(1.College of Earth Science and Engineering, Shandong University of Science and Technology, Qingdao, Shandong 266590, China; 2.Research Institute of Exploration and Development, Qinghai Oilfield Company, PetroChina, Dunhuang, Gansu 736202, China; 3.State Key Laboratory of Continental Dynamics, Northwest University, Xian, Shaanxi 710069, China)