Computer-assisted tomography for the observation of oil displacement in porous media

Computer assisted tomography (CAT) uses computerized mathematical algorithms to reconstruct tomographic images of an object. The image reconstruction is based on multiple X-ray measurements made around the object's periphery. This technique has been used to obtain oil saturation distribution information during immiscible oil displacement in Berea Sandstone cores. This technique is directed toward investigating the various problems involved in oil recovery processes: (1) heterogeneity of the porous structure; (2) surface interactions between oil, the displacing fluid, and the reservoir rock formation; and (3) the viscosity ratio between the 2 fluids. The flow phenomenon is complex. Previous experimental methods have offered insufficient information for the understanding of oil recovery processes. The CAT scan image acquisition is rapid, thus it yields directly the local oil compositions over a cross section as a function of spatial position and time. Dynamic fluid distribution profiles then can be used to analyze the effectiveness of various oil recovery strategies. 10 references.