UNDERSTANDING AND CHARACTERIZING SLOPE HETEROGENEITY IN CARBONATES

摘要

Modern and ancient carbonate slopes are depositionally complex due to a spectrum of autochthonous and allochthonous deposit types that exhibit variability along strike, dip, and across stratigraphy. A hierarchy of geological frameworks, including sequence stratigraphy, depositional regions, and rock types, is fundamental to capturing the temporal and spatial variability of carbonate slopes. Efforts to characterize this framework rely on integrating a variety of data with different scales of observation, including modern and ancient outcrop analog and application, well logs, core, and seismic. Of particular interest to the hydrocarbon industry are the origins of impedance contrasts in carbonate slopes; resulting reflection patterns are ultimately interpreted as indications of the sequence stratigraphic framework in geological and reservoir models. Without the aid of other tools, it is challenging to determine if the reflection patterns from seismic derive from lithostratigraphy, diagenesis, or original bedding. Each of these possibilities affects the confidence of the geological framework. In this study, we use an integrative approach to describe the compositional and architectural variability of the geological model from the Karachaganak Field as a workflow example that ultimately reduced reservoir uncertainty and improved our knowledge of carbonate slope variability.