Method for improving stability of coal-bed methane surface drill well

A surface drilling and stability technology, applied in drilling equipment and methods, drilling with liquid/gas jet, drilling equipment, etc., can solve problems such as closed hole and wellbore deformation, achieve low cost, strong impact absorption ability, Simple construction effect

Inactive Publication Date: 2015-07-01
INST OF ROCK & SOIL MECHANICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The problem to be solved by the present invention is to overcome the phenomena such as well body deformation and closed holes caused by the influence of mining during the underground coal mining period of current coalbed methane surface drilling, improve the stability of coalbed methane ground drilling, and then realize the "one well" of coalbed methane wells. multi-purpose"

Method used

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  • Method for improving stability of coal-bed methane surface drill well
  • Method for improving stability of coal-bed methane surface drill well
  • Method for improving stability of coal-bed methane surface drill well

Examples

Experimental program
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Effect test

Embodiment 1

[0035] (1) if figure 1 As shown, based on the mature drilling equipment in the field of coalbed methane development, the drill bit 2 with the hydraulic jet drilling equipment 1 is used to drill from the surface, and the drilling diameter is D 1 ,D 1 is 2 meters, the drilling head 5 is located in the direct roof 3, and the distance from the roof of the coal seam 4 is L 1 , L 1 It is 4m.

[0036] (2) Use the empirical formula for the height of the caving zone in coal mines to determine the height of the caving zone after mining the coal seam, and then determine the height of the expansion section according to the height of the caving zone.

[0037] (3) The inclination angle of the coal seam is less than 54°, the compressive strength of direct top 3 is σ≤20MPa, and the height of the caving zone is H 1 =2M, M is the mining height, and its value is 2 meters; Utilize hydraulic jet drilling equipment 1 to start expanding the well from 5 places of the drilling well head, the expan...

Embodiment 2

[0044] Steps (1), (2), (4) to (7) are the same as in Example 1, except for step (3), the specific operation is as follows: the inclination angle of the coal seam is less than 54°, and the compressive strength of the direct top 3 is 20MPa≤ σ≤40MPa, height of caving zone H 2 =4M, M is the mining height, and its value is 2 meters; Utilize hydraulic jet drilling equipment 1 to start expanding the well from 5 places of the drilling well head, the expanding well height is 4M or 8 meters, and the expanding well diameter is D 2 , take the borehole diameter D 1 10 times the value, that is, the expansion diameter is 20 meters.

Embodiment 3

[0046] Steps (1), (2), (4) to (7) are the same as in Example 1, except for step (3), the specific operation is as follows: the inclination angle of the coal seam is less than 54°, and the compressive strength of the direct top 3 is 40MPa≤ σ≤60MPa, height of caving zone H 3 =5M, M is the mining height, and its value is 2 meters; Utilize hydraulic jet drilling equipment 1 to start expanding the well from 5 places of the drilling well head, the expanding well height is 2M or 10 meters, and the expanding well diameter is D 2 , take the borehole diameter D 1 10 times the value, that is, the expansion diameter is 20 meters.

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Abstract

The invention relates to a method for improving the stability of a coal-bed methane surface drill well. The method comprises the steps that 1, a hydraulic jet drilling device is used for extending a drill well in the earth surface in a coal-bed methane exploitation region; 2, the extending depth is the height of a caving zone of a mine, and the extending diameter is 8-10 times the bore diameter of the drill well; 3, foam concrete is conveyed to the extended section after well extending is completed, secondary well drilling is conducted after the foam concrete is formed, and an outer sleeve, an inner extraction pipe and a screen pipe are mounted after the drill well is formed; 4, an axial deformation device is mounted between the screen pipe and the inner extraction pipe. By means of the method, construction is easy, and cost is low; the stability of the coal-bed methane surface drill well is improved, the coal-bed gas well is free of being influenced by stratum movement during the mining influence period and the post-mining stable period and will not get closed or blocked, the purpose that the coal-bed methane surface drill well has multiple functions can be achieved truly, the utilization rate of the coal-bed methane drill well is increased, and the whole life cycle cost of the coal-bed methane drill well is lowered.

Description

technical field [0001] The invention relates to the technical field of coalbed methane exploitation, in particular to a method for improving the stability of coalbed methane ground drilling. Background technique [0002] In the field of coalbed methane development in my country, surface drilling and extraction of coalbed methane is one of the methods for efficient extraction of coalbed methane, but this method requires a huge investment and requires sufficient economic recovery guarantees. At the same time, most ground drilling cannot achieve " One well is multi-purpose”, and the drilling utilization rate is low. This is because in the mining impact stage, the surrounding rock of the well body deforms violently, which in turn causes the well body deformation and blockage, which makes the coalbed methane wells close during the mining impact period and the post-mining stable period. Pore ​​phenomenon, can not continue to extract coalbed methane. In order to achieve "one well wi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B7/18E21B7/28
CPCE21B7/18E21B7/28
Inventor 亓宪寅杨典森陈卫忠谭贤君邹俊鹏
Owner INST OF ROCK & SOIL MECHANICS CHINESE ACAD OF SCI
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