Well drilling method for powder coal seam

Abstract

The invention provides a powder coal seam drilling method which comprises the steps that drilling is conducted on the ground perpendicular to the earth surface to a first preset depth below the earth surface, and then surface casing well cementation is conducted to obtain a vertical well; drilling a well into the vertical well, deflecting at a second preset depth on the vertical well and the coal seam top plate, drilling to the intersection of the coal seam bottom plate and the lower rock stratum, and then forming a curved well through casing well cementation; a continuous oil pipe, a guiding tool and a drilling tool assembly are put into the vertical well; oil-based mud is continuously and circularly injected into the continuous oil pipe; a coiled tubing, a guiding tool and a drilling tool assembly are made to drill in the powder coal seam along the coal seam bottom plate through the bent well, and a directional well parallel to the coal seam bottom plate is formed in the coal seam bottom plate through drilling; the guiding tool and the drilling tool assembly are loosened so that a nozzle can be formed in the tail end opening of the continuous oil pipe; and after the directional well is drilled, the oil-based mud is pumped out of the directional well through the coiled tubing. According to the technical scheme, the problem that in the prior art, the drilling difficulty of the powder coal seam is large is effectively solved.

Description

technical field [0001] The invention relates to the technical field of underground coal gasification coal mining, in particular to a fine coal seam drilling method. Background technique [0002] The in-situ controllable combustion and pressure-holding gasification technology of deep underground coal is a brand-new concept and a brand-new pressure-holding gasification theory. The modern underground coal gasification process technology originated from the Lawrence Livermore National Laboratory of the US Department of Energy in the 1970s. The research results and application practice of the retractable underground coal gasification continuous gas injection process invented by the laboratory have passed the world. Thanks to decades of dedicated research and practice by engineers and technicians from many countries, underground coal gasification technology has made great technological progress, but it has also encountered huge bottlenecks in technology and development costs. Wit...

AI Technical Summary

Problems solved by technology

[0004] The main purpose of the present invention is to provide a method for drilling a pulverized coal seam to solve the problem that the pulverized coal seam drilling is relatively difficult in the related art

Images