The fine studies of depositional micro-facies on the middle-post development stages in Wennan Oilfield

For a reservoir on the middle post development stages, a fine study about micro facies is very important for modeling a proper reservoir, getting a proper knowledge of remaining oil distribution and improving oil recovery rate. Based on the basis of comprehensive analyses of the features of the paleontology, geochemistry, depositional structure, petrology and granularity, the depositional environment of the sub zone of No.2 member of the Shahejie Formation in age of Paleogene could be identified as an intermission fluctuating shore shallow lake under a drought weather. The depositional facies should be swallow delta sedimentary system. A few of type of micro facies are marked off, such as underwater channel, overflow bank sands, and so on. The nature of the micro facies are described, it is clearly that the physical and storage properties of reservoirs, taken a sequence from the best to the worse, are underwater channel, overflow bank sands, respectively.