Abstract: Coal-bed gas resources are huge in China.However,its scaled exploitation is limited due to unique occurrence status.Scientific methods are needed to identify the key geologic factors influencing its effective exploitation.In view of that the influencing factors are large in number and high in dynamic complexity,this paper established a model to identify and analyze the key geological factors based on rough set attribute reduction theory.First,sixteen original geologic factors were selected in respects of coal petrologic characteristics,coal seam features and geologic influences and were optimized according to the available data from 40 CBM wells selected for study in different regions of China.Then,decision data were constructed and attribute reduction of decision table was performed through rough set data analysis.Finally,sorting was performed according to their relative importance and the key influential geologic factors were identified.Eight geolo-gic factors including,geological structure type,in-situ stress,coal seam pores and fractures are relatively high in importance.Overall,external influential geologic factors have stronger power than internal ones such as coal seam and coal rock.Therefore,more attentions should be paid to the influence degree and action mode of the external geologic factors to enhance the level of mining gas hazard management in practice.

Key words: geologic factor, rough set, importance degree of factors, decision data, coal-bed gas exploitation