1. Drilling and Production Engineering Technology Research Institute, CNPC Chuanqing Drilling Engineering Co. , Ltd. , Guanghan, Sichuan 618300, China; 2. National Energy R&D Center of High-Sulfur Gas Reservoir Exploitation, Chengdu, Sichuan 610041, China; 3. Engineering Technology Research Institute of PetroChina Southwest Oil & Gas Field Company, Chengdu, Sichuan 610031, China