Abstract

Fractures in subsurface reservoirs are known to have significant impacts on reservoir productivity. Quantifying their importance, however, is challenged by limited subsurface observations, and intense computations for modelling and upscaling. In this paper, we present a workflow to construct and upscale fracture models based on outcrop studies in the Latemar carbonate platform (northern Italy). Fractures were first analysed to investigate their distinct characteristics throughout different sedimentological domains; that is, slope, margin and platform interior. Several fracture models were then built to represent different domains and were used to upscale fracture-network properties. Small-scale models were preferred to the reservoir-scale ones to enable multiple realizations and various sensitivity analyses in a time-efficient manner.

The fracture characteristics of the Latemar Platform vary across different sedimentological domains. This variation results in a non-homogeneous permeability field that will influence flow behaviours. Fractures in the slope domain are typically tall but low in intensity, resulting in relatively low effective permeabilities. In the platform interior, smaller sizes of fractures combined with higher intensities give rise to higher effective permeabilities. In general, fracture intensities, aperture and their intrinsic permeability would have a significant impact on the permeability field. Fracture shape and orientations are more important in affecting the connectivity.