1. Petroleum Engineering School, Southwest Petroleum University, Sichuan, Chengdu 610500, China
2. Petrochina Changqing Oilfield Company, Shaanxi, Xi’an 710018, China
3. South Sulige Operating Company of Changqing Oilfield Company, PetroChina, Shaanxi, Xi’an 710018, China
4. The Second Gas Production Plant of PetroChina Changqing Oilfield Company, Shaanxi, Xi’an 710018, China