MOX-Report No . 33 / 2015 An upscaling procedure for fractured reservoirs with non-matching grids

Upscaling of geological models for reservoir simulation is an active and important area of research. In particular, we are interested in reservoirs where the rock matrix exhibits an intricate network of fractures, which usually act as a preferential path to the flow. Accounting for fractures’ contribution in the simulation of a reservoir is of paramount importance. Here, we have focused on obtaining effective parameters (e.g. transmissibility) on a 3D computational grid on the reservoir scale, that account for the presence, at a finer spatial scale, of fractures, and network of fractures. We have, essentially, followed the idea illustrated in [24], yet this work has some notable aspects of innovation in the way the procedure has been implemented, and in its capability to consider rather general corner-point grids, like the ones normally used in reservoir simulations in the industry, and complex and realistic fracture networks. In particular, novel contribution is the employment of EDFM for computing fracture-fracture and matrixfracture transmissibilities, with a remarkable gain in speed-up. The output is in form of transmissibility that can be used for reservoir simulations with software like Eclipse, Intersect, or GPRS. The results demonstrate the effectiveness and computational efficiency of the numerical procedure, and of the developed software, which is now ready for further testing and industrialization.