Abstract
Four horizontal wells producing a heavy oil from a sand formation were successfully treated with a new polymer process to reduce their water production. In this process, Polyacrylamide is injected with a swelling agent which induces a strong viscosity build-up in-situ before production release. The treatment was shown to reduce the relative permeability to water with little effect on the relative permeability to oil. Because of the high oil/water mobility ratio, the polymer was expected to invade the zones of highest water saturation preferentially and thus did not require zone isolation during injection. Polymer slug volume was optimized by numerical simulations. In the best case, the treatment induced a drop in the water cut from 85 to less than 50% and a strong increase in oil production. The treatments performed in 1989 are still efficient in 1992. In addition to its effect on the water cut, the treatment reduced sand production in three of the wells.
