Polymer flooding is investigated in laboratory corefloods for potential application in a 2000 cP - 5000 cP heavy oil field. An incremental oil recovery is noted with the addition of very low concentrations of partially-hydrolyzed polyacrylamide (HPAM), either in secondary or tertiary (i.e. after waterflooding) injection. However, increasing polymer viscosity from 3 cP to 60 cP does not significantly change recovery from two pore volumes (PV) of tertiary polymer injection.
Existing scaling groups for viscous instability are investigated. Corefloods in this study and others are found to be in or near the transition zone, where recovery may be sensitive to variables such as core diameter, while field floods are all in the &"pseudo-stable" region, where this may not be the case.
Mounting evidence suggests that polymer flooding can be economically applied to very viscous oils, despite the fact that it is not feasible to obtain unit mobility ratio with non-thermal methods. Additional work is necessary to determine appropriate optimization methods and criteria for these floods.