1. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Chengdu University of Technology Chengdu 610059 Sichuan China
2. Research Institute of Petroleum Exploration and Development PetroChina Beijing 100083 China
3. National Energy Shale Gas R&D (Experiment) Centre Langfang 065007 Hebei China
4. PetroChina Unconventional Oil & Gas Key Laboratory Langfang 065007 Hebei China