Evaluation of closed gob methane sweet spots: A case study of the Tiefa mining area

Abstract

Abstract The coal seam gas development in closed gob zone is still in the exploratory stage in China, and potential evaluation and sweet spots selection are the key issues. This paper establishes a complete evaluation system for selecting sweet spots for closed gob methane extraction with surface wells in the Tiefa mining area to reduce the blindness of area selection. The one‐vote veto system, the comprehensive evaluation index system, and the AHP‐entropy combined weight model are used to screen and evaluate the closed gob zones in the Tiefa mining area. A total of twenty evaluation units are evaluated and the development potential of which is classified as three levels by the optimal segmentation method. The relationship between the results of the assessment and the closed gob methane resource is also discussed, as well as the combined weight distribution coefficient. The results show that the development potential of the block cannot be estimated simply by the closed gob methane resource because the consistency between the comprehensive evaluation value and the closed gob methane resource is poor. The size of the combined weight distribution coefficient has little effect on the comprehensive evaluation values and only affects the ranking of evaluation units in a small range.

Keywords

• closed gob methane
• combined weight
• comprehensive evaluation
• resource assessment
• sweet spots