Sedimentary System Characteristics Of Rift Strata In The Great Campos Basin,Eastern Brazil

The Great Campos Basin is an important petroliferous basin group in the west of the South Atlantic Ocean and the east of Brazil.It consists of Santos basin,Campos Basin and Espirito Santo Basin.The great Campos Basin has experienced three main sedimentary periods: rift stage,transitional stage and passive continental margin stage,of which rift stage is an important oil production period.Based on the theory of sequence stratigraphy and sedimentology,this paper uses seismic,logging and core data in sequence stratigraphic framework,combined with previous research results,to carry out relevant research on the characteristics of sedimentary system of rift strata in the Great Campos Basin,and on the basis of the research of each basin,to compare the sedimentary characteristics among basins,and finally to predict the exploration favorable areas The main achievements are as follows: the rifting strata of the great Campos Basin are divided into two second-order sequences: barremian period early Aptian period(SSQ1 sequence)and middle Aptian period(SSQ2 sequence),of which the SSQ2 sequence of the Espirito Santo Basin is not developed;the rifting strata of the Santos basin and Campos Basin mainly develop fluvial delta facies,lake facies and carbonate platform facies.There is no carbonate platform deposit in Espirito Santo Basin,and the sedimentary sub facies and some sedimentary microfacies are further identified for the developed sedimentary facies;the seismic facies and logging facies characteristics of each basin are analyzed,and the sedimentary facies plane distribution map of each layer of rift system is drawn,and the carbonate platform of rift system in Santos basin and Campos Basin is established on this basis Based on the geological depositional model and Lacustrine facies clastic rock depositional model of rift system in Espirito Santo Basin,it is clear that the development characteristics of the strata in rift period are mainly controlled by the unique "uplift and depression" structural pattern of the basin.Finally,on the basis of clearly understanding the sedimentary system characteristics of rift system,combined with the structural background of the basin and the actual situation of exploration and development in the basin,the rift system is predicted the favorable exploration areas are the structural uplifts in the basin and the nearshore near source areas.