Direct fitting determination method of gas content of coal seam

Abstract

The invention discloses a fitting measurement method for coal seam gas content. Firstly, a fitting calculation model is established, and the general expression of the coal sample gas desorption law is deduced according to the calculation. ; Then take samples from the downhole coal core, and measure the atmospheric pressure p of the downhole measurement site sequentially 1 and temperature T 1 1. Downhole natural desorption gas volume; correct the downhole natural desorption gas volume data, and after the temperature and pressure are corrected to the standard state, the gas loss per unit mass of coal core can be calculated. In the present invention, the relative error δ between the gas content obtained by the direct fitting measurement method and the gas content measured by the indirect method is less than 10%, which meets the actual requirements of the site, and the method is feasible; the method can measure a large number of measuring points, and can be better It is widely used in coal seam outburst dangerous working face and regional prediction, pre-extraction gas effect evaluation and mine coal seam gas emission prediction, etc.

Description

technical field [0001] The invention relates to the technical field of measuring coal mine gas content, in particular to a direct fitting measuring method for coal seam gas content. Background technique [0002] The coal seam gas content determines the size of mine gas emission and mine gas grade, and is an important index for the prediction and evaluation of coal and gas outburst risks. At present, the coal seam gas content measurement methods used at home and abroad include indirect method and direct method: the indirect method is based on the theory of coal adsorption gas, and needs to measure the original gas pressure, porosity, gas adsorption constant and other parameters of the coal seam, which takes a long time and is subject to The impact of geological conditions is greater; as the preferred method for actually measuring the gas content of coal seams on site, the direct method has the advantages of simplicity, time saving, intuitionistic, strong applicability, and le...

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Problems solved by technology

At present, the coal seam gas content measurement methods used at home and abroad include indirect method and direct method: the indirect method is based on the theory of coal adsorption gas, and needs to measure the original gas pressure, porosity, gas adsorption constant and other parameters of the coal seam, which takes a long time and is subject to The impact of geological conditions is greater; as the preferred method for actually measuring the gas content of coal seams on site, the direct method has the advantages of simplicity, time saving, intuitionistic, strong applicability, and less affected by geological conditions. The desorption law is used to calculate the gas content dissipated in the process of collecting coal samples, which is prone to large errors and affects the accuracy of the measurement results of gas content in coal seams

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