1. Natural Gas Research Institute, PetroChina Southwest Oil and Gas Field Company, Chengdu 610213, PR China
2. School of Chemical Engineering, Sichuan University, Chengdu 610065, China
3. Institute for Advanced Study, Chengdu University, Chengdu 610106, PR China
4. Shunan Gas Mine of PetroChina Southwest Oil and Gas Field Company, Luzhou 646000, PR China