Soft coal seam one-time hole forming while-drilling casing device

Abstract

The invention relates to a soft coal seam one-time hole forming while-drilling casing device. The soft coal seam one-time hole forming while-drilling casing device comprises a multi-stage reamer bit, wherein a blade contraction mechanism is arranged on the right surface of the multi-stage reamer bit, a rotary casing dragging mechanism is arranged on the right surface of the blade contraction mechanism, and the blade contraction mechanism comprises a first butt joint sleeve. According to the soft coal seam one-time hole forming while-drilling casing device, the multi-stage reamer bit and the blade contraction mechanism are arranged, the multi-stage reamer bit can achieve the effect that multiple times of reaming can be completed through one bit and one-time drilling, disturbance to the hole wall is reduced, the hole exposure time is greatly shortened, and therefore the hole collapse probability is greatly reduced; if hole wall collapse occurs in the drilling process, a casing following the bit can support collapsed crushed coal outside the casing, and drilling accidents such as drilling tool falling and breaking, drill jamming and drill burying cannot be caused; and the casing can be pulled back and forth to crush coal briquettes, the crushed coal briquettes are discharged out of holes through drilling fluid, and local hole collapse can be treated.

Description

technical field [0001] The invention relates to the technical field of gas drainage in soft coal seams underground in coal mines, in particular to a drilling-while-drilling casing device for one-time forming of soft coal seams. Background technique [0002] Gas drainage in high-gas mines can reduce the amount of gas gushing out during mining, reduce gas hazards and gas overruns, and is a preventive measure to ensure safe production in coal mines. For high-gas mines or mining areas, gas drainage must It is technically and economically necessary. The pre-pumping of coal seam gas in the coal seam and the pre-pumping of coal seam gas through bed drilling in the bottom roadway are one of the important means of coal mine gas control and prevention of coal and gas outburst. Boreholes are used to relieve the pressure of the coal body, and the gas pressure of the coal body and the gas content per ton of coal are reduced through drainage, so as to achieve the purpose of eliminating ou...

AI Technical Summary

Problems solved by technology

[0005] Aiming at the deficiencies of the prior art, the present invention provides a drilling-while-drilling casing device for one-time drilling of soft coal seams, which has the advantages of being able to improve drilling quality, synchronously transporting casings, and minimizing the problem of drilling collapse, and solving the problem of It solves the problem that the existing drilling device reams the hole many times, which causes the coal seam around the hole wall to be disturbed and squeezed for many times, and the hole is easy to collapse.

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