Device and method for layered collaborative mining of tight gas and coal bed gas

Abstract

The invention discloses a tight gas and coal bed gas layered collaborative mining device and method. The device comprises a casing pipe and an oil pipe, the casing pipe is arranged in a gas well, and the bottom end of the casing pipe penetrates through a tight sandstone layer; the oil pipe penetrates through the casing pipe, the bottom end of the oil pipe reaches the tight sandstone layer, a first annular space is reserved between the casing pipe and the oil pipe, and a packer is arranged in the first annular space; the first perforation, the bottom in the oil pipe and the gas channel of the oil pipe are sequentially communicated from bottom to top to form a tight sandstone layer gas-liquid channel; perforation holes capable of enabling gas and liquid of a coal seam to circulate are distributed in the pipe wall of the casing pipe above the packer, and the perforation holes are communicated with the first annular space to form a coal seam gas channel; the compact sandstone layer gas-liquid channel can convey gas in the compact sandstone layer, the coal bed gas channel can convey gas in the coal bed, and the compact sandstone layer gas-liquid channel and the coal bed gas channel are independent of each other, so that layered collaborative mining of the compact sandstone layer gas and the coal bed gas is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of natural gas mining, and in particular to a device and method for coordinated stratified mining of tight gas and coalbed methane. Background Art

[0002] Tight gas and coalbed methane exist in multiple layers stacked vertically. The advantages of taking both into account and developing them in a coordinated manner in the same wellbore are obvious. This is an effective means to achieve high production with fewer wells and economical and efficient development, and is imperative. However, tight gas and coalbed methane differ greatly in their occurrence state, seepage mechanism, pressure characteristics, and drainage methods. The rod pump mechanical drainage process currently used by the two is mostly used for single-layer development, which has great limitations for the efficient development of tight gas and coalbed methane under multi-layer overlapping conditions. Moreover, in multi-layer combined production scenarios, if the existing rod pump drainage process is used, there will be interference between the pressure and output of different layers, such as interlayer water backflow and solid phase intrusion, which will cause damage to the low-pressure layer reservoir. Therefore, for tight gas and coalbed methane in vertical multi-layer stacking conditions, the conventional sucker rod lifting combined production process is difficult to adapt to the different drainage needs of coalbed methane and tight gas, two gases with different properties. Especially for the situation where the superposition relationship is coalbed methane above and tight gas below, because the water content of coalbed methane is generally higher, it is more likely to cause gas-water interference and backflow problems, and the drainage and gas production for the coordinated development of the two gases in the same wellbore are more challenging.

[0003] In short, at present, in the process of natural gas extraction in the formation with dense sandstone layer below and coal seam above, it is not possible to carry out stratified and coordinated extraction of gas from the dense sandstone layer and gas from the coal seam. Summary of the Invention

[0004] In response to the above problems, the purpose of the present invention is to provide a device and method for the coordinated layered exploitation of tight gas and coalbed methane, which is used to solve the problem that in the current natural gas exploitation process in the strata with tight sandstone layers below and coal seams above, the gas in the tight sandstone layers and the gas in the coal seams cannot be exploited in a coordinated layered manner.

[0005] To achieve the above object, the present invention adopts the following technical solutions: In a first aspect, the present invention discloses a device for coordinated stratified mining of tight gas and coalbed methane, which is used to be installed in a gas well in a stratum with a tight sandstone layer below and a coal seam above, and the gas well passes through the coal seam and the tight sandstone layer from top to bottom, comprising: A casing is used to be set in a gas well, with the bottom end of the casing passing through a dense sandstone layer; an oil pipe, which is inserted into the casing, wherein the bottom end of the oil pipe reaches a depth of the dense sandstone layer, a first annular space is left between the casing and the oil pipe, and a packer is provided in the first annular space, wherein the packer is located between the coal seam and the dense sandstone layer; The casing wall corresponding to the dense sandstone layer is provided with first perforations, the first perforations being capable of circulating gas in the dense sandstone layer, and the bottom of the oil pipe being connected to the first perforations; A gas passage is provided in the oil pipe above the packer, and the first perforation, the bottom of the oil pipe and the gas passage of the oil pipe are connected in sequence from bottom to top to form a gas-liquid passage in the tight sandstone layer; Second perforations are arranged on the wall of the casing above the packer, the second perforations are capable of circulating coal seam gas, and the second perforations are connected to the first annular space to form a coal seam gas channel; The dense sandstone layer gas-liquid channel can transport the gas in the dense sandstone layer, and the coalbed methane channel can transport the gas in the coal seam. The dense sandstone layer gas-liquid channel and the coalbed methane channel are independent of each other, thereby realizing layered and coordinated mining of the gas in the dense sandstone layer and the gas in the coal seam.

[0006] Preferably, a diverter is provided on the oil pipe corresponding to the coal seam, and the diverter divides the interior of the oil pipe above the packer into two parts, an upper part and an lower part, wherein the gas and liquid entering the interior of the oil pipe after passing through the packer first enter the lower part of the oil pipe; the diverter includes a valve block body, a central liquid outlet hole is provided in the center of the valve block body, and a plurality of longitudinal channels are arranged circumferentially around the central liquid outlet hole; the two ends of each longitudinal channel are respectively connected with the lower part and the upper part of the oil pipe, and the lower part of the oil pipe, the multiple longitudinal channels and the upper part of the oil pipe are connected in sequence from bottom to top to form the gas channel.

[0007] Preferably, a liquid channel is further provided in the oil pipe above the packer. Specifically, a transverse channel is provided on the side of the valve block of the diverter, and the transverse channel is only connected to the central liquid outlet hole. The second perforation can also circulate liquid from the coal seam, and the second perforation is connected to the transverse channel of the diverter. The transverse channel, the central liquid outlet hole, and the liquid channel in the oil pipe are sequentially connected to form the coal seam liquid channel for outputting liquid from the coal seam. The dense sandstone layer gas-liquid channel, the coalbed methane channel, and the coalbed liquid channel are independent of each other, and respectively transport gas and liquid in the dense sandstone layer and gas and liquid in the coal seam simultaneously.

[0008] Preferably, a tubular pump is also provided on the oil pipe, and the tubular pump includes a pump barrel and a pump piston; the pump barrel is connected to the oil pipe through threads; a central hole and multiple side holes are provided in the pump barrel, and the multiple side holes surround the central hole; the pump piston is provided in the central hole of the pump barrel; wherein the multiple side holes of the pump barrel serve as channels for gas circulation; and the central hole in the pump barrel serves as a channel for liquid circulation.

[0009] Preferably, the pump piston is connected to a hollow sucker rod; the hollow sucker rod has a built-in hollow channel, the hollow sucker rod is inserted into the oil pipe, and the bottom end of the hollow sucker rod extends into the pump barrel, and the hollow channel of the hollow sucker rod is connected to the central hole in the pump barrel; a second annular space is left between the hollow sucker rod and the oil pipe; the pump piston is provided with the bottom end of the hollow sucker rod.

[0010] Preferably, a gas-liquid separation device is also provided on the oil pipe, and the gas-liquid separation device is located between the diverter and the tube pump; a liquid through hole and multiple gas through holes are provided in the gas-liquid separation device, the liquid through hole is located in the center of the gas-liquid separation device, and the multiple gas through holes are located around the liquid through hole; the liquid through hole of the gas-liquid separation device is inserted into the central liquid outlet hole of the diverter through a sealing ring to achieve docking with the central liquid outlet hole of the diverter, and the central liquid outlet hole of the diverter is connected with the central hole of the pump barrel of the tube pump through the liquid through hole of the gas-liquid separation device; multiple gas through holes are provided in the gas-liquid separation device, which correspond to the multiple longitudinal channels of the diverter, and the multiple longitudinal channels of the diverter are respectively connected with the multiple side holes of the pump barrel of the tube pump through the multiple gas through holes provided in the gas-liquid separation device.

[0011] Preferably, the diverter, the gas-liquid separation device, the tubular pump and the hollow sucker rod are arranged in sequence from bottom to top on the oil pipe above the packer; the central liquid outlet hole of the diverter, the liquid through hole of the gas-liquid separation device, the central hole of the pump barrel of the tubular pump and the hollow channel in the hollow sucker rod are connected in sequence from top to bottom to form a liquid channel in the oil pipe; the multiple longitudinal channels of the diverter, the multiple gas through holes of the gas-liquid separation device and the multiple side holes in the pump barrel of the tubular pump correspond to each other and are connected to the second annular space between the hollow sucker rod and the oil pipe to form a gas channel in the oil pipe.

[0012] Preferably, a bubble injection and drug discharge pipe is provided from top to bottom in the first annular space, the bubble injection and drug discharge pipe passes through the packer and exposes the bottom end, and an injection valve is provided at the bottom end of the bubble injection and drug discharge pipe.

[0013] In a second aspect, the present invention also discloses a method for coordinated mining of tight gas and coalbed methane, using the above-mentioned device for coordinated mining of tight gas and coalbed methane in layers, the method comprises: Step A: The gas in the tight sandstone layer is transported to the ground through the gas-liquid channel of the tight sandstone layer; Step B: The gas in the coal seam is transported to the ground through the coal seam gas channel; Wherein, the step A and the step B are performed simultaneously.

[0014] The step A comprises the following specific steps: The gas and liquid in the dense sandstone layer pass through the first perforations and reach the bottom of the casing. Due to the isolation of the packer, they can only enter the oil pipe, pass through the lower part of the oil pipe and multiple longitudinal channels of the diverter in sequence, reach the upper part of the oil pipe, and then pass through multiple bypass holes in the pump barrel of the tubing pump to reach the second annular space between the hollow sucker rod and the oil pipe, and finally reach the ground through the second annular space.

[0015] Described step B comprises the following specific steps: The gas-liquid mixture of the coal seam reaches the first annular space between the casing and the oil pipe above the packer through the second perforation above the packer; The gas in the gas-liquid mixture directly reaches the ground through the first annular space.

[0016] During the process of step B, the liquid in the coal seam is transported to the ground through the liquid channel, which includes the following specific steps: The gas-liquid mixture of the coal seam reaches the first annular space between the casing and the oil pipe above the packer through the second perforation above the packer; The liquid in the gas-liquid mixture enters the diverter through the transverse channel of the diverter, passes through the central liquid outlet hole of the diverter, the liquid through hole of the gas-liquid separation device, and the central hole of the pump barrel of the tubular pump in sequence, and reaches the second annular space between the hollow sucker rod and the oil pipe; The liquid finally reaches the surface through the second annular space.

[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention discloses a device for coordinated stratified mining of tight gas and coalbed methane, which is used to be set on a gas well in a stratum with a tight sandstone layer below and a coal seam above, and the gas well passes through the coal seam and the tight sandstone layer from top to bottom. The device includes a casing and an oil pipe, the casing is set in the oil and gas well, and the bottom end of the casing passes through the tight sandstone layer; the oil pipe is passed through the casing and the depth at the bottom end reaches the tight sandstone layer, a first annular space is left between the casing and the oil pipe, and a packer is set in the first annular space, and the packer is located between the coal seam and the tight sandstone layer; wherein, a first perforation is arranged on the pipe wall of the casing corresponding to the tight sandstone layer, the first perforation can circulate the gas in the tight sandstone layer, and the bottom of the oil pipe is connected to the first perforation; a gas The channel, the first perforation, the bottom of the oil pipe and the gas channel of the oil pipe are connected in sequence from bottom to top to form a gas-liquid channel in the dense sandstone layer; a second perforation is arranged on the pipe wall of the casing above the packer, and the second perforation can circulate the gas of the coal seam, and the second perforation is connected with the first annular space to form a coalbed methane channel; the gas-liquid channel of the dense sandstone layer can transport the gas in the dense sandstone layer, and the coalbed methane channel can transport the gas of the coal seam, and the gas-liquid channel of the dense sandstone layer and the coalbed methane channel are independent of each other, thereby realizing the stratified coordinated exploitation of the gas in the dense sandstone layer and the gas in the coal seam, solving the problem that the gas in the dense sandstone layer and the gas in the coal seam cannot be stratified and coordinated in the natural gas exploitation process of the stratum with the dense sandstone layer below and the coal seam above.

[0018] (2) The present invention discloses a method for the coordinated stratified mining of tight gas and coalbed methane, comprising: Step A: transporting gas from the tight sandstone layer to the surface via a gas-liquid channel in the tight sandstone layer; Step B: transporting gas from the coalbed to the surface via a coalbed methane channel. Steps A and B are performed simultaneously. The present invention discloses a method for the coordinated stratified mining of tight gas and coalbed methane, wherein the gas from the tight sandstone layer and the gas from the coalbed are independently mined without affecting each other, thereby achieving efficient mining of both coalbed methane and tight gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the overall structure of the device for coordinated stratified mining of tight gas and coalbed methane provided in Example 1 of the present invention; Figure 2 Schematic diagram of gas from a tight sandstone layer being transported to the ground through a gas-liquid channel in the tight sandstone layer, provided in Example 2 of the present invention, wherein the hollow arrows indicate the flow direction of the tight gas; Figure 3 Schematic diagram of coal seam gas being transported to the ground through a coal seam gas channel provided by Example 2 of the present invention, wherein the dotted arrows indicate the flow direction of the coal seam gas; Figure 4This is a schematic diagram of the liquid in the coal seam provided by Example 2 of the present invention being transported to the ground through a liquid channel, wherein the solid arrows indicate the flow direction of the liquid in the coal seam.

[0020] Description of reference numerals: 100 - first annular space, 200 - second annular space; 1- casing; 2-tubing, 20-packer; 3- flow divider, 30- central liquid outlet, 31- longitudinal channel, 32- transverse channel; 4-tube pump, 41-pump barrel, 42-pump piston, 43-hollow sucker rod; 5-gas-liquid separation device, 50-sealing ring, 51-liquid through hole, 52-gas through hole; 6- injection and discharge pipe, 60- injection valve. DETAILED DESCRIPTION

[0021] Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0022] Example 1: A device for collaborative stratified mining of tight gas and coalbed methane Embodiment 1 of the present invention provides a device for coordinated stratified mining of tight gas and coalbed methane, and its structure is described in detail below with reference to the accompanying drawings.

[0023] refer to Figure 1 The device for coordinated stratified mining of tight gas and coalbed methane is used to be installed in a gas well in a stratum with a tight sandstone layer below and a coal seam above, and the gas well passes through the coal seam and the tight sandstone layer from top to bottom, comprising: Casing 1, used for being set in a gas well, with the bottom end of the casing 1 passing through a dense sandstone layer; An oil pipe 2 is inserted into the casing 1. The bottom end of the oil pipe 2 reaches a depth in the dense sandstone layer. A first annular space 100 is left between the casing 1 and the oil pipe 2. A packer 20 is provided in the first annular space 100. The packer 20 is located between the coal seam and the dense sandstone layer. The casing 1 corresponding to the dense sandstone layer is provided with first perforations, which can allow gas in the dense sandstone layer to flow through. The bottom of the oil pipe 2 is connected to the first perforations. A gas passage is provided in the oil pipe 2 above the packer 20, and the first perforation, the bottom of the oil pipe 2 and the gas passage of the oil pipe 2 are connected in sequence from bottom to top to form a gas-liquid passage in the tight sandstone layer; Second perforations are arranged on the wall of the casing 1 above the packer 20 , and the second perforations can circulate gas from the coal seam. The second perforations are connected to the first annular space 100 to form a coal seam gas channel. The dense sandstone layer gas-liquid channel can transport the gas in the dense sandstone layer, and the coalbed methane channel can transport the gas in the coal seam. The dense sandstone layer gas-liquid channel and the coalbed methane channel are independent of each other, thereby realizing layered and coordinated mining of the gas in the dense sandstone layer and the gas in the coal seam.

[0024] It should be noted that the first perforations not only allow the flow of gas through the dense sandstone layer, but also allow the flow of liquid through the dense sandstone layer. The liquid and gas in the dense sandstone layer pass through the first perforations and enter the bottom of the casing 1 corresponding to the dense sandstone layer, and then reach the surface through the gas-liquid channel in the dense sandstone layer. Since the technical effect of the present invention is to achieve the coordinated and separate extraction of tight gas and coalbed methane, and the separation of gas and liquid in a dense sandstone layer along the same path is common knowledge in the art, the extraction of liquid from a dense sandstone layer will not be described in detail.

[0025] It should also be noted that the "tight gas" referred to in the present invention refers to the gas in the tight sandstone layer, and the "coalbed methane" refers to the gas in the coal seam.

[0026] As a specific example of realizing the setting of a gas channel in the oil pipe 2 above the packer 20, a diverter 3 is provided on the oil pipe 2 corresponding to the coal seam, and the diverter 3 divides the interior of the oil pipe 2 above the packer 20 into two parts, an upper part and an lower part, wherein the gas and liquid entering the interior of the oil pipe 2 after passing through the packer 20 first enter the lower part of the oil pipe 2; the diverter 3 includes a valve block body, a central liquid outlet 30 is provided in the center of the valve block body, and a plurality of longitudinal channels 31 are circumferentially arranged around the central liquid outlet 30; the two ends of each longitudinal channel 31 are respectively connected with the lower part and the upper part of the oil pipe 2, and the lower part of the oil pipe 2, the plurality of longitudinal channels 31 and the upper part of the oil pipe 2 are connected in sequence from bottom to top to form the gas channel.

[0027] To drain the coal seam liquid, a liquid channel is also provided within the oil pipe 2 above the packer 20. Specifically, a transverse channel 32 is provided on the side of the valve block of the diverter 3. This transverse channel 32 is connected only to the central liquid outlet hole 30. The second perforations can also circulate coal seam liquid and are connected to the transverse channel 32 of the diverter 3. The transverse channel 32, the central liquid outlet hole 30, and the liquid channel within the oil pipe 2 are sequentially connected to form the coal seam liquid channel for draining the coal seam liquid.

[0028] The dense sandstone layer gas-liquid channel, the coalbed methane channel and the coalbed liquid channel are independent of each other and transport the gas and liquid of the dense sandstone layer and the gas and liquid of the coalbed simultaneously.

[0029] In order to provide the liquid channel with power to output liquid, a tubular pump 4 is also provided on the oil pipe 2, and the tubular pump 4 includes a pump barrel 41 and a pump piston 42; the pump barrel 41 is connected to the oil pipe 2 through threads; a central hole and multiple side holes are provided in the pump barrel 41, and the multiple side holes are surrounded by the central hole; the pump piston 42 is provided in the central hole of the pump barrel 41; wherein the multiple side holes of the pump barrel 41 serve as channels for gas circulation; and a central hole in the pump barrel 41 serves as a channel for liquid circulation.

[0030] To push the pump piston 42 of the tubular pump 4 and create negative pressure within the pump barrel 41, the pump piston 42 is connected to a hollow sucker rod 43. Specifically, the hollow sucker rod 43 has a hollow passageway built into it. The hollow sucker rod 43 extends through the oil pipe 2, with its bottom end extending into the pump barrel 41. The hollow passageway of the hollow sucker rod 43 communicates with the central hole within the pump barrel 41. A second annular space 200 is left between the hollow sucker rod 43 and the oil pipe 2. Specifically, the pump piston 42 is disposed at the bottom end of the hollow sucker rod 43.

[0031] Furthermore, a gas-liquid separation device 5 is provided on the oil pipe 2, and the gas-liquid separation device 5 is located between the diverter 3 and the tubing pump 4; The gas-liquid separation device 5 is provided with a liquid through hole 51 and a plurality of gas through holes 52. The liquid through hole 51 is located in the center of the gas-liquid separation device 5, and the plurality of gas through holes 52 are located around the liquid through hole 51. The liquid through hole 51 of the gas-liquid separation device 5 is inserted into the central liquid outlet hole 30 of the diverter 3 through the sealing ring 50 to achieve docking with the central liquid outlet hole 30 of the diverter 3, and the central liquid outlet hole 30 of the diverter 3 is connected to the central hole of the pump barrel 41 of the tube pump 4 through the liquid through hole 51 of the gas-liquid separation device 5; The gas-liquid separation device 5 is provided with multiple gas through holes 52 corresponding to the multiple longitudinal channels 31 of the diverter 3, and the multiple longitudinal channels 31 of the diverter 3 are respectively connected with the multiple side holes of the pump barrel 41 of the tube pump 4 through the multiple gas through holes 52 provided in the gas-liquid separation device 5.

[0032] In order to achieve sealing between the gas-liquid separation device 5 and the diverter 3, a sealing ring 50 is provided at the connection between the liquid through hole 51 of the gas-liquid separation device 5 and the central liquid outlet hole 30 of the diverter 3, and the liquid through hole 51 of the gas-liquid separation device 5 is inserted into the central liquid outlet hole 30 of the diverter 3 through the sealing ring 50.

[0033] As a specific implementation, the diverter 3 , the gas-liquid separation device 5 , the tubing pump 4 and the hollow sucker rod 43 are sequentially arranged from bottom to top on the oil pipe 2 above the packer 20 .

[0034] The central liquid outlet 30 of the diverter 3, the liquid through hole 51 of the gas-liquid separation device 5, the central hole of the pump barrel 41 of the tubular pump 4 and the hollow channel in the hollow sucker rod 43 are connected in sequence from top to bottom to form a liquid channel in the oil pipe 2; The multiple longitudinal channels 31 of the diverter 3, the multiple gas through holes 52 of the gas-liquid separation device 5, and the multiple side holes in the pump barrel 41 of the tubular pump 4 respectively correspond to each other and are connected to the second annular space 200 between the hollow sucker rod 43 and the oil pipe 2, forming a gas channel in the oil pipe 2.

[0035] In order to inject foaming agent into the dense sandstone layer to assist lifting, the first annular space 100 is provided with foaming agent injection pipes 6 from top to bottom. The bubble injection and drug discharge pipe 6 passes through the packer 20 and exposes the bottom end. The bottom end of the bubble injection and drug discharge pipe 6 is provided with an injection valve 60 .

[0036] Example 2: A method for collaborative stratified mining of tight gas and coalbed methane Example 2 of the present invention provides a method for the coordinated stratified mining of tight gas and coalbed methane, using the apparatus for the coordinated stratified mining of tight gas and coalbed methane of Example 1. The method comprises the following steps: Step A: The gas in the tight sandstone layer is transported to the ground through the gas-liquid channel of the tight sandstone layer, such as Figure 2 At the same time, the liquid in the tight sandstone layer is also transported to the ground through the gas-liquid channel in the tight sandstone layer.

[0037] Specifically, step A includes the following steps: The gas in the dense sandstone layer passes through the first perforations densely distributed on the wall of the casing 1 corresponding to the dense sandstone layer and reaches the bottom of the casing 1. Due to the isolation of the packer 20, the gas can only enter the oil pipe 2, and successively passes through the lower part of the oil pipe 2 and multiple longitudinal channels of the diverter 3 to reach the upper part of the oil pipe 2, and then passes through multiple bypass holes in the pump barrel 41 of the tubular pump 4 to reach the second annular space 200 between the hollow sucker rod 43 and the oil pipe 2, and finally reaches the ground through the second annular space 200.

[0038] Step B: The gas from the coal seam is transported to the ground through the coal seam gas channel, such as Figure 3 shown.

[0039] Specifically, step B includes the following steps: The gas-liquid mixture of the coal seam passes through the second perforations above the packer 20 and reaches the first annular space 100 between the casing 1 and the oil pipe 2 above the packer 20; The gas in the gas-liquid mixture directly reaches the ground through the first annular space 100 .

[0040] Wherein, the step A and the step B are performed simultaneously.

[0041] More specifically, during the process of step B, the liquid in the coal seam is transported to the ground through the liquid channel. Figure 4 , the process includes the following specific steps: The gas-liquid mixture of the coal seam passes through the second perforations above the packer 20 and reaches the first annular space 100 between the casing 1 and the oil pipe 2 above the packer 20; The liquid in the gas-liquid mixture enters the diverter 3 through the transverse channel 32 of the diverter 3, passes through the central liquid outlet 30 of the diverter 3, the liquid through hole 51 of the gas-liquid separator 5, and the central hole of the pump barrel 41 of the tubular pump 4, and reaches the second annular space 200 between the hollow sucker rod 43 and the oil pipe 2. The liquid finally reaches the surface through the second annular space 200 .

[0042] More specifically, the step A, the step B and the transport of the liquid in the coal seam to the ground through the liquid channel are carried out simultaneously.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A device for coordinated stratified mining of tight gas and coalbed methane, which is used to be installed in a gas well in a stratum with a tight sandstone layer below and a coal seam above, and the gas well passes through the coal seam and the tight sandstone layer from top to bottom, characterized in that: include: A casing (1) is used for being arranged in a gas well, and the bottom end of the casing (1) passes through a dense sandstone layer; An oil pipe (2) is inserted into the casing (1), the bottom end of the oil pipe (2) is located at a depth reaching a dense sandstone layer, a first annular space (100) is left between the casing (1) and the oil pipe (2), and a packer (20) is provided in the first annular space (100), and the packer (20) is located between the coal seam and the dense sandstone layer; Wherein, a first perforation is arranged on the wall of the casing (1) corresponding to the dense sandstone layer, the first perforation can flow the gas in the dense sandstone layer, and the bottom of the oil pipe (2) is connected to the first perforation; A gas passage is provided in the oil pipe (2) above the packer (20), and the first perforation, the bottom of the oil pipe (2) and the gas passage of the oil pipe (2) are sequentially connected from bottom to top to form a gas-liquid passage in the dense sandstone layer; A second perforation is arranged on the wall of the casing (1) above the packer (20), wherein the second perforation can flow gas from the coal seam, and the second perforation is connected to the first annular space (100) to form a coal seam gas channel; The dense sandstone layer gas-liquid channel can transport the gas in the dense sandstone layer, and the coalbed methane channel can transport the gas in the coal seam. The dense sandstone layer gas-liquid channel and the coalbed methane channel are independent of each other, thereby realizing layered and coordinated mining of the gas in the dense sandstone layer and the gas in the coal seam.

2. The device according to claim 1, characterized in that A flow divider (3) is provided on the oil pipe (2) corresponding to the coal seam. The flow divider (3) divides the interior of the oil pipe (2) above the packer (20) into two upper and lower parts, wherein the gas and liquid that enter the interior of the oil pipe (2) after passing through the packer (20) first enter the lower part of the oil pipe (2); The flow divider (3) comprises a valve block body, a central liquid outlet hole (30) is provided at the center of the valve block body, and a plurality of longitudinal channels (31) are arranged circumferentially around the central liquid outlet hole (30); The two ends of each longitudinal channel (31) are respectively connected to the lower part and the upper part of the oil pipe (2); the lower part of the oil pipe (2), the plurality of longitudinal channels (31) and the upper part of the oil pipe (2) are sequentially connected from bottom to top to form the gas channel.

3. The device according to claim 2, characterized in that A liquid channel is also provided in the oil pipe (2) above the packer (20). A transverse channel (32) is provided on the side of the valve block of the diverter (3), and the transverse channel (32) is only connected to the central liquid outlet hole (30); The second perforation is also capable of circulating liquid in the coal seam. The second perforation is connected to the transverse channel (32) of the diverter (3). The transverse channel (32), the central liquid outlet hole (30) and the liquid channel in the oil pipe (2) are sequentially connected to form the coal seam liquid channel for outputting the liquid from the coal seam. The dense sandstone layer gas-liquid channel, the coalbed methane channel and the coalbed liquid channel are independent of each other and respectively transport the gas and liquid of the dense sandstone layer and the gas and liquid of the coalbed simultaneously.

4. The device according to claim 3, characterized in that A tubular pump (4) is also provided on the oil pipe (2), and the tubular pump (4) comprises a pump barrel (41) and a pump piston (42); The pump barrel (41) and the oil pipe (2) are butted together via threads; The pump barrel (41) is provided with a central hole and a plurality of side holes, and the plurality of side holes surround the central hole; The pump piston (42) is arranged in the central hole of the pump barrel (41); Wherein, the multiple side holes of the pump barrel (41) serve as channels for gas circulation; A central hole in the pump barrel (41) serves as a channel for liquid circulation.

5. The device according to claim 4, characterized in that The pump piston (42) is connected to a hollow sucker rod (43); The hollow sucker rod (43) has a built-in hollow passage, the hollow sucker rod (43) is inserted into the oil pipe (2), and the bottom end of the hollow sucker rod (43) extends into the pump barrel (41), and the hollow passage of the hollow sucker rod (43) is connected to the central hole in the pump barrel (41); A second annular space (200) is left between the hollow sucker rod (43) and the oil pipe (2); The pump piston (42) is provided at the bottom end of a hollow sucker rod (43).

6. The device according to claim 5, characterized in that A gas-liquid separation device (5) is also provided on the oil pipe (2), and the gas-liquid separation device (5) is located between the diverter (3) and the tubular pump (4); A liquid through hole (51) and a plurality of gas through holes (52) are provided in the gas-liquid separation device (5), wherein the liquid through hole (51) is located in the center of the gas-liquid separation device (5), and the plurality of gas through holes (52) are located around the liquid through hole (51); The liquid through hole (51) of the gas-liquid separation device (5) is inserted into the central liquid outlet hole (30) of the diverter (3) through the sealing ring (50) to achieve docking with the central liquid outlet hole (30) of the diverter (3), and the central liquid outlet hole (30) of the diverter (3) is connected to the central hole of the pump barrel (41) of the tube pump (4) through the liquid through hole (51) of the gas-liquid separation device (5); The gas-liquid separation device (5) is provided with a plurality of gas through holes (52) corresponding to the plurality of longitudinal channels (31) of the diverter (3), and the plurality of longitudinal channels (31) of the diverter (3) are respectively connected to the plurality of side holes of the pump barrel (41) of the tube pump (4) through the plurality of gas through holes (52) provided in the gas-liquid separation device (5).

7. The device according to claim 5, characterized in that The diverter (3), the gas-liquid separation device (5), the tubular pump (4) and the hollow sucker rod (43) are sequentially arranged from bottom to top on the oil pipe (2) above the packer (20); The central liquid outlet hole (30) of the diverter (3), the liquid through hole (51) of the gas-liquid separation device (5), the central hole of the pump barrel (41) of the tubular pump (4) and the hollow channel in the hollow sucker rod (43) are connected in sequence from top to bottom to form a liquid channel in the oil pipe (2); The multiple longitudinal channels (31) of the diverter (3), the multiple gas through holes (52) of the gas-liquid separation device (5), and the multiple side holes in the pump barrel (41) of the tubular pump (4) correspond to each other and are connected to the second annular space (200) between the hollow sucker rod (43) and the oil pipe (2), forming a gas channel in the oil pipe (2).

8. The device according to claim 1, characterized in that The first annular space (100) is provided with a bubble injection and medicine discharge pipe (6) from top to bottom. The bubble injection and drug discharge pipe (6) passes through the packer (20) and exposes the bottom end, and the bottom end of the bubble injection and drug discharge pipe (6) is provided with an injection valve (60).

9. A method for coordinated mining of tight gas and coalbed methane, using the device for coordinated mining of tight gas and coalbed methane in layers according to claim 5, characterized in that: include Step A: The gas in the tight sandstone layer is transported to the ground through the gas-liquid channel of the tight sandstone layer; Step B: The gas in the coal seam is transported to the ground through the coal seam gas channel; Wherein, the step A and the step B are performed simultaneously.

10. The method according to claim 9, characterized in that The step A comprises the following specific steps: The gas and liquid in the dense sandstone layer pass through the first perforation and reach the bottom of the casing (1). Due to the isolation of the packer (20), the gas and liquid can only enter the oil pipe (2), pass through the lower part of the oil pipe (2) and the multiple longitudinal channels of the diverter (3) in sequence, reach the upper part of the oil pipe (2), and then pass through the multiple side holes in the pump barrel (41) of the tubular pump (4) to reach the second annular space (200) between the hollow sucker rod (43) and the oil pipe (2), and finally reach the ground through the second annular space (200); Described step B comprises the following specific steps: The gas-liquid mixture of the coal seam reaches the first annular space (100) between the casing (1) and the oil pipe (2) above the packer (20) through the second perforation above the packer (20); The gas in the gas-liquid mixture directly reaches the ground through the first annular space (100); During the process of step B, the liquid in the coal seam is transported to the ground through the liquid channel, which includes the following specific steps: The gas-liquid mixture of the coal seam reaches the first annular space (100) between the casing (1) and the oil pipe (2) above the packer (20) through the second perforation above the packer (20); The liquid in the gas-liquid mixture enters the diverter (3) through the transverse channel (32) of the diverter (3), passes through the central liquid outlet (30) of the diverter (3), the liquid through hole (51) of the gas-liquid separation device (5), and the central hole of the pump barrel (41) of the tubular pump (4), and reaches the second annular space (200) between the hollow sucker rod (43) and the oil pipe (2); The liquid finally reaches the surface through the second annular space (200).

Images