1. China University of Petroleum, School of Geoscience, Qingdao, China and Key Laboratory of Deep Oil and Gas, Qingdao, China.
2. China University of Petroleum, School of Geoscience, Qingdao, China and Key Laboratory of Deep Oil and Gas, Qingdao, China. (corresponding author)
3. China University of Petroleum, School of Geoscience, Qingdao, China.