Waterflooding is the most widely used form of enhancing oil production from oil and gas reservoirs. Since all hydrocarbon reservoirs are heterogeneous, it is necessary to understand the physics associated with flow in these reservoirs to better predict production performance, and to allow for the proper placement of injection and production wells. This paper focuses on effects of well-defined heterogeneities on the immiscible displacement processes.
Flow experiments were performed using two-dimensional visual models packed with unconsolidated glass beads, and having carefully controlled permeability and wettability heterogeneities. The immiscible displacement experiments demonstrated the significant effect of such permeability and wettability heterogeneities on flow patterns, residual saturations and recoveries. In some instances, during waterflooding experiments, high permeability regions were bypassed due to capillary pressure differences. Nodal crossflow was also observed.
These results can be used to validate the results of numerical simulators and x-ray CT scanning. They can also be used to assist in the understanding of actual reservoir production performance under immiscible type displacement processes.