In carbonate reservoirs, heterogeneity is usually drivenrnboth by the depositional and the diagenetic patterns. Whenrnoriginal reservoir properties have been strongly modified byrndissolution, the assessment and the modeling of karstic highrnpermeability areas constitute key issues duringrnreservoir appraisal.rnIn this paper, a very innovative methodology is proposedrnfor the evaluation and modeling of reservoirs in whichrndissolution occurred at an early stage, and was controlled byrnsequence stratigraphy.rnUsing stochastic models of depositional facies built usingrnNeptune (a modeling methodology/tool that uses cubes ofrnfacies proportions derived from paleobathymetry), thernprobability for facies to be affected by early karstification isrnevaluated. This can be possible thanks to the 3D grid ofrnpaleobathymetry previously computed with Neptune.rnThen, the distinction is made between the regionsrnpotentially exposed to dissolution, and the regions with nornchance to be exposed. The last stage consists in simulatingrnpetrophysics according to the depositional facies and itsrndiagenetic behavior.rnSuch a methodology enables to take into account the 4Drnaspect of the reservoir construction. The prediction and thernmanagement of the areas of emersion are possible, andrncontribute to obtain significant advances in the realistic aspectrnof the 3D distribution of reservoir properties in stochasticrnmodels. Moreover, consistency between sedimentology,rndiagenesis, and petrophysics is input at a very high level in thernmodel. This makes possible to preserve the key heterogeneityrnin reservoir models for fluids flow simulation.rnApplication to an oil field in Middle East illustratesrnthe methodology.
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