Study On Calculation Method Of Gas Loss In Coal Seam By Desorption Method

Desorption method for the determination of coal seam gas content,the coal seam gas content measurement error of the main source of gas loss.The current method of calculating the amount of gas loss is based on the relationship between the gas desorption parameters and the time,and the results of each method are affected by the time factor.In this paper,the method of calculating the amount of gas loss is studied in this paper.The method of calculating the gas loss is studied by using the theoretical,experimental and field research methods to determine the gas content of coal seam accurately and quickly.Based on the theory of gas adsorption and desorption,the natural desorption process of coal was simulated in the laboratory.The influence of gas adsorption equilibrium pressure,coal particle size and hardness on gas desorption was obtained by comparing the experimental data.Based on the experimental data,the method of calculating the current loss of gas is analyzed on the time factor.The larger the sampling time is,the larger the sampling time is,the greater the absolute value of the difference between the calculated value and the true value,and the coal content The larger the proportion,the increase in coal seam gas content measurement error;reading interval on the calculation results will also have an impact,but the effect is not significant.When the coal samples are the same,the gas desorption curves under different adsorption equilibrium pressures are the same.From the side,the gas desorption laws of the same kind of coal samples under different adsorption equilibrium pressures are in accordance with the same function type,but only under different adsorption equilibrium pressure The fitting parameters are different.Based on the established data matching model,the downhole data were matched with the laboratory data.The desorption data matched with the downhole data were found in the laboratory data,and the relationship between the two sets of data was fitted.In combination with the sampling time,Push the amount of gas loss.The calculation method is verified by field and the calculation result is reliable.