Hole Forming Technology of Radial Well Construction with Low-Pressure Jet Pullback

Abstract

The invention belongs to the technical field of coal-bed gas well radial direction well construction, and particularly relates to a lower-pressure jetting reversed-drawing pore-forming technology in radial direction well construction. In order to improve the down-hole natural permeability and the overall radial direction well construction effect, the lower-pressure jetting reversed-drawing pore-forming technology in radial direction well construction is provided. The technology comprises a locating procedure, a grinding and milling procedure, a jetting procedure and a reversed-drawing procedure, wherein the reversed-drawing procedure lies in that reversed-drawing pore-forming is carried out in a reservoir pressure environment lower than a construction coal bed, the problems that the natural permeability is reduced and the coal dust flowback rate is reduced due to the fact that pulverized coal particles are pressed into fractures of a coal bed by high-pressure water flow is solved, the overall radial direction well construction effect is improved; besides, reversed drawing is carried out under a low-pressure condition, the situation of high-load operation of a high-pressure pump is relived, the service life of the pump is prolonged, and the cost is reduced.

Description

technical field [0001] The invention belongs to the technical field of coal bed gas well radial well construction technology, and in particular relates to a radial well construction low-pressure injection pull-back hole-forming process. Background technique [0002] In the radial well technology construction of coalbed methane wells, some coalbed methane wells have measured natural permeability not increasing but decreasing after the construction of all radial holes, which fails to achieve the expected effect. The main reason for this phenomenon is that during the pullback process of the sprayed coal seam, the high-pressure water jet will bring part of the fine coal powder and coal dust particles formed in the process of spraying the holes into the natural cracks and micropores of the coal seam around the radial holes, and Under the action of high-pressure water jets, the compaction and blockage of cracks will lead to a decrease in the porosity and permeability of the coal s...

AI Technical Summary

Problems solved by technology

The main reason for this phenomenon is that during the pullback process of the sprayed coal seam, the high-pressure water jet will bring part of the fine coal powder and coal dust particles formed during the spraying hole forming process to the natural cracks and micropores of the coal seam around the radial hole, and Under the action of high-pressure water jets, the compaction and blockage of cracks will lead to a decrease in the porosity and permeability of the coal seam, which will directly affect the construction effect and construction progress.

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