Reservoir Evaluation Of Fuyu Oil Layer In Sanzhao Depression

The Block B125of Gucheng oil field locates in the northern slope of Biyang Sag,Nanxiang basin. It has been brought into development since1987, and thedevelopment effect for the three sets of dominant formations has gone worse with thedevelopment of20years. Hence, subdivision and comparison, reservoir parameters,sedimentary micro-facies of dominant formations, sand body spreading regularity andthe oil-water distribution law need further recognition.The research region is mainly dispersed over Member3of Hetaoyuan Formationthe lower Tertiary, and is controlled by structure, faults and sand. Based on the faultunderstanding of the research region, combining with the predecessors’ explanationabout earthquake, this essay studies3oil layer groups’ top microstructures and haswaved a top microstructure map with10m contour intervals, which indicated theBlock B125is the horst-type faulted nose structure which was formed by two stripsof reverse arc normal fault with east and west intersecting. Based on the predecessors’thin-layer division and combining contrast analysis of well logging data, the G4109well is chosen as a standard well, established5framework sections. Regarding thelithology curve as a major contrast and dividing foundation, meanwhile referencing tothe electric property curve, from point to line, from line to surface, finally thesubdivision contracts of111wells within the region are completed, indicating that theformation thickness of research region is relatively stable with a lower south part andhigher north part and stratal connectivity is mainly altered by faults. The analysis ofcore observation, grain-size characteristics, sedimentary structure and logging faciesindicates that the reservoir mainly developed from the underwater distributary channel,the estuary dam sand bodies of the near-source fan-deltaic front, sheet sand and thegulf of the watercourse etc; reservoir sand bodies is continuous in plane, and has avertically large quantity with small thickness. Mercury intrusion tests have shown that the reservoir is mainly macro-pore path and moderate sorting, the pore types aremainly intergranular pores which belong to the moderate and higher pore and higherpermeability reservoir. On the base of rock core physical properties, this paper sets uplog interpretation model and the model is used to interpret the physical parameters ofmore than11new wells within the region. In this way, the value of the pore andpermeability of every single layer is got, and with these parameters, the planardistribution characters of pore and permeability are studied. This paper mainly adoptsthe cross plot method, and constructs a model for oil-water recognition which is usedto identify oil and water. By means of respective parameters, the reservoir is classifiedinto4categories: class one reservoir (better), class two reservoir (good), class threereservoir (bad) and class four reservoir (non-reservoir). Based on the study for theplanar distribution characters of effective sand body, the author classified andevaluated the good reservoir of the research region. The main development types inthe research region are class two reservoir and class three reservoir, but class onereservoir scatters widely.