1. Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education, School of Energy and Power Engineering, Dalian University of Technology, Dalian 116024, P. R. China
2. Research Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083, P. R. China
3. State Key Laboratory of Continental Shale Oil, Daqing 163002, P. R. China