Eyvind Aker, Knut Jørgen Måløy
Department of Physics, University of Oslo, N-0316 Oslo, Norway
Alex Hansen
Department of Physics, Norwegian University of Science
and Technology, N-7491 Trondheim, Norway
We investigate the stabilization mechanisms due to viscous forces in the invasion front during drainage displacement in two-dimensional porous media using a network simulator. We find that in horizontal displacement the capillary pressure difference between two different points along the front varies almost linearly as function of height separation in the direction of the displacement. The numerical result supports arguments taking into account the loopless displacement pattern where nonwetting fluid flow in separate strands (paths). As a consequence, we show that existing theories developed for viscous stabilization, are not compatible with drainage when loopless strands dominate the displacement process.
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