Optimal techniques to simulate flow in fractured reservoirs

28/2014

Optimal techniques to simulate flow in fractured reservoirs

Sunday 13th July 2014

Antonietti, P; Panfili, P.; Scotti, A.; Turconi, L. ; Verani, M.; Cominelli,A.; Formaggia,L.

Simulation of multiphase flow in fractured reservoir is a computational challenge. A key issue is the effective coupling between flow in the porous matrix and in the fracture network. It requires computational grids honouring as much as possible the fracture geometry without degenerated/distorted elements. Standard techniques may degrade efficiency and are not a foolproof solution. Moreover, two point flux approximation (TPFA) demands a good quality of the mesh to mitigate discretization error. In this work compare two different approaches. The first one has been proposed by B.T Mallison et al. in 2010. The second method we consider is the one originally proposed by H. Mustapha, in 2009. We evaluate the two techniques by means of 2D synthetic problems based on realistic discrete fracture networks. Steady state and unsteady state simulations are performed using TPFA. We also present results obtained with computational methods based on coupling the fracture network with mimetic finite differences or extended mixed finite elements. The latter two approaches, even though more complex, are more robust with respect to mesh geometry and can be beneficial for the problem at hand.