Outcrop-Derived Quantitative Models of Permeability Heterogeneity for Genetically Different Sand Bodies

Abstract

ABSTRACT Core based reservoir data is insufficient in most cases for the accurate prediction and quantification of reservoir heterogeneity. In order to understand the scales and magnitudes of reservoir heterogeneity developed within specific reservoirs, we need to quantify reservoir heterogeneities in large two- and preferably three-dimensionally exposed outcrops of analogous sediments. Variations in depositional architecture are the main cause of reservoir heterogeneity and such variations can be hierarchically classified into a limited number of scales. This hierarchical classification can then be used as a framework with which to quantify reservoir heterogeneities in the field. To apply the data we derive at outcrop to actual reservoirs, we can adopt the sediment-body as the basic reservoir "building block". These building blocks are quantitative models of the scales and degrees of reservoir heterogeneity developed in genetic sediment-body types. Being genetically based, they are widely applicable and not reservoir specific. Seven such quantitative models are being constructed for sand-bodies within carbonate sand depositional environments. Permeability anisotropy can also be considered at a number of depositional scales and it is important to incorporate the correct scale of permeability anisotropy in reservoir simulation grid blocks.