Alkaline-Polymer Flooding of the David Pool, Lloydminster Alberta

Abstract An alkaline-polymer flood was implemented in the center of the David Field (now called Black Creek) outside of Lloydminster, Alberta, Canada. Simultaneously, waterfloods were conducted in the same reservoir to the north, west, and south of the chemical flood area. The alkaline-polymer area produced 5.7% OOIP by primary production from 1969 to 1978. Waterflood production from 1978 to June 1987 produced an additional 25.5% OOIP, for a total primary plus waterflood oil recovery of 31.2% OOIP. Average primary plus waterflood production of the north, west, and south waterflood areas as of September 2001 is 51.9% OOIP with an average oil cut of 2% in the three-waterflood areas. Alkali plus polymer co-injection was initiated in the David Field during June 1987. The project has an irregular pattern consisting of seven injection wells and eighteen production wells on twenty acre spacing. Water followed the tapered polymer slug. Oil cut in the alkaline-polymer flood area is 1.5%. Alkaline-polymer injection produced an incremental 21.1% OOIP. Primary, waterflood, and alkaline-polymer flood oil production is 73.0% OOIP. Total project cost is C$7,284,000 for a chemical mixing plant with water softening, drilling of fourteen new wells, purchase of injected chemicals, and engineering and design expenses. Incremental chemical cost per produced barrel of oil is C$1.41/bbl or US$0.99/bbl. Total cost per incremental barrel is C$3.53 or US$2.48. Selection of injected chemicals was based on a laboratory design process. Fluid-fluid screening, linear corefloods, and radial corefloods were performed to develop the most economically and technically viable injected solution. Surfactant was eliminated from the injected solution based on coreflood data, capillary theory, and Taber number calculations. Because fourteen new wells were drilled just prior to alkaline-polymer solution injection and the project was started when the oil cut was 40%, performance is difficult to interpret the alkaline-polymer flood in a conventional manner. This paper provides an interpretive analysis of the David Pool alkaline-polymer flood performance.