AUTHOR=Dai Linchao , Lei Hongyan , Cheng Xiaoyang , Li Rifu 

TITLE=Prediction of coal seam gas content based on the correlation between gas basic parameters and coal quality indexes

JOURNAL=Frontiers in Energy Research

VOLUME=10

YEAR=2023

URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2022.1096539

DOI=10.3389/fenrg.2022.1096539

ISSN=2296-598X

ABSTRACT=<p>The measurement of gas content in coal seam by means of indirect method involves heavy workload, long period, high cost and complicated operation and a proneness of negative values in the process of measuring gas absorption constant. To address these problems, the gas basic parameters and coal quality indexes of 90 coal samples from 90 coal mines in 13 provinces of China are determined experimentally in this paper. The intrinsic relationship between gas adsorption constant <italic>a</italic> and atmospheric adsorption capacity <inline-formula id="inf1"><mml:math id="m1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>Q</mml:mi><mml:mn>0</mml:mn></mml:msub></mml:mrow></mml:math></inline-formula>-initial velocity index of gas emission <inline-formula id="inf2"><mml:math id="m2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mo>Δ</mml:mo><mml:mi>p</mml:mi></mml:mrow></mml:math></inline-formula>, gas adsorption constant <italic>b</italic> and volatile <italic>V</italic><sub><italic>daf</italic></sub> - apparent density <italic>ARD</italic> is analyzed, and a prediction model of coal seam gas content based on gas basic parameters and coal quality index is established. The results show that the effect of <inline-formula id="inf3"><mml:math id="m3" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>Q</mml:mi><mml:mn>0</mml:mn></mml:msub></mml:mrow></mml:math></inline-formula>-<inline-formula id="inf4"><mml:math id="m4" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mo>Δ</mml:mo><mml:mi>p</mml:mi></mml:mrow></mml:math></inline-formula> correlation on <italic>a</italic> is mainly caused by the change of specific surface area and gas pressure of coal, while the effect of <italic>V</italic><sub><italic>daf</italic></sub>-<italic>ARD</italic> correlation on <italic>b</italic> is mainly caused by the change of pore volume of coal. By comparing the predicated value from the prediction model of coal seam gas content with the measured value, it is found that the average absolute error rate of predicted value is 8.15%. This method is proven to be effective and feasible in routine gas content predictions, and can provide a reference for coal seam gas content prediction in China.</p>