CBM accumulation characteristics and exploration target selection in northeastern Yunnan, China
Shao Longyi, Wang Xuetian, Zhang Jiaqiang, Hou Haihai, Tang Yue, Wang Jumin & Lin Yucheng
1. College of Geoscience and Surveying Engineering, China University of Mining and Technology, Beijing 100083, China; 2. Oil and Gas Resource Survey Center, China Geological Survey, Beijing 100011, China; 3. Yunnan Provincial Coal Geological Survey Institute, Kunming, Yunnan 650218, China; 4. Yunnan Provincial Bureau of Coal Geology, Kunming, Yunnan 650034, China
There are abundant coal resources and coalbed methane (CBM) resources in the Zhenxiong–Weixin Coalfield in the northeastern Yunnan Province and its CBM exploration and development prospect is promising. In order to promote the exploration and development of CBM resources in this area, we studied previous coalfield survey data and CBM geological exploration data. Then, we analyzed the relationships of gas content and methane concentration vs. coal seam thickness, burial depth, coal petrology, coal quality and roof and floor lithology from the aspects of gas bearing property, coal seam distribution, coal petrology, coal quality, and lithological assemblage of coal bearing strata. Besides, we briefly discussed the main influential factors of CBM accumulation. Finally, we established a CBM area selection evaluation model based on multi-layered fuzzy mathematics and applied it to CBM favorable zone evaluation in this study area. And the following research results were obtained. First, the main factors controlling CBM accumulation are coal seam thickness, burial depth and sealing capacity of roof and floor. Second, eleven third-order evaluation parameters are selected out from the aspects of resource potential, reservoir property, storage condition and development condition as CBM exploration target evaluation indicators. Third, the evaluation results of CBM area selection evaluation model show that the CBM exploration and development potential is the best in the Xinzhuang Field, followed by Luowang, Niuchang–Yigu, and Mahe. These research results provide a geological basis for CBM exploration and development in northeastern Yunnan in the following step.