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