The heavy oil pools of Alberta and Saskatchewan can be grouped into four reservoir types: Lloydminster, Wainwright, Basal Quartz and Bakken.

This study reviews briefly the recovery attainable in these reservoir by secondary and non-fireflood processes, and then evaluates in situ combustion using both oxygen and air in dry and wet fire-floods. Recent studies by a national energy agency have shown that fireflood is the best enhanced oil recovery process that can be used in heavy oil reservoirs, with anticipated recoveries of 30% of the original oil in place. The paper reports the computed recoveries using the Tejas, Nelson-McNeil, Fassihi and Brigham methods and then presents an incremental recovery correlation due to the immiscible CO2 flood established ahead of the oxygen firefront.

The experimental evaluation of key fireflood parameters is examined and compared to those predicted by correlations available in the literature. Air/oxygen requirements, fuel laydown and rate of firefront advance, as well as oxidant injectivity are discussed; recommendations are made on the laboratory and field testing needed prior to implementation of in situ combustion.

An economic comparison of both air and oxygen firefloods, which considers the recoveries and field costs for the two processes, has been carried out for a demonstration pilot in a Wainwright type field.

Keywords:
oil saturation, requirement, upstream oil & gas, waterflood, air requirement, steam-assisted gravity drainage, recovery, thermal method, enhanced recovery, correlation
Subjects:
Fluid Characterization, Improved and Enhanced Recovery, Unconventional and Complex Reservoirs, Phase behavior and PVT measurements, Waterflooding, Thermal methods, Chemical flooding methods, Oil sand, oil shale, bitumen
Copyright 1986, Society of Petroleum Engineers
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