Sequence Characteristics and Hydrocarbon Accumulation Model of Nantun Formation in Beixi Slope of Beier Sags

Reservoir prediction based on sequence stratigraphy is one of popular and significant research subjects in hydrocarbon exploration. Based on the theory of sequence stratigraphy,comprehensively used the seismic,well logging,core and materials,comprehensively analyzed by well-seismic correlation,and verified by acoustic impedance,two third-order sequences which are mainly composed of fan delta-lacustrine sedimentary system can be identified in Nantun group of Beier depression:sequence Ⅰequal to K1n1,sequence Ⅱ equal to K1n2. Every sequence develops well and all consist of lowstand system tracts (LST),transgressive system tracts(TST) and highstand system tracts (HST). According to the development characteristics of sequence in the formation in the region of interest,based on the identification and correlation of sequence stratigraphic units,characteristics of sediment and sequence stratigraphic model of different sequence framework are summarized,and the hydrocarbon accumulation model is established.