Structural features of terrigenous deposits of the Kolgan strata according to geological modeling data

On the basis of 3D seismic data the clinoform structure of the Upper Frasnian -Lower Famenian carbonate-clastic Kolganian suite has been identified.Sediments of this suite have formed series of heterochronous shelves, which were advanced progradationaly toward deep water basin from eroding island land -Orenburg swell.Sea level fluctuation caused changes of terrigenous sedimentation to carbonate sedimentation and vice versa.River systems were developed and deltaic complexes were formed during the Evlanov-Liven and Lower Famenian sea level falls.Deltaic genesis of the Evlanov-Liven (Upper Frasnian) producing sandstones has been identified on the Vakhitov oil field.The Elets (Lower Famenian) complex of deltaic deposits that is considered as perspective for oil exploration was identified.