Meandering river sand body architecture and heterogeneity: A case study of Permian meandering river outcrop in Palougou, Baode, Shanxi Province

Through actual measurement, careful sand body anatomy and lithofacies analysis of the meandering river sand bodies in the Permian of the Palougou profile in Baode county, Shanxi province, the architectural models of different kinds of meandering river sand bodies are established to characterize their interior sedimentary heterogeneity quantitatively, and predict the remaining oil areas in different kinds of meandering river sand bodies. Based on the outcrop characteristics, such as lithology, grain size, sedimentary structure, color, and so on, eight kinds of lithofacies are identified. By careful anatomy and lithofacies analysis of sand bodies, the bottom trough cross bedding sand body was separated from the classical point bar and named “bottom bar”, and the upper planar cross bedding was named “marginal bar”. Based on fine description of the sedimentary characteristics and superimposed relationships of bottom bar and marginal bar, four kinds of channel sand bodies, namely, lateral migration channel type, chute cutoff channel type, neck cutoff channel type and abandoned channel type, were identified. According to the architecture and heterogeneity characteristics of different types of channel sand bodies, it is concluded the lateral migration channel sand body has weak heterogeneity and little remaining oil, the chute cutoff and abandoned channel sand bodies with a little stronger heterogeneity is richer in remaining oil, and the neck cutoff channel sand body with the strongest heterogeneity has the most abundant remaining oil.