Integration of multiscale carbonate reservoir heterogeneities in reservoir simulation

Abstract

Abstract The construction of robust reservoir models considering geological carbonate heterogeneities, such as fractures and vugs, upscaling and numerical flow simulation remains a challenge. This work performs a methodology aiming a suitable representation of flow simulation and upscaling techniques according to small and large scale carbonate reservoir heterogeneities. The methodology is applied to one specific flow unit type considering diffuse fractures, sub-seismic fractures and isolated vugs. The methodology follows four elementary steps: division of reservoir into flow units, geostatistical modeling, upscaling procedures and flow simulation modeling of carbonate reservoirs. Given the presence of multiscale geological features and computational limitations, the upscaling procedure is separated as a function of heterogeneities scale. The process is shown for one flow unit of a specific case where flow progress in matrix and fracture occur at different time steps which make the single porosity approach difficult. For regions of fractures not fully connected, the flow takes place in the matrix. A dual permeability flow model is the best approach since it can take into account both flow progresses in connected fracture networks and in matrix medium. The methodology has shown several advantages: sequential control over static properties and pseudo-functions integrated with upscaling procedure; definition of the accurate simulation flow model; and improvement of the integration of multiscale heterogeneities in reservoir simulation. This work presents a new methodology and analysis that can be useful for multidisciplinary areas.