Use of X-Ray Computed Microtomography to Understand Why Gels Reduce Permeability to Water More Than That to Oil

摘要

X-ray computed microtomography was used to investigate why gels reduce permeability to water more than that to oil in strongly water-wet Berea sandstone. We studied a Cr(III)-acetate-HPAM gel that reduced permeability to water by a factor 80 to 90 times more than that to oil. In Berea, the gel caused disproportionate permeability reduction by trapping substantial volumes of oil that remained immobile during water flooding. With this high trapped oil saturation, water was forced to flow through narrow films, through the smallest pores, and through the gel itself. In contrast, during oil flooding, oil pathways remained relatively free from constriction by the gel.