1. Key Laboratory of Petroleum Resource Research, Institute of Geology and Geophysics, Chinese Academy of Sciences , Beijing 100029, P. R. China
2. Innovation Academy of Earth Science, Chinese Academy of Sciences , Beijing 100029, P. R. China
3. Department of Geosciences, The University of Calgary , Calgary, Alberta T2N 1N4, Canada
4. University of Chinese Academy of Sciences , Beijing 100029, P. R. China