1. College of Earth Sciences, Jilin University, Changchun 130061, China;
2. College of Applied Technology, Jilin University, Changchun 130022, China;
3. Exploration Department, PetroChina Jilin Oilfield Company, Songyuan 138000, Jilin, China;
4. Key2 Laboratory for Oil Shale and Coexisting Minerals, Jilin University, Changchun 130061, China

With very few studies undertaken so far and failure to achieve a breakthrough in oil and gas exploration, a systematic analysis of sedimentary characteristics and oil and gas accumulation conditions has been carried out in Zengsheng fault depression. The results show that the Zengsheng fault depression consists of a fan delta-lake-sublacustrine fan sedimentary system developed in a semi-deep lacustrine or a shallow lacustrine background. Certain size of argillaceous medium quality source rock and clastic reservoir with ultra-low porosity and low permeability occurred in Shahezi Formation, and clastic reservoir of ultra-low porosity and permeability in Yingcheng Formation occurred. Three types of source-reservoir-cap assemblage are formed, i.e., lower-generating and upper-storing type, upper-generating and lower-storing type, self-generating and self-storing type, with a certain prospects for oil and gas exploration. The key exploration horizon is Shahezi Formation, followed by Yingcheng Formation. The favorable exploration target is the updip pinch out of the sand body at the lower slope.