High Performance Computing for Darcy Compositional Single Phase Fluid Flow Simulations

L. Agélas, I. Faille, S. Wolf, and S. Réquéna
Institut Francais du Petrole

The compositional description of flow through heterogeneous porous media is of primary interest to many applications such as basin modeling. The flow equations that we consider model a Darcy compositional single phase migration in a porous media. Our interest is to predict the pressure, the saturation and the fluid composition.

After finite volume type discretization in space and Euler Implicit integration in time we are left, at each time step, with the solution of a large sparse non linear system coupling the set of unknowns on the grid.

Darcy fluid flow simulations on nowadays megacells and highly heterogeneous basin models are tremendously CPU-time consuming. In order to make Darcy flow simulation tractable, different numerical techniques have been studied to improve the solution of the non linear system on parallel computers.

The main difficulties to cope with are the strong coupling of the primary unknowns (pressure, saturation and compositions) on each cell, the strong non linearities of the closure laws (relative permeabilities, capillary pressures, phase densities), and the non smoothness of the non linear system due to upwinding. This often leads to a non convergence of the Newton algorithm and severe reduction of the time step.

We propose new numerical techniques which considerably improve the convergence of the Newton algorithm both in terms of robustness and CPU time enabling the efficient simulations of millions cells models on parallel computers.

A series of tests was performed for different cases in two and three-dimension. In all these cases, we considerably speed up the Darcy compositional single phase fluid flow simulations.

 

AAPG Search and Discover Article #90066©2007 AAPG Hedberg Conference, The Hague, The Netherlands

 

AAPG Search and Discover Article #90066©2007 AAPG Hedberg Conference, The Hague, The Netherlands