1. State Key Laboratory of Oil and Gas Equipment, CNPC Tubular Goods Research Institute, Xi’an 710077, China
2. CNPC Oil and Gas Technology Research Institute Changqing Oilfield, Xi’an 710021, China
3. CNPC Exploration and Production Company, Beijing 100007, China
4. CNPC Chuanqing Drilling Engineering Co., Ltd., Chengdu 610051, China