Oil And Water Distribution Of NI Reservoir In AB Sag Of NC Basin

AB Sag of NC Basin has good prospects for exploration with complicated petroleum geology background,less pre-information,unclear oil and water distribution,lacking fine reservoir anatomization.This thesis is focus on reservoir subdivision,identification of reservoir type and oil and water distribution of N1 Formation in AB Sag of NC Basin.Applying logging data,seismic data and neighborhood stratification results,based on mark bed control,electrical characteristic curve combination to sedimentary cycles,using the principle of sequential control,5 interface controlling 4 set of strata with sedimentary evolvement from sandy conglomerate,sand and mud interstratification,oil shale to lacustrine mudstone is defined,4 Pay zones and 45 layers are divided.By normalized logging curve,wavelet extraction and precise calibrating downhole seismic,geological model,selecting inversion parameter,comprehensive inversion,reservoir characteristics and many other inversion processes,pointing out that sand of Pay zone I in block X-35?X-52 is poor,while sand of Pay zone ? in block X-7-3,X-53 develops well.Sand in high structural part of Pay zone ? in block X-35,X-52 develops better than that of lower structural part.Affected by multi-source supply system,sand of Pay zone I is too well to distribute in the whole blocks.Major subzone of Pay zone I of both block X-35 and X-7-3 is N ? 3,major subzone of Pay zone ? of both block X-52 and X-53 is N I 5,with average thickness is 1.15m.With oil and gas drilling data and hydrocarbon shows,reservoir type and oil and water distribution of N1 Formation in AB Sag are summarized,the main reservoir types of N1 Formation in AB Sag are backward faults reservoir,lithologic reservoir,fault lithologic reservoir and stratigraphic unconformity reservoir.On the plane,oil and gas mainly distributed in north-south direction with the rule of "well-poor-well" from south to north,each block has undefined oil-water interface.Vertically,oil is mainly concentrated in Pay zone I and ? of N ? Reservoir,oil bearing formations is lower with elevation depth increases;generally with the feature of "oil up water down" or "oil up dry down";the lower layer is mainly water layer.Further studies shows that source rocks,sand distribution,the high or low tectonic and fault sealing are controlling factors affecting the distribution of oil and gas.