1. School of Resources and Geosciences, Key Laboratory of Coalbed Methane Resources & Reservoir Formation Process, Ministry of Education, China University of Mining and Technology, Xuzhou 221116, China
2. Key Laboratory for Resource Exploration Research of Hebei Province, Hebei University of Engineering, Handan 056038, China
3. College of Earth Science and Engineering, Shandong University of Science and Technology, Qingdao 266590, China