1. Shandong Key Laboratory of Oilfield Chemistry, China University of Petroleum (East China), Qingdao 266580, P. R. China
2. Key Laboratory of Unconventional Oil & Gas Development, Ministry of Education, China University of Petroleum (East China), Qingdao 266580, P. R. China
3. PipeChina Eastern Storage and Transportation Company, Xuzhou 221000, P. R. China