An Accurate Anatomizing Method for Structure of Reservoir of Alluvial Fan:A Case Study on Lower Karamay Formation,Liuzhong Area,Karamay Oilfield

In order to recognize the internal structure of the alluvial fan reservoir and distribution of remaining oil and provide a more accurate geological basis for the well pattern adjustment and the remaining oil potentiality of production tail in oilfield, the Liuzhong area of Karamay oilfield, as a case, is studied. Using the method of scale analysis and model fitting, the data of coring, outcrop, logging and performance, reservoir characteristics of alluvial fan in studied area is well researched. A comprehensive analysis method for reservoir architecture of alluvial fan is proposed. The result shows that the study area belongs to a part of the alluvial fan. The depositional model of alluvial fan was established. It can be divided into four zones, fanhead, intra middle fan, outer middle fan and fan margin-wetlands. The distribution of composite glutenite is divided into three patterns: a sheet distribution pattern in fanhead and intra middle fan, a broad ribbon distribution pattern in outer middle fan and a narrow ribbon distribution pattern in fan margin-wetlands. The overlying manners of a single conglomerate body are listed as five types, vertical-overlay, lateral-interleaving, lateral-overlying, lateral-separating, lateral-stitching.The quantitative scale of a single conglomerate body was established. The result of detailed architecture was verified by pressure coring well. Authors point out that the remaining oil is enriched near the sand body boundary.