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Overmined-goaf coal-bed methane surface well drilling method

A technology for surface drilling and passing through gobs, which is applied to surface mining, drilling equipment, and driving devices for drilling in boreholes. It can solve problems such as failure to establish normal circulation, increase safety hazards in underground production in coal mines, and loss of drilling fluid. To achieve the effect of ensuring safe and efficient construction, ensuring safe and efficient progress, and high safety

Inactive Publication Date: 2018-12-21
SHANXI JINCHENG ANTHRACITE COAL MINING GRP CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Compared with conventional ground pre-pumping wells, the biggest construction difficulty of drilling through the gob is that the drilling fluid in the gob is drilled with clean water, and normal circulation cannot be established; when the air drill is used to cross the gob, part of the air will be injected into the goaf. Mixing with gas in the goaf will increase the hidden dangers of coal mine production safety; in order to ensure safe and efficient drilling through the goaf, a new method of ground drilling through the goaf has been invented

Method used

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  • Overmined-goaf coal-bed methane surface well drilling method
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Examples

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Embodiment Construction

[0019] A ground drilling method for coalbed methane in a goaf, the specific implementation method is as follows:

[0020] The known conventional drilling method is adopted in the first stage, and the drilling tool combination is Φ425.00mm impactor bit + double male joint + Φ168.00mm drill collar + adapter + drill pipe. Corresponding drilling parameters were adopted for the drilling tools. The first section was used to prevent deflection, and the method of hoisting with small drilling pressure was adopted, and the drilling was drilled to 10m below the bedrock; the 377.7mm casing was run in, and conventional density cement was used for cementing , the cement returns to the surface.

[0021] Air drilling is used in the second opening, and the drilling tool combination is Φ311.15mm air down-the-hole hammer bit + one male and one female bit + Φ168.00mm drill collar + adapter + drill pipe, and then nitrogen drilling is used. When the target coal seam floor is 90m above the floor, n...

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Abstract

The invention aims at solving the problems in a well drilling process of a surface extraction goaf underlying coal-bed methane well of a coal mining area and provides an overmined-goaf coal-bed methane surface well drilling method according to requirements of an overmined-goaf well drilling technology. The method comprises the following specific steps: firstly, exploiting; drilling down to a surface soil layer for 10m by adopting a conventional well drilling method; carrying out well cementation through a sleeve and returning cement to the surface; secondly, constructing by adopting a nitrogengas well drilling manner when constructing to a 90m part of a goaf top plate; finishing drilling when drilling down to a coal bed bottom plate for 25m and carrying out the well cementation through technical sleeve; returning cement to a goaf coal bed bottom plate; thirdly, exploiting; finishing drilling when drilling down to a target layer for 40m by adopting a clean water drill carrying out thewell cementation through the sleeve; returning the cement to a part which is 100m above the goaf top plate. The overmined-goaf coal-bed methane surface well drilling methodis characterized in that overmined-goaf drilling of nitrogen gas can be realized and underground potential safety hazards can be eliminated; safe and efficient construction of overmined-goaf well drilling of coalmines is ensured.

Description

technical field [0001] The invention belongs to the technical field of a coalbed methane surface drilling system, and in particular relates to a coalbed methane surface drilling method in a goaf. Background technique [0002] The traditional multi-layer coal mining method is a downward mining procedure of "thick first, then thin, top-down". The ground pre-drainage drilling test for underground coal seam gas drainage in the area has achieved good pre-drainage effect. Compared with conventional ground pre-pumping wells, the biggest construction difficulty of drilling through the gob is that the drilling fluid in the gob is lost by using clean water, and normal circulation cannot be established; when the air drill is used to cross the gob, part of the air will be injected into the goaf. The goaf is mixed with gas, which increases the safety hazards of underground production in coal mines; in order to ensure safe and efficient drilling through the goaf, a new method of ground d...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21C41/18E21B4/14E21F5/04E21F7/00E21F11/00E21F17/18
Inventor 张永成李兵刘亮亮王森徐云张江华张为秦玉霞李德慧王越白杨
Owner SHANXI JINCHENG ANTHRACITE COAL MINING GRP CO LTD
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