A Novel Approach Linking Structural Restoration and Multi-phase Fluid Flow Modeling via 3-D Geomechanics for a Giant Carbonate Reservoir in North Kuwait

Abstract

Description: The Mauddud is a late cretaceous carbonate reservoir dominated by mid-ramp packstones with an average permeability around 30 mD. The spatial distribution of initial porosity and permeability using classical geostatistical methods showed difficulties to history match the reservoir production data of Mauddud reservoir in Sabriya field NK. Structural restoration followed by geomechanical forward modeling was conducted to obtain representative 3D porosity and permeability distributions prior to production. By performing coupled fluid flow-geomechanics simulations, the spatial and temporal variations of rock deformation, shearing and dilation response can be predicted reliably. As a result, the change in porosity and permeability can be updated dynamically in the reservoir simulations which provide more realistic and accurate analysis of pressure and saturation distributions within the reservoir. With information on the pressure front and its progression rate and saturation, reservoir development decisions can be optimized with greater certainty and improved recovery factor. Application: Structural restoration “back-stripping” modeling was carried out to describe the structural evolution through geological time. Geomechanical forward modeling in geological time was performed and validated with log measurements along the wells. Based on geomechanical forward modeling results, an initial porosity distribution was obtained for the reservoir. The core test permeability data and the computed porosity were combined to describe the initial reservoir permeability. In addition, a new permeability updating technique was derived. Results and Conclusions: The existing dynamic model did not incorporate formation deformation due to production. Accordingly, coupled multi-phase reservoir geomechanics analysis was carried out to investigate permeability change using the permeability updating technique on improving the history match for the Mauddud reservoir. The numerical results showed 10% improvement in history matching- compared to the available dynamic one- of individual wells as well as the overall field behavior. The history match reservoir model is more representative of the in-situ condition which can be used to predict deformation behavior and performance of the field in the future.

AAPG Datapages/Search and Discovery Article #90194 © 2014 International Conference & Exhibition, Istanbul, Turkey, September 14-17, 2014