1. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan, China
2. Southwest Oil & Gas Field Company, PetroChina, Chengdu, Sichuan, China
3. PetroChina Coalbed Methane Company Limited, Xian, Shanxi, China
4. The University of Tulsa Drilling Research Projects, University kf Tulsa, Tulsa, Oklahoma