High-permeability coal bed gas development well type device

Abstract

The utility model discloses a high permeability coalbed methane development well type device which comprises a straight well section and a horizontal well which are communicated with each other, a casing pipe is arranged in the straight well section, the lower end of the casing pipe extends into the horizontal well and is communicated with a screen pipe, a plurality of sets of screen holes are evenly formed in the peripheral wall of the screen pipe at intervals, and the screen holes are communicated with the horizontal well. Each group of screen holes are uniformly formed in the circumferential direction of the screen pipe at intervals; a sealing sliding seat is arranged in the screen pipe in a sliding mode, an ejector is arranged at the end, facing the sleeve pipe, of the sealing sliding seat, a plurality of ejection pipes are evenly arranged on the periphery of the ejector in the circumferential direction, and the ejection pipes correspond to the multiple screen holes of each group in a one-to-one mode. The coal bed gas production device is applied to coal bed gas development operation of a high-permeability coal bed, due to the fact that the permeability of gas in the coal bed is high in the initial stage of development, gas can be produced without the fracturing technology, and water energy waste and equipment investment are reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of coalbed methane development wells, in particular to a high-permeability coalbed methane development well type device. Background Art

[0002] Coalbed methane refers to hydrocarbon gas adsorbed on the surface of coal matrix particles in the coal seam, or partially free in the coal pores or dissolved in the coal seam water. Its main component is methane. It is a coal-associated mineral resource and an unconventional natural gas. It is a clean, high-quality energy and chemical raw material that has emerged internationally in the past 10 to 20 years.

[0003] At present, the exploitation of coalbed methane is mainly horizontal well exploitation, which mainly adopts hydraulic fracturing technology. Specifically, liquid can be injected into the coal seam through the wellbore to form a very high pressure in the coal seam, so that the coal seam will produce multiple fractures extending far. When exploiting coalbed methane, a large area of ​​pressure drop occurs around the wellbore channel. The surface area of ​​gas decomposition caused by the pressure reduction of coalbed methane increases, and the coalbed methane is quickly decomposed and then exploited. However, for some high-permeability areas, if the fracturing process is directly used, it will lead to serious waste of water resources, large equipment investment, and will cause a certain degree of damage to the coal seam. Therefore, a high-permeability coalbed methane development well type device is developed. Utility Model Content

[0004] The purpose of the utility model is to provide a high-permeability coalbed methane development well device to solve the technical problems mentioned in the above background technology.

[0005] In order to solve the above technical problems, the utility model adopts the following technical solutions:

[0006] The utility model discloses a high-permeability coalbed methane development well type device, comprising a vertical well section and a horizontal well which are interconnected, wherein a casing is arranged inside the vertical well section, the lower end of the casing extends into the horizontal well and is connected with a screen pipe, a plurality of groups of screen holes are evenly spaced on the peripheral wall of the screen pipe, and the screen holes of each group are evenly spaced along the circumference of the screen pipe; a sealing sliding seat is slidably arranged inside the screen pipe, an injector is arranged at one end of the sealing sliding seat facing the casing, a plurality of injection pipes are evenly arranged along the circumference of the outer periphery of the injector, and each of the injection pipes is arranged in one-to-one correspondence with the plurality of screen holes of each group; an end of the injector which is away from the sealing sliding seat is connected with one end of a water supply pipe through a first joint, and the other end of the water supply pipe extends to the top of the vertical well section and is connected with a winch mechanism.

[0007] Furthermore, a sealing ring groove is formed on the inner peripheral wall of the screen tube between each two adjacent groups of screen holes; and an expansion sealing ring matched with the sealing ring groove is arranged outside the sealing sliding seat.

[0008] Furthermore, the sealing slide is connected to the injector via a second joint, and a water passage cavity connected to the second joint is provided inside the sealing slide, and the water passage cavity is connected to the expansion sealing ring via a plurality of water passage channels.

[0009] Furthermore, an electric on-off valve is arranged on the second joint, and an electric pressure relief valve connected with the water passage chamber is arranged on the side of the sealing slide away from the injector.

[0010] Furthermore, the hoisting mechanism includes two symmetrically arranged frame plates, a hoisting drum is rotatably arranged between the two frame plates, and a hydraulic motor for driving the hoisting drum to rotate is arranged on the outer side of one of the frame plates, the part of the water supply pipe located outside the straight well section is wound around the outer peripheral wall of the hoisting drum, the interior of the hoisting drum is a cavity structure, which is connected to the other end of the water supply pipe through a third joint, and the end of the hoisting drum away from the hydraulic motor is connected to an external high-pressure water source.

[0011] Furthermore, a rotary joint is provided on the frame plate where the hydraulic motor is not provided, one end of the rotary joint is connected to the end of the winch drum away from the hydraulic motor, and the other end is connected to a high-pressure water source through a corresponding pipeline.

[0012] Compared with the prior art, the beneficial technical effects of the utility model are:

[0013] The utility model is generally applied to the coalbed methane development operation of high-permeability coal seams. Through the well type arrangement mode combining casing and screen pipe, in the initial stage of development, due to the relatively high permeability of gas inside the coal seam, gas can be produced without fracturing process, thus reducing water energy waste and equipment investment. In the later stage, the coal seams of the horizontal well section are sequentially subjected to high-pressure jetting operation through the ejector, thereby improving the coal seam permeability effect and effectively preventing the occurrence of liquid flow backflow. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The utility model will be further described below in conjunction with the accompanying drawings.

[0015] Figure 1 It is a schematic diagram of the structure of the utility model;

[0016] Figure 2 This is a schematic diagram of the cooperation between the sealing slide and the screen tube of the utility model;

[0017] Figure 3 This is a schematic diagram of the connecting seat structure of the utility model;

[0018] Explanation of the reference numerals: 1. vertical well section; 2. horizontal well; 3. casing; 4. screen tube; 5. screen hole; 6. sealing slide; 7. ejector; 9. ejector pipe; 9. first joint; 10. water supply pipe; 11. sealing ring groove; 12. expansion sealing ring; 13. second joint; 14. water passage chamber; 15. water passage; 16. electric on-off valve; 17. electric pressure relief valve; 18. frame plate; 19. winch drum; 20. hydraulic motor; 21. third joint; 22. rotary joint. DETAILED DESCRIPTION

[0019] like Figure 1-Figure 3 As shown, a high-permeability coalbed methane development well device includes a vertical well section 1 and a horizontal well 2 that are interconnected. A casing 3 is arranged inside the vertical well section 1. The lower end of the casing 3 extends into the horizontal well 2 and is connected to a screen pipe 4. Multiple groups of screen holes 5 are evenly spaced on the peripheral wall of the screen pipe 4, and each group of the screen holes 5 is evenly spaced along the circumference of the screen pipe 4.

[0020] A sealing slide 6 is slidably arranged inside the screen tube 4, an injector 7 is arranged at one end of the sealing slide 6 facing the casing, a plurality of injection pipes 8 are evenly arranged along the circumferential direction on the outer periphery of the injector 7, and each of the injection pipes 8 is arranged one-to-one correspondingly to each group of the plurality of screen holes 5.

[0021] The end of the ejector 7 facing away from the sealing slide 6 is connected to one end of a water supply pipe 10 through a first joint 9. The other end of the water supply pipe 10 extends to the top of the vertical well section 1 and is connected to a winch mechanism.

[0022] In this embodiment, the inner peripheral wall of the screen tube 4 is provided with a sealing ring groove 11 between each two adjacent groups of screen holes 5; the outer side of the sealing slide 6 is provided with an expansion sealing ring 12 adapted to the sealing ring groove 11. The sealing slide 6 is connected to the injector 7 through a second joint 13, and a water passage cavity 14 connected to the second joint 13 is provided inside the sealing slide 6, and the water passage cavity 14 is connected to the expansion sealing ring 12 through a plurality of water passage channels 15. In addition, an electric on-off valve 16 is installed on the second joint 13, and an electric pressure relief valve 17 connected to the water passage cavity 14 is installed on the side of the sealing slide 6 away from the injector 7.

[0023] The hoisting mechanism includes two symmetrically fixed vertically arranged frame plates 18, a hoisting drum 19 is rotatably mounted between the two frame plates 18, and a hydraulic motor 20 for driving the hoisting drum 19 to rotate is mounted on the outer side of one of the frame plates 18, and the portion of the water supply pipe 10 located outside the vertical well section 1 is wound around the outer peripheral wall of the hoisting drum 19. The interior of the hoisting drum 19 is a cavity structure, which is connected to the other end of the water supply pipe 10 through a third joint 21. The end of the hoisting drum 19 away from the hydraulic motor 20 is connected to an external high-pressure water source. Specifically, a rotary joint 22 is installed on the frame plate 18 where the hydraulic motor 20 is not installed, one end of the rotary joint 22 is connected to the end of the hoisting drum 19 away from the hydraulic motor 20, and the other end is connected to the high-pressure water source through a corresponding pipeline.

[0024] The utility model is applied to the coalbed methane development operation of high-permeability coal seams. In the initial stage of development, since the permeability of the gas inside the coal seam is relatively high, gas can be produced without the need for a fracturing process. In this stage, the injector and the sealing slide are arranged at the innermost end of the screen tube of the horizontal well. At this time, coalbed methane is mined under normal conditions. After a period of gas production, the permeability of the coal seam may decrease. At this time, the coal seam can be transformed by a fracturing process. Similarly, the hoisting device pulls the water supply pipe outward, and the injector stops when it is aligned with the first group of sieve holes near the tail end of the screen tube. The external high-pressure water source enters the injector through the water supply pipe. The injector injects high-pressure water to the coal seam through each injection pipe, so that the coal seam forms perforated holes and improves the permeability of the coal seam. At the same time, the high-pressure water flow enters the sealing slide seat to cause the expansion sealing ring to expand outward and cooperate with the sealing slide groove on the screen tube, thereby ensuring the sealing of the rear section and avoiding the backflow of liquid during the operation. When the jet improvement of the coal seam in this area is completed, the expansion sealing ring on the sealing slide is depressurized and contracted through the electric pressure relief valve. According to the above working method, the water supply pipe is pulled by the winch mechanism to make the ejector pass through each group of sieve holes on the screen pipe in turn, thereby improving the jet of the coal seams in various parts of the horizontal well and improving the permeability of the coal seams.

[0025] The embodiments described above are only descriptions of the preferred methods of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the protection scope determined by the claims of the present invention.

Claims

1. A high permeability coalbed methane development well device, characterized by: It comprises a vertical well section and a horizontal well which are interconnected, wherein a casing is arranged inside the vertical well section, the lower end of the casing extends into the horizontal well and is connected with the screen pipe, a plurality of groups of screen holes are evenly spaced on the peripheral wall of the screen pipe, and each group of the screen holes is evenly spaced along the circumference of the screen pipe; a sealing slide is slidably arranged inside the screen pipe, an injector is arranged at one end of the sealing slide facing the casing, a plurality of injection pipes are evenly arranged along the circumference of the outer periphery of the injector, and each of the injection pipes is arranged one by one corresponding to the plurality of screen holes in each group; an end of the injector which is away from the sealing slide is connected with one end of a water supply pipe through a first joint, and the other end of the water supply pipe extends to the top of the vertical well section and is connected with a winch mechanism.

2. The high permeability coalbed methane development well device according to claim 1 is characterized in that: The inner peripheral wall of the screen tube is provided with a sealing ring groove between each two adjacent groups of screen holes; and the outside of the sealing sliding seat is provided with an expansion sealing ring matched with the sealing ring groove.

3. The high permeability coalbed methane development well device according to claim 2 is characterized in that: The sealing slide is connected to the injector via a second joint, and a water passage cavity connected to the second joint is provided inside the sealing slide. The water passage cavity is connected to the expansion sealing ring via a plurality of water passage channels.

4. The high permeability coalbed methane development well device according to claim 3 is characterized in that: The second joint is provided with an electric on-off valve, and the side of the sealing slide away from the injector is provided with an electric pressure relief valve connected with the water passage chamber.

5. The high permeability coalbed methane development well device according to claim 1 is characterized in that: The hoisting mechanism includes two symmetrically arranged frame plates, a hoisting drum is rotatably arranged between the two frame plates, and a hydraulic motor for driving the hoisting drum to rotate is arranged on the outer side of one of the frame plates, the part of the water supply pipe located outside the straight well section is wound around the outer peripheral wall of the hoisting drum, the interior of the hoisting drum is a cavity structure, which is connected to the other end of the water supply pipe through a third joint, and the end of the hoisting drum away from the hydraulic motor is connected to an external high-pressure water source.

6. The high permeability coalbed methane development well device according to claim 5 is characterized in that: A rotary joint is arranged on the frame plate without the hydraulic motor, one end of the rotary joint is connected with the end of the hoisting drum away from the hydraulic motor, and the other end is connected with the high-pressure water source through a corresponding pipeline.

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