A fast and effective method to evaluate the polymer flooding potential for heavy oil reservoirs in Western Canada

Laboratory polymer flooding tests conducted in sandpacks show great potential for improving heavy oil recovery. The high price of crude oil and wide application of horizontal wells make polymer flooding both economically affordable and technically feasible for heavy oil reservoirs. Field applications of polymer flooding in heavy oil reservoirs are currently being pursued. As polymer injection involves great investment, laboratory evaluations are essential prior to the field-scale application. However, due to high oil viscosities, large volumes of fluids have to be injected into sandpacks or reservoir cores in order to reach reasonable recoveries, which is a time-consuming process. This study establishes a fast and effective method to examine the potential of enhanced heavy oil recovery by polymer flooding. Experimental results of sandpack polymer flooding tests, for heavy oil samples with different viscosities, are analyzed. For each heavy oil sample, the polymer viscosity-sensitive range, within which tertiary recovery increases dramatically with increasing polymer viscosity, is different To facilitate the evaluation of polymer flooding potential for heavy oils with various viscosities, the oil-water mobility ratio at the end of initial waterflooding is chosen as a normalization factor. Using normalization, an identical oil-water mobility ratio-sensitive range can be obtained for heavy oils with different viscosities. Based on the normalized relationship, the potential of enhanced heavy oil recovery by polymer injection can be quickly and effectively evaluated. (C) 2013 Elsevier B.V. All rights reserved.