Construction method of deep and large-caliber gas extraction well

Abstract

The invention discloses a construction method of a deep and large-caliber gas extraction well. The construction method comprises the following steps of: preparing drilling equipment according to design and construction requirements, measuring a hole site at a to-be-drilled part, measuring the elevation of a wellhead, and determining the well depth; vertically fixing an orifice pipe in a stratum ata specified position of a drilled hole and enabling the orifice pipe to be 200 mm higher than the ground surface, burying the periphery of the orifice pipe with cement mortar, and cutting a slurry outlet in the slurry outlet direction; matching a combined drill bit with a drill collar for full-section opening drilling, drilling to 100 m, measuring the hole once, and ensuring that deflection of the upper portion of the drilled hole is controlled within 0.2%; installing a wall protection pipe and fixing the pipe; drilling a bed rock section, and determining several stages of drilling accordingto the diameter of the drilled hole; and lowering pipes, injecting pure cement paste into the well bottom, injecting the cement paste into an annular space between the pipe walls, achieving the effectthat working pipes and the stratum are fully fused and fixedly connected into a whole, removing the paste in the working pipes after pipe fixing is qualified, cleaning the inner walls of the workingpipes once, and completing the construction. The method has the advantages of good pore-forming quality, small influence of geological conditions, low construction cost, small environmental influenceand small environmental pollution.

Description

technical field [0001] The invention relates to a construction method for a gas extraction well, in particular to a construction method for a deep and large diameter gas extraction well. Background technique [0002] In recent years, with the coal mine "green" mining and sustainable development model of "creating benefits with utilization, promoting drainage with benefits, ensuring safety with drainage, and promoting production with safety", the construction of independent gas drainage wells in underground coal mines has Technology is gradually becoming more widely used. [0003] The construction technology of deep and large-diameter gas drainage wells is mainly used for the construction of independent gas drainage wells in underground mines, and can also be applied to coal mines and non-coal mining industries, especially in underground mines. The invention is suitable for underground gas drainage in soft and hard rock layers, such as silt, cohesive soil, sandy soil, soft r...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a construction method for deep and large-diameter gas drainage wells, which successfully solves the difficult problem of underground high-content gas drainage under complex stratum conditions, and eliminates the problem of underground gas extraction at the mining surface. It is a major safety hazard and effectively guarantees the safe production of coal mines. It is suitable for underground gas drainage wells in soft and hard rock formations, such as silt, cohesive soil, sandy soil, soft rock, hard rock and other soil layers. It is also suitable for Various deep and large-diameter drilling constructions such as drainage channels, emergency rescue channels, and material transportation

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