Sensitivities to Flow–modeling Assumptions for a Heterogeneous Carbonate Ramp – An Example from a Jurassic Carbonate Ramp

Carbonate reservoirs pose significant challenges for reservoir simulation and flow prediction due to lateral and vertical heterogeneities that are difficult to predict. Limits to seismic resolution, heterogeneities in rock properties and limited constraints on subsurface data require the consideration of multiple geologic scenarios for flow predictions. Hence, a systematic and streamlined approach is needed to construct geologic models and to quickly evaluate key sensitivities in the flow models. This paper discusses results from a reservoir analogue study in a Mesozoic carbonate ramp in the High Atlas of Morocco. Here, geologic models have been constructed from the integration of sedimentological, diagenetic and structural studies in the area. Novel methods have been applied to develop a consistent approach for rock property definitions in outcrops and incorporate multi-scale fractures to test the response in flow simulations. In these simulations we have tested the response of presence or absence of specific geologic features, including hardgrounds, stylolites and fracture populations as a way to guide the level of detail that is suitable for modeling objectives. Based on these studies, we have been able to evaluate the relative impacts of some of the geologic features on flow behavior and gain further insights to effective recovery strategies.