Impact of Gas Components on the Determination of Coal Mine Gas Content: A Case Study from China

Accurate measurement of coal seam gas content forms the core foundation for coal mine disaster prevention and coalbed methane resource development. However, as coal mining in China extends into deeper strata, multi-component gases (CH4, CO2, N2, etc.) exhibit competitive adsorption effects and dynamic differentiation characteristics. These behaviors pose significant challenges to traditional measurement standards based on the “single methane-dominated system” assumption. This study systematically analyzes the competitive adsorption mechanisms of multi-component gases. By integrating gas data from major coal-producing provinces in China (such as Guizhou, Anhui, and Xinjiang), we reveal the heterogeneous distribution characteristics of gas components and their controlling factors, including coalification degree, burial depth, and maceral components. Case studies from Henan and Shanxi provinces demonstrate that neglecting the strong adsorption hysteresis of CO2 and the rapid desorption characteristics of N2 induces a systematic error exceeding 25% in total gas content measurements within areas high in non-methane components. To address these issues, we propose a “hierarchical measurement and real-time correction” framework for multi-component gas content. This framework categorizes gas measurement into four levels—ranging from single-component to all components—based on the complexity of geological conditions. It combines differentiated measurement with dynamic correction to improve the accuracy of gas content evaluation under complex geological conditions. This research provides a more reliable theoretical basis for gas pressure prediction and mine gas grade identification, offering substantial theoretical significance and engineering value for enhancing safety guarantees in deep coal mining.