1. Key Laboratory of Petroleum Resources Research, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, PR China
2. College of Geosciences, China University of Petroleum, Beijing 102249, PR China
3. State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum (Beijing), Beijing 102249, PR China
4. CNOOC Research Institute Co. Ltd, Beijing, 100027, PR China
5. Virginia Polytechnic Institute and State University, 24060, U.S.A.