Sedimentary system analysis of Es2 to upper part of Es3 in Gubei sub-sag of Zhanhua depression

This paper aims to clarify the distribution regularities of the sedimentary systems,to determine the source direction and sedimentary boundaries of Es2 to upper part of Es3 in Gubei sub-sag,Zhanhua depression,making full use of the cores,granularity,logging data and seismic to analyze sedimentary systems of the area,and to analyze the distribution regularities of the sedimentary facies.The results show that the research area develops five sedimentary facies including braided river delta,fan delta,wave-controlled delta,lake and beach and bar.The sediment sources are mainly from the north,the east and the south,while the western and northeastern also have weaker sources injection.The braided river delta develops in the east area and the nouth nose-like structure belt and the fan delta distributes mainly along Chengdong bulge with narrow banded shape,limited distribution.The wave-controlled delta develops in the south nose-like structure belt;the shallow lacustrine basin developed in the east and west of the paleo uplift,while the semi deep lake-deep lake is concentrated in the western depression,and the above sedimentary system have certain inheritances.At the same time,the basin suffered lake level rising and falling during the second member of Shahejie formation deposition period,mainly developed beach and bar sedimentary system.The study has guiding significance to improve the sedimentary facies types and distribution regularities of recognition accuracy,and to explore deep formation and new exploration area.