1. State Key Laboratory of Deep Oil and Gas, China University of Petroleum (East China), Qingdao 266580, P. R. China
2. School of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, P. R. China
3. Shandong Provincial Key Laboratory of Oilfield Chemistry, China University of Petroleum (East China), Qingdao 266580, P. R. China