The prediction of water breakthrough and oil recovery for naturally fractured reservoirs (NFRs) cannot be performed accurately without dynamic upscaled relative permeability functions. Relative permeability is commonly assumed to be a scalar quantity, although a justification for NFRs has yet to be presented. In this study, we show how accurate this assumption is for fracture-matrix ensemble relative permeabilities determined by numeric simulations of unsteady-state core flooding.
Numerical determination of relative permeability requires a realistic flow model, a spatially adaptive simulation approach and a sophisticated analysis procedure. To fulfil these requirements, we apply discrete fracture and matrix (DFM) modelling to well characterized hm-km outcrop analogues. These are parametrized with aperture, permeability, and capillary pressure data. Fracture attributes are allowed to vary from segment to segment, trying to emulate in situ conditions.