Mining method for support pipe following air liquid spraying and drilling into coal bed gas of radial well

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

[0001] The invention relates to a coalbed methane mining method in the field of coalbed methane mining, in particular to a coalbed well section after vertical well reaming, the oil pipe is lowered into a directional radial guide tool, and then the support pipe is followed by spraying with a steel wire rope The drilling tool assembly is lowered into the oil pipe and the directional radial guide tool, and the high-pressure gas-water mixture is used to jet drill in and out of one or more groups (multi-coal seam) radial horizontal holes in the radial direction in the coal seam, and the drilling At the same time as entering the radial holes, follow up and place high-strength PVC slotted screens to form radial horizontal holes with support and diversion functions, and realize underbalanced drilling and negative pressure enhanced coal seam CBM mining in radial wells method. Background technique [0002] In the field of coalbed methane exploration and development, vertical fracturing ...

AI Technical Summary

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, In particular, in order to achieve underbalanced drilling into coal seams while achieving negative pressure intensification to increase single-well production on a large scale and effectively realize the successful drilling and exploitation of coalbed methane in structural coal and low-rank soft coal reservoirs, the present invention provides an oil pipe as a working pipe In the coal seam section after vertical well reaming, a directional radial guide tool connected by a spherical joint is lowered for orientation and radial guidance, and then a steel wire rope is used to guide the directional guide tool composed of a weighted rod, a piston, an injection pipe, and a PVC slotted screen. The support pipe composed of pipe and hydraulic crawler follows the combination of jet drilling tools and is lowered into the directional radial guide tool for radial guidance. Using high-pressure gas-water mixture as the working medium, jet drilling in the coal seam forms a In the process of drilling radial holes, underbalanced drilling and enhanced plugging removal of coal seams around the wellbore are realized. At the same time, the high-strength PVC slotted screens that play the role of support and diversion follow up to all the holes simultaneously. In the drilled radial hole, the crawler and the support pipe are permanently placed in the drilled radial hole to support and divert water through the high-pressure jet pipe

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