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Abstract: Dual Mesh Method in Heterogeneous Porous Media

Sophie Verdiere, Dominque Guerillot

More and more computerised geological models provide reservoir descriptions of million cells. Currently fluid flow simulations with these media need upscaling techniques. Sometimes these averaging techniques modify drastically the behaviour of the solutions. In fact, the results are averaged phase pressure and saturations, and for compositional modelling, components of the oil or gas.

A specific discretisation in time and space for each unknown is proposed in the poster to overcome this drawback. For a typical two phase problem, a high resolution grid for the water saturation equation, and a low resolution grid for the pressure equation are used. The interest of this "Dual Mesh Method" is to keep the information on the distribution of the saturation to compute accurate averaged parameters for the pressure equation. The method is then a way to dynamically update the pseudo functions for the relative and capillary pressure curves.

The poster presents applications to both homogeneous and heterogeneous geological models. Comparing this method with current numerical scheme demonstrates that it is possible to apply this approach to full field simulations with more accurate solutions for the same computer cost. For cases where a priori pseudos are not valid, this Dual Mesh Method is the only way to overcome this difficulty.

AAPG Search and Discovery Article #90956©1995 AAPG International Convention and Exposition Meeting, Nice, France