Main Controlling Factors Of Sedimentary Characteristics Of The Third Member Of The Shahejie Formation In The West Slope Of Gudao Uplift

Taking the Third Member of Shahejie Formation(Es3)in west slope of Gudao Uplift as the research object,based on core,borehole log,logging and seismic data,well-to-seismic integration fine strata classification and correlation was completed,and the finely regional stratigraphic framework was established under the guides of stratigraphy and sedimentology.Es3 in west slope of Gudao Uplift in Zhanhua Sag was divided into 3sub-members,and subdivided into 12 sand groups further.Five types of sedimentary facies were identified,including nearshore subaqueous fan,fan-delta,braid delta,slump fan and lacustrine facies.Nearshore subaqueous fan is mainly developed in the eastern part of the study area,near the flank of the Gudao Uplift.Braided delta,of which sediments were supplied by Chenjiazhuang Uplift is located in the southern part of the study area,where lake level was at low level during depositional period of lower sub-member of Es3.Fan delta is mainly developed in the eastern part of the study area during sedimentary period of middle sub-member of Es3;while middle of the study area is characterized by development of slump fan.Sediment gravity flows in the study area are widely developed.By employing methods including core observation,grain size analysis,thin section examination,log data and seismic data interpretation,etc.,this paper studied the evolution process of sediment gravity flows under different triggering mechanisms,and control of tectonic activities over sedimentary process of gravity flows and sand body distribution was also explored.The results indicate that during the sedimentary period of Es3,there developed two kinds of sediment gravity flows,which was induced by flood and slope failure,relatively.Structure development mainly exerts significant control over sedimentary structural features,formation of gravity flow and distribution pattern of sand bodies.Four sand control patterns have been established,which include slope break,transform zone,mono-faulted,and fault trough.Paleotopography mainly controls the distribution of sedimentary facies and transformation of gravity flow;provenance system mainly controls lithology and its composition characteristics;ancient water level and salinity mainly controls mudstone color and paleontological characteristics.