Permeability Heterogeneity in Cross-Bedded Sandstones: Impact on Water/OilDisplacement in Fluvial Reservoirs

摘要

This study focuses on quantitatively defining the permeability/capillary-pressurecharacteristics in a number of well-exposed analoges and cored reservoirs by minipermeametry. Average contrasts in permeability are determined for fluvial cross-bedding and combined with thin-section studies to characterize the grain size, sorting and compositional characteristics that determine permeability contrasts. In addition capillary pressure experiments of laminated samples were carried out to study the contrasting capillary-pressure characteristics between the laminae. Water/oil displacement through cross-bedding by numerical and physical modelling were performed in close corporation with reservoir engineers to increase our understanding of the geological and physical conditions under which movable-oil entrapment occurs. Finally, the likely percentages of movable oil that are initially trapped in a cross-bedded reservoir are estimated.