By studing the lithofacies of coring well sections, lithofacies assemblages and vertical sedimentary sequences , several types of sedimentary environments including sandy braided channels, low sinuosity channels , crevasse splays, interstreams lakes , transgressive deltas , shore shallow lakes etc. can be recOgnized in Fuyang oil reservoirs(K1q3+4).During the sedimentary period of Yangdachengzi oil reservoir, the braided and low sinuosity channels in northern, western and southern sedimentary systems converged in the eastern basin and developed into meandering streams. Along with the sedimentation of Fuyu reservoirs, streams in the western basin began to form lakes. At the late sedimentary stage of Fuyu oil reservoir, lakes quickly extended. Only the sedimentary system in the south developed transgressive delta deposit because of the abundant supplies of sediments. But in other regions, estuarine sandbars were transformed to shore shallow lakes composed of siltstones and thin interbeds.
