1. State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Qingdao 266555, Shandong, P. R. China
2. College of Science, China University of Petroleum, Qingdao 266555, Shandong, P. R. China
3. Institute of Unconventional Oil and Gas and New Energy, China University of Petroleum, Qingdao 266555, Shandong, P. R. China