An apparatus and method for simulating reservoir damage in coal bed methane drainage
By designing a tempered glass tank and a device simulating a wellbore, and using a hydraulic and pressurization system to simulate the coalbed methane drainage process, the problem of the inability to realistically simulate reservoir damage in existing technologies has been solved, enabling the observation and analysis of coal dust migration patterns.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANXI COAL GEOLOGICAL EXPLORATION RES INST CO LTD
- Filing Date
- 2023-11-21
- Publication Date
- 2026-07-24
AI Technical Summary
Existing technologies lack devices to realistically simulate reservoir damage during coalbed methane drainage, making it impossible to clearly and intuitively understand the movement patterns of pulverized coal and the reservoir damage process.
A device comprising a tempered glass tank and a simulated wellbore was designed. The device simulates the reservoir environment through a hydraulic system and a booster pump system, observes the migration of pulverized coal during fracturing and drainage, and uses the transparent material to observe reservoir changes.
It enables a realistic simulation of reservoir damage during coalbed methane drainage, allowing for multi-faceted study of coal dust migration patterns and providing clear observation methods to help understand and address reservoir damage.
Smart Images
Figure CN117536607B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of coalbed methane exploration and development, specifically relating to a method for simulating coalbed methane drainage. Apparatus and methods for reservoir damage during production. Background Technology
[0002] As coalbed methane exploration and development deepens, there is still a lack of relevant simulation devices for downhole coalbed methane operations research. In particular, in coalbed methane drainage operations, the movement patterns of coal dust are mostly still based on theoretical research. There is a lack of relevant devices to realistically simulate reservoir damage in the reservoir environment, making it impossible to clearly and intuitively understand the patterns of coal dust damage in the reservoir during fracturing and drainage. Summary of the Invention
[0003] This invention provides an apparatus and method for simulating reservoir damage during coalbed methane drainage, which can realistically reproduce the reservoir environment and perform simulation, providing a corresponding apparatus and method for studying coal dust damage in reservoirs during fracturing and drainage.
[0004] The device for simulating reservoir damage during coalbed methane drainage according to the present invention is implemented using the following technical solution: A device for simulating reservoir damage during coalbed methane drainage includes a fan-shaped tempered glass tank and a simulated wellbore made of transparent material and connected to the tempered glass tank; the top of the tempered glass tank is covered with a fan-shaped steel plate, and the connection between the opening edge of the top of the tempered glass tank and the edge of the fan-shaped steel plate is sealed with sealing rubber cloth; a hydraulic device is provided above the fan-shaped steel plate, with the hydraulic rod of the hydraulic device facing downwards and connected to the top of the fan-shaped steel plate; a first methane storage tank is connected to one side of the arc surface of the tempered glass tank via a pipeline, and a second switch and a first gas booster pump are connected in series on this pipeline; a second pressure gauge is also connected to one side of the arc surface of the tempered glass tank; a first water tank is connected to the fan-shaped steel plate via a pipeline, and a third switch and a first liquid booster pump are also connected in series on this pipeline; The tempered glass tank is connected to a vertically arranged simulated wellbore at its center, with multiple reservoir discharge outlets at the connection point. A first pulverized coal outlet is located at the bottom of the simulated wellbore, and a first switch is installed at the outlet. A first pressure gauge is connected to the top side wall of the simulated wellbore. A simulated oil production pipe is installed inside the simulated wellbore. A second water tank is connected to the top of the simulated oil production pipe via a water outlet pipe. A third pressure gauge, a fourth switch, and a second liquid booster pump are connected in series on the water outlet pipe. A fifth switch and a second pulverized coal outlet are located at the bottom of the second water tank. A second methane storage tank is connected to the top side wall of the simulated wellbore via a gas outlet pipe. A sixth switch and a second gas booster pump are connected in series on the gas outlet pipe. The tempered glass tank is filled with coal chunks, coal powder, and fracturing sand.
[0005] The method for simulating reservoir damage during coalbed methane drainage according to the present invention is implemented using the following technical solution: A method for simulating reservoir damage during coalbed methane drainage includes the following steps: Coal blocks of a specified quality are placed in a tempered glass tank according to requirements, with gaps between the coal blocks at a certain distance; coal powder of a certain thickness is placed on the coal blocks and gaps; medium-particle fracturing sand is placed on the coal powder, followed by coal powder of the same thickness; and the specified coal blocks are placed on top of the coal powder; a fan-shaped steel plate is connected to the top of the tempered glass tank via a sealing rubber sheet to seal the tempered glass tank; water is then injected into the tempered glass tank using a first liquid booster pump; pressure is then applied to the fan-shaped steel plate using a hydraulic rod to provide the set pressure; at this time, the water in the tempered glass tank is forced into the simulated wellbore; by setting the flow rates of the second liquid booster pump and the second gas booster pump, the three pressures P are adjusted. 气 +P 液 +P 液柱 =Reservoir pressure, maintaining balance; the P 气 reservoir pressure, P 液 The pressure values P are measured by the first, second, and third pressure gauges, respectively. 液柱 To simulate the pressure of a liquid column of height h from the liquid level inside the wellbore to the top of the reservoir discharge outlet, P 液柱 =ρgh; Then slowly reduce the flow rate of the second liquid booster pump, and slowly discharge the water through the reservoir discharge outlet; reduce the pressure so that the water in the reservoir (in the tempered glass tank) enters the second water tank; When P 气 +P 液 +P 液柱 When the reservoir pressure is low, the first gas booster pump is turned on to inject methane gas into the tempered glass tank to simulate dissolved and free gas in the water. At this time, under the action of hydraulic force and gas-liquid two-phase action, the coal powder begins to migrate, and some of it will enter the simulated wellbore. Larger coal particles will be deposited at the bottom of the simulated well shaft and discharged through the first coal powder outlet for drying and particle size separation. The coal dust suspended in the water will be discharged into the second water tank, where it will settle at the bottom and be discharged through the second coal dust outlet.
[0006] Furthermore, since the simulated wellbore is made of transparent material, changes inside the simulated wellbore can be observed at any time; and since the tempered glass tank is also made of transparent material, the migration of coal dust can be observed at any time.
[0007] Furthermore, after the experiment is completed, the tempered glass tank will be opened to dissect and analyze the coal powder within the sand body.
[0008] The apparatus and method of this invention can simulate the movement of coal powder during coal reservoir fracturing and drainage in various ways and from multiple perspectives by placing coal powder of different coal qualities and different degrees of crushing, controlling the size of the fracturing sand body, controlling the reservoir pressure, and controlling the dissolved gas content of the reservoir liquid.
[0009] Reservoir damage occurs when, after fracturing and filling with fracturing sand, the coal body is pulverized, and during the drainage process, coal dust gradually deposits in the sand body, clogging it and causing reservoir damage. This invention uses a transparent material to allow for real-time observation of reservoir changes, thereby understanding the process of reservoir damage and enabling further understanding and treatment of this process. Attached Figure Description
[0010] Figure 1 This is a top view of the tempered glass tank and the simulated well shaft in this invention.
[0011] Figure 2 This is a schematic diagram of the structure of an apparatus and method for simulating reservoir damage during coalbed methane drainage according to the present invention.
[0012] Figure 3 This is a schematic diagram of the various pressures in the tempered glass tank and simulated wellbore described in this invention.
[0013] 1-Tempered glass tank, 2-Sealing rubber cloth, 3-Fan-shaped steel plate, 4-Hydraulic device, 5-Hydraulic rod, 6-Reservoir drainage outlet, 7-Simulated wellbore, 8-First pulverized coal outlet, 9-First switch, 10-Coal block, 11-Pulverized coal, 12-Fracturing sand, 13-Second switch, 14-First gas booster pump, 15-First methane storage tank, 16-Third switch, 17-First liquid booster pump, 18-First water tank, 19-Simulated oil production pipe, 20-Water outlet pipe, 21-Fourth switch, 22-Second liquid booster pump, 23-Second water tank, 24-Fifth switch, 25-Second pulverized coal outlet, 26-Gas outlet pipe, 27-Sixth switch, 28-Second gas booster pump, 29-Second methane storage tank, 30-First pressure gauge, 31-Second pressure gauge, 32-Third pressure gauge. Detailed Implementation
[0014] To make the technical means, creative features, objectives, and effects of this invention easier to understand, the invention is further described below in conjunction with specific embodiments: A device for simulating reservoir damage during coalbed methane drainage includes a tempered glass tank 1 and a sector-shaped steel plate 3 wrapped with a sealing rubber sheet 2 to keep the space of the sector-shaped tempered glass tank 1 sealed, while the sector-shaped steel plate 3 can move up and down; the hydraulic device 4 controls the hydraulic rod 5 to apply pressure to the sector-shaped steel plate 3; the right side of the tempered glass tank 1 is connected to a first gas booster pump 14 and a first methane storage tank 15 via threads, and a second switch 13 is installed in front of the first gas booster pump 14; a water inlet steel pipe is connected to a third switch 16 on the sector-shaped steel plate 3, and the third switch 16 is connected to a first liquid booster pump 17 and a first water tank 18; The simulated wellbore 7 is connected to the fan-shaped tempered glass trough 1 (on one side of the center of the tempered glass trough) through the reservoir discharge outlet 6. The reservoir discharge outlet 6 is filled with medium-grained sand (fracturing sand). A first pulverized coal outlet 8 is set at the bottom of the simulated wellbore 7, and a first switch 9 is set on the first pulverized coal outlet 8. The simulated oil production pipe 19 is connected to the simulated wellbore 7 (the wellbore opening is sealed by annularity) by threaded connection, and is connected to the water outlet pipe 20 by threaded connection to the second liquid booster pump 22 and the second water tank 23; the fourth switch 21 is set in front of the second liquid booster pump 22, the second coal powder outlet 25 is set at the bottom of the second water tank 23, and the fifth switch 24 is set on the outlet. The gas outlet pipe 26 is connected to the simulated well 7 by a threaded connection. The gas outlet pipe is connected to the sixth switch 27, the second gas booster pump 28 and the second methane storage tank 29. Furthermore, the fan-shaped tempered glass groove is 40° fan-shaped, and the top is covered by a fan-shaped steel plate; the hydraulic rods 5 of the hydraulic device 4 are multiple and evenly distributed on the top of the fan-shaped steel plate 3.
[0015] Furthermore, the simulated wellbore 7 is made of a transparent material.
[0016] The working principle of the method described in this invention is as follows: Coal blocks 10 of a specified quality are placed in the tempered glass tank 1 according to requirements, with gaps between the coal blocks 10. A certain thickness of coal powder 11 is placed on the coal blocks 10 and the gaps. Medium-grained fracturing sand 12 is placed on the coal powder 11, and coal powder 11 of the same thickness is placed on the fracturing sand 12. The specified coal blocks 10 are then placed on top of the coal powder 11 (the fracturing sand enters the coal body through perforations, so sand accumulates at both the coal body and the outlet). A fan-shaped steel plate 3 is connected to the top of the tempered glass tank 1 via a sealing rubber sheet 2, thus sealing the tempered glass tank 1. Water is then pumped into the tempered glass tank 1 through the first liquid booster pump 17. Pressure is then applied to the fan-shaped steel plate 3 using a hydraulic rod 5, providing the set pressure. At this time, the water in the tempered glass tank 1 is forced into the simulated wellbore 7. By setting the flow rates of the second liquid booster pump 22 and the second gas booster pump 28, the three pressures P are adjusted. 气 +P 液 +P 液柱=Reservoir pressure, maintaining balance; the P 气 reservoir pressure, P 液 The pressure values P are measured by the first, second, and third pressure gauges, respectively. 液柱 To simulate the pressure of a liquid column of height h from the liquid level inside wellbore 7 to the top of reservoir discharge outlet 6, P 液柱 =ρgh; Then slowly reduce the flow rate of the second liquid booster pump, and slowly discharge the water through the reservoir discharge outlet 6; reduce the pressure to allow the water in the reservoir to be discharged from the simulated wellbore 7; When P 气 +P 液 +P 液柱 When the reservoir pressure is <, the first gas booster pump 14 is turned on to inject methane gas into the tempered glass tank 1 to simulate dissolved gas and free gas in the water. At this time, under the action of hydraulic force and gas-liquid two-phase action, the coal powder 11 begins to migrate, and some of it will enter the simulated wellbore 7. Larger coal powder 11 will be deposited at the bottom of the simulated well shaft 7 and discharged through the first coal powder outlet 8 for drying and sieving of its particle size; The coal powder 11 suspended in the water will be discharged into the second water tank 23, deposited at the bottom of the second water tank 23, and discharged through the second coal powder outlet 25.
[0017] Since the simulated wellbore 7 is made of transparent material, changes inside the simulated wellbore 7 can be observed at any time; since the tempered glass tank 1 is also made of transparent material, the migration of coal powder 11 can be observed at any time.
[0018] After the experiment, the tempered glass tank 1 was opened, and the coal powder 11 within the sand body was dissected and analyzed. The above embodiments are not intended to limit the shape, structure, or any other aspect of the invention. Any simple modifications, equivalent changes, or alterations made to the above embodiments based on the technical essence of the invention are within the protection scope of the invention.
Claims
1. A device for simulating reservoir damage during coalbed methane drainage, characterized in that, The system includes a fan-shaped tempered glass tank (1) and a simulated wellbore (7) made of transparent material and connected to the tempered glass tank (1); the top of the tempered glass tank (1) is covered with a fan-shaped steel plate (3), and the connection between the top opening edge of the tempered glass tank (1) and the edge of the fan-shaped steel plate (3) is sealed with a sealing rubber cloth (2); a hydraulic device (4) is provided above the fan-shaped steel plate (3), and the hydraulic rod (5) of the hydraulic device (4) is set downward and connected to the top of the fan-shaped steel plate (3); a first methane storage tank (15) is connected to one side of the arc surface of the tempered glass tank (1) through a pipeline, and a second switch (13) and a first gas booster pump (14) are connected in series on the pipeline; a second pressure gauge (31) is also connected to one side of the arc surface of the tempered glass tank (1); a first water tank (18) is connected to the fan-shaped steel plate (3) through a pipeline, and a third switch (16) and a first liquid booster pump (17) are also connected in series on the pipeline. The center side of the tempered glass tank (1) is connected to the vertically set simulated wellbore (7), and multiple reservoir discharge outlets (6) are opened at the connection point; the bottom of the simulated wellbore (7) has a first coal powder outlet (8) and a first switch (9) is provided at the outlet; a first pressure gauge (30) is connected to the top side wall of the simulated wellbore (7), and a simulated oil production pipe (19) is provided inside the simulated wellbore (7). The top of the simulated oil production pipe (19) is connected to a second water tank (23) through a water outlet pipe (20). A third pressure gauge (32), a fourth switch (21) and a second liquid booster pump (22) are connected in series on the water outlet pipe (20). A fifth switch (24) and a second coal powder outlet (25) are provided at the bottom of the second water tank (23); a second methane storage tank (29) is connected to the top side wall of the simulated wellbore (7) through a gas outlet pipe (26). A sixth switch (27) and a second gas booster pump (28) are connected in series on the gas outlet pipe (26). The tempered glass tank (1) is filled with coal blocks (10), coal powder (11), and fracturing sand (12).
2. The apparatus for simulating reservoir damage during coalbed methane drainage as described in claim 1, characterized in that, The fan-shaped arc of the tempered glass groove (1) is 40°.
3. The apparatus for simulating reservoir damage during coalbed methane drainage as described in claim 1 or 2, characterized in that, The hydraulic rods (5) of the hydraulic device (4) are multiple and are evenly distributed on the top of the fan-shaped steel plate (3).
4. A method for simulating reservoir damage during coalbed methane drainage, implemented using the apparatus for simulating reservoir damage during coalbed methane drainage as described in any one of claims 1-3, characterized in that, The process includes the following steps: Place coal blocks (10) of a specified quality into the tempered glass tank (1) as required, leaving a certain distance between the coal blocks (10); place coal powder (11) of a certain thickness on the coal blocks (10) and the gaps; place medium-sized fracturing sand (12) on the coal powder (11), place coal powder (11) of the same thickness on the fracturing sand (12), and place the specified coal blocks (10) on the coal powder (11); [The text abruptly ends here, likely due to an incomplete sentence or missing information.] The tempered glass tank (1) is sealed by connecting the sector-shaped steel plate (3) with a sealing rubber sheet (2); then water is injected into the tempered glass tank (1) by the first liquid booster pump (17); then pressure is applied to the sector-shaped steel plate (3) by the hydraulic rod (5) to give the set pressure; at this time, the water in the tempered glass tank (1) will be pressed into the simulated well (7), and by setting the flow rates of the second liquid booster pump (22) and the second gas booster pump (28), the three pressures P are made to be adjusted. 气 +P 液 +P 液柱 =Reservoir pressure, maintaining balance; the P 气 reservoir pressure, P 液 The pressure values P are measured by the first, second, and third pressure gauges, respectively. 液柱 To simulate the pressure of a liquid column of height h from the liquid level inside the wellbore (7) to the top of the reservoir discharge outlet (6), P 液柱 =ρgh; then slowly reduce the flow rate of the second liquid booster pump (22) and slowly discharge the water through the reservoir discharge outlet (6); reduce the pressure so that the water in the reservoir enters the second water tank (23). When P 气 +P 液 +P 液柱 When the reservoir pressure is <, the first gas booster pump (14) is turned on to inject methane gas into the tempered glass tank (1) to simulate dissolved gas and free gas in the water. At this time, under the action of hydraulic force and gas-liquid two-phase action, coal powder (11) begins to migrate, and some will enter the simulated wellbore (7). Large coal powder (11) will be deposited at the bottom of the simulated well shaft (7), discharged through the first coal powder outlet (8), dried, and screened for particle size; The coal powder (11) suspended in the water will be discharged to the second water tank (23), deposited at the bottom of the second water tank (23), and discharged through the second coal powder outlet (25).
5. The method for simulating reservoir damage during coalbed methane drainage as described in claim 4, characterized in that, Since the simulated wellbore (7) is made of transparent material, the changes inside the simulated wellbore (7) can be observed at any time; since the tempered glass tank (1) is also made of transparent material, the migration of coal powder (11) can be observed at any time.
6. A method for simulating reservoir damage during coalbed methane drainage as described in claim 4 or 5, characterized in that, After the experiment was completed, the tempered glass tank (1) was opened, and the coal powder (11) in the sand body was dissected and analyzed.