Research On Depositional Systems Of Palaeogene Of Member3of Shahejie Formation In Baxian Depression In North China Oilfield

Based on the theory of sequence stratigraphy, the paper aims to study sequencestratigraphy and reservoir in Paleogene in Member3of Shahejie Formation inBa’xian Depression.The sequence of Member3of Sha’hejie Formation is one2ndorder sequence,which can be divided into three3rdorder sequence.Based on the theory of Sedimentology, three kinds of depositional systems canbe identified. They are lake, fan delta and delta depositional systems.The type of the depositional system, position and the scale is mainly controlledby material source, palaeogeomorphology and relative lake-level change. The periodof Shahejie3Member deposited, there are three major provenance. Sublacustrine fanand the braided delta deposital system are developed in the provenance from SWW.Fan-delta deposital system is developed in the provenance from NWW. The braideddelta deposital system is developed in the provenance from Wen’an slpoe.Shore and shallow lake-beach systems and the braided delta deposital systemare developed in upper segment of Shahejie3Member. Fan-delta, shore-shallowlake, fluvial delta and sublacustrine fan deposital systems are developed in middlesegment of Shahejie3Member. Fan-delta and shore-shallow lake deposital systemsare developed in lower segment of Sha’hejie3Member.