Lower Cretaceous Cedimentary-Structure Response Characteristics of Baolegentaohai Sag North Subsags in Erlian Basin

The drilling and earthquake research material shows that Baolegentaohai sag north subsags developt Saihantala Formation,Tengger Formation,Aershan Formation and the Jurassic stratum,Lower Cretaceous,for asymmetric single broken unsymmetrical fault-depression sag.According to different areas of sedimentary structure characteristics,the sag can be divided into eastern steep belt,central subsags belt the west slope inside belt and outside belt count up four subprime units.Baolegentaohai sag fault systems mainly composed of the eastern boundary large faults controlled and its derived level 2 or 3 fault,based on the principle of east to north fault,the faults controlled the formation of sediment-ary and structure.The westfaulting east overlapping of Baolegen-taohai sag geologic structure controlled the exhibition of sedimentary facies belt,many structural movements formated serial sedimentary break and transgression(source center),sedimentary formations that is nearer provenance,multiple origins and coarse sediment,the sand types were fandelta,braid river deltas and nearshore subaqueous fan,reservoir type was low compositional and textural maturities of turbidites and middle-low porosity and low-low penetrance.The hydrocarbon generation center of ramp zone and central subsags belt in north lord subsags area are favorable zones for the stand industrial reservoir.