Coal bed methane production method in radial well drilled with support pipe and gas jet

Abstract

The invention relates to a mining method for coal bed gas in the field of mining of the coal bed gas, in particular to a mining method for a coal bed gas of a radial well. A directional radial guide tool is placed from an oil pipe on a coal bed well after chambering of a vertical well, then a steel wire rope is used to combine and place a support pipe following spraying and drilling tool into the oil pipe and the directional radial guide tool, a group or a plurality of groups (multiple coal bed) of radial horizontal holes are sprayed and drilled along the radial direction in a coal bed by high pressure air water mixed liquid. Meanwhile, when the radial holes are drilled, high-strength polyvinyl chloride (PVC) kerf sieve pipe is automatically followed to form the radial horizontal holes with a support function and a river diversion function, and underbalance drilling and negative pressure reinforced coal bed are achieved.

Description

technical field [0001] The invention relates to the technical field of coalbed methane exploitation, in particular to a method for mining coalbed methane in radial wells drilled with support pipes and gas fluid jets. Background technique [0002] In the field of coalbed methane exploration and development, vertical fracturing wells, various types of horizontal wells and different forms of multi-branched horizontal wells are usually drilled, and the methane gas in the coalbed is desorbed and produced by draining water to reduce the pressure of the coalbed reservoir (drainage mining gas) to realize the exploitation of coalbed methane. Vertical wells penetrate the coal seam vertically through the drilling process, and realize the commercial exploitation of coalbed methane through hydraulic fracturing and cavitation after completion. The advantages of vertical wells are that the drilling process is simple, the strengthening process method is mature, and the engineering cost is ...

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Problems solved by technology

[0003] In order to overcome the large ground area occupied by vertical fracturing wells, the small drainage area of ​​single well controlled coal seam, the low gas production, especially the short length of effective support fractures for fracturing, the serious damage of coal reservoir structure leads to the generation of a large amount of coal powder and blockage Coal seam diversion channel, which in turn causes coal seam drainage water slow down, low economic benefits and other shortcomings, but also in order to overcome the difficulty of horizontal well drilling construction, complex process, high cost, long completion period, drilling fluid pollution of coal seam, coal seam collapse leading to buried In order to realize low-cost, high-efficiency, large-area drainage and depressurization gas production in a single well, and reduce construction risks and process complexity, Especially in order to achieve underbalanced drilling in coal seams while realizing negative pressure intensification and large-scale increase in single well production and effectively realize the successful drilling and exploitation of coalbed methane in structural coal and low-rank soft coal reservoirs, the present invention provides a support pipe followed by gas flow Liquid jet drilling radial well coalbed methane mining method, easy construction, low cost, high benefit

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