1. School of Storage &Transportation and Architectural Engineering, China University of Petroleum (Huadong),Dongying Shandong 257061, P. R. China;
2. School of Petroleum Engineering, Liaoning Shihua University, Fushun Liaoning 113001, P. R. China;
3. Sinopec Huabei Chemical Products Sales Company, Beijing 100120, P. R. China;
4. PetroChina West Pipeline Company, Urumqi Xinjiang 830012, P. R. China