Abstract: The Jishan sand body is the main sand body explored in Huimin Sag, the prospect for the exploration of Jishan sand body is broad. The Jishan sand body is found to be a set of deltachannelturbidity fan sedimentary system by means of analysis of lithologic characteristics, sedimentary structural characteristics and lithologic texture characteristic. The Jishan sand body is divided into four stages vertically. Grain size of the Jishan sand body is fine, and the rock is mainly composed of finegrained sandstones and siltstones. Influenced by the sedimentation and diagenesis, reservoir properties are of the characteristics of medium porosity, low permeability, strong heterogeneities and well developed secondary pore. On the basis of recognition, reservoir forming factors of Jishan sand body are analyzed, the results show that the such reservoir forming conditions as rich oil source, good reservoir, favorable migration conditions, good assemblage of generation, reservation and capsulation and various trap types, are favorable for hydrocarbon migration and accumulation. Palaeostructurallithologic traps of Panhe anticlines in the west Jishan trough and lithologic traps of Mengsi low uplift are the targets for further exploration.

Key words: sedimentary features, reservoirforming conditions, Jishan sand body, exploration orientation, Huimin sag