Evaluation model for in-situ pyrolysis development potential of tar-rich coal based on fuzzy analysis, combined...

In-situ pyrolysis of tar-rich coal represents a critical pathway for achieving clean and efficient coal utilization, with systematic and scientific potential evaluation and site selection serving as essential prerequisites for its engineering implementation. Taking the No. 15 coal seam of the F1 South Minefield in the Dananhu mining area of the Turpan-Hami Basin, Xinjiang, as the study object, this research established a comprehensive evaluation index system comprising five primary dimensions, namely coal quality conditions, coal seam occurrence conditions, containment stability, hydrogeological conditions, and environmental conditions, along with 15 secondary indicators. A multi-criteria comprehensive evaluation model integrating fuzzy analysis, combined weighting, and Grey-TOPSIS was subsequently constructed. The fuzzy comprehensive evaluation (FCE) method was employed to conduct a qualitative assessment of the overall engineering geological suitability of the study area, thereby characterizing the engineering geological conditions and identifying potential risks. A combined weighting approach integrating the Analytic Hierarchy Process (AHP), the Entropy Weight Method (EWM), and game theory was adopted to derive balanced and reasonable comprehensive weights for each evaluation indicator. Finally, the improved Grey-TOPSIS method was applied to perform a quantitative evaluation of the in-situ pyrolysis development potential of tar-rich coal in the study area and to delineate favorable zones. The results indicate that the comprehensive geological conditions of the study area are suitable for in-situ pyrolysis development, with only the hydrogeological conditions being relatively weak. Among the primary indicators, containment stability and coal seam occurrence conditions exert dominant influences on in-situ pyrolysis, with weights of 24.8% and 24.62%, respectively. Coal quality conditions and hydrogeological conditions exhibit comparable weights of 20.24% and 19.19%, respectively, occupying a secondary yet significant position. Environmental conditions have the lowest weight at 11.18%. The evaluation results classify the development potential of the No. 15 coal seam in the study area into three categories: favorable areas are primarily concentrated in the central part of the mining area, relatively favorable areas are located in the central-southern and northeastern parts of the mining area, while the southwestern and eastern marginal zones are identified as unfavorable for development.