Coal bed roadside pressure relief zone width measuring method based on drill hole gas leakage

Abstract

The invention discloses a coal bed roadside pressure relief zone width measuring system and a method based on drill hole gas leakage. The measuring system comprises a seepage gas pipeline, a connecting bar and a hole sealing capsule on the connecting bar, wherein one end of the seepage gas pipeline is connected with a high-pressure gas source, a difunctional flowmeter is arranged on the seepage gas pipeline, and the hole sealing capsule is connected with a fluid infilling mechanism. The coal bed roadside pressure relief zone width measuring method based on the drill hole gas leakage is based on the system and realized through measuring the drill hole gas leakage per unit length. According to the system and the method, gas leakage in different depths of gas seepage chambers per unit length is measured to determine the roadside pressure relief zone width after a coal bed roadway is excavated; and the measuring technology and method are provided for determining the hole sealing depth for a roadside gas drainage drill hole, determining the range of a coal face for implementing an outburst prevention measure in an inclined direction, highlighting the excavation deployment of the coal bed roadway, and improving the forecast accuracy of gas emission quality of an excavation working surface.

Description

technical field [0001] The invention relates to a technique for measuring the width of a pressure relief zone beside a coal seam roadway along the inclined direction of a coal seam after excavation of a coal seam roadway, in particular to a system and method for measuring the width of a pressure relief zone beside a coal seam roadway based on the amount of gas leakage in a drilling hole. Background technique [0002] The excavation space after coal seam mining has a good pressure relief effect on the gas occurrence, migration and stress state within a certain range of adjacent coal bodies. Due to the continuous destruction of the excavation ground stress of the roadway and the balance state of coal seam gas pressure, the coal seam The body is broken and loose, the air permeability is increased, and the gas is discharged, forming a pressure relief zone with a certain width. Measuring the width of the pressure relief belt beside the coal seam roadway is useful for determining ...

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Problems solved by technology

[0004] (1) Drilling cuttings method: adopt drilling beside the roadway, collect cuttings to measure parameters such as cuttings amount and desorption index of cuttings, analyze and determine the width of the pressure relief zone beside the roadway, but it cannot be realized in the deep part of the drilling hole Fixed-point sampling”, the measured data is restricted by many influencing factors, and the measurement results have great uncertainty

[0005] (2) Gas content method: use drilling beside the roadway to collect drilling cuttings to measure parameters such as coal seam gas content. Also, because "fixed-point sampling" cannot be realized, the measurement results have great uncertainty

However, there is currently no indicator for judging when the borehole enters the stress concentration zone, so this method also has great limitations

[0007] (4) Gas drainage parameter method: The width of the pressure relief zone is determined according to the parameters of the gas drainage boreholes with different sealing depths. negative pressure and concentration are relatively low, but this method requires the construction of multiple boreholes, the measurement process is greatly affected by other factors, and the measurement period is long

[0008] The only published patent literature on "leakage" at home and abroad is "zero-leakage sonic nozzle method gas flow standard device (patent number 200820134181.7)", which is a standard device for measuring nozzle gas flow; The patent documents of "hole leakage" and "drilling gas leakage" have not been reported yet

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