The southern West Depression of the Liaohe Basin has been developed with favorable geological conditions for oil and gas accumulation and thus is an important exploration area of the Liaohe Oil Company. In Shasan (third membre of the Shahejie Formation) period, huge deep water mudstone and multiple low-angle sloped lake floor fan sediments were deposited as a result of active faulting and subsiding. These deposits have provided abundant hydrocarben source rock and reservoir for the formation of oil and gas pools. During this period, the Qijia-Dujiatai and Jinzhou-Huanxiling lake floor fan depositional systems were developed in the southern West Depression. Controlled by the distance to the terrigenous province, basement structure and main faults, these lake floor fans can be sub-divided into three subfacies, inner fan, middle fan and outer fan. Both of these lake floor fans have smaller scale in the early Shasan period, largest scale in the middle Shasan period and decreased scale in the late Shasan period. The properties of the Shasan reservoirs are very poor in the study area, which are characterized by low porosity-permeability, extremely low porosity-permeability. The best reservoir of lake floor fan is the sandbodies of the middle-fan braided channel microfacies, and reservoir properties decrease from the middle-fan braided channel deposits through the middle fan front to the outer fan deposits. Reservoir characteristics are mainly controlled by lithology of parent rocks, deposition and diagenesis. The Shasan lake floor fan sandbodies distributed widely in the study area are surrounded by mature hydrocarbon source rocks and are located at the beneficial direction of oil and gas migration, hence having a promising exploration potential.