Application Of Sequence Stratigraphy To The Reservoir Prediction Of The First Member Of Wanchang Formation In Xinanpu Sag

In recent years,continental sequence stratigraphy is considered more and more serious by international and domestic geological scientists,which provides a completely new method to petroleum exploration and development.Taking Xinanpu sag of Yitong basin as a case,isochronous stratigraphy framework of system tracts have been established through logging,seismic data and regional geology.And based on the isochronous stratigraphic frae work,the article analyzes sequence stratigraphy style and main controlling factors of target in the varied structural zone,restores depositional paleogeomorphology of different systems tracts,extracts waveform clustering of systems tracts,and finally predicts favorable reservoir development region of systems tracts through comprehensive analysis.The study show that Wanchang group have been divided into three third-order sequences,and the first member of Wanchang formation of target has been divided into a complete set of three systems tracts,which includes the lowstand system tract,the transgressive system tract and the highstand system tract.Three kinds of sequence stratigraphic patterns have been recognized in researched area,which includes flexure slope break,faulted slope break and slope without break.The palaeogeomorphic form is the most obvious before the lowstand system tract deposition,which has a great control on source direction and deposition.Then the palaeogeomorphic form of transgressive system tract and highstand system tract gradually becomes indistinct,and of which control rules on sedimentary also becomes gradually weaken.Favorable reservoir development zone of lowstand system tract mainly concentrates on below flexure slope break and fracture slope breaks,structural high of Liangjia and slope area and northeast part of northwestern margin.Favorable reservoirs of transgressive system tract develops zonational along the clinoform to depression in Wanchang tectonic belt structural high and slope area of Liangjia.And that,highstand system tract principally centralizes favorable reservoirs on Liang's structural high and slope area,southwest of the sag of the central part,slope to the concave part of Wanchang structural belt and northeast part of northwestern margin structural high and northeast part of northwestern margin.