Assessment of favorable areas for coalbed methane resources exploration in the Muli coalfield of Qinghai Province based on multi-layered fuzzy mathematics

The influencing factors of the coalbed methane (CBM) exploitation potential were investigated in the paper. Three second-order indices, i.e., gas-generation potential, reservoir physical property, sealing capacity, and their corresponding third-order indices for assessment of the CBM exploitation potential were established. The weight values of all second and third-order indices were determined by the fuzzy mathematics, and the multi-layered fuzzy mathematic model for assessment of the CBM exploitation potential was set up. As a case study, the multi-layered fuzzy mathematic model was applied to the assessment of exploration and development potential of the mid-low ranked CBM in the Muli coalfield of Qinghai Province. The results show that the Jiangcang coal mine area has the best potential for CBM exploitation in the Muli coalfield and hence should be the most favorable testing area of the CBM exploitation. The assessment system established in the paper can be regarded as a reference model in the assessment of potential of CBM exploration and development of the mid-low rank coal seams.