The primary waterflood applications of Polymer Gels are injection profile modification and control of directional channeling and the resulting early water breakthrough in offset producing wells. Polymer Gels are often used to effectively block high permeability streaks deep in the reservoir, and divert the injected fluid to areas in the reservoir which had been bypassed previously. The result is improved sweep efficiency and a lower water-oil ratio throughout the field. Gel Treatments are run on either the injection well or the affected producing well, and sometimes both, depending on the specific problem. Spinner surveys or other injection profile logs and inter-well tracer surveys should be run to pinpoint the problem and develop a plan of action.

A Barton County, Kansas waterflood producing well had experienced a rapid increase in Water-Oil ratio, and production on the lease had been steadily dropping. A review of information with the operator confirmed suspicion of early water breakthrough in the producing well directly offsetting the injection well in a live-drive pattern. Since this was the only producing well affected, it was decided to perform a near-wellbore water-blocking polymer treatment on this well. Production from this well prior to treatment was 8 BOPD and 173 BWPD. A 320 bbl Polymer Gel Treatment was designed and pumped on this well. 10 days after this well was placed back on production, water coming to this well had been reduced by 60% with no loss in oil production. Production for the lease had increased 3-4 BOPD, and injection pressure had begun to increase, indicating the fluid was being diverted to lower permeability areas in the reservoir.

This Chester Sanstone injection well in Seward County, Kansas was taking 1800 BWPD on a vacuum, over a 100' perforated interval. Injection Profile logs determined 20' of this interval was taking 52% of the injected fluid, by passing much of the oil-saturated part of the zone. Water production from offsetting production wells was increasing rapidly, with a similar decline in oil production. Inter-well tracer surveys indicated very rapid water breakthrough to the producers, with tracer showing up in the first well after less than 300 bbl of water had been injected following the tracer. Accordingly, a small 325 bbl polymer treatment was designed for the injection well. Fifteen days after treatment, produced water on the lease had declined by more than 200 BPD, and total oil had increased by 18 bbl. Post-treatment tracer studies indicated travel time for the dye to reach the first production well had more than tripled, indicating the injected fluid was being diverted to other areas of the reservoir, which should result in a continued, steady increase in oil-water ratio for this waterflood.