The Research Of Sedimentary Characteristic Of Dalianhe Formation In Three-Dimensional Of Fangzheng Fault-depression

Paleogene Dalianhe Formation is one of the main strata at oil and gas exploration of Fangzheng Fault-depression,this paper will set up the isochronous sequence stratigraphic framework in the 3D area based on the basic theory of sedimentary petrology,combined with the sequence stratigraphy,petroleum geology and tectonics theory,as well as drilling cores,logging,seismic and mud logging data,then the space-time distribution,controlling factors and evolution law of Dalianhe Formation sedimentary system in the sequence stratigraphic framework can be analyzed and researched comprehensively,and combined with the results of previous studies to predict favorable zone of the target layer.Dalianhe Formation of Fangzheng Fault-depression is between two regional unconformities:T3 and T4,the sequence stratigraphic division and comparison is done through the selecting key wells,joint wells and relevant seismic section data,combined wells and seismic,achiving the unity of well-drilling stratification and seismic boundary,Dalianhe Formation can be divided into 3 Third-order sequence and six Base level cycle units,then the sequence stratigraphic framework is established.By the core,well logging and logging data,combined with seismic data,we can draw an conclusion that there are four sedimentary faces in the Dalianhe Formation of Fangzheng Fault-depression 3D area:fan-delta facies,lacustrine facies,sublacustrine fan facies and fluvial fan facies.Fan-delta facies is most development,can be divided into 10 subfacies and 18 sedimentary micro-facies detailedly.Through the research on the sedimentary system within the isochronous sequence stratigraphic framework,we conclude that there are multiple source characteristics in Fangzheng Fault-depression,and provenance's directions are different in different sedimentary period.sedimentary facies distribution law is definitely,combined with the drilling data and previous summary of hydrocarbon migration and accumulation rules,we indicate that fan delta front is the most favorable hydrocarbon accumulation area in Dalianhe Formation of Fangzheng Fault-depression 3D area.