1. Provincial Key Laboratory of Unusual Well Stimulation, Xi’an Shiyou University, Xi’an, China;
2. College of Petroleum Engineering, Xi’an Shiyou University, Xi’an, China;
3. E&D Research Institute of Changqing Oilfield Co Ltd, Xi’an, China;
4. E&D Research Institute of Daqing Oilfield Co Ltd, Daqing, China;
5. PetroChina Research Institute of Petroleum E&D, Beijing, China