Abstract: Based on studies of sedimentary fades of reservoirs in the Daqing oil field,delta complexec deposited along the Long axis of a continental lake basin,are classified into three depositional models depending on the differences of energy between the river and the lake.They are(1)bird-foot delta formed during rapid regressions(2)lobate-delta developed during slow regression,and(3)sheet delta formed during transgression.The main sand-bodies deposited under fluvial-deltaic environment in a lake basin include channel sand-bodies(point bax,abandoned channel sand); distributary channel sandstones(straight or meandering); delta front sand-bodies(river-mouth bar,sheet sand in the inner fringe and outer fringe),and inter-delta sheet sand-bodies.They are different from each other in geometry and internal texture.Therefore,they have different performances in oil-water movement during water-flooding.Generally speaking,the river-mouth bar yields the best results in development,followed by distributary channel sand and channel sand.Sheet sand stands last in the list.Sweeping efficiency and pattexn of water-flooding of the various types of sand bodies are discussed with more details.