Research On The Lower Cretaceous Reservoir Control Factor In Southern Tamsag Depression

Research area is the central fault depression of Haita Basin,containing the Wunan sub-sag,Beixi sub-sag,Nanbeier east sub-sag and Tanan drpression.The area is 3700km~2.Exploration show that the oil-rich effective reservoir exist deeper formation in depression,is the new field on exploration.This text uses the geological theory and geophysical technique,observing and describing cores,geological statistics,reservoir microcosmic study,secondary porosity prediction,reservoir forming condition and comprehensive evaluation,summarize the oil and reservoir geological characteristics,reservoir geological condition and effective reservoir prediction.The deeper oil concentrated distribution in secondary porosity zone in longitudinal direction.Fault control the macroscopic hydrocarbon accumulation,secondary porosity control the concrete reservoir,oil change of phase enlarge the space of reservoir.In formation,reservoir concentrated distribution near the unconformity of the T3,T23,T22 and in the reservoir between source rock.The deeper reservoir related to secondary porosity,unrelated to amplitude of structure.In the plane,reservoir mainly distribute in central of sag and fault development area.Reservoir is controled by secondary porosity zone,this is the reservoir distribution and hydrocarbon accumulation law in central fault depression of Haita Basin.