PHYSICALLY CONSTRAINED KINEMATIC SALT FLOW RESTORATION
Ulisses T. Mello (1) , Garry D. Karner (2)
(1) Petrobrás Research Center, Cidade Universitária, Qd 7, Ilha do Fundão, Rio de Janeiro, RJ, CEP 21910,
Current address: IBM Thomas J. Watson Research Center, Yorktown Heights, NY 10598.
(2) Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York, 10964, U.S.A.
In this paper we propose some techniques to simulate kinematically the salt flow lines
during its motion. The internal salt flow is constrained by the imposed velocity field on
the deforming boundaries, mass conservation and the incompressibility condition of
during the salt deformation. This approach has the advantage of reproducing exactly
the geologist's view of the salt evolution and the very complex salt shapes observed in
the field can be simulated without the difficulties normally involved in the solution of
dynamic viscous flow formulations. Therefore, this approach is alternative to the
traditional ones that calculate the salt motion dynamically using continuity and
momentum conservation equations, in which the salt is driven by the sediment loading
and buoyancy. In our approach the salt is assumed an incompressible slow (creeping)
viscous fluid with constant viscosity that is in steady-state between the time interval
considered in the deformation. Under these conditions the internal salt flow is governed
by the Stokes flow equation. Two techniques are introduced to restore the internal salt
flow with time. In the first one, for salt motion in its early stages of diapirism, it is
assumed that the salt layer is constrained in between two sediment layer and it has a
horizontal parabolic flow pattern similar to the pipe flow models. The second one, can
be used for any arbitrary salt shape but it is more costly because it uses finite element
method to calculate the flow path lines.