  In this paper we study the use of Virtual Element method for geomechanics.
Our emphasis is on applications to reservoir simulations. The physical
processes that form the reservoirs, such as sedimentation, erosion and
faulting, lead to complex geometrical structures. A minimal representation,
with respect to the physical parameters of the system, then naturally leads to
general polyhedral grids. Numerical methods which can directly handle this
representation will be highly favorable, in particular in the setting of
advanced work-flows. The Virtual Element method is a promising candidate to
solve the linear elasticity equations on such models. In this paper, we
investigate some of the limits of the VEM method when used on reservoir models.
First, we demonstrate that care must be taken to make the method robust for
highly elongated cells, which is common in these applications, and show the
importance of calculating forces in terms of traction on the boundary of the
elements for elongated distorted cells. Second, we study the effect of
triangulations on the surfaces of curved faces, which also naturally occur in
subsurface models. We also demonstrate how a more stable regularization term
for reservoir application can be derived.
