Fluvio-eolian successions are generally characterized by a high degree of complexity and internal heterogeneity. Quantifying the rapid facies changes in time and space is a major challenge to hydrocarbon reservoir characterisation.We present a method for facies discrimination in fluvio-eolian successions. The method is developed on the modern fluvio-eolian sediments from the Skeleton Coast dune field, Namibia. The examined sediments comprise eight different facies types; eolian dune sands, inter dune fluvial channel sands, intra erg mass flow deposits, intra erg hyperconcentrated flow deposits, fluvial channel sands, fluvial mud, lacustrine heterolithic sand and lacustrine heterolithic mud. The contrasting provenance of the fluvial and eolian sediments results in a distinct source fingerprint which can be discriminated using elemental whole rock geochemistry. Multivariate statistical technique performed on the geochemical data has enabled discrimination of seven of the eight facies types. Furthermore, the facies discrimination method allowed a quantitative estimate of the degree of fluvial reworking of eolian sand. We believe that the method presented here, when calibrated to a reference well or outcrop, and used together with sedimentological interpretation, has the potential for facies discrimination in the subsurface, thus improving reservoir quality evaluation.
Journal of Sedimentary Research, 2007, Vol 77, Issue 1, p. 23-33