1. Key Laboratory of Unconventional Oil & Gas Development (China University of Petroleum (East China)), Ministry of Education, Qingdao 266580, P. R. China
2. School of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, P. R. China
3. Petroleum Engineering Research Institute of Dagang Oilfield Company, Binhai New area, Tianjin 300280, P. R. China
4. CNOOC Energy Technology & Services Limited, Binhai New area, Tianjin 300452, P. R. China