Self-drilling type in-situ measuring device of coal seam gas pressure

Abstract

The invention discloses a self-drilling type in-situ measuring device of coal seam gas pressure, is capable of measuring the coal seam gas pressure on the premise of not drawing out a drill rod, and is in particular suitable for measuring the hole easily collapsed coal seam gas pressure. The self-drilling type in-situ measuring device of the coal seam gas pressure comprises a drilling system, a hole sealing system and a pressure measuring system. After drilling reaches a designed drilling depth, a drilling machine is retreated and the drill rod is retracted by a distance which is larger than the width of a packer capsule groove, liquid supply pipelines and drainage pipelines are communicated, a gas pressure measuring lead and an instrument are connected, and cooling water channels are sealed and the periphery of the drill rod and a gap between walls of drilling holes are packed to form a closed space. A gas pressure measurer is opened to measure gas pressure changes in the closed space, and the stable pressure is the in-situ gas pressure. Finally, capsule pistons, packer capsules and casing capsules are operated, therefore, the communication of cooling water channels are restored, a gas pressure probe cavity is sealed, the thread position of a sliding thread casing is restored, external liquid supply pipelines and the drainage pipelines as well as a gas pressure measuring device are dismantled, and the drill rod is pulled out or continuously drilled.

Description

technical field [0001] The invention relates to a self-drilling type coal seam gas pressure in-situ measuring device, which can measure the coal seam gas pressure in situ, and is especially suitable for measuring the gas pressure of soft coal seams with easily collapsed holes. Background technique [0002] Coal seam gas pressure is the driving force for gas eruption and coal and gas outburst, and has a positive relationship with coal seam gas content. The measurement of coal seam gas pressure is a basic work for the prevention and control of coal mine gas disasters, and it is also an important means to test whether the outburst coal seam has subsided after drainage. At present, the test of coal seam gas pressure mostly adopts the passive method of grouting pump sealing as stipulated in the coal industry standard AQ10478-2007 "Regulations on the Direct Measurement Method of Underground Coal Seam Gas Pressure in Coal Mine". The principle of the test is to use the principle of...

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Problems solved by technology

The process of withdrawing the drill pipe after the hole is formed will lead to the rapid release of gas in a certain range of coal around the hole, and the sealing process will prolong the gas release time in the coal around the hole, resulting in the need for a longer measurement time Only in this way can the real gas pressure value be measured; in addition, when the borehole pressure measurement is carried out on the soft coal seam, the borehole collapse and blockage often occur, which makes the subsequent pressure measurement work unable to be carried out.

[0004] Due to the advancement of mining technology and equipment, the excavation speed of coal roadways is getting faster and faster, and the pressure of outburst prevention is also increasing. Only by continuously shortening the test time of various prevention outstanding indicators can the production efficiency brought about by outburst prevention be compensated. loss

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