Coal bed gas drainage and mining pipe column

Abstract

The utility model relates to the technical field of coal bed gas exploitation, in particular to a coal bed gas drainage and exploitation pipe column. The coal bed gas drainage and mining pipe column comprises an oil pipe column and a connecting base fixedly installed at the bottom end of the oil pipe column. The screen pipe is mounted on the connecting seat, and a plugging head is mounted at the bottom end of the screen pipe; the adapter pipe is fixedly mounted at the top end of the screen pipe, a plurality of backwashing holes are formed in the adapter pipe, and plugging pieces are mounted on the backwashing holes; the scraping assembly used for scraping and washing the outer wall of the screen pipe is installed on the connecting base. The pump cylinder pipe is fixedly installed at the top end of the adapter pipe, a sucker rod string is installed on the pump cylinder pipe in a sliding mode, a first one-way valve is installed at the bottom end of the pump cylinder pipe, the sucker rod string is hollow, the bottom end of the sucker rod string is communicated with an oil pumping cavity cylinder, and a second one-way valve is arranged at the bottom end of the oil pumping cavity cylinder. The coal bed gas drainage and mining pipe column has the advantages of being convenient to backwash and smooth in drainage and mining.

Description

Technical Field

[0001] The utility model relates to the technical field of coalbed methane mining, in particular to a coalbed methane drainage pipe string. Background Art

[0002] Coalbed methane extraction refers to the process of collecting natural gas (mainly methane) in coal seams to the ground through specific processes and technical means. Coalbed methane is an unconventional natural gas found in coal seams. It exists on the surface of coal in an adsorbed state, and some of it is free in the coal pores or dissolved in the coalbed water. The coalbed methane extraction process mainly includes the following important steps: drainage and pressure reduction: by extracting groundwater from the coal seam and its surrounding rock, the pressure of the coal reservoir is reduced, thereby inducing methane to be desorbed from the coal seam; gas extraction: after reducing the pressure, the adsorbed gas in the coal seam is collected; this usually includes two processes: water injection and exhaust. Water injection is to inject water into the coalbed methane layer and pressurize it to release the coalbed methane. Exhaust is to collect the discharged coalbed methane and transport it to the user end through a pipeline.

[0003] Traditional coalbed methane (CBM) well drainage and production generally uses tubing pumps or rod pumps, and the sucker rod strings of these pumps are all solid. When there is a high concentration of pulverized coal, low water production, or during a temporary shutdown, the pulverized coal carried in the annular liquid column between the sucker rod string and the tubing string of the tubing pump or rod pump will sink and accumulate at the upper port of the tubing pump or rod pump. As the sucker rod string reciprocates, the pulverized coal will enter the gap between the piston and the pump barrel, causing the piston to become stuck in the pump barrel, forcing the CBM well to shut down. Once shut down, traditional unblocking requires removing the production tubing from the well and disassembling it one by one to clear the blockage, which is time-consuming and labor-intensive.

[0004] Therefore, it is necessary to provide a new coalbed methane drainage pipe string to solve the above technical problems. Utility Model Content

[0005] In order to solve the above technical problems, the utility model provides a coalbed methane drainage pipe string which is convenient for backwashing and has smooth drainage.

[0006] The coalbed methane drainage pipe string provided by the utility model comprises: an oil pipe string, and a connecting seat fixedly installed at the bottom end of the oil pipe string;

[0007] A screen pipe is installed on the connecting seat, and a plugging head is installed at the bottom end of the screen pipe;

[0008] A transfer pipe is fixedly installed on the top of the screen tube, and a plurality of backwash holes are opened on the transfer pipe, and a plurality of backwash holes are installed with blocking members;

[0009] A scraping assembly for scraping and cleaning the outer wall of the screen tube is installed on the connecting seat;

[0010] The pump barrel tube is fixedly installed on the top of the transfer tube, and a sucker rod string is slidably installed on the pump barrel tube. A one-way valve is installed at the bottom end of the pump barrel tube. The sucker rod string is hollow, and the bottom end of the sucker rod string is connected to an oil pumping cavity tube. A one-way valve is provided at the bottom end of the oil pumping cavity tube.

[0011] Preferably, the sealing member includes a mounting block, which is fixedly mounted on the outside of the transfer tube, and the mounting block is provided with a through hole connected to the backwash hole, a connecting spring is fixedly mounted in the through hole, and a sealing block for sealing the backwash hole is mounted at the bottom end of the connecting spring.

[0012] Preferably, the scraping assembly includes a sliding rod, and there are several sliding rods. Several of the sliding rods are slidably installed on the connecting seat, and the bottom ends of the several sliding rods pass through the connecting seat and are commonly fixedly installed with a cleaning ring, and the top ends of the several sliding rods are commonly fixedly installed with a piston ring, the outer side wall of the piston ring is slidably fitted with the inner wall of the oil pipe string, and the inner side wall of the piston ring is slidably fitted with the outer side wall of the transfer tube.

[0013] Preferably, a cleaning brush for cleaning the screen tube is fixedly mounted on the inner side wall of the cleaning ring.

[0014] Preferably, mounting grooves are provided on both the inner and outer sides of the piston ring, and sealing rings are installed in the mounting grooves.

[0015] Preferably, a one-way valve three is installed at the top of the screen tube.

[0016] Compared with related technologies, the coalbed methane drainage string provided by the present invention has the following beneficial effects:

[0017] The utility model provides a coalbed methane drainage pipe string, which is provided with a transfer pipe on a connecting seat, a backwash hole on the transfer pipe, and a sealing piece for facilitating backwashing. A scraping assembly is provided, and the scraping assembly cooperates with a slide rod, a cleaning ring, a piston ring, a cleaning brush and a sealing ring. When performing unblocking and backwashing, the sieve holes of the sieve pipe can be cleaned synchronously, which helps to improve the smoothness of drainage. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic structural diagram of a preferred embodiment of a coalbed methane drainage pipe string provided by the utility model;

[0019] Figure 2 A schematic diagram of the cross-sectional structure of the coalbed methane drainage pipe string provided by the utility model;

[0020] Figure 3 This is a structural diagram of a screen tube installed on the connecting seat provided by the present invention;

[0021] Figure 4 A schematic diagram of the internal structure of a screen tube installed on the connecting seat provided by the present invention;

[0022] Figure 5 for Figure 2 A partial enlarged view of A shown.

[0023] Numbers in the figure: 1. Oil tubing string; 11. Connecting seat; 2. Screen tube; 21. Blocking head; 22. One-way valve three; 3. Transfer tube; 301. Backwash hole; 4. Blocking piece; 41. Mounting block; 42. Connecting spring; 43. Blocking block; 401. Through hole; 5. Scraper assembly; 51. Sliding rod; 52. Cleaning ring; 53. Piston ring; 54. Cleaning brush; 55. Sealing ring; 6. Pump barrel; 61. One-way valve one; 7. Sucker rod string; 71. Sucker chamber; 72. One-way valve two. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0025] The specific implementation of the present invention is described in detail below with reference to specific embodiments.

[0026] See also Figures 1 to 5 The present invention provides a coalbed methane drainage string, which includes:

[0027] An oil tubing string 1, and a connecting seat 11 fixedly mounted at the bottom end of the oil tubing string 1;

[0028] The screen tube 2 is installed on the connecting seat 11, and a plugging head 21 is installed at the bottom end of the screen tube 2;

[0029] The transfer pipe 3 is fixedly installed on the top of the screen tube 2, and a plurality of backwash holes 301 are opened on the transfer pipe 3, and a plurality of backwash holes 301 are installed with blocking members 4;

[0030] A scraping assembly 5 for scraping and cleaning the outer wall of the screen tube 2 is installed on the connecting seat 11;

[0031] The pump barrel tube 6 is fixedly installed on the top end of the transfer tube 3, and a sucker rod string 7 is slidably installed on the pump barrel tube 6. A one-way valve 61 is installed at the bottom end of the pump barrel tube 6. The sucker rod string 7 is hollow, and the bottom end of the sucker rod string 7 is connected to a pumping cavity 71. The bottom end of the pumping cavity 71 is provided with a one-way valve 2 72.

[0032] Among them, a one-way valve 3 22 is installed at the top of the screen pipe 2.

[0033] It should be noted that: when in use, the screen tube 2 is moved to the coal seam following the oil pipe string 1, and then the coal oil layer is filtered by the screen tube 2, and then the gas-liquid mixture is pumped from the one-way valve three 22, the transfer pipe 3 and the pump barrel 6 by the sucker rod string 7 to discharge the mixture. When backwashing is required, the pumping of the sucker rod string 7 is stopped, and then the backwashing liquid is flushed from the gap between the oil pipe string 1 and the transfer pipe 3, the sealing part 4 is flushed open, and the entire transfer pipe 3, the pump barrel 6 and the sucker rod string 7 are backwashed from the backwash hole 301, and the flushing liquid is discharged from the one-way valve two 72 and the pumping cavity 71, thereby realizing rapid backwashing. After backwashing, the backwashing liquid is intermittently injected to drive the scraping assembly 5 to scrape the screen tube 2 up and down, thereby cleaning the screen tube 2, which helps to improve the smoothness of drainage.

[0034] In the embodiments of the present invention, please refer to Figures 1 to 5 The sealing member 4 includes a mounting block 41, which is fixedly mounted on the outside of the transfer tube 3, and the mounting block 41 is provided with a through hole 401 connected to the backwash hole 301, a connecting spring 42 is fixedly mounted in the through hole 401, and a sealing block 43 for sealing the backwash hole 301 is mounted at the bottom end of the connecting spring 42.

[0035] It should be noted that: when the sealing member 4 is performing drainage, the connecting spring 42 drives the sealing block 43 to seal the backwash hole 301, thereby preventing gas and liquid leakage during drainage. When backwashing is performed, the backwashing liquid pushes the sealing block 43 upward from the through hole 401, thereby opening the backwash hole 301 for backwashing.

[0036] In the embodiments of the present invention, please refer to Figures 1 to 5 The scraping assembly 5 includes a sliding rod 51, and there are several sliding rods 51. Several of the sliding rods 51 are slidably installed on the connecting seat 11, and the bottom ends of the several sliding rods 51 pass through the connecting seat 11 and are fixedly installed with a cleaning ring 52. The top ends of the several sliding rods 51 are fixedly installed with a piston ring 53. The outer wall of the piston ring 53 slides with the inner wall of the oil pipe string 1, and the inner wall of the piston ring 53 slides with the outer wall of the transfer tube 3.

[0037] A cleaning brush 54 for cleaning the screen tube 2 is fixedly mounted on the inner side wall of the cleaning ring 52 , and mounting grooves are provided on both the inner and outer sides of the piston ring 53 , with sealing rings 55 mounted in the mounting grooves.

[0038] It should be noted that when the scraping assembly 5 is in use and backwashing liquid is injected into the gap, the flushing liquid drives the piston ring 53 to move up and down alternately along the transfer tube 3. During the movement, the cleaning ring 52 and the cleaning brush 54 are driven by the sliding rod 51 to clean the outer wall of the screen tube 2 up and down, thereby avoiding congestion of the screen tube 2 and improving the smoothness of drainage.

[0039] The working principle of the coalbed methane drainage pipe string provided by the utility model is as follows:

[0040] When in use, the screen tube 2 is moved to the coal seam following the oil pipe string 1, and then the screen tube 2 is used to filter the coal oil layer, and then the gas-liquid mixture is pumped from the one-way valve three 22, the transfer pipe 3 and the pump barrel 6 by the sucker rod string 7 to discharge the mixture. When backwashing is required, the pumping of the sucker rod string 7 is stopped, and then the backwashing liquid is flushed from the gap between the oil pipe string 1 and the transfer pipe 3 to open the sealing member 4 and backwash the entire transfer pipe 3, the pump barrel 6 and the sucker rod string 7 from the backwashing hole 301, and the flushing liquid is discharged from the one-way valve two 72 and the oil pumping cavity 71, thereby achieving rapid backwashing. After backwashing, the backwashing liquid is intermittently injected to drive the scraper assembly 5 to scrape the screen tube 2 up and down, thereby cleaning the screen tube 2, which helps to improve the smoothness of drainage.

[0041] Specifically, when backwashing liquid is injected into the gap, the flushing liquid drives the piston ring 53 to move up and down alternately along the transfer tube 3. During the movement, the sliding rod 51 drives the cleaning ring 52 and the cleaning brush 54 to clean the outer wall of the screen tube 2 up and down, thereby avoiding congestion of the screen tube 2 and improving the smoothness of drainage.

[0042] The circuits and controls involved in the present invention are all prior art and will not be described in detail here.

[0043] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A coalbed methane drainage string, comprising: An oil tubing string (1), and a connecting seat (11) fixedly mounted on the bottom end of the oil tubing string (1); A screen tube (2) is installed on the connecting seat (11), and a plugging head (21) is installed at the bottom end of the screen tube (2); It is characterized by further comprising: A transfer pipe (3) is fixedly mounted on the top end of the screen tube (2), and a plurality of backwash holes (301) are opened on the transfer pipe (3), and a plurality of backwash holes (301) are equipped with blocking members (4); A scraping assembly (5) for scraping and cleaning the outer wall of the screen tube (2), wherein the scraping assembly (5) is mounted on the connecting seat (11); A pump barrel tube (6) is fixedly mounted on the top end of the transfer tube (3), and a sucker rod column (7) is slidably mounted on the pump barrel tube (6). A one-way valve (61) is mounted at the bottom end of the pump barrel tube (6). The sucker rod column (7) is hollow, and the bottom end of the sucker rod column (7) is connected to a pumping cavity tube (71). A one-way valve (72) is mounted at the bottom end of the pumping cavity tube (71).

2. The coalbed methane drainage string according to claim 1, characterized in that: The blocking member (4) comprises a mounting block (41), the mounting block (41) being fixedly mounted on the outside of the transfer tube (3), and the mounting block (41) being provided with a through hole (401) communicating with the backwash hole (301), a connecting spring (42) being fixedly mounted in the through hole (401), and a blocking block (43) for sealing the backwash hole (301) being mounted at the bottom end of the connecting spring (42).

3. The coalbed methane drainage string according to claim 1, characterized in that: The scraping assembly (5) includes a plurality of sliding rods (51), wherein the plurality of sliding rods (51) are slidably mounted on the connecting seat (11), and the bottom ends of the plurality of sliding rods (51) pass through the connecting seat (11) and are fixedly mounted with a cleaning ring (52), and the top ends of the plurality of sliding rods (51) are fixedly mounted with a piston ring (53), the outer wall of the piston ring (53) is slidably matched with the inner wall of the oil pipe string (1), and the inner wall of the piston ring (53) is slidably matched with the outer wall of the transfer tube (3).

4. The coalbed methane drainage string according to claim 3, characterized in that: A cleaning brush (54) for cleaning the screen tube (2) is fixedly mounted on the inner side wall of the cleaning ring (52).

5. The coalbed methane drainage string according to claim 3, characterized in that: The piston ring (53) is provided with mounting grooves on both the inner and outer sides, and sealing rings (55) are installed in the mounting grooves.

6. The coalbed methane drainage string according to claim 1, characterized in that: A one-way valve three (22) is installed at the top end of the screen tube (2).

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