Rock Typing for a Carbonate Gas Field in Central Luconia Province - An Integrated Approach from Microscale to Macroscale

Rock typing is often a highly debatable topic between multi-disciplines of a field development team. This paper demonstrates an integrated approach to reconcile information and data obtained from various scales for rock type classification up to its application and impact on dynamic models. In our previous field development, discrimination of rock types are based on subjective geological observations and empirical porosity-permeability relationships. However, in carbonates, for any porosity within a given rock type, permeability can vary by several orders of magnitude, indicating existence of several flow units, which is the subject of current proposed rock typing workflow. As a pre-requisite, sedimentological evaluation of cores provides the depositional and diagenetic frameworks, and controls on pore types and geometries. In this context, six rock typing approaches were evaluated and compared across all static and dynamic data sources through several data visualisation, quantification and qualification tools. The final rock typing approach selected is one which exhibits consistency among all data sources. Finally, a numerical simulation run on two realisations (existing porosity cut-off method vs FZI integrated method) showed that an integrated FZI method significantly reduces the magnitude of deviation from actual production data, thereby reducing iterations (and time) spent for model calibration.