Well head gas recovery device for coal-bed gas well

Abstract

The utility model belongs to the technical field of coal-bed gas extraction, and particularly relates to a well head gas recovery device of a coal-bed gas well. Comprising a water inlet pipe, a water outlet pipe and a U-shaped pipe, a first pipe opening of the U-shaped pipe is closed, a second pipe opening is used for being connected with the water outlet pipe, the first pipe opening of the U-shaped pipe is higher than the second pipe opening, the water inlet pipe is perpendicularly communicated with a vertical pipe where the first pipe opening of the U-shaped pipe is located, and a tubular joint is lower than the first pipe opening of the U-shaped pipe and higher than the second pipe opening; a first pipe orifice of the U-shaped pipe is connected with an exhaust pipeline; a blow-off pipe is connected to the bottom of the U-shaped bend of the U-shaped pipe, and a blow-off valve is arranged on the blow-off pipe; by means of the coal-bed gas well mouth dissolved gas recovery device, recovery of water dissolved gas, part of free gas and dissolved gas in produced pulverized coal at a coal-bed gas well mouth can be achieved, and low-cost energy conservation and emission reduction are achieved.

Description

Technical Field

[0001] The utility model belongs to the technical field of coalbed methane extraction, and in particular relates to a coalbed methane wellhead gas recovery device. Background Art

[0002] CBM can be produced by drainage to reduce reservoir pressure and realize water and gas production in CBM wells. When CBM wells are mined, in addition to a large amount of CBM, some water will be produced in the wellbore at the same time, which will also carry a certain amount of coal powder into the wellbore. The existence forms of CBM in the wellbore mainly include free, dissolved and adsorbed. Under normal circumstances, most of the free CBM is produced from the annular space between the oil pipe and the casing to the ground and enter the ground pipeline system; a small amount of free, dissolved and adsorbed CBM is discharged into the ground drainage pool with the drainage water. In this case, it will cause waste in the development of CBM resources. On this basis, the recovery and reuse of gas in the water produced by CBM wellhead will be beneficial to saving energy and improving the economic benefits of CBM development. At present, gas recovery and reuse technology mainly draws on the oil and gas recovery technology in the development of oil and gas fields. Its main oil and gas recovery methods include adsorption, condensation, absorption, membrane separation, etc. For coalbed methane, these technical methods are relatively complex, costly and difficult to operate. There is an urgent need for a simple, efficient and low-cost process device to recover coalbed methane wellhead gas. Utility Model Content

[0003] The utility model aims to solve the problem that part of free, dissolved and adsorbed coalbed methane is carried away with the drainage water during the liquid production process of coalbed methane wells, resulting in energy waste.

[0004] The utility model provides the following technical scheme: a gas recovery device at the wellhead of a coalbed methane well, comprising an inlet pipe, an outlet pipe and a U-shaped pipe, wherein the first pipe opening of the U-shaped pipe is closed, and the second pipe opening is used to connect the outlet pipe, the first pipe opening of the U-shaped pipe is higher than the second pipe opening, the inlet pipe and the riser where the first pipe opening of the U-shaped pipe is located are vertically intersected, and the intersection node is lower than the first pipe opening of the U-shaped pipe and higher than the second pipe opening; the first pipe opening of the U-shaped pipe is connected to an exhaust pipeline; the bottom of the U-shaped bend of the U-shaped pipe is connected to a sewage pipe, and a sewage valve is arranged on the sewage pipe.

[0005] Furthermore, the exhaust pipeline includes a first exhaust pipe and a second exhaust pipe, the first exhaust pipe is connected to the first pipe opening of the U-shaped pipe, and the first exhaust pipe is parallel to the vertical pipe where the first pipe opening is located; the second exhaust pipe intersects the first exhaust pipe vertically; a vent valve is arranged on the first exhaust pipe above the intersection node of the second exhaust pipe, and an exhaust valve is arranged on the second exhaust pipe.

[0006] Furthermore, a pressure gauge is connected to the first pipe opening of the U-shaped pipe, and a valve is provided on the air inlet pipe of the pressure gauge.

[0007] Furthermore, a gas one-way valve is provided on the second exhaust pipe.

[0008] Furthermore, the water outlet pipe is a 90° elbow, the water outlet pipe is smoothly connected to the second pipe opening of the U-shaped pipe, a flange is connected to the pipe opening of the water outlet pipe; and a flange is connected to the pipe opening of the water inlet pipe.

[0009] Furthermore, the diameter of the water inlet pipe is smaller than that of the U-shaped pipe.

[0010] Compared with the prior art, the advantages of the present invention are:

[0011] The utility model provides a gas recovery device at the wellhead of a coalbed methane well, which connects the drainage outlet pipeline of the coalbed methane well to a designed curved pipeline. The curved pipeline can be manufactured in different sizes and specifications according to needs, and can achieve gas-water separation, coal powder sedimentation and sufficient desorption of adsorbed gas, and can block the gas from flowing out along the drainage pipeline outlet. The gas recovery outlet is located at the top of the device and can be directly connected to a low-pressure pipeline or a low-pressure gathering and transportation device. The low-cost imported coalbed methane recovery and reuse is realized, which is beneficial to saving energy and improving the economic benefits of coalbed methane development. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural schematic diagram of the utility model.

[0013] In the figure: 1-water inlet pipe; 2-water outlet pipe; 3-U-shaped pipe; 3.1-first pipe opening; 3.2-second pipe opening; 4-second exhaust pipe; 5-first exhaust pipe; 6-pressure gauge; 7-drain valve; 8-drain pipe; 9-valve; 10-vent valve; 11-exhaust valve; 12-gas one-way valve. DETAILED DESCRIPTION

[0014] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0015] like Figure 1As shown: a gas recovery device at the wellhead of a coalbed methane well, comprising an inlet pipe 1, an outlet pipe 2 and a U-shaped pipe 3, wherein the first pipe opening 3.1 of the U-shaped pipe 3 is closed, and the second pipe opening 3.2 is used to connect the outlet pipe 2, the first pipe opening 3.1 of the U-shaped pipe 3 is higher than the second pipe opening 3.2, the inlet pipe 1 and the riser where the first pipe opening 3.1 of the U-shaped pipe 3 is located are vertically intersected, and the intersection node is lower than the first pipe opening 3.1 of the U-shaped pipe 3 and higher than the second pipe opening 3.2; the first pipe opening 3.1 of the U-shaped pipe 3 is connected to an exhaust pipeline; the bottom of the U-shaped bend of the U-shaped pipe 3 is connected to a sewage pipe 8, and a sewage valve 7 is provided on the sewage pipe 8.

[0016] The water entering from the water inlet pipe 1 impacts the wall of the U-shaped pipe 3, and the water falls to the bottom of the U-shaped pipe 3. The coalbed methane carried in the water floats up to the first pipe opening 3.1 of the U-shaped pipe 3, and the coalbed methane enters the low-pressure gathering and transportation device through the exhaust pipeline; the coalbed produced water and a small amount of coal powder carried enter the U-shaped bend of the U-shaped pipe 3, and the coal powder is fully settled in the U-shaped bend, which also makes the adsorbed gas in the coal powder fully desorbed. After opening the sewage valve 7, the fully desorbed coal powder is discharged into the sewage pool through the sewage pipe 8. Finally, the produced water flows to the water outlet pipe 2, so that the produced water of the coalbed methane well is discharged normally.

[0017] The diameter of the water inlet pipe 1 is smaller than that of the U-shaped pipe 3, so the water entering the U-shaped pipe 3 from the water inlet pipe 1 can complete gas-water separation more efficiently.

[0018] The exhaust pipeline includes a first exhaust pipe 5 and a second exhaust pipe 4. The first exhaust pipe 5 is connected to the first pipe opening 3.1 of the U-shaped pipe 3, and the first exhaust pipe 5 is parallel to the vertical pipe where the first pipe opening 3.1 is located; the second exhaust pipe 4 and the first exhaust pipe 5 are vertically intersected; a vent valve 10 is arranged on the first exhaust pipe 5 above the intersection node with the second exhaust pipe 4, and an exhaust valve 11 is arranged on the second exhaust pipe 4.

[0019] A pressure gauge 6 is connected to the first pipe opening 3.1 of the U-shaped tube 3, and a valve 9 is provided on the air inlet pipe of the pressure gauge 6. The air pressure in the U-shaped tube 3 is observed by the pressure gauge 6, and when the air pressure in the U-shaped tube 3 is too high, the vent valve 10 is opened to release the pressure.

[0020] A gas one-way valve 12 is provided on the second exhaust pipe 4 to prevent the coalbed methane in the second exhaust pipe 4 from being sucked back when the vent valve 10 is opened to release pressure.

[0021] The water outlet pipe 2 is a 90° elbow pipe, and is smoothly connected to the second pipe opening 3.2 of the U-shaped pipe 3. A flange is connected to the pipe opening of the water outlet pipe 2; and a flange is connected to the pipe opening of the water inlet pipe 1.

[0022] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A coalbed methane wellhead gas recovery device, characterized in that: The invention comprises a water inlet pipe (1), a water outlet pipe (2) and a U-shaped pipe (3); the first pipe opening (3.1) of the U-shaped pipe (3) is closed, and the second pipe opening (3.2) is used to connect to the water outlet pipe (2); the first pipe opening (3.1) of the U-shaped pipe (3) is higher than the second pipe opening (3.2); the water inlet pipe (1) and a vertical pipe where the first pipe opening (3.1) of the U-shaped pipe (3) is located intersect vertically, and the intersection node is lower than the first pipe opening (3.1) of the U-shaped pipe (3) and higher than the second pipe opening (3.2); the first pipe opening (3.1) of the U-shaped pipe (3) is connected to an exhaust pipeline; the bottom of the U-shaped bend of the U-shaped pipe (3) is connected to a sewage pipe (8), and a sewage valve (7) is provided on the sewage pipe (8).

2. A coalbed methane wellhead gas recovery device according to claim 1, characterized in that: The exhaust pipeline comprises a first exhaust pipe (5) and a second exhaust pipe (4); the first exhaust pipe (5) is connected to a first pipe opening (3.1) of the U-shaped pipe (3); the first exhaust pipe (5) is parallel to a vertical pipe where the first pipe opening (3.1) is located; the second exhaust pipe (4) intersects the first exhaust pipe (5) vertically; a vent valve (10) is arranged on the first exhaust pipe (5) above a node where the first exhaust pipe (5) intersects with the second exhaust pipe (4); and an exhaust valve (11) is arranged on the second exhaust pipe (4).

3. A coalbed methane wellhead gas recovery device according to claim 2, characterized in that: The first pipe opening (3.1) of the U-shaped pipe (3) is connected to a pressure gauge (6), and a valve (9) is provided on the air inlet pipeline of the pressure gauge (6).

4. A coalbed methane wellhead gas recovery device according to claim 2, characterized in that: The second exhaust pipe (4) is provided with a gas one-way valve (12).

5. A coalbed methane wellhead gas recovery device according to claim 1, characterized in that: The water outlet pipe (2) is a 90° elbow pipe, the water outlet pipe (2) is smoothly connected to the second pipe opening (3.2) of the U-shaped pipe (3), the pipe opening of the water outlet pipe (2) is connected to a flange; the pipe opening of the water inlet pipe (1) is connected to a flange.

6. A coalbed methane wellhead gas recovery device according to claim 1, characterized in that: The diameter of the water inlet pipe (1) is smaller than that of the U-shaped pipe (3).

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