George F. Schurz, Dow Chemical Company
Efficient oil recovery by waterflooding requires that certain fluid and reservoir properties lie in an appropriate range. The mobility ratio of the oil being produced to the water being injected is one such parameter which fortunately can be adjusted by one technique or another to obtain satisfactory recoveries. The most recent technique for adjusting the water oil mobility ratio is to dissolve small amounts of a water soluble polymer in the injection brine. It has been found that very small quantities of polymer greatly reduce the mobility of injection fluid thus increasing oil recovery. The increased recovery is due to a more effective sweep of the reservoir and can be quantitatively predicted in advance of the flooding operation. Laboratory and field tests of the process have previously been reported. lf the present discussion concerns the new commercial applications of this process.