow directions and various phases. After passing through devices such as an erosion cavity and the like or pipe fittings, the three phases of gas, water and sand enter a three-phase separator, and the three-phase separation can be realized at the three-phase separator. The gas phase flows out from the top of the three-phase separator and then enters the nitrogen tank for recycling, the water phase flows out from the middle of the three-phase separator and then enters the water tank for recycling, and similarly, the solid phase (sand) flows out from the bottom of the three-phase separator and then can be introduced into the movable feeding device to realize the recycling of sand.

The utility model discloses owing to take above technical scheme, it has following advantage:

1. the utility model integrates the processes of air compression, air delivery, sand adding, sand production, sand discharge, erosion and measurement, realizes the repeated use of sand grains, and the whole pipeline erosion experiment loop platform has small occupied area, is most economical in economy, efficient in environmental protection, feasible in technology, safe and convenient;

2. the utility model can optimize the radius when the erosion wear is minimum by analyzing the radius of the 90-degree corner of the circular path with different pipe diameters, thereby achieving the purpose of economy and energy conservation;

3. the erosion cavity is designed into a detachable device, and horizontal straight pipes with different pipe diameters and 90-degree corner elbows can be replaced, so that the diameter of the gathering and transportation pipeline at the 90-degree corner is optimized;

4. the erosion cavity can be replaced by pipe fittings such as a reducer pipe, a reducer, a tee joint, elbows at corners except 90 degrees and the like after being disassembled so as to research the erosion influence degree of different running conditions of the gathering and transportation pipeline on each pipe fitting;

5. the utility model can control the grain size of the sand through the centrifugal filter and control the density of the sand through the solid densimeter;

6. the utility model can control the sand output by adjusting the opening of the sand outlet valve at the bottom of the movable material lifting device, and the sand output can be accurately measured by the scale which is tightly attached to the outer wall surface of the device and is marked with volume scales;

7. the utility model can timely adjust the erosion angle when the sample section hits sand grains by changing the placing gradient of the sample section;

8. the utility model discloses considered because the sand grain smugglies a large amount of bacteriums secretly and lead to the corruption problem that produces at defeated pipeline of collection to the research is corroded and erodees the influence condition to defeated pipeline of collection and pipe fitting under the synergism at the bacterium.

Drawings

Fig. 1 is the utility model discloses a structural schematic of sand-containing shale gas gathering and transportation pipeline erosion experiment loop platform. The labels in the figure are: 1. a nitrogen tank; 2. a first gate valve; 3. a gas flow meter; 4. a second gate valve; 5. a pressure gauge; 6. a third gate valve; 7. a water tank; 8. a fourth gate valve; 9. a pump; 10. a fifth gate valve; 11. heating furnace; 12. a sixth gate valve; 13. a liquid flow meter; 14. a seventh gate valve; 15. collecting pipes; 16. an eighth gate valve; 17. a movable charging device; 18. a heat exchanger; 19. an erosion chamber; 20. a three-phase separator; 21. a reducer pipe; 22. bending the pipe; 23. a tee joint; 24. a reducer; a ninth gate valve.

Detailed Description

The following describes the embodiments of the present invention with reference to the accompanying drawings.

As shown in fig. 1, the utility model relates to a contain sand shale gas gathering and transportation pipeline erosion experiment loop platform mainly comprises nitrogen gas jar 1, first gate valve 2, gas flowmeter 3, second gate valve 4, manometer 5, third gate valve 6, water pitcher 7, fourth gate valve 8, pump 9, fifth gate valve 10, heating furnace 11, sixth gate valve 12, fluidflowmeter 13, seventh gate valve 14, manifold 15, eighth gate valve 16, movable feeding device 17, heat exchanger 18, erosion chamber 19, three-phase separator 20, reducing pipe 21, elbow 22, tee bend 23, reducer 24, ninth gate valve 25. The nitrogen tank 1 is a device for providing a gas source and is a pressure generating device for compressed gas. The right end of an air injection valve in the nitrogen tank 1 is connected with a horizontal pipe, and a first gate valve 2, a gas flowmeter 3, a second gate valve 4, a pressure gauge 5 and a third gate valve 6 are arranged in the horizontal pipe. The right end of the injection valve in the water tank 7 is connected with a horizontal pipe, and the horizontal pipe is internally provided with a fourth gate valve 8, a pump 9, a fifth gate valve 10, a heating furnace 11, a sixth gate valve 12, a liquid flow meter 13, a seventh gate valve 14 and a ninth gate valve 25. The gas flowing out of the nitrogen tank 1 and the liquid flowing out of the water tank 7 are mixed in the manifold 15, the gas-water phase flowing out of the manifold 15 is connected with a sand outlet at the bottom of the movable feeding device 17 through a three-way pipe at the middle section of the horizontal pipe, and the horizontal height of the gas injection valve is ensured to be larger than that of the sand outlet so as to avoid sand particles from flowing back to the movable feeding device 17. The flow of gas entering a gathering and transportation pipeline (a circulation pipeline) can be controlled by adjusting the opening of the gas injection valve at the bottom of the nitrogen tank 1, and a gas flowmeter (a vortex flowmeter) 3 is arranged on a horizontal pipe at the outlet of the nitrogen tank 1 to play a role in measuring the gas flow. The nitrogen tank 1, the vortex flowmeter 3, the gate valves 2, 4 and 6 and the pressure gauge 5 jointly form a gas phase supply unit. Disposed in parallel with the gas phase supply unit is an aqueous phase supply unit. The water phase supply unit is composed of a water tank 7, a fourth gate valve 8, a pump 9, a fifth gate valve 10, a heating furnace 11, a sixth gate valve 12, a liquid flow meter (mass flow meter) 13, a seventh gate valve 14 and a ninth gate valve 25. The heating furnace 11 is used for removing oxygen components in water in the water tank 7 to create an anaerobic environment in which bacteria can survive, so that a certain coupling effect of bacterial corrosion and erosion of the shale gas gathering and transporting pipeline is considered, and a precondition is provided for researching erosion influence on the gathering and transporting pipeline and pipe fittings in the environment in which subsequent bacteria exist. The gas phase and the aqueous phase are collected at a manifold after passing through respective supply units. The gas-water phases pass through a header 15 and then enter a movable feeding device 17, and then pass through a heat exchanger 18 for heat exchange and temperature rise to a preset temperature. The movable feeding device 17 has to be a closed structure with a cylinder at the upper part and a cone at the lower part to ensure that bacteria carried in sand can survive and provide research conditions for the influence of bacterial corrosion and erosion on gathering and transportation pipelines and pipe fittings. The top of the movable feeding device 17 is provided with filter screens of different shapes, the filter screens can be taken out and replaced, and the filter screens can be fixed through clamps after replacement to adapt to the experimental requirements of sand grains of different shapes, so that the influence of the sand grains of different shapes on the erosion strength and the speed can be analyzed. And a spiral stirrer which can extend into the bottom of the movable feeding device 17 is arranged at the axis of the filter screen, and sand grains in the movable feeding device 17 can be prevented from being solidified through the rotation of the stirring rod. The movable feeding device 17 is provided with a hopper at the bottom, which can play a role in screening sand grains with different diameters, so that the influence characteristics of the sand grains with different particle size ranges on the erosion process of the gathering and transportation pipeline can be analyzed, the sand amount can be measured by combining a scale which is tightly attached to the outer wall surface of the device and is marked with volume scales, the sand amount can be used as a basis for accurately controlling the sand content ratio, and the bottom of the movable feeding device 17 is provided with a sand discharge port for emptying the sand grains in the movable feeding device 17, so that the sand grains can be recycled and periodically used. A solids density meter is added to the mobile feeder 17 to control the sand density so that different solids densities can be analyzed for the magnitude of the erosive strength and rate of the gathering and transportation pipeline. The side of the movable feeding device 17 is provided with a transparent window, and one side of the transparent window is adhered with a staff gauge. The bottom of the cone of the movable feeding device 17 is provided with a sand injection port, the sand injection port is provided with a sand adding valve, and the sand adding amount can be controlled by adjusting the sand adding valve, so that the lifting control of the position of the sand surface in the movable feeding device 17 is within the measurable range of the scale. A sand discharge port is formed beside the sand injection port of the movable feeding device 17, a sand discharge valve is arranged at the sand discharge port, and when the experiment is finished, the sand discharge port can be opened to empty sand in the movable feeding device 17. The movable feeding device 17 is connected with the erosion cavity through a horizontal pipe, the erosion cavity 19 is a closed combined three-dimensional space, the middle section of the erosion cavity is a cylinder, two ends of the erosion cavity are tapered cones, and the cylinder is connected with the cones through threads. The middle section of the erosion cavity 19 is provided with a sample with an adjustable placing inclination angle, the sample is made of a rectangular composite material with a certain thickness, the relative position of the sample on a clamp is adjusted through a clamp holder, the erosion angle can be adjusted, and the influence of the impact angle on the erosion abrasion of the material performance is analyzed. The top end of the erosion cavity 19 is connected with an elbow which extends into the movable feeding device 17 through the elbow and has a downward opening, the outlet of the elbow is higher than the highest sand surface position in the movable feeding device 17, and after sand-carrying airflow is sprayed out from the elbow, gas-solid separation can be realized in the movable feeding device 17. A heat exchanger 18 is arranged at the inlet of the erosion cavity 19, the heating power of a thermocouple connected with a test piece table is controlled through the heat exchanger (temperature control instrument) 18, and the surface temperature of the test piece is controlled, so that the erosion rate of the material under different temperature conditions is researched. The heat exchanger 18 can also control the temperature of the gas-water-sand three-phase flow so as to research the erosion effect of the multiphase flow on the gathering and transportation pipeline and the pipe fitting under different temperature working conditions. The erosion chamber 19 is designed not only as a detachable device but also as a movable erosion experimental device, which can be replaced by horizontal straight pipes of different pipe diameters and elbows 22 at 90-degree corners to optimize the diameter of the gathering and transportation pipeline at the 90-degree corner. The erosion cavity 19 can be replaced by the reducer 21, the elbow 22 at the corner other than 90 degrees, the tee 23, the reducer 24 and other pipe fittings after being disassembled or removed, so as to research the erosion influence degree of the gas-liquid-solid three-phase flow on each pipe fitting under different operating conditions of the collecting and conveying pipeline. The pipe fitting mainly comprises a reducer 21, an elbow 22, a tee 23 and a reducer 24 which are formed by different geometric dimensions, installation positions, structural materials, diameters and flow directions. After passing through the erosion cavity 19 and other devices or pipes, the three phases of gas, water and sand enter the three-phase separator 20, and the three-phase separation can be realized at the three-phase separator 20. Wherein the gas phase flows out from the top of the three-phase separator 20 and then enters the nitrogen tank 1 for recycling, the water phase flows out from the middle of the three-phase separator 20 and then enters the water tank 7 for recycling, and similarly, the solid phase (sand) flows out from the bottom of the three-phase separator 20 and then can be introduced into the movable feeding device 17 to realize the recycling of sand materials. It should be noted that the ninth gate valve 25 can function as a bypass valve, and since the passage is not provided with a heating furnace, oxygen components in the water cannot be removed, so that anaerobic bacteria cannot survive. Therefore, a single erosion and bacterial corrosion-free experimental loop platform is formed.

Claims (5)

1. The utility model provides a contain sand shale gas gathering pipeline erosion experiment loop platform which characterized in that includes following content: the device comprises a nitrogen tank (1), a first gate valve (2), a gas flowmeter (3), a second gate valve (4), a pressure gauge (5), a third gate valve (6), a water tank (7), a fourth gate valve (8), a pump (9), a fifth gate valve (10), a heating furnace (11), a sixth gate valve (12), a liquid flowmeter (13), a seventh gate valve (14), a header pipe (15), an eighth gate valve (16), a movable feeding device (17), a heat exchanger (18), an erosion cavity (19), a three-phase separator (20), a reducer pipe (21), an elbow (22), a tee joint (23), a reducer (24) and a ninth gate valve (25); the nitrogen tank (1) is a device for providing experiment shale gas, an air injection valve is arranged at the bottom of the nitrogen tank, the flow of the gas can be controlled, and the value of the gas can be measured through a gas flowmeter (3); the nitrogen tank (1) has higher internal pressure and can provide power for the flow and erosion of gas phase in the gathering and transportation pipeline; the pressure gauge (5) can visually observe the flowing condition of nitrogen in the horizontal gathering and transportation pipeline in real time, check whether the air flow is stable, and if the air flow is unstable, the air supply amount is controlled by adjusting the opening degree of a valve port through an air injection valve at the bottom of the nitrogen tank (1), so that the effect of stabilizing the air flow is achieved.

2. The sand-containing shale gas gathering and transportation pipeline erosion experiment loop platform of claim 1, wherein: the water tank (7) is a device for providing liquid phase experimental fluid, and the bottom of the water tank (7) is also provided with a water injection valve, so that the discharge amount of a water phase can be controlled, and the water phase can be accurately measured through the liquid flowmeter (13); the first gate valve (2) and the second gate valve (4) are arranged at two ends of the gas flowmeter (3) and serve as functions of cutting off a pipeline when the gas flowmeter (3) breaks down and needs to be maintained; similarly, the second gate valve (4) and the third gate valve (6) are arranged at the two ends of the pressure gauge (5) and also serve as functions of cutting off the pipeline when the pressure gauge (5) breaks down and needs to be maintained; similarly, the fourth gate valve (8) and the fifth gate valve (10) are arranged at two ends of the pump (9) and are used for closing the pipeline when the pump (9) is in failure and needs maintenance; the fifth gate valve (10) and the sixth gate valve (12) are arranged at two ends of the heating furnace (11) and are used for closing pipelines when the heating furnace (11) breaks down and needs maintenance; the sixth gate valve (12) and the seventh gate valve (14) are arranged at two ends of the liquid flowmeter (13) and are used for shutting off the pipeline when the liquid flowmeter (13) breaks down and needs to be maintained; when the ninth gate valve (25) is in normal operation, the fifth gate valve (10) and the sixth gate valve (12) need to be closed, and an erosion pipeline of the gas-water-sand three-phase flow to the gathering and transportation pipeline and the pipe fitting is formed at the moment; and conversely, the ninth gate valve (25) is closed, the fifth gate valve (10) and the sixth gate valve (12) are opened, and a gas-water-sand three-phase flow double coupling pipeline for erosion and bacterial corrosion of the gathering and transportation pipeline and the pipe fitting is formed.

3. The sand-containing shale gas gathering and transportation pipeline erosion experiment loop platform of claim 1, wherein: the gathering pipe (15) is a place where gas-water phases are mixed with each other, and the gas phase has buoyancy lifting effect on the liquid phase, so that the gas phase and the liquid phase flow out of the middle part of the gathering pipe (15) and then enter the movable feeding device (17); the movable feeding device (17) is provided with a filter screen, a stirrer, a solid densimeter, a centrifugal filter, a hopper, a scale and a transparent window; wherein the filter screen can screen sand grains with different shapes; the stirrer can prevent sand grains from forming a consolidation state; the solid densitometer can control the sand density; the centrifugal filter can enable the filtering speed to be faster and more efficient, and is matched with the filter screen to finish the precise filtering of sand grains; the hopper can play a role in screening sand grains with different diameters; the scale can accurately measure the sand yield; the scale is attached in transparent window one side, can observe the sand yield of mark on the scale through transparent window.

4. The sand-containing shale gas gathering and transportation pipeline erosion experiment loop platform of claim 1, wherein: the erosion cavity (19) is a closed combined three-dimensional space, the middle section of the erosion cavity is a cylinder, two ends of the erosion cavity are tapered cones, and the cylinder and the cones are connected through threads; the middle section of the erosion cavity (19) is provided with a sample with an adjustable placing inclination angle, the sample is made of a rectangular composite material with a certain thickness, and the relative position of the sample on the clamp is adjusted through the clamp holder, so that the erosion angle can be adjusted; a heat exchanger (18) is arranged at the inlet of the erosion cavity (19), and the temperature of the surface of the sample can be controlled by controlling the heating power of a thermocouple connected with the test piece table through the heat exchanger (18); the temperature of the gas-water-sand three-phase flow can be controlled through the heat exchanger (18); the erosion cavity (19) can be designed as a movable erosion experiment generating device, and horizontal straight pipes with different pipe diameters and elbows (22) at corners of 90 degrees can replace the erosion cavity; the erosion cavity (19) can be replaced by a reducer (21), an elbow (22), a tee (23) and a reducer (24) after being removed.

5. The sand-containing shale gas gathering and transportation pipeline erosion experiment loop platform of claim 1, wherein: the gas phase flows out from the top of the three-phase separator (20) and then enters the nitrogen tank (1) for recycling, the water phase flows out from the middle of the three-phase separator (20) and then enters the water tank (7) for recycling, and similarly, sand grains can be introduced into the movable feeding device (17) for recycling after flowing out from the bottom of the three-phase separator (20).

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