Structural Characteristics Of The Shahejie Formation And Its Effects On Reservoir-forming In BZ 34-2/4 Oilfield,Bozhong Depression

BZ34-2/4 oilfield is located in the central uplift belt of River Mouth Sag in Bohai gulf basin. The overall structure of the face of the field area, is a north east trending fault anticline, NE development and EW groups break.In the full use of seismic and drilling and logging data, on the basis of the Shahejie Formation in the studied area to conduct fine structure interpretation, then through the structural development features, breaking combination of features and the formation and evolution, matching relationship with other fault accumulation and fault sealing elements ability of combining study the spatial distribution of water,thereby determining the effect of breaking the control of the reservoir formation and distribution, and ultimately this basis, favorable exploration target optimization of the Shahejie Formation.By strike-slip extensional stress, the study area and development of NE-NEE parallel to overstep shape echelon faults and NEE-nearly EW trending faults constitute a "Z" shaped grid-like structure. Fracture morphology and fracture types and patterns of diversity, where a negative flower combo most typical; fault is divided into three levels and three second.Favorable sand body morphology, matching tectonic position, determines the sand body can be favorable traps. BZ34-2 oilfield belongs to the typical structure of reservoir, suggests that fault trap effect in the district. Thus, the structure of the different layers of sedimentary body position, may decide the form of trap types. We evaluate the A, B two favorable underlying potential target area combined with reservoir potential analysis. A region where a favorable level segment III, IV oil group;and B, then I, II oil group more favorable.BZ34-2 oilfield reservoir anatomy shows that the matching relation between fault and sand body determines the characteristics of oil and gas. Group III and IV reservoir of BZ34-2 oil field belongs to structural reservoir, sand body length axis pointing diagonally matching relation between faults and determines the distribution of the reservoir and form; Group II oil reservoir belongs to composite reservoirs, andshale interbed and have stable cover layer of sand body and fault, tectonic lithologic composite contour matching form oil and gas reservoirs.Fault sealing and reservoir heterogeneity of BZ34-2 oilfield determine its oil-water system, the area can be divided into three oil-water unit; Three oil group III and IV in the oil sand group upper oil-bearing condition is good, in the southeast of greater development potential; Sand one of group II oil sand body origin, pointing to the relationship between fault cutting shows that oil and gas area is bigger, has the feature of common oil.