The Cessford Field is located approximately 150 miles east of Calgary, Alberta, Canada. It produces from the Colorado Basal A sand at 3000 ft. The sandstone has 24% porosity and an average permeability of 300 mD. The 24o API gravity crude oil viscosity is 24 cp at the reservoir temperature of 89oF. The reservoir was discovered in 1958 and was produced on primary until February 1981, when a waterflood was begun. Primary production was 10% OOIP or 7,500,000 barrels of oil. The waterflood and the alkali plus polymer flood was performed in north, middle, and south pods of the field. A total of 19 production wells and 7 injection wells comprise the project operated by Dome Petroleum. The chemical flood began in July 1984 with the injection of 1.0 wt% sodium hydroxide. In June 1985, co-injection of 800 mg/L Alcoflood 1175 (polyacrylamide polymer) plus 1.0 wt% sodium hydroxide began. The injection scheme will be to co-inject 0.17 pore volume of 1.0 wt% sodium hydroxide plus 800 mg/L Alcoflood 1175 followed by 0.25 pore volume of Alcoflood 1175 in a tapered fashion. Water will follow the tapered polymer solution. Production data from the project is not available because it is confidential and controlled by the Alberta Oil and Tar Sands Research Authority due to its experimental status. However, the Oil and Gas Journal of April 23, 1990 lists the project as technologically promising and economically successful. Enhanced oil production is listed as 100 BOPD and the total oil production is listed as 350 BOPD. A paper discusses some of the history of the field and the selection of the alkali type and concentration.1
1 Journal of Petroleum Technology, December 1980, pages 2103 to 2110
SURTEK, INC. 1511 Washington Ave Golden, Colorado 80401 Phone: (303) 278-0877 Email: surtek@surtek.com
