Measuring Method of Effective Radius of Borehole Drainage Gas Based on Residual Gas Content

A technology of gas content and drainage radius, which is applied in the field of testing the effective radius of gas drainage in boreholes, can solve the problems of large measurement errors, high difficulty coefficients, and difficulty in measuring the gas pressure of coal seams, so as to reduce the difficulty of drilling, Effect of reducing error in measurement results

Active Publication Date: 2017-05-24
HENAN POLYTECHNIC UNIV
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  • Abstract
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AI Technical Summary

Problems solved by technology

Under normal circumstances, the gas-bearing coal mass is relatively soft compared to the rock mass, and the drilling is affected by the pressure relief of the roadway. The sealing of bedding drilling is more difficult than that of penetrating drilling, and the sealing quality for a long time is poor.
Therefore, it is difficult to measure the accurate coal seam gas pressure by using the general coal seam gas pressure measurement method in the bedding drilling, especially under the interaction between the negative pressure of the drainage and the drilling, the measurement error is even greater

Method used

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  • Measuring Method of Effective Radius of Borehole Drainage Gas Based on Residual Gas Content
  • Measuring Method of Effective Radius of Borehole Drainage Gas Based on Residual Gas Content
  • Measuring Method of Effective Radius of Borehole Drainage Gas Based on Residual Gas Content

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Effect test

Embodiment 1

[0074] Embodiment 1 step type residual gas content determination method

[0075] (1) In the pre-pumping area, select the area with simple structure and stable coal seam occurrence according to the "Direct Measuring Method of Coal Seam Gas Content Underground" to drill hole A, vertical coal wall construction, diameter 42mm; after drilling 15m, every 2~3m Sampling to measure coal seam gas content, at least 3 sets of data (Q 1 , Q 2 , Q 3 ...), take the average value as the average gas content Q before pre-pumping 均 The research shows that: the pressure relief zone of the coal wall is 10-15m, and the gas content measured in the pressure relief zone is low; at the same time, the "Direct Measurement Method of Coal Seam Gas Content Underground" stipulates: when sampling and measuring the gas content in the mining face, The sampling depth should not be less than 12m. Therefore, in order to accurately measure the residual gas content, it is usually measured after the drilling dept...

Embodiment 2

[0101] Embodiment 2 group residual gas content determination method

[0102] When measuring the effective radius of drilling gas drainage in a soft coal seam, it is difficult to investigate the drilling in the construction oblique direction, and it is difficult to take coal samples. The group residual gas content measurement method can be used, and the steps are:

[0103] (1) In the pre-pumping area, select the area with simple structure and stable coal seam occurrence, and the vertical coal walls at the same horizontal height are separated by different distances. According to the gas occurrence situation, a group of conventional drainage borehole;

[0104] (2) For this group of drainage boreholes, conduct sealing and joint drainage, and continuously measure the drainage concentration and drainage flow. After a period of time of extraction, according to the "Direct Measurement Method of Underground Gas Content in Coal Seams", drill holes 1', 2', 3', and 4' were constructed in...

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Abstract

The invention relates to a measurement method of effective extracting radius of bedding boreholes based on the content of residual gas. The measurement method comprises a stepped measurement method of the content of residual gas and a grouping measurement method of the content of residual gas. The measurement method comprises the following steps: selecting districts which are simple in structure and stable in coal seam occurrence at districts to be pumped, and drilling holes; performing broaching and drilling on sampled drill holes so as to conform to stands of conventional bedding drill holes to be pumped; performing hole sealing and tube connecting extraction on drill holes to be pumped, continuously measuring extraction parameters, and after stable extraction is performed for 30 days, measuring the content of residual gas after extraction; repeating steps, measuring n groups of the content of residual gas; obtaining measurement results according to statistics, drawing a curve of results, and confirming the effective extracting radius. Through the adoption of the measurement method disclosed by the invention, the drilling difficulties are reduced, and the errors of measurement results are reduced, so that the measurement method is favorable for safety production of coal mines.

Description

technical field [0001] The invention belongs to the technical field of coal mining, and in particular relates to a method for testing the effective radius of drilling gas extraction based on residual gas content. Background technique [0002] 1. Definition of effective radius of borehole drainage gas [0003] When gas is extracted from underground boreholes, the gas in the coal seam migrates to the center of the borehole under the driving force formed by gas pressure and extraction negative pressure, and the area affected by this driving force is called the drainage influence range. The drainage influence range determined according to the purpose of gas drainage in boreholes is the effective radius of gas drainage in boreholes. [0004] In order to prevent outbursts, the coal seam gas within the area affected by the drainage should lose its ability to outburst; [0005] In order to prevent the gas concentration from exceeding the limit, the gas content or gas emission in t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): E21F7/00E21B47/10
CPCE21B47/10E21F7/00
Inventor 韩颖张飞燕程虹铭曹文涛周玉军朱林剑王博余伟凡宋德尚
Owner HENAN POLYTECHNIC UNIV
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