Study On Gravity-flow Sedimentary Characteristics Of Es3 In Niuzhuang Sag

In the last 60 years,gravity flow has developed from the turbidity current deposits classic mode to slump,debris flow,grain flow,liquefied flow and turbidity current gravity flow deposits.Due to the complexity of the underwater environment and the diversity of the supporting mechanism of sediment transport,there are still a lot of controversy in the academic circle on the classification of sediment gravity flow and the understanding of sedimentary model.Nowadays people are more concern marine gravity flow than classifying and modeling lake delta ftont gravity flow.Niuzhuang Sag locates at the southeast part of dongying sag in Shengli Oilfield,delta set is developed along the long-axis direction of the sag during Shahejie Group Es3 section.We obeserved and did researches thorougly about the delta front slope cores from Niu 48 well,Shi 114 well,Gao 898 well and other wells.We analyzed and summarized the development characteristics of gravity flow in different rocks,for example,dark mudstone mixed with reddish-brown mudstone caused by gravity erosion,and there are many inverted,convolute bedding caused by sand sliding and collapse in sand mud interbe.Combined with the studies of the deposition mechanism of Niuzhuang Sag gravity flows,the gravity flows can be divided into four sedimentary types: sliding,collapse,debris flow and turbidity.According to the marks of differernt sedimentary types on the cores,we discussed the evolutionary relationships of various types,and established the deposition sequence,drawed the sedimentary model figures.We think that sedimentary sequences in a set of ideal gravity flow should develop slide,collapse,debris flow and turbidity from bottom to top,and slope moving fan is one form of gravity flow,which belongs to the gravitational sliding stage.Finally,combined with the data of core size from more than 20 wells,we studied the properties of different sedimentary types of gravity flow,concluded that high density turbidity currents and sandy debris flows are favorable for oil and gas storage.