Single-phase flow simulation in 3-D naturally fractured reservoirs using a locally conservative formulation, an embedded discrete fracture model and unstructured tetrahedral meshes

Resumo

Fluid flow in fractured porous media is a truly relevant phenomenon for the oil industry, but also for
water extraction and aquifer remediation. Modeling this type of problem represents a great challenge, due to the
complexity of depositional environments. In such cases, it is particularly complex to construct structured meshes
capable of adequately modeling the reservoir. In this context, in the present paper, we describe a new strategy to
simulate the single-phase fluid flows in three-dimensional heterogeneous, anisotropic and fractured porous
media using tetrahedral unstructured meshes. Aiming to model fractures, we use the Embedded Discrete Fracture
Model (EDFM) in which fractures are represented explicitly, but without the necessity of building a “fracture
fitting mesh”, which could be an overly complex task. To discretize the elliptic pressure equation, we use the

recently developed 3-D version of the MultiPoint Flux Approximation that uses the "Diamond stencil" (MPFA-
D) which is a robust and flexible formulation, capable of handling highly heterogeneous and anisotropic

reservoir rocks, achieving second order accuracy for the scalar variable and first order accuracy for fluxes. Our
strategy has shown to be notably flexible, and our preliminary results are very promising. has achieved good preliminary results.