STABILITY CRITERIA FOR THE DESIGN OF GRADED POLYMER BUFFERS

Prouvost, L. and Quintard, M., 1990. Stability criteria for the design of graded polymer buffers. J. Pet. Sci. Eng, 3: 333-343. The graded polymer buffer technique is often used to minimize the amount of polymer to be injected during polymer flooding. A drawback of this method is the impairment of mobility control due to viscous instabilities within the polymer slug itself. This paper presents new criteria for the economic optimization of polymer usage, while preserving the efficiency of the mobility control. The numerical model takes into account dispersion and time-dependent effects in the polymer concentration profile. Stability domains are presented as function of the injection parameters, i.e., the flow rate and the rate of decrease of the polymer concentration. The method is illustrated for the case of Xanthan polymer flow in Berea sandstone.