| Xiaoji Oilfield is a multi-layer heterogeneous reservoir with abundant oil and gas accumulated in production in Dagang.It is currently in the development stage characterized by high water content and low recovery rate.The distribution of residual oil is complicated in subsurface for further extraction.Taking the 2ndand 3rdlayers of the 1stmember of Kongdian Formation in Xiaoji Oilfield as an example,this study chracterizes the reservoir configuration and models of alluvial fan in Xiaoji Oilfield and sumarizes the influence of sandbody configuration on flooding.Based on the previous research,we determined the models of stratigraphic development within the 2ndand 3rdlayers of the 1stmember of Kongdian Formation by comparison and review of the target intervals.We further characterize the sedimentary by analyses of the lithology,grain size,mudstone color,reservoir heterogeneity and reservoir classification.Based on the data of core observation,seismic,well logging and dynamic monitoring data of production,the reservoir configuration level is further divided into four levels including sixth level,seventh level,eighth level,and ninth level:?1?the sixth level architecture unit is a multi-period turbulent flow belt with a multi-stage sandbody;?2?the seventh level architectural unit is a single turbulent zone with a single-stage sandbody;?3?the eighth level architecture unit is single sandbody featured by sedimentary microfacies,including turbulent sand islands,turbulent flow channels,diffused sandbodies and diffused fine particles;?4?the ninth level architecture unit is a interlayer of single sandbody.We summarize the interface types and characteristics of different sub-structures,implement qualitative and quantitative statistics analyses,and set up the models for reservoir configuration controlled by debris flows and braided rivers.Finally,we analyze the influences on flooding by superposition of sandbodies and interlayers of single sandbody. |
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