Chemical enhanced-oil-recovery (EOR) methods such as polymer and alkaline/surfactant/polymer (ASP) flooding are generally not considered suitable for oil viscosities greater than 100 or 200 cp. However, this perception is changing, in particular because of field results from a number of chemical EOR pilots or full-field floods conducted in Canada in higher-viscosity oil. The aim of this paper is to review some of these projects.
Canada is well-known for its heavy-oil and bitumen reserves. Most of the bitumen reserves are exploited using thermal methods, such as cyclic steam stimulation or steam-assisted gravity drainage, while heavy oil is exploited mostly using cold production methods, such as cold heavy-oil production with sand. Cold production leads to recovery of less than 10% of original oil in place (OOIP). Thermal methods are not always applicable, in particular when the pay is thin. In that case, alternatives such as chemical EOR are required to increase recovery. The two main chemical EOR processes are polymer and ASP flooding.
In the past 10 years, several chemical-flooding projects have taken place in Canadian heavy-oil fields. The most successful of these is the Pelican Lake project, which is currently producing more than 60,000 B/D, much of it through polymer flooding. But other less-well-known projects such as the Taber South project, the Mooney project, and the Seal project are all interesting and worthy of discussion. For full descriptions of these fields, please see the complete paper.
Chemical EOR for Heavy Oil: The Canadian Experience
15 February 2016