Coal measures gas multi-layer combined mining device, method and system

Abstract

The application provides a coal measure gas multilayer combined mining device, method and system. The device comprises a plurality of mining assemblies arranged at respective target reservoirs in a well. The mining assemblies are arranged in the perforated sections of the target reservoirs. The mining assemblies divide the oil casing annular area in the well into independent mining areas corresponding to the perforated sections and flow channels that keep the oil casing annular area continuously communicated. The independent mining areas have a mining outlet that is communicated with the oil casing annular area and unidirectionally conducted. Based on the technical scheme of the application, the interference between different reservoirs of a coal measure straight well can be avoided, the significance of combined mining due to interlayer interference can be avoided, precise control can be provided for gas well extraction, accurate production data can be provided in real time, and reliable technical means can be provided for fine management of coal measure gas straight well extraction.

Description

Technical Field

[0001] This invention relates to the field of coalbed methane extraction technology, and particularly to a multi-layer coalbed methane extraction device, method and system. Background Technology

[0002] In recent years, with the rapid development of unconventional oil and gas exploration and development, the Permian coal-bearing strata in my country's Ordos Basin, Sichuan Basin, and other southern regions have enormous potential for coalbed methane, shale gas, and tight gas resources, with broad prospects for development and utilization. Currently, integrated coalbed methane production tests have been conducted in the eastern edge of the Ordos Basin and in southern Sichuan and northern Guizhou, achieving good exploration results. However, the current integrated coalbed methane production tests mainly involve multi-layer fracturing and stratified extraction in vertical wells, with interlayer pressure differences generally less than 0.5 MPa, resulting in minimal interference; or, coalbed methane extraction is carried out first, followed by stratification and tight gas development to avoid the water-locking effect caused by coal seam water flowing back into the tight reservoir, which would prevent tight gas production. Therefore, a coalbed methane extraction technology based on pressure separation has not yet been established. Some scholars believe that the extraction mechanisms of the three types of coal-bearing gases are different, and the pressure systems between different reservoirs are also different. It is necessary to explore the theory and technology of coal-bearing gas synergy extraction, optimize the extraction process, and improve the production capacity of single wells to maximize the release of coal-bearing gas resources.

[0003] Currently, optimization methods and devices for coal-seam vertical well pressure-differentiated syngas production only consider the small pressure difference between adjacent reservoirs and do not account for reservoir damage caused by differences in gas and water production methods in different reservoirs. Devices and monitoring systems for multi-coal-seam syngas production are generally concentrated in coal seam groups and wellhead equipment, and do not consider optimization methods and devices for the different mining methods required for coal-seam three-gas syngas production. Therefore, existing multi-coal-seam syngas production methods, devices, and laboratory simulation devices cannot meet the requirements of coal-seam three-gas syngas production.

[0004] Experimental studies have shown that employing an automatic control device for multi-reservoir separation in coal-bearing formations and optimized mining methods can achieve combined production of three types of gas in coal-bearing formations, effectively avoiding inter-layer interference and maximizing single-well productivity. Therefore, it is essential to develop a method and device capable of automatically producing gas from different reservoirs in a vertical well section after pressure treatment without interference from inter-layers, achieving the goal of refined management to maximize gas production in coal-bearing gas wells through automatic and precise control of the drainage and gas production rate. Summary of the Invention

[0005] To address the shortcomings of existing technologies in the combined extraction of coal-bearing gases, this application proposes a multi-layer combined extraction device, method, and system for coal-bearing gases.

[0006] In a first aspect, the present invention proposes a coalbed methane multi-layer combined production device, comprising multiple production components respectively disposed at each target reservoir underground, wherein the production components are disposed in the perforation section of the target reservoir;

[0007] The mining assembly separates an independent mining zone corresponding to the perforated section in the downhole annulus region and a flow channel that maintains continuous communication between the annulus region and the casing region. The independent mining zone has a unidirectional production outlet that connects to the annulus region.

[0008] In one embodiment, the extension direction of the flow channel is consistent with the extension direction of the wellbore at its location.

[0009] In one embodiment, the extraction assembly includes a packer sleeve fitted over the downhole tubing and packers respectively disposed at both ends of the packer sleeve;

[0010] The packer sleeve and the downhole tubing have an annular region that serves as the flow channel, and the packer sleeve, along with the packers at both ends and the downhole casing, enclose the independent production zone. Through this embodiment,

[0011] In one embodiment, the outlet is located on the channel wall of the flow channel, and the independent mining area is connected to the flow channel through the outlet.

[0012] In one embodiment, a one-way valve is provided at the production outlet, which can maintain one-way flow from the independent production area to the annulus region.

[0013] In one embodiment, a sensor assembly is provided at the outlet, the sensor assembly including a temperature sensor, a pressure sensor, a gas flow sensor, and a liquid flow sensor.

[0014] In one embodiment, the combined mining device includes three mining components, which respectively correspond to the target coal reservoir, the target shale reservoir, and the target sandstone reservoir underground.

[0015] Secondly, this invention proposes a multi-layer syngas extraction method, comprising:

[0016] Acquire downhole pressure data, which includes a first pressure value in the downhole annulus region and a second pressure value in the independent production zone corresponding to each target reservoir.

[0017] Based on the downhole pressure data, determine the relationship between the second pressure value and the first pressure value in each of the independent mining areas, and obtain the determination result;

[0018] Based on the judgment result, open the check valve at the outlet of the independent mining area corresponding to the second pressure value that is larger than the first pressure value and has the largest pressure value, and close the check valves at the outlets of all other independent mining areas.

[0019] In one implementation, prior to acquiring the downhole pressure data, the method further includes:

[0020] The produced fluid is pumped from the bottom of the well through the tubing, and the bottom pressure value is continuously monitored. When the bottom pressure value decreases, the downhole pressure data is obtained.

[0021] Thirdly, the present invention proposes a multi-layer coalbed methane extraction system, which includes the aforementioned multi-layer coalbed methane extraction device, and thus possesses all the technical effects it has.

[0022] The above-mentioned technical features can be combined in various suitable ways or replaced by equivalent technical features, as long as the purpose of the present invention can be achieved.

[0023] The coalbed methane multi-layer commingled extraction device, method, and system provided by this invention have at least the following advantages compared with the prior art:

[0024] This invention discloses a multi-layer synergistic production device, method, and system for coalbed methane. The production components isolate multiple production spaces targeting different reservoirs underground, and automatically control the multi-layer pressure-differentiated synergistic production of coalbed methane vertical wells and conventional gas-producing wells through one-way valves in each production space. This avoids interference between different reservoirs in coalbed methane vertical wells, preventing the loss of the purpose of synergistic production due to inter-layer interference. It provides precise control for gas well extraction and delivers accurate production data in real time, offering a reliable technical means for refined drainage management of coalbed methane vertical wells. Attached Figure Description

[0025] The invention will now be described in more detail with reference to embodiments and the accompanying drawings.

[0026] Figure 1 This shows an overall structural diagram of the combined mining device of the present invention installed downhole;

[0027] Figure 2 A schematic diagram of the mining components of the combined mining apparatus of the present invention is shown.

[0028] In the accompanying drawings, the same parts use the same reference numerals. The drawings are not to scale.

[0029] Figure label:

[0030] 1-Production component, 11-Production outlet, 111-Check valve, 12-Package sleeve, 13-Packer, 14-Sensor assembly, 2-Target reservoir, 21-Perforation section, 3-Annulus region, 4-Independent production area, 5-Flow channel, 6-Tubing, 7-Casing. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and the following embodiments.

[0032] Example 1

[0033] An embodiment of the present invention provides a coalbed methane multi-layer syngas production device, including multiple production components 1 respectively installed at each target reservoir 2 underground, the production components 1 being installed in the perforation section 21 of the target reservoir 2;

[0034] The production component 1 separates an independent production zone 4 corresponding to the perforation section 21 and a flow channel 5 that maintains continuous connection between the oil casing annulus region 3 and the downhole annulus region 3. The independent production zone 4 has a production outlet 11 that connects to the oil casing annulus region 3 and is unidirectionally oriented.

[0035] Specifically, as shown in the attached diagram. Figure 1 As shown, the commingled production device of the present invention mainly adopts a technical solution of separating different target reservoirs 2 by means of multiple production components 1. The production components 1 are set at the perforated section 21 of the corresponding target reservoir 2. The production components 1 are located in the annular region 3 (the annular region between the downhole tubing 6 and the casing 7) corresponding to the location of the perforated section 21, and divide the annular region 3 at that location into two parts, namely, the independent production zone 4 and the flow channel 5.

[0036] The perforations in perforated section 21 are located in independent production zones 4. Multiple production components 1 isolate multiple independent production zones 4, thereby achieving pressure-separated and combined production of target reservoirs in different layers and avoiding mutual interference between different reservoirs. Due to the setting of production components 1, the downhole annulus region 3 is divided into multiple segments. The presence of flow channels 5 ensures the continuous connection of the multiple segments of the annulus region 3, thus ensuring the normal production function of the wellbore.

[0037] In addition, the produced material entering the independent production zone 4 through the perforation is then output outward through the production outlet 11 of the independent production zone 4. The production outlet is set to unidirectional conduction, that is, the production outlet only allows the output of produced material and does not allow the input, so as to avoid the backflow of produced material in the annulus region 3 into the independent production zone 4, thereby avoiding the adverse effects that may be caused to the target reservoir 2.

[0038] Furthermore, the extension direction of the flow channel 5 is consistent with the extension direction of the wellbore at its location.

[0039] Specifically, the extension direction of the flow channel 5 is consistent with the extension direction of the corresponding position in the wellbore, so as to match the flow direction of the produced material in the wellbore, avoid excessive interference with the flow of the produced material, ensure smooth flow, and ensure normal mining operations.

[0040] Furthermore, the extraction assembly 1 includes a packer sleeve 12 fitted over the downhole tubing 6 and packers 13 respectively disposed at both ends of the packer sleeve 12;

[0041] There is an annular region between the packer sleeve 12 and the downhole tubing 6, which serves as a flow channel 5. The packer sleeve 12, the packers 13 at both ends, and the downhole casing 7 form an independent mining area 4.

[0042] Specifically, as shown in the attached diagram. Figure 1 and Figure 2 As shown, the extraction assembly 1 mainly includes a packer sleeve 12 and two packers 13 disposed at both ends of the packer sleeve 12. The packer sleeve 12, the two packers 13, and the casing 7 together enclose an independent annular extraction zone 4 in the annular region 3 and are fixed to the casing 7. Furthermore, the packer sleeve 12 is configured to be fitted over the tubing 6 with its inner diameter larger than the outer diameter of the tubing 6, thereby forming a flow channel 5 between the tubing 6 and the packer sleeve 12; in other words, the tubing 6 is a flow channel 5 passing through the center of the packer sleeve 12. (Refer to the attached drawing.) Figure 1 For multiple mining components 1 installed downhole, the tubing 6 passes through the flow channel 5 in the center of each component in sequence.

[0043] In this way, by simply controlling the radial dimension of the packer sleeve 12, an independent production zone 4 and flow channel 5 can be naturally formed without the need for additional structural design. This also ensures that there is no connecting force relationship between the tubing 6 and the production assembly 1, preventing the production assembly 1 from affecting the normal function of the tubing 6.

[0044] Furthermore, this embodiment only describes the basic structure of the mining assembly 1. Based on this basic structure, the mining assembly 1 can have various construction methods. For example, the mining assembly 1 can be composed of three parts: two packers 13 at both ends of the packer sleeve 12 as described in this embodiment. Of course, the mining assembly 1 can also be directly composed of two packers 13, but the structure and shape of the packers 13 need to be specifically designed to form the shape shown in the attached figure. Figure 1 and Figure 2 The structure and shape shown are as follows: For different reservoirs, after fracturing the perforated section, cylindrical upper and lower packers 13 are used to seal the fracturing section, and the cylindrical packers 13 are connected by a one-way valve 111.

[0045] Furthermore, the outlet 11 is located on the wall of the flow channel 5, and the independent mining area 4 is connected to the flow channel 5 through the outlet 11.

[0046] Specifically, as shown in the attached diagram. Figure 1 As shown, the outlet 11 is located on the wall of the flow channel 5. This arrangement has at least two advantages:

[0047] Firstly, the outlet 11 is set on the flow channel wall of the flow channel 5, so that the output direction of the outlet 11 is perpendicular to the extension direction of the flow channel 5. In this way, when the extracted material is output outward through the outlet 11, it will not directly impact the extracted material flowing in the flow channel 5, which is beneficial to the output of the extracted material in the independent mining area 4.

[0048] Secondly, since the flow channel 5 is separated in the annular region 3 by the mining component 1, the flow area of ​​the flow channel 5 is smaller than the area of ​​the original annular region 3. Therefore, the flow channel 5 actually forms a "throat" relative to the original annular region 3. Based on the relationship between the flow area and the flow velocity, as well as the relationship between the flow velocity and the local pressure of the flow, the local pressure of the fluid at the flow channel 5 becomes smaller. As a result, the local pressure difference can enable the produced material in the independent mining area 4 to be output more quickly through the production outlet 11, thereby improving the production efficiency.

[0049] In addition, multiple outlets 11 can be provided along the circumference of the flow channel wall. Multiple outlets 11 can be located at the same height or at different heights.

[0050] Furthermore, a one-way valve 111 is installed at the outlet 11, which can maintain one-way flow from the independent mining area 4 to the annulus region 3.

[0051] Specifically, a one-way method is used to achieve the one-way flow function of the outlet 11, and the one-way valve 111 can be automatically controlled by the control system.

[0052] Furthermore, a sensor assembly 14 is provided at the outlet 11, which includes a temperature sensor, a pressure sensor, a gas flow sensor, and a liquid flow sensor.

[0053] Specifically, as shown in the attached diagram. Figure 2 As shown, a sensor assembly 14 is installed at the production outlet 11. Alternatively, the sensor assembly 14 can be integrated inside the one-way valve 111. The pressure sensor in the sensor assembly 14 is primarily used to detect the pressure value in the independent production zone 4 and compare it with the pressure value detected in the external annular region 3 to control the opening and closing of the production outlet 11. When the sensor detects that the pressure in the independent production zone 4 is lower than the pressure in the external annular region 3, the production outlet 11 is closed. This is because when the pressure in the independent production zone 4 is lower than the pressure in the annular region 3, the produced material from the independent production zone 4 cannot be output, and there is a risk of backflow; therefore, the production outlet 11 needs to be closed at this time.

[0054] Gas and liquid production is automatically controlled by one-way valves 111 between each reservoir according to pressure changes, and the flow rates of gas and liquid are monitored in real time. The temperature, pressure and gas and liquid flow rates of each reservoir are accurately controlled and calculated, providing more accurate data for coalbed methane exploration, development and drainage.

[0055] Example 2

[0056] The present invention provides a coalbed methane multi-layer commingled extraction device, which is applied to the commingled extraction of target coal reservoirs, target shale reservoirs and target sandstone reservoirs underground.

[0057] Refer to the attached diagram. Figure 1 An embodiment of the present invention provides a coalbed methane multi-layer commingled mining device, including three mining components 1 respectively installed in the target coal reservoir, target shale reservoir and target sandstone reservoir in the vertical well. The mining components 1 are installed in the perforation section 21 of the target reservoir 2.

[0058] The mining component 1 separates three independent mining zones 4 in the downhole annulus region 3, corresponding to the perforated sections 21 of the target coal reservoir, the target shale reservoir, and the target sandstone reservoir, respectively. The three independent mining zones are distributed at different heights along the vertical direction.

[0059] Each independent production area 4 has a flow channel 5 that maintains continuous connection between the oil casing annulus region 3 and the flow channel 5 extends in the same direction as the vertical extension direction of the wellbore. The independent production area 4 has a production outlet 11 that connects the oil casing annulus region 3 and is unidirectionally oriented.

[0060] Specifically, as shown in the attached diagram. Figure 1 As shown, in this embodiment, the production component 1 is installed at the perforation section 21 of the corresponding target reservoir 2. The production component 1 is located in the annular region 3 (the annular region between the downhole tubing 6 and the casing 7) corresponding to the location of the perforation section 21, and divides the annular region 3 at that location into two parts, namely the independent production zone 4 and the flow channel 5.

[0061] The perforations in perforated section 21 are located in independent production zone 4. Three production components 1 isolate three independent production zones 4, thereby achieving pressure-separated and combined production of the target coal reservoir, target shale reservoir, and target sandstone reservoir, and avoiding mutual interference between different reservoirs. Due to the setting of production components 1, the downhole annulus region 3 is divided into multiple segments. The presence of flow channels 5 ensures the continuous connection of the multiple segments of the annulus region 3, thus ensuring the normal production function of the wellbore.

[0062] In addition, the produced material entering the independent production zone 4 through the perforation is then output outward through the production outlet 11 of the independent production zone 4. The production outlet is set to unidirectional conduction, that is, the production outlet only allows the output of produced material and does not allow the input, so as to avoid the backflow of produced material in the annulus region 3 into the independent production zone 4, thereby avoiding the adverse effects that may be caused to the target reservoir 2.

[0063] In this embodiment, the produced material from the perforated section 21 is output from the independent production area 4 through the production outlet 11 to the annulus region 3. The liquid portion of the produced material is stored in the annulus region 3 and enters the tubing 6 from the bottom of the annulus region 3 through the pipe opening at the bottom of the tubing 6. It is then output under the action of the wellhead pumping device. The gas portion of the produced material enters the liquid produced material in the annulus region 3 and naturally floats up along the annulus region 3 to the wellhead for centralized collection and output.

[0064] Furthermore, the mining component 1 includes a packer sleeve 12 fitted over the downhole tubing 6 and packers 13 respectively disposed at both ends of the packer sleeve 12; there is an annular area between the packer sleeve 12 and the downhole tubing 6, which serves as a flow channel 5, and the packer sleeve 12, the packers 13 at both ends, and the downhole casing 7 form an independent mining area 4.

[0065] Furthermore, the production outlet 11 is opened on the flow channel wall of the flow channel 5. The independent mining area 4 is connected to the flow channel 5 through the production outlet 11. There are two production outlets 11 arranged circumferentially along the flow channel wall. The two production outlets 11 are opposite to each other and are located on both sides of the oil pipe 6 passing through the flow channel 5.

[0066] Specifically, as shown in the figure Figure 1 and Figure 2 As shown, the two extraction outlets 11 are opened on the flow channel wall of the flow channel 5, which has the two advantages described in the aforementioned embodiment 1, namely: First, when the extracted material is output outward through the extraction outlets 11, it will not directly impact the extracted material flowing in the flow channel 5, which is beneficial to the output of the extracted material in the independent mining area 4; Second, the local pressure of the fluid at the flow channel 5 is reduced, and the local pressure difference can be used to make the extracted material in the independent mining area 4 output more quickly through the extraction outlets 11, thereby improving the extraction efficiency.

[0067] In addition, the two production outlets 11 are set to be opposite each other and located on both sides of the oil pipe 6 passing through the flow channel 5. In this way, the oil pipe 6 acts as a barrier between the two production outlets 11, which can prevent the produced material output from the two production outlets 11 from impacting each other to a certain extent.

[0068] Furthermore, a one-way valve 111 is installed at the outlet 11. The one-way valve 111 can maintain one-way flow from the independent production area 4 to the annulus region 3. The one-way valve 111 has a built-in sensor assembly 14, which includes a temperature sensor, a pressure sensor, a gas flow sensor and a liquid flow sensor.

[0069] Example 3

[0070] Embodiments of the present invention provide a method for multi-layer syngas extraction, comprising:

[0071] Step S00: Pump the produced fluid from the bottom of the well through the tubing and continuously monitor the bottom pressure value;

[0072] Specifically, during production operations, the first step is to pump the produced fluid from the bottom of the well through the tubing. The pumping of the fluid from the bottom of the well will cause a change in the bottom pressure value. This change, or the change that can be detected, may take a process.

[0073] Step S10: When the bottom hole pressure value decreases, acquire downhole pressure data. The downhole pressure data includes the first pressure value in the downhole annulus region and the second pressure value in the independent production area corresponding to each target reservoir.

[0074] Specifically, when the bottom hole pressure is detected to have decreased due to pumping from the tubing, production in the independent production zone needs to be controlled. This requires first obtaining pressure data as the basis for control, so it is necessary to obtain the second pressure value for each independent production zone and the first pressure value for the annulus region.

[0075] Step S20: Based on the downhole pressure data, determine the relationship between the second pressure value and the first pressure value in each independent mining area, and obtain the determination result;

[0076] Specifically, the magnitudes of the second pressure values ​​in each independent mining area and the first pressure values ​​in the annulus region are compared one by one to determine the magnitude relationship.

[0077] Step S30: Based on the judgment result, open the check valve at the outlet of the independent mining area corresponding to the second pressure value that is larger than the first pressure value and has the largest pressure value, take this independent mining area as the target mining area, and close the check valves at the outlets of all other independent mining areas.

[0078] Specifically, the principle of production operations is to prioritize the exploitation of target reservoirs with higher pressures, provided that the pressure is greater than that in the annulus region. Therefore, based on the assessment results, independent production zones with a second pressure value greater than the first pressure value are first identified. Then, based on the relationship between their second pressure values, the zone with the highest pressure value among these independent production zones is selected as the target production zone. The check valve at the production outlet of the target production zone is opened, while the check valves at the production outlets of other independent production zones are closed, ensuring that the target reservoir with the highest pressure is exploited first.

[0079] For example, in the combined production of target coal reservoirs, target shale reservoirs, and target sandstone reservoirs downhole, the pressure in the annulus region is P. O The pressure of the coal reservoir is P. C The pressure in the shale reservoir is P. S The pressure in the sandstone reservoir is P. T P OThe first pressure value, P C P S and P T All are the second pressure values. When the tubing pumps out fluid to reduce the bottom hole pressure, if P... T >P O >P C (or P) S At this point, the one-way valves in the independent mining areas of shale and coal seams automatically close, and gas is produced from the sandstone reservoir; if P C >P O >P T (or P) S If the pressure in a coal-bearing reservoir exceeds the pressure in the annulus, gas is produced from the higher-pressure reservoir; similarly, if the pressure in a coal-bearing reservoir is lower than the pressure in the annulus, the corresponding check valve automatically closes.

[0080] Step S40: Continuously monitor downhole pressure data. When the second pressure value of the current target production area is less than the current first pressure value, close the check valve at the production outlet of the current target production area.

[0081] Specifically, after continuous mining, the pressure of the independent mining area that is currently the target production area may continue to decrease. When its pressure decreases to the point that it does not meet the mining conditions, that is, when its second pressure value is less than the current first pressure value of the annulus region, a one-way valve at its production outlet is required to prevent backflow due to insufficient pressure.

[0082] Step S50: Based on the downhole pressure data, determine whether there are other independent mining areas with a second pressure value greater than the first pressure value. If so, open the check valve at the production outlet of the independent mining area corresponding to the second pressure value with the largest pressure value that is greater than the first pressure value, and designate it as the new target production area.

[0083] Specifically, when the pressure in the current independent mining area, which is the target extraction area, is insufficient, it is necessary to switch to another independent mining area for extraction. The specific procedure is essentially to repeat step S30 and select another independent mining area with a second pressure value greater than the first pressure value and the largest pressure value as the new target extraction area.

[0084] Example 4

[0085] The embodiments of the present invention propose a multi-layer coalbed methane extraction system, which includes the aforementioned multi-layer coalbed methane extraction device, and thus possesses all the technical effects it has.

[0086] In the description of this invention, it should be understood that the terms "upper", "lower", "bottom", "top", "front", "rear", "inner", "outer", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0087] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A coal-bed gas multi-layer combined production device, characterized in that, It includes multiple production components respectively installed at each target reservoir in the downhole, and the production components are installed in the perforated section of the target reservoir; The mining assembly separates an independent mining zone corresponding to the perforated section in the downhole annulus region and a flow channel that maintains continuous communication between the annulus region and the casing region. The independent mining zone has a unidirectional production outlet that connects to the annulus region. The mining assembly includes a packer sleeve fitted over the downhole tubing and packers respectively disposed at both ends of the packer sleeve; The packer sleeve and the downhole tubing have an annular region that serves as the flow channel, and the packer sleeve, the packers at both ends, and the downhole casing enclose the independent mining area. The extraction outlet is located on the flow channel wall, and the independent mining area is connected to the flow channel through the extraction outlet; The direction of the flow channel is consistent with the direction of the wellbore at its location; A one-way valve is provided at the outlet, which can maintain one-way flow from the independent mining area to the annulus region. A sensor assembly is installed at the production outlet, including a temperature sensor, a pressure sensor, a gas flow sensor, and a liquid flow sensor. The pressure sensor in the sensor assembly is used to detect the pressure value in the independent production area and compare it with the pressure value detected in the annulus region of the oil casing, so as to control the opening and closing of the production outlet.

2. The coal gas multi-layer combined production device according to claim 1, characterized in that, The combined mining device includes three mining components, which respectively correspond to the target coal reservoir, the target shale reservoir, and the target sandstone reservoir underground.

3. A coalbed gas multilayer commingling method characterized by, The coalbed methane multi-layer combined extraction method employs the coalbed methane multi-layer combined extraction device as described in claim 1 or 2, comprising: Acquire downhole pressure data, which includes a first pressure value in the downhole annulus region and a second pressure value in the independent production zone corresponding to each target reservoir. Based on the downhole pressure data, determine the relationship between the second pressure value and the first pressure value in each of the independent mining areas, and obtain the determination result; Based on the judgment result, open the check valve at the outlet of the independent mining area corresponding to the second pressure value that is larger than the first pressure value and has the largest pressure value, and close the check valves at the outlets of all other independent mining areas.

4. The method according to claim 3, wherein, Before acquiring the downhole pressure data, the following steps are also included: The produced fluid is pumped from the bottom of the well through the tubing, and the bottom pressure value is continuously monitored. When the bottom pressure value decreases, the downhole pressure data is obtained.

5. A coalbed methane multi-layer comminution system, comprising the coalbed methane multi-layer comminution device as described in claim 1 or 2.

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