Integrated Rock Typing in Asmari Formation of Gachsaran Field

As part of an integrated reservoir modelling and simulation project, a rock-typing study has been performed on the carbonate Asmari Formation of Gachsaran Field (Iran). The current paper presents the challenges and results of integrating different disciplines in the definition of rock-types. Rock-types represent geological aspects such as stratigraphy, log facies and porosity, but their true added value is the dynamic characterization of facies and strong link with geology, which allows spatial distribution. This study has allowed definition of integrated rock-types representing geological facies and groups with similar dynamic rock properties, and identifying these from their log signature. As log data is much more abundant and presents a good spatial distribution over the field, this is the ideal means to refine the conceptual geological models (sedimentary environment, stratigraphy, diagenesis) and trace the extent of stratigraphic sequences. These subsequently allow propagating the rock-types away from the wells, and combined with the dynamic rock properties, allow simulation of these properties in a 3D reservoir model. The definition has resulted in a classification of 10 rock-types with a unique set of geological, log and dynamic properties along some 150 wells.