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Photo: Canadian Natural
Chemicals added to water create a polymer solution roughly matching the mobility of heavy oil, enhancing the fluid’s ability to flush crude out of the reservoir.
Canadian Natural expects to recover close to another 60 million barrels through primary production, it believes the biggest prize—about 400 million barrels—will come from polymer waterflooding, including future enhancements to the existing process, says Rob Richardson, Canadian Natural’s exploitation manager for Pelican Lake. In primary production, recovery factors ranged from 4 to 6.5 per cent. But in many areas on polymer flood it is possible
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to recover more than 20 per cent, says Richardson. “So the response has been absolutely fantastic for us.” Cenovus, meanwhile, has a smaller polymer project at Pelican Lake. So far, only four per cent of the estimated 1.4 billion barrels of original Wabiskaw oil in place on the company’s lands has been recovered. More than 95 per cent is being considered for polymer flooding. Cenovus expects to recover six per cent of the original oil in place through primary production, 12 per cent through straight waterflooding and six per cent by polymer flooding—for an ultimate expected recovery factor of 24 per cent. In the case of both Canadian Natural and Cenovus, it’s too soon for polymer flooding to have much impact on daily production. The reservoir must first go through a fill-up process, replacing the voidage from primary production. Depending on the void that has to be filled, it can take up to two years to get a significant production increase, explains Canadian Natural’s Richardson. ASP pilot Mention heavy oil in western Canada and most people think of the heavy oil belt straddling the Alberta-Saskatchewan border. But Cenovus has about a billion barrels of original heavy oil in place in the Suffield area of southeastern Alberta, which is best known for shallow natural gas. Oil densities range from about 10 to 18 degrees API gravity, but the average is around 12.5 API. Viscosities are similar to