Seismic Sedimentology Research Of The Dongying Formation,Eastern Shanan Sag,Bohai Bay Basin

The East Shanan Sag in Bohai Bay Basin is studied as an example in this paper,under the instruction of sequence stratigraphy,sedimentology and seismic sedimentology theories,combined with three-dimensional seismic data,logging data,core data and log data for the analysis of sedimentary facies and depositional systems development in the study area.In consideration of regional tectonic evolution of the East Shanan Sag,the Dongying Formation in the study area is devided into three third-order sequence,and six sequence system tracts.By analysis of the core facies,geophysical data,as well as the palaeogeomorphology,internal sedimentary facies types and their distribution characteristics of Dongying Formation in the East Shanan Sag are determined.Seismic sedimentology study has been carried out on Dongying Formation in the study area integrating facies adjustment,petrophysical properties analysis and strata slicing technology.The interpreted geological interpretation of strata slices is done under the combination of drill logging data and synthetic seismogram calibration.Sedimentary facies characterization and the distribution of reservoir sand have also been discussed.Besides,the longitudinal evolution characteristics of the Dongying Formation have been portrayed,using seismic sedimentology method.The East Shanan Sag is majorly sourced by Shaleitian salient.Four kinds of sedimentary facies are developed in Dongying period.In the Dongying Third period,fan delta sedimentation played the main role and slump turbidite fan deposit at the position of distal fan delta front.As it came to the lower Dong Second period,the lake level rose and lake facies are mainly developed in the study area.For the upper Dong second period,braided river delta deposited in the research area,and delta lobes had large scales and extended very far.Finer characterization has been done on sedimentary facies and their distribution in the study area.Potential reservoir sand distribution and favorable exploration zone are predicted,which shows the leading edge of fan delta,braided river delta front as well as fluxoturbidite bodies are favorable exploration zones.