Gas Sorption Characteristics of Tectonically Deformed Coals and Their Implications on Gas Drainage and Outburst Control

The tectonically deformed coals (TDC), formed by various geological deformations during the process of coalification, is different from those of intact and non-deformed coals. Areas containing TDC are enormous reservoirs of coalbed methane (CBM) as they hold higher gas content and energy than primary coals due to its unique physical properties. In this work, fractal analysis was conducted using N₂ sorption data to obtain pore structural parameters (i.e. fractal dimensions), and Langmuir's equation was applied to model gas sorption behavior from CH4 sortpion experiment. No apparent empirical correlations could be found between fractal dimensions and sorption parameters. Theoretical developments was then made to comprehensively understand the role of pore structure of TDC acting on gas sorption behavior. The developed model was validated by the experimental data, where a strong negative correlation was observed between Langmuir pressure (P_L) and characteristic sorption capacity (equation), which is a power term of Langmuir's volume (V_L) and surface heterogeneity factor (?). The result implies that coals with complex structure would have both higher adsorption capacity and potential and as a result, P_L dcreases as (equation) increases. The established model can be directly used in future gas drainage and gas production planning