Method and device for quickly determining gas pressure of coal bed in downward superdeep borehole

Abstract

The invention relates to a method and device for quickly determining gas pressure of a coal bed in a downward superdeep borehole. The method comprises the steps of: carrying out high-pressure grouting on rock stratums above the coal bed to be determined through the borehole to block various cracks; then, drilling holes to the coal bed, retrieving a drill pipe and inserting a capsule hole packer with a long gas pipe and a water injection tube to the borehole part of the rock stratums on the upper part of the coal bed, and pressing water to the capsule hole packer, so that the capsule is expanded to pre-seal the borehole; then, pouring cement paste to the borehole till the cement paste fills the borehole; connecting a pressure gauge to the gas pipe; and sealing by means of the pre-sealing hole of the capsule in the initial stage, and sealing by means of solidification of cement paste in the later stage so as to determine the gas pressure of the coal bed. The method can be used to determine the gas pressure of the downward superdeep coal bed which is far from 50m, and a heading roadway project for determining the gas pressure of the coal bed can be reduced. The determining device is simple, simple and convenient to operate, immediate to read in the gauge, quick in rise of the gas pressure and accurate in result, and has wide practicality.

Description

technical field [0001] The invention relates to a method for measuring coal seam gas pressure and a device thereof, and is especially suitable for rapidly measuring coal seam gas pressure in a descending ultra-deep borehole under complex geological conditions. Background technique [0002] As we all know, coal and gas outburst is a dynamic phenomenon that occurs in soft coal containing high-pressure gas. Once outburst occurs, it often endangers the lives of coal miners. Identify coal seams within a certain range in advance, and give the conclusion whether coal and gas outburst will occur during the mining process of the coal seam. For determining the type of mine design, take anti-outburst measures in advance, improve coal mine management methods, and avoid outbursts. Hazards play an important role. In the process of identifying coal seam outburst, it is often necessary to measure the gas pressure of the coal seam, which is an important index to measure whether the coal sea...

AI Technical Summary

Problems solved by technology

Among these hole sealing methods, the mucus hole sealer method has a better effect. Its principle is to place the hole sealer in the drill hole, use two capsules to seal the mucus in the middle, and then use the mucus to seal the hole of the pressure measuring chamber. Gas, ensure that the gas in the pressure measuring chamber does not leak, the disadvantage is that the distance of sealing is about 10-20 meters

The advantage of cement mortar sealing is that it can seal deeper boreholes. The disadvantage is that the cement mortar solidifies slowly. During the solidification, the gas in the pressure measuring chamber is easily lost, and the pressure stabilization time is longer.

Especially when complex geological conditions are encountered, such as the development of cracks in the rock formation, the underground water pressure in the rock formation is easy to communicate with the coal hole, and the coal seam is far below the pressure measurement point, it is difficult to measure the accurate gas pressure value of the coal seam by using the above methods

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