The Sedimentary Characteristics Research Of Fuyu Reservoir In Daan Oilfield

Dan an oilfield is located in the secondary structural belt of Hong gang terrace in the central depression area of southern Songliao basin. River-dominated delta is the mainly developed sedimentary system in the study area. The reservoir type belongs to low permeability, tight sandstone reservoir. Complex formation changes in the region, having regional thickness change in strata, contemporaneous fault and graben, lithological also changes quickly in the study area, there is large cut pile composite sand body formed by rivers incised and side cut. So the research on sedimentary characteristics of the area is important to the next oilfield exploration and development.Aiming at the complexity of the ultra-low permeability sandstone reservoir in the study area and basing on the fuyu reservoir study of predecessors, we established high resolution sequence stratigraphic stratum framework and logging facies model of fuyu reservoir in Daan oilfield by the data of core, logging, seismic and analyze test. We also drew sedimentary microfacies map of every time unit of fuyu reservoir and summarized the macroscopic distribution regularity of sedimentary facies belt, made single sand body analysis of every time unit, established physical property distribution patterns of fuyu oil reservoir. We drew different scales of microfacies controlled physical properties and sand body regular exhibition layout map. The research reveals the sedimentary characteristics of the study area: fuyu reservoir in Daan oilfield is fluvial-dominated delta sedimentary system controlled by northwest development source. Most sand bodies distribution are from northwest to southeast,Large area of banded distributary channel, mouth bar, overbank sand and natural levee are mainly developed. Distributary channels are mainly small-medium, large-oversize river are developed in several positions, mouth bar microfacies is under river control, Single article is banded and has multi-subbranches. On the basis of above work, the physical property lower limit of effective reservoir is determined and ultra-low permeability reservoir classification evaluation standard is established. We made weight analysis to the four indicators affecting reservoir evaluation(permeability, effective thickness, oil saturation, microfacies types) using grey correlation analysis method and identified correlation order of the four indicators.Finally we drew the high-quality reservoirs plane prognostic map of fuyu reservoir in Da an oilfield and optimized favorable wellblock, provided six suggestions well locations.