Determination of Spatial Heterogeneity Index for Naturally Fractured Reservoirs

Abstract

Modeling variations in reservoir properties as a function of space is an important task in evaluating reservoir heterogeneity. While it provides considerable value to capture the relative change in properties in the entire reservoir, it is an overwhelming task to perform in 3D. Various scientific approaches exist that facilitate measuring static reservoir heterogeneity along the wellbore. However, they are very limited and confined to small static datasets that are very often not representative. This chapter introduces a new approach to quantify a metric of 3D static reservoir heterogeneity. It describes the methodology to calculate a spatial heterogeneity index that encapsulates complex features to benchmark formations, zones, reservoirs, and fields. The introduced workflow expands on Lorenz’s scientific approach as the basis for this methodology to develop the heterogeneity index. The systematic approach excels in rendering a universal systematic 3D spatial heterogeneity index where typically data are not available, representative of overall prolificacy for a particular region of interest, zone, or the entire reservoir. The chapter also envisions possible applications, where the spatial heterogeneity index is utilized as a 3D conditioning attribute in dynamic model calibration and optimization.