1. State Key Laboratory of Enhanced Oil Recovery, Research Institute of Petroleum Exploration and Development, CNPC , Beijing 100083 , P.R.China
2. NO.2 Produce Plant, Xinjiang Oilfield Company, Petro China , Karamay 834008 , P. R. China
3. School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou , Jiangsu , 225002 , P.R.China