Surface well-downhole long borehole fracturing coal seam method

Abstract

The invention relates to a method for fracturing a coal seam, in particular to a method for fracturing a coal seam with a surface well-downhole long borehole. This method connects the fracturing equipment on the surface well site and the long borehole through the high-pressure pipeline, and the fracturing equipment on the surface well site injects high-pressure fracturing fluid into the high-pressure pipeline, and the high-pressure fracturing fluid in the high-pressure pipeline is controlled by a valve. When entering the target coal seam, the coal seam will generate cracks under the action of high-pressure fracturing fluid, and the air permeability will be enhanced, which will accelerate the escape of coal gas. The present invention combines the advantages of high-pressure fracturing on the well, avoids the disadvantages of direct fracturing downhole, selects less fracturing sites, arranges fracturing pipelines in the underground roadway, and connects with ground fracturing equipment to perform ground-fracturing For downhole combined fracturing, the fracturing range is adjusted by the length of the fracturing pipeline. Compared with surface well fracturing, the fracturing range is wider, and the ground fracturing site can be fully utilized. Compared with downhole fracturing, the pressure increases and the fracturing wide range.

Description

technical field [0001] The invention relates to a method for fracturing a coal seam, mainly by arranging fracturing equipment on the ground, connecting the ground fracturing equipment and an underground long borehole through a high-pressure pipeline, performing high-pressure fracturing of a target coal seam, and increasing the air permeability and fracturing range of the coal seam. Background technique [0002] Surface drilling pre-splitting coal seam anti-permeability technology and underground pre-splitting coal seam anti-permeability technology have been widely used. The fracturing site in the surface well site is large, the fracturing equipment is conveniently arranged, and the fracturing pressure is high. However, after the fracturing of the target coal seam is completed, the fracturing site needs to be re-selected and arranged for the fracturing of the next target coal seam. The layout of the ground fracturing site Affected by the coordination of ground topography and ...

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Problems solved by technology

[0003] The present invention aims to solve the problem that the downhole fracturing technology in the current coal well gas extraction technology is affected by the size of the fracturing site, the fracturing equipment is small, and the fracturing pressure is small, resulting in a small fracturing range, and it is impossible to realize large-scale, high-pressure fracturing. To solve the technical problem of fracturing, provide a surface well-downhole long drilling method for fracturing coal seams

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