Reformation device for old coal bed gas well reservoir

Abstract

The utility model relates to the field of coal bed gas, in particular to a coal bed gas old well reservoir transformation device which comprises a sand blasting sliding sleeve, the sand blasting sliding sleeve comprises a sliding sleeve outer cylinder and a sliding sleeve core pipe, a plurality of sand blasting openings are formed in the sliding sleeve outer cylinder in the radial direction, and the sand blasting openings are matched with the sliding sleeve core pipe in a plugging mode. The piston hole is located in front of the sand blasting opening and matched with the sliding sleeve core pipe in a plugging mode, a piston is movably connected into the piston hole in a sealed mode, a piston rod is arranged on the piston, extends outwards in the radial direction of the sliding sleeve outer cylinder and is matched with the elastic supporting plate in an abutting mode, and the front end of the elastic supporting plate is fixed to the sliding sleeve outer cylinder. The coal-bed gas well side wall supporting device can abut against the side wall of a coal-bed gas well in the fracturing process, supporting force on the well wall is effectively increased, collapse or instability of the well wall can be prevented, the stability of the well wall is improved, and it is guaranteed that the well wall can bear pressure from fracturing fluid in the fracturing operation without adverse reaction.

Description

Technical Field

[0001] The utility model relates to the field of coalbed methane, in particular to a coalbed methane old well reservoir transformation device. Background Art

[0002] At present, the industry widely uses hydraulic fracturing technology to transform coal seams. Through hydraulic fracturing, a seam network is formed in the coal reservoir to improve the permeability of the coal reservoir. Then, the coalbed methane is produced by draining water and reducing pressure. In the prior art, the Chinese utility model patent with application number CN201020624719.X discloses a segmented fracturing string for oil and gas horizontal wells. This technology can perform fracturing transformation of multiple layers with only one column, and achieve the purpose of multi-layer combined production. However, some old coalbed methane wells do not have the protection of wellbore casing (the completion method is open hole completion, which causes poor stability of the well wall in the horizontal section and easy collapse of the coal seam). The well wall is easily unstable or even collapsed during the fracturing process, which affects the stable operation of the coalbed methane well. Utility Model Content

[0003] Based on the above problems, the purpose of this utility model is to provide a coalbed methane old well reservoir transformation device, and the utility model adopts the following technical solutions:

[0004] The utility model provides a coalbed methane old well reservoir reconstruction device, including a sandblasting sleeve, the sandblasting sleeve including a sleeve outer tube and a sleeve core tube, the sleeve outer tube is radially provided with a plurality of sandblasting ports, the sandblasting ports correspond to the sleeve core tube plugging cooperation, and the utility model is characterized in that: the sleeve outer tube is radially provided with a piston hole, the piston hole is located in front of the sandblasting port, the piston hole corresponds to the sleeve core tube plugging cooperation, a piston is movably sealed and connected with a piston in the piston hole, a piston rod is arranged on the piston, the piston rod extends radially outwardly along the sleeve outer tube and is pressed and cooperated with an elastic support plate, and the front end of the elastic support plate is fixed on the sleeve outer tube.

[0005] Preferably, the matching surfaces between the sliding sleeve outer tube and the sliding sleeve core tube are provided with shear pins.

[0006] Preferably, the cross section of the elastic support plate is an arc-shaped plate.

[0007] Preferably, a plate groove is provided on the outer wall of the sliding sleeve outer cylinder at a position corresponding to the piston hole, and the elastic support plate is arranged in the plate groove.

[0008] Preferably, the front end of the elastic support plate is fixed in the plate groove by screws.

[0009] Preferably, the outer port of the piston hole is provided with a retaining spring, and the inner port is provided with an annular step.

[0010] Preferably, the pressing end of the piston rod is arc-shaped.

[0011] Preferably, an internal thread is arranged on the inner wall at the front end of the sliding sleeve outer cylinder, and an external thread is arranged on the outer wall at the rear end of the sliding sleeve outer cylinder.

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

[0013] The utility model can support the side wall of the coalbed methane well during the fracturing process, effectively increase the supporting force on the well wall, help prevent the well wall from collapsing or causing instability, improve the stability of the well wall, and ensure that the well wall can withstand the pressure from the fracturing fluid without any adverse reaction during the fracturing operation. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0015] Figure 1 This is a schematic diagram of the main structure of the utility model of the coalbed methane old well reservoir transformation device;

[0016] Figure 2 It is a partial structural schematic diagram of the piston of the utility model;

[0017] Figure 3 This is a schematic diagram of the installation and connection between the utility model and the oil and gas pipes.

[0018] Explanation of the reference numerals in the accompanying drawings: 1. Oil and gas pipe; 2. Sandblasting sleeve; 201-1. Plate groove; 201. Sleeve outer tube; 202. Sleeve core tube; 203. Sandblasting port; 204. Piston hole; 204-1. Retaining spring; 204-2. Annular step; 205. Piston; 206. Piston rod; 207. Elastic support plate; 208. Shear pin; 3. Ball receiving seat. DETAILED DESCRIPTION

[0019] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0020] like Figures 1 to 3As shown, the present embodiment discloses a coalbed methane old well reservoir reconstruction device, including a sandblasting sleeve 2, which specifically includes a sleeve outer tube 201 and a sleeve core tube 202. The sleeve outer tube 201 is radially provided with a plurality of sandblasting ports 203, which are sealed with the sleeve core tube 202. The sleeve outer tube 201 is radially provided with a piston hole 204, which is located in front of the sandblasting ports 203. The piston hole 204 is sealed with the sleeve core tube 202. A piston 205 is movably sealed and connected in the piston hole 204. A piston rod 206 is arranged on the piston 205. The piston rod 206 extends radially outward along the sleeve outer tube 201 and is pressed against the elastic support plate 207. The front end of the elastic support plate 207 is fixed on the sleeve outer tube 201.

[0021] The front end of the sleeve core tube 202 has a sealing mating surface for receiving the start ball, and the sealing mating surface is adapted to the start ball. The start ball is a low-density material ball, generally a nylon ball or a hollow steel ball. When working, the oil and gas production pipe 1 is pressurized, and the start ball pushes the sleeve core tube 202 to move backward. When the sleeve core tube 202 is dislocated and separated from the piston hole 204, the fracturing fluid in the sandblasting sleeve 2 first pushes the piston 205 to move radially outward, and then pushes the elastic support plate 207 outward and circumferentially through the piston rod 206. The elastic support plate 207 is first supported on the well wall. When the start ball continues to push the sleeve core tube 202 and the sandblasting port 203 to be dislocated and separated, the fracturing fluid carries the proppant and pressure to press the formation open, squeezes the proppant into the crack, and changes the porosity of the formation through the proppant to support the crack, improve the fluidity of the gas, and increase the gas production. When the fracturing fluid pressure in the sandblasting sleeve 2 decreases, the piston 205 is reset under the elastic action of the elastic support plate 207 .

[0022] In this embodiment, a shear pin 208 is provided on the mating surface of the sliding sleeve outer tube 201 and the sliding sleeve core tube 202. The shear pin 208 fixes the sliding sleeve outer tube 201 and the sliding sleeve core tube 202, and when the start ball pushes the sliding sleeve core tube 202 to move backward, the shear pin 208 breaks.

[0023] In this embodiment, a plate groove 201-1 is provided on the outer wall of the sliding sleeve outer cylinder 201 at a position corresponding to the piston hole 204, and an elastic support plate 207 is provided in the plate groove 201-1. The front end of the elastic support plate 207 is fixed in the plate groove 201-1 by screws. In this embodiment, the elastic support plate 207 is specifically a steel plate with an arc-shaped cross section.

[0024] In this embodiment, the outer end of the piston hole 204 is provided with a retaining spring 204-1, which is fixed to the annular groove on the inner wall of the piston hole 204, and the inner end of the piston hole 204 is provided with an annular step 204-2, which is restricted by the cooperation of the annular step 204-2 and the retaining spring 204-1.

[0025] In this embodiment, the pressing end of the piston rod 206 is arc-shaped, so that it can better press and cooperate with the elastic support plate 207.

[0026] The sandblasting sleeve 2 in the utility model is installed between two adjacent oil and gas pipes 1, and an internal thread is provided on the inner wall of the front end of the sleeve outer tube 201, and an external thread is provided on the outer wall of the rear end of the sleeve outer tube 201. A ball receiving seat 3 is installed between the rear end of the sandblasting sleeve 2 and the oil and gas pipe 1. It should be noted that the oil and gas pipe 1 and the ball receiving seat 3 are both prior art.

[0027] 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 coalbed methane old well reservoir reconstruction device, comprising a sandblasting sleeve (2), the sandblasting sleeve (2) comprising a sleeve outer tube (201) and a sleeve core tube (202), the sleeve outer tube (201) being radially provided with a plurality of sandblasting ports (203), the sandblasting ports (203) corresponding to the sleeve core tube (202) for sealing, characterized in that: A piston hole (204) is radially provided on the sliding sleeve outer tube (201). The piston hole (204) is located in front of the sandblasting port (203). The piston hole (204) corresponds to the sliding sleeve core tube (202) for sealing. A piston (205) is movably sealed in the piston hole (204). A piston rod (206) is provided on the piston (205). The piston rod (206) extends radially outwards of the sliding sleeve outer tube (201) and is pressed against an elastic support plate (207). The front end of the elastic support plate (207) is fixed on the sliding sleeve outer tube (201).

2. The device for transforming the old coalbed methane well reservoir according to claim 1 is characterized in that: The matching surfaces of the sliding sleeve outer tube (201) and the sliding sleeve core tube (202) are provided with shear pins (208).

3. The device for transforming old coalbed methane well reservoir according to claim 1 is characterized in that: The cross section of the elastic support plate (207) is an arc-shaped plate.

4. The device for transforming the old coalbed methane well reservoir according to claim 1 is characterized in that: A plate groove (201-1) is provided on the outer wall of the sliding sleeve outer cylinder (201) at a position corresponding to the piston hole (204), and the elastic support plate (207) is arranged in the plate groove (201-1).

5. The device for transforming the old coalbed methane well reservoir according to claim 4 is characterized in that: The front end of the elastic support plate (207) is fixed in the plate groove (201-1) by means of screws.

6. The device for transforming the old coalbed methane well reservoir according to claim 1 is characterized in that: The outer end of the piston hole (204) is provided with a retaining spring (204-1), and the inner end is provided with an annular step (204-2).

7. The device for transforming old coalbed methane well reservoir according to claim 1 is characterized in that: The pressing end of the piston rod (206) is in an arc shape.

8. The device for transforming the old coalbed methane well reservoir according to claim 1 is characterized in that: An internal thread is provided on the inner wall at the front end of the sliding sleeve outer cylinder (201), and an external thread is provided on the outer wall at the rear end of the sliding sleeve outer cylinder (201).

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