A new approach for outcrop characterization and geostatistical analysis of a low-sinuosity fluvial-dominated succession using digital outcrop models: Upper Triassic Oukaimeden Sandstone Formation, central High Atlas, Morocco

Abstract

The use of digital outcrop models in combination with traditional sedimentological field data improves the accuracy and efficiency of qualitative and quantitative characterization of outcrop analogs for reservoir modeling purposes. In this article, we apply an innovative methodology of outcrop characterization to an Upper Triassic fluvial-dominated system, exposed in extensive outcrops with limited three-dimensional (3-D) exposure. Qualitative analysis of the study outcrop allows the subdivision of the formation into three architectural intervals. Each interval can be further subdivided into subintervals on the basis of architectural style. This subdivision provides information on reservoir compartmentalization, which is used for zonation of the geocellular model. Qualitative analysis also provides valuable information on reservoir facies distribution. A new technique termed perpendicular projection plane is presented as a tool for quantitative analysis of outcrops with reduced 3-D exposure. This technique improves the accuracy of apparent width measurements of geobodies exposed in outcrops, which are subparallel to paleoflow. The quantitative analysis provides a detailed data set of geobody dimensions to use as conditioning data for analog reservoir models. Statistical analysis of the dimensions provides empirical relationships to apply in subsurface analog systems to reduce uncertainty related to stochastic modeling approaches.