Drilling and protecting integrated method for directional long drill hole

Abstract

The invention provides a directional long drill hole drilling and protecting integrated method. The method is different from a traditional screen pipe, the expansion degree of the flexible hole protection support is determined by support elastic contraction force, injection water pressure and external hole protection stress, the support is dynamically balanced when the three forces reach balance, at the moment, the expansion degree of the flexible support is changed along with the change of the drill hole shape, and the flexible hole protection support is adaptive to different drilling links and attached to the hole wall in real time. Compared with passive hole protection of a traditional screen pipe, the flexible hole protection support has the advantages that the hole protection range is larger, the flexible hole protection support can achieve active hole protection when deformation is small in the initial stage of borehole instability, a more complete annular structure of a borehole is maintained, and supporting force needed by hole protection is reduced. After extraction reaches the standard, the flexible support can be shrunk and recycled along with the water injection supporting pipe, the coal seam is prevented from being polluted, mining is prevented from being affected, and the hole protection cost is reduced.

Description

technical field [0001] The invention relates to the field of coal mine gas prevention and control, in particular to a drilling-protection integrated method for directional long boreholes. Background technique [0002] With the gradual extension of my country's coal mining to the deep, the geological conditions tend to be complex, and disasters, mainly coal and gas outbursts, occur frequently. Drilling for gas extraction is currently widely used, but ordinary drill holes are short in length, cannot be bent, and have a small extraction range. On this basis, the directional long-hole drilling technology came into being. The directional long-hole drilling technology uses the natural bending of the drill hole. A drilling technology that regularly or uses special tools to make the drilling trajectory drill to the predetermined target according to the design requirements, that is, purposefully turning the drilling axis from straight to straight or from curved to straight. With the...

AI Technical Summary

Problems solved by technology

Borehole gas extraction is widely used at present, but ordinary boreholes are short in length, cannot be bent, and the drainage range is small. On this basis, directional long-hole drilling technology emerged as the times require. A drilling technique that regularly or uses special tools to make the drilling trajectory drill to the predetermined target according to the design requirements, that is, purposely turn the drilling axis from straight to straight or from curved to straight

With the advancement of coal seam mining in my country, the characteristics of high geostress and high gas pressure are becoming more and more obvious. Under the conditions of high geostress and high gas pressure, directional long drilling is unstable and easy to lose stability, and it is difficult to form effective gas transportation. However, due to the long drilling length and the curved drilling trajectory, traditional hole protection methods such as screen protection methods cannot be applied to directional long drilling.

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