1. Key Laboratory of Unconventional Oil and Gas Development, China University of Petroleum (East China), Ministry of Education, Qingdao 266580, People’s Republic of China
2. School of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, People’s Republic of China
3. Saskatchewan Res Council, Energy & Min. Div., Regina, Saskatchewan S4S 7J7, Canada