Coal bed gas U-shaped well segmented step-by-step drainage method

A technology for coalbed methane wells and coalbed methane, which is applied in the direction of mining fluids, earthwork drilling, wellbore/well components, etc., can solve problems such as unreasonable drainage system, poor gas production effect, and unstable production, and prevent large coal seams. The effect of bare area

Active Publication Date: 2019-03-29
SHANXI JINCHENG ANTHRACITE COAL MINING GRP CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The main purpose of the present invention is to provide a method for step-by-step step-by-step depressurization and extraction of U-shaped coalbed methane wells,

Method used

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  • Coal bed gas U-shaped well segmented step-by-step drainage method
  • Coal bed gas U-shaped well segmented step-by-step drainage method

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Embodiment Construction

[0017] The present invention is aimed at the characteristics of the coal seam with a large dip angle, and uses the fracturing point of the U-shaped well as the key point of drainage control, and depressurizes step by step, and the specific process is as follows:

[0018] (1) The principle of gas production first in the remote butt joint horizontal well project. Since the horizontal section of the far-end docking well is generally drilled in the downhill manner, the coal seam section near the engineering well reaches the desorption condition first. If the coal seam dip angle is large, this phenomenon is more obvious.

[0019] (2) Three-stage drainage stage. The stage from the initial liquid level of the CBM well to the critical desorption pressure point is regarded as the first drainage stage; the liquid level from the critical desorption pressure point to the liquid level 20m above the roof of the target coal seam is regarded as the second drainage stage; subsequent drainage i...

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Abstract

The invention relates to the technical field of coal bed gas drainage, in particular to a coal bed gas U-shaped well segmented step-by-step drainage method. Three drainage stages are divided accordingto the characteristic of the track of a large-tilt-angle coal bed U-shaped well; the stage that the initial liquid level of the coal bed gas well reaches a critical desorption pressure point serves as the first drainage stage; the stage that the critical desorption pressure point reaches the liquid level 20 m above a target coal bed top plate serves as the second drainage stage; the stage of following drainage serves as the third drainage stage. Different drainage stages of the large-tilt-angle coal bed U-shaped well are definitely divided, and it is guaranteed that the coal bed gas well canbe stably depressurized and desorbed; fracture points of the U-shaped well serve as key points of drainage control, drainage of the coal bed gas well can be more precisely controlled, all coal bed sections can be fully desorbed, and the situation that as the liquid level is reduced too fast, a coal bed is massively exposed, and desorption of the coal bed gas is not facilitated is avoided.

Description

technical field [0001] The invention relates to the technical field of coalbed methane drainage, in particular to a step-by-step step-by-step depressurization drainage method for U-shaped coalbed methane wells. Background technique [0002] Conventional vertical well development has a small impact range, low single well production, and poor economic benefits, while horizontal wells have the advantage of penetrating more cleat fracture systems, communicating with a large number of fracture channels, expanding the area of ​​drainage, depressurization and gas release, and allowing more As more gas enters the main channel, horizontal wells, as an efficient development technology for low-permeability coal reservoirs, have been increasingly used in the exploitation of coalbed methane. [0003] However, coal seams, as gas-generating beds and reservoirs of coalbed methane, have the characteristics of low porosity, low permeability, low mechanical strength, strong heterogeneity, and ...

Claims

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Application Information

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IPC IPC(8): E21B43/00E21B43/26E21B43/20
CPCE21B43/006E21B43/20E21B43/26
Inventor 陈召英郝春生李军军常会珍李进强赵晋斌姚晋宝王维杨昌永贾晋生
Owner SHANXI JINCHENG ANTHRACITE COAL MINING GRP CO LTD
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