Sweep efficiency improvement by blocking already swept high permeable zones in reservoir with biodegradable polymer gel

Blocking the already swept high permeable zone with a biodegradable polymer gel is expected to be a more effective and innovative sweep efficiency improvement (SEI) method. This is because it has no risk of formation damage, and it is expected to show additional oil recovery if the microbes have a MEOR effect. In this study, in order to confirm the effect of this blocking on the SEI, a waterflooding visualization experiment and numerical simulations to a multilayered reservoir model, in which high permeable formations and low permeable formations were alternate, were conducted. From the waterflooding visualization experiment, it was recognized that the sweep efficiency was improved by the blocking, and the oil recovery increased as a result. However, it became apparent that the injected water bypasses the blocked zones in high permeable formation from the low permeable formations after the blocking and the 100% of sweep efficiency is difficult to be achieved. From the numerical simulations, it became apparent for the multilayered reservoir that the blocking near the producer should be the most effective way on SEI, but it is not always the best way to maximize the oil recovery.