Key Laboratory of Coalbed Methane Resources and Reservoir Formation Process(Ministry of Education of China) China University of Mining and Technology Xuzhou 221008 China;
School of Resources and Geosciences China University of Mining and Technology Xuzhou 221116 China;
China United Coalbed Methane Co. Ltd. Beijing 100016 China;
PetroChina Coalbed Methane Company Limited Xinzhou Branch Baode 041000 China;