Perpustakaan Digital ITB

Diagenesis is rarely accounted for in the standard modeling workfows for carbonate reservoirs, although it has a huge impact on both porosity and permeability. This can be explained by at least two reasons: frst, it is difcult to quantify the infuence of diagenetic overprints on porosity and permeability; second, the integration of the diagenetic efects in carbonate reservoir models makes history matching much more difcult. Herein, a modeling methodology is proposed, in which the diagenetic imprints are included in the reservoir model and calibrated with dynamic data. The key point consists in defning a parametrization technique able to capture these diagenetic imprints. We assume that distinct regions of occurrence of a given diagenetic phase can be identifed within the reservoir. Therefore, restricting our attention to a facies, we may distinguish regions characterized by low, medium or high proportions of the targeted diagenetic phase. The advantage of this parametrization technique is that the proportions of these regions can be easily driven by a reduced number of proportionality coefcients. Then, the overall modeling approach is integrated in an optimization workfow making it possible to vary the proportions of the region with a given occurrence for a given diagenetic phase, the variograms characterizing the spatial distribution of the regions, or even the way they are spatially distributed. The optimization process is run to adjust these various unknown parameters in order to match production history. The potential of the proposed methodology is fnally investigated through the study of a two-dimensional numerical example.