Seismic Sedimentology And Its Application Of The Upper Sub-member Of Es3 In Chexi Area

In this paper,the complex turbidite reservoir of the Upper Sub-member of Es3 in Chexi Sag is taken as an example.The turbidite fan in the study area has the characteristics of small scale,large buried depth,thin sand body,complicated lateral variation,multiple vertical overlap,high difficulty of identification and prediction by well data,etc.In this study,well data and seismic are combined to carry out seismic sedimentary facies research under the guidance of seismic sedimentology theory and technology.The isochronal stratigraphic framework is established by making use of the core,logging and seismic attribute,and the sedimentary distribution of turbidite fan is studied.The following results have been achieved through this study:(1)Based on the result of isochronal stratigraphic division in each well,and guided by the sequence stratigraphy principle,the strata of the Upper Sub-member of Es3 in the study area is divided into four sand groups by using wavelet transform,time-frequency analysis and other seismic techniques.And the frequency division interpretation,attribute analysis and other seismic sedimentology techniques are used to identify the horizon and the fault,so that the isochronal stratigraphic framework could be established more accurately.(2)The Upper Sub-member of Es3 in the study area is considered to have developed the turbidite fans in gentle slope of faulted lake basin which mainly got the sediments from waterways.And it could be de subdivided into the braided channel and other sedimentary microfacies types.(3)Under the constraints of the isochronal stratigraphic framework and guided by the sedimentary model,the turbidite fan is identified by the targeted seismic sedimentology method according to the different development scale.Waveform classification,attribute analysis,spectral decomposition,and stratigraphic sectioning are four different technical means used,and the distribution pattern of sedimentary facies in each sand group is clarified.(4)The combination of well data and seismic clarified the distribution law of sedimentary facies in the Upper Sub-member of Es3,which provides an important basis for further exploration in this area.