A pore level network simulator was developed and used to study the relationship between pore microstructure and macroscopic flow properties. The network is based on a regular 3D lattice which is populated by pores and pore throats based on pore space statistics. Graph theory is used to perform efficient path searches for modeling invasion/drainage processes. Absolute permeability was found to be sensitive to porosity, pore and throat size (and their ratio) and the variation in pore sizes. Relative permeability was found to be most sensitive to the distribution of pore sizes and the geometric shape of the pore throats. Good agreement was found between simulations and laboratory measurements on a range of sandstone rocks.
Un simulateur de reseaux à l'echelle du pore a ete develope et utilise pour etudier les relations entre la structure microscopique des pores et les proprietes macroscopique de l'ecoulement. Le reseau est base sur une grille reguliere en trois dimensions, dans laquelle des pores et leurs ouvertures sont repartis d'apres leur distribution statistique spatiale. La Theorie des Graphes est utilisee pour effectuer avec efficience la recherche de parcours afin de modeliser les processus de drainage et d'invasion. II a ete constate que la permeabilite relative est tres sensible à la distribution statistique de la taille des pores et de la geometrie de leurs ouvertures. Une bonne coherence est observee entre les resultats des simulations et les mesures de permeabilite effectuees en laboratoire sur un nombre de roches greseuses.
Ein Netzwerkmodell des Porenraums wurde entwickelt zur Untersuchung der Beziehung zwischen der mikroskopischen Porenstruktur und den makroskopischen Fliesseigenschaften des porösen Mediums. Das Netzwerkmodell basiert auf einem regelmassigen, dreidimensionalen Gitter, in dem - basierend auf einer statistischen Beschreibung des Porenraums - Poren und Porenverengungen eingebettet sind. Ein effizientes Verfahren zur Fliesswegidentifizierung wurde verwendet, um sowohl Drainageals auch Benetzungsvorgange zu simulieren. Absolute Permeabilitat zeigte sich sensitiv hinsichtlich der Porositat, der Grösse der Poren und der Verengungen (sowie deren Verhaltnis) und der Variation in der Porengrösse, Relative Permeabilitat war vor allem sensitive hinsichtlich der Porengrössenverteilung sowie der Geometrie der Porenverengungen. Gute Übereinstimmung wurde erzielt zwischen den Simulationsergebnissen und Labormessungen an verschiedenen Sandsteinproben.
Porosity, absolute and relative permeability and capillary pressure relationships are very important in modeling and calculation of flow in porous media. Considerable effort has been devoted in the petroleum industry to developing correlations between these parameters. The considerable scatter and uncertainty in these correlations is, in large part, attributed to a lack of understanding of the relationship between the microscopic pore space geometry and macroscopic flow properties. Since being introduced in 1956 by Fatt (195680b, c), network models have been used to study the multiphase flow in porous media by many researchers (Chatzis & Dullien 1977, Wilkinson & Willemsen 1983, Jerauld & Salter 1990, and others). However, the understanding of the pore geometry effects on macroscopic flow properties is still limited and, except for a few cases (Øren & Bakke 1996), pore network calculations have not been linked directly to data on real rock The research reported in this paper, therefore, had two objectives. The first objective was to investigate the relationship between the microscopic pore geometry and the macroscopic flow properties and to advance understanding of the physics of fluid flow in porous media.
