阅读说明：本技术 一种煤粉堵塞煤层气水平井筒的模拟试验台和试验方法 (Simulation test bed and test method for coal-bed gas horizontal shaft blocked by pulverized coal ) 是由 黄启铭 程卫民 王刚 孙路路 刘义鑫 于 2020-04-27 设计创作，主要内容包括：本发明公开了一种煤粉堵塞煤层气水平井筒的模拟试验台和试验方法,涉及煤层气开采技术领域,试验台包括模拟煤层气开采时的水平段井筒的模拟水平井筒、混匀煤浆与甲烷的储液箱,模拟水平井筒的左端与出液管相连接,右端与进液管的一端相连接,进液管的另一端与储液箱的出液口相连接,储液箱的进液口通过高压管线与注气泵的出气口相连接。本发明的有益效果是,基于现场观测的井底压力、温度数据,可以真实反映井筒堵塞的实际特征,并可以直观地观测模拟水平井筒内的煤粉运移和堵塞特征,分析煤粉堵塞水平井筒的发生条件。(The invention discloses a simulation test bed and a test method for coal powder blocking a coal bed gas horizontal shaft, and relates to the technical field of coal bed gas exploitation. The method has the advantages that the actual characteristics of shaft blockage can be truly reflected based on the bottom hole pressure and temperature data observed on site, the coal powder migration and blockage characteristics in the simulated horizontal shaft can be intuitively observed, and the occurrence conditions of the coal powder blockage in the horizontal shaft can be analyzed.)

1. The utility model provides a simulation test platform of buggy jam coal bed gas horizontal shaft, its characterized in that, the liquid reserve tank of simulation horizontal shaft, mixing coal slurry and methane of horizontal section pit shaft when the coal bed gas exploitation, the left end of simulation horizontal shaft is connected with the drain pipe, and the right-hand member is connected with the one end of feed liquor pipe, and the other end of feed liquor pipe is connected with the liquid outlet of liquid reserve tank, and the inlet of liquid reserve tank is connected with the gas outlet of gas injection pump through high-pressure pipeline, and the air inlet of gas injection pump links to each other with the methane gas cylinder.

2. The simulation test bed for coal dust blockage of the coal bed gas horizontal shaft according to claim 1, wherein a charging hole for filling coal dust and water into the liquid storage tank is formed in the top of the liquid storage tank, and a top cover for sealing is further arranged at the charging hole; the liquid storage tank is internally provided with a temperature control device for adjusting the temperature of the fluid in the tank, a stirrer for stirring the fluid in the tank and a temperature sensor for monitoring the temperature of the fluid in the tank; the top of the liquid storage tank is provided with a pressure gauge for displaying the pressure in the liquid storage tank.

3. The simulation test bed for the coal-bed gas horizontal shaft blocked by the pulverized coal as claimed in claim 1, wherein a plurality of high-speed cameras are arranged right below the simulation horizontal shaft, and the high-speed cameras are transversely arranged along the simulation horizontal shaft and used for observing the flowing form of fluid in the simulation horizontal shaft; the simulated horizontal shaft is designed to be a cylindrical structure and is made of high-strength transparent toughened glass materials.

4. The simulation test bed for coal dust blocking of the coal bed gas horizontal shaft according to claim 2, wherein a flow meter, an electrically-controlled liquid outlet pressure stabilizing valve and a liquid outlet pressure sensor are arranged on the liquid outlet pipe; the liquid inlet pipe is provided with a liquid inlet pressure sensor and an electric control liquid inlet pressure stabilizing valve.

5. The simulation test bed for coal dust blocking of the coal bed methane horizontal shaft according to claim 4, wherein automatic control of the electric control liquid outlet pressure stabilizing valve, the electric control liquid inlet pressure stabilizing valve, the temperature control device, the stirrer and the gas injection pump is realized through a computer, monitoring data transmitted by a flowmeter, a liquid outlet pressure sensor, a temperature sensor and a liquid inlet pressure sensor are received, and a high-speed camera transmits the real-time monitored mixed flow form in the simulated horizontal shaft to the computer.

6. A simulation test method for coal dust blocking of a coal bed gas horizontal shaft is adopted by the simulation test bed according to any one of claims 1 to 5, and is characterized by comprising the following steps:

(1) monitoring the pressure and temperature of the well bottom;

(2) drawing a parameter change curve and programming a control program;

(3) building a simulation test bed;

(4) simulating the process of coal-bed gas horizontal shaft blockage by coal powder.

7. The method for simulating the coal-bed gas horizontal shaft blocked by the pulverized coal as claimed in claim 6, wherein in the step (1), the coal-bed gas shaft is firstly arranged, before hydraulic fracturing, the temperature and pressure sensor is sent to the bottom of the well along the vertical shaft section of the shaft through a cable, and when the hydraulic fracturing of the coal bed is carried out, the temperature and pressure sensor is started to monitor the pressure and temperature parameters of the horizontal section of the bottom of the well, and data are transmitted to a data acquisition instrument on the ground through the cable.

8. The method for simulating the coal-bed gas horizontal shaft blocked by the pulverized coal as claimed in claim 6, wherein in the step (2), the temperature and pressure data monitored by the data acquisition instrument are introduced into a computer, the monitoring data from the beginning of the fracturing fluid flowback are selected, origin software is used for carrying out data fitting, curves of the temperature and the bottom hole pressure along with the time change are obtained by drawing, and the curves of the temperature and the bottom hole pressure along with the time change are programmed into a servo control program by adopting a computer programming method.

9. The method for simulating the coal-bed gas horizontal shaft blockage by the coal powder as claimed in claim 6, wherein the step (4) specifically comprises the following steps:

(1) adding coal powder and water into a liquid storage tank through a feeding port according to a certain mass ratio, screwing a top cover at the feeding port to keep the liquid storage tank in a closed state, starting an air injection pump to inject methane gas into the liquid storage tank until the pressure in the tank reaches 6-8MPa, starting a stirrer to continuously stir, and uniformly mixing coal slurry and methane;

(2) the temperature sensor transmits the real-time monitored temperature data of the fluid in the liquid storage tank to the computer, and the temperature of the fluid in the liquid storage tank is regulated by controlling the temperature control device through the computer according to the temperature change setting in the programmed servo control program, so that the fluid changes along with time according to the bottom temperature monitoring data;

(3) the liquid inlet pressure sensor transmits and feeds back pressure monitoring data inside the liquid inlet pipe to the computer, the electronic control liquid inlet pressure stabilizing valve is controlled by the computer to slowly adjust, the liquid inlet pressure is controlled, and the fluid pressure inside the liquid inlet pipe is kept at the pressure level of the coal reservoir;

(4) the liquid outlet pressure sensor transmits and feeds back pressure monitoring data inside the liquid outlet pipe to the computer, the electronic control liquid outlet pressure stabilizing valve is controlled by the computer to slowly adjust to realize the control of liquid outlet pressure, the liquid outlet pressure is set according to the bottom hole pressure change in a servo program, the opening of the electronic control liquid outlet pressure stabilizing valve is controlled by the computer to adjust the pressure inside the liquid outlet pipe, and the liquid outlet pipe is changed along with time according to the bottom hole pressure monitoring data;

(5) the flow meter monitors the liquid outlet amount at the liquid outlet pipe in real time and transmits monitoring data to the computer, and the high-speed camera monitors the mixed flow form of methane bubbles and coal slurry in the simulated horizontal shaft in real time and transmits video data to the computer.

Technical Field

The invention relates to the technical field of coal bed gas exploitation, in particular to a simulation test bed and a test method for coal powder blocking a coal bed gas horizontal shaft.

Background

Currently, the production of coal bed gas usually adopts a ground well extraction mode, and the coal bed gas is desorbed and diffused by vertically arranging a shaft into a coal bed on the ground under the action of reservoir pressure, and finally, seepage is collected into the shaft. The design method for horizontal well exploitation enables the coal bed gas well to have a larger contact area with a coal bed, and the single well yield of the coal bed gas is obviously improved.

Coal reservoirs are low-permeability reservoirs, the natural seepage capability of internal gas is poor, and a hydraulic fracturing mode is usually needed for increasing the yield. After the well bore is arranged and hydraulic fracturing is carried out, the drainage and production stage of the coal bed gas is formally entered. It is worth noting that coal seams have low elastic modulus and fragile characteristics, coal reservoirs contain a large amount of coal powder inside, and meanwhile, coal seams are usually water-rich reservoirs. Therefore, in the stage of fracturing fluid flowback and drainage, the coal powder and water are easily mixed together to form viscous coal slurry and enter the shaft under the driving of reservoir pressure, the shaft is often blocked to cause yield reduction, and the action mechanism of the coal powder blocking the shaft of the coal bed gas is more complex under the mixing action of the coal bed gas (the main component is methane) contained in the coal bed.

For a long time, the research on coal dust blockage of the shaft usually adopts field yield analysis speculation, or theoretical analysis and numerical simulation methods, and develops shaft blockage removal technology on the basis of the field yield analysis speculation, or the theoretical analysis and the numerical simulation methods. However, the plugging characteristics of the shaft cannot be visually observed, so that the shaft blocked by the coal powder cannot be further studied, and the development of the plugging removal technology of the coal bed methane shaft is limited to a certain extent.

Based on the method, the invention is dedicated to research and development of a simulation test method for coal powder to block the horizontal shaft of the coal bed gas, solves the problem of limitation of the existing test method, and provides a scientific and effective research means for the action mechanism of the coal powder to block the horizontal shaft section in the drainage and production process.

Disclosure of Invention

In order to solve the technical problem that shaft blockage cannot be observed visually, the invention discloses a simulation test bed and a test method for coal dust blocked coal bed methane horizontal shaft, and provides a scientific and effective research means for the action mechanism of coal dust blocked horizontal shaft section in the drainage and production process.

In order to achieve the purpose, the invention adopts the following technical scheme:

the utility model provides a simulation test platform of buggy jam coal bed gas horizontal shaft, the liquid reserve tank of simulation horizontal shaft, mixing coal slurry and methane of horizontal section pit shaft when the coal bed gas exploitation of simulation, the left end of simulation horizontal shaft is connected with the drain pipe, and the right-hand member is connected with the one end of feed liquor pipe, and the other end of feed liquor pipe is connected with the liquid outlet of liquid reserve tank, and the inlet of liquid reserve tank is connected with the gas outlet of gas injection pump through high-pressure pipeline, and the air inlet of gas injection pump links to each other with the methane gas bottle.

As a further optimization of the invention, the top of the liquid storage tank is provided with a charging hole for filling coal powder and water into the liquid storage tank, and the charging hole is also provided with a top cover for sealing; the liquid storage tank is internally provided with a temperature control device for adjusting the temperature of the fluid in the tank, a stirrer for stirring the fluid in the tank and a temperature sensor for monitoring the temperature of the fluid in the tank; the top of the liquid storage tank is provided with a pressure gauge for displaying the pressure in the liquid storage tank.

As a further preferable mode of the present invention, a plurality of high-speed cameras are disposed right below the simulated horizontal wellbore, and the high-speed cameras are transversely disposed along the simulated horizontal wellbore and used for observing the flow pattern of the fluid in the simulated horizontal wellbore; the simulated horizontal shaft is designed to be a cylindrical structure and is made of high-strength transparent toughened glass materials.

As a further optimization of the invention, a flow meter, an electric control liquid outlet pressure stabilizing valve and a liquid outlet pressure sensor are arranged on the liquid outlet pipe; and a liquid inlet pressure sensor and an electric control liquid inlet pressure stabilizing valve are arranged on the liquid inlet pipe.

As a further optimization of the invention, the automatic control of the electric control liquid outlet pressure stabilizing valve, the electric control liquid inlet pressure stabilizing valve, the temperature control device, the stirrer and the gas injection pump is realized through the computer, the monitoring data transmitted by the flowmeter, the liquid outlet pressure sensor, the temperature sensor and the liquid inlet pressure sensor is received, and the high-speed camera transmits the real-time monitored mixed flow form in the simulated horizontal shaft to the computer.

The invention also aims to disclose a simulation test method for coal-bed gas horizontal shaft blockage by coal powder, which adopts the simulation test bed and comprises the following steps:

(1) monitoring the pressure and temperature of the well bottom;

(2) drawing a parameter change curve and programming a control program;

(3) building a simulation test bed;

(4) simulating the process of coal-bed gas horizontal shaft blockage by coal powder.

As a further preferable mode of the invention, in the step (1), a coal bed gas shaft is firstly arranged, before hydraulic fracturing is performed, the temperature and pressure sensor is sent to the bottom of the well along the vertical shaft section of the shaft through a cable, when hydraulic fracturing of the coal bed is performed, the temperature and pressure sensor is started to monitor pressure and temperature parameters of the horizontal section of the bottom of the well, and data are transmitted to a data acquisition instrument on the ground through the cable.

As a further preferable mode of the present invention, in the step (2), the temperature and pressure data monitored by the data acquisition instrument are introduced into a computer, the monitoring data from the beginning of the fracturing fluid flowback is selected, origin software is used for performing data fitting, a curve of the temperature and the bottom hole pressure along with the time change is obtained by drawing, and the curve of the temperature and the bottom hole pressure along with the time change is programmed into a servo control program by using a computer programming method.

As a further preferable aspect of the present invention, the step (4) specifically includes:

(1) adding coal powder and water into a liquid storage tank through a feeding port according to a certain mass ratio, screwing a top cover at the feeding port to keep the liquid storage tank in a closed state, starting an air injection pump to inject methane gas into the liquid storage tank until the pressure in the tank reaches 6-8MPa, starting a stirrer to continuously stir, and uniformly mixing coal slurry and methane;

(2) the temperature sensor transmits the real-time monitored temperature data of the fluid in the liquid storage tank to the computer, and the temperature of the fluid in the liquid storage tank is regulated by controlling the temperature control device through the computer according to the temperature change setting in the programmed servo control program, so that the fluid changes along with time according to the bottom temperature monitoring data;

(3) the liquid inlet pressure sensor transmits and feeds back pressure monitoring data inside the liquid inlet pipe to the computer, the electronic control liquid inlet pressure stabilizing valve is controlled by the computer to slowly adjust, the liquid inlet pressure is controlled, and the fluid pressure inside the liquid inlet pipe is kept at the pressure level of the coal reservoir;

(4) the liquid outlet pressure sensor transmits and feeds back pressure monitoring data inside the liquid outlet pipe to the computer, the electronic control liquid outlet pressure stabilizing valve is controlled by the computer to slowly adjust to realize the control of liquid outlet pressure, the liquid outlet pressure is set according to the bottom hole pressure change in a servo program, the opening of the electronic control liquid outlet pressure stabilizing valve is controlled by the computer to adjust the pressure inside the liquid outlet pipe, and the liquid outlet pipe is changed along with time according to the bottom hole pressure monitoring data;

(5) the flow meter monitors the liquid outlet amount at the liquid outlet pipe in real time and transmits monitoring data to the computer, and the high-speed camera monitors the mixed flow form of methane bubbles and coal slurry in the simulated horizontal shaft in real time and transmits video data to the computer.

The method has the advantages that based on the bottom hole pressure and temperature data monitored in the coal bed gas exploitation site, a servo control program is compiled according to the data change characteristics, a physical simulation test bed is built for simulation test of coal powder blockage of the shaft, and the blockage process of the shaft under the three-phase mixing action of the coal powder, formation water and methane gas in the coal bed can be effectively simulated.

The invention provides a feasible laboratory research means, can truly reflect the actual characteristics of shaft blockage based on the bottom hole pressure and temperature data observed on site, can intuitively observe and simulate the coal powder migration and blockage characteristics in the horizontal shaft, and analyzes the occurrence conditions of the horizontal shaft blocked by the coal powder. The method provided by the invention is used for carrying out physical simulation test, and can provide scientific theoretical basis for researching the coal bed gas shaft anti-blocking technology.

Drawings

FIG. 1 is a schematic structural view of example 1 of the present invention;

fig. 2 is a schematic view of the installation of a temperature and pressure sensor in embodiment 2 of the present invention;

description of reference numerals:

1. a cable; 2. a temperature and pressure sensor; 3. a wellbore; 4. a data acquisition instrument; 5. a liquid outlet pipe; 6. a flow meter; 7. an electric control liquid outlet pressure stabilizing valve; 8. a liquid outlet pressure sensor; 9. simulating a horizontal wellbore; 10. a high-speed camera; 11. a liquid inlet pressure sensor; 12. a liquid inlet pipe; 13. an electric control liquid inlet pressure stabilizing valve; 14. a liquid storage tank; 15. a feed inlet; 16. a temperature control device; 17. a stirrer; 18. a temperature sensor; 19. a pressure gauge; 20. an air injection pump; 21. a methane cylinder; 22. a computer;

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention. Furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art through specific situations.