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Heavy Oil

Heavy Oil is a form of unconventional oil that is thick and highly viscous, and therefore does not flow to production wells under normal reservoir conditions.


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What is Heavy Oil?

Heavy oil is a type of crude oil that is very viscous, meaning that it is thick and does not flow easily. This is caused by both a low hydrogen to carbon ratio in the molecular make-up and the presence of other minerals such as asphaltenes, resins, sulfur and metals such as vanadium and nickel, which all increase its density.

Nearly all the deposits of heavy oil are degraded remnants of conventional oils. Degradation begins when oil migrates toward the earth’s surface and encounters water containing oxygen and bacteria. A tar-like material is formed at oil-water contact that eventually invades the entire oil accumulation. A process known as “water washing” removes the more water-soluble, light hydrocarbons, leaving a heavy oil accumulation.  Heavy oil accumulations may represent as little as 10 percent of the original conventional oil1.

Due to their high density and viscosity, special extraction methods are needed to recover heavy oil efficiently. These methods include: surface mining, cold production and thermal recovery. Heavy oil may also require additional processing, usually referred to as upgrading, after being produced in order to be transported and refined. Large amounts of energy are put into the extraction and production of heavy oil – about 20% to 30% of the energy that is actually produced2.



Heavy oil makes up a significant portion of the world’s discovered petroleum resources, while only a very small fraction of these resources have been produced so far. High density and viscosity have traditionally made their recovery energy demanding in comparison to lighter oils.

Heavy crudes are expected to be a large contributor to the world’s energy needs in the future, as conventional supplies decrease. However, the technological costs to produce a barrel are currently much higher than with conventional resources.  Additionally, the increased energy requirements and unconventional practices in production raise various environmental concerns such as land disturbance, tailing ponds, and higher greenhouse gas emissions.

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External resources


Canadian Association of Petroleum Producers

National Petroleum Council (US)

Canadian Heavy Oil Association (CHOA)

International Council on Mining and Metals

Society of Petroleum Engineers

International Minerals & Mining Association

U.S. National Mining Association


Canadian Energy Research Institute 

Total-EP Canada

Alberta’s Petroleum Heritage Edukits

Canadian Centre for Energy Information


Oil & Gas Journal

Oil Sands Review


Energy & Fuels

Journal of Geology and Mining Research


Oil Sands Discovery Centre

Canadian Association of Petroleum Producers (CAPP)


University of Alberta

Fuel Chemistry Division 

CRS Report for Congress – North American Oil Sands: History of Development, Prospects for the Future

Alberta Oil Magazine

Alberta Government – Rules, Reports and Regulations
The Economist – Oil sands

Alberta Energy Regulator

Parlee – Avoiding the Resource Curse: Indigenous Communities and Canada’s Oil Sands

Alberta Energy: Oil Sands Sustainable Development Secretariat

The Oil Sands Developers Group

Alberta Government – Alberta’s Oil Sands 
Canadian Energy Research Institute – Refining Bitumen: Costs, Benefits and Analysis
Canadian Energy Research Institute – Economic Impacts of New Oil Sands Projects in Alberta (2010-2035)

Total Energy

Alberta Tech Futures

Alberta Energy

Teledyne ISCO

MEG Energy


How SAGD Works | Cenovus Energy

Talk About SAGD | Alberta Energy

SAGD 3D Animation | CAPP


In Situ Report Card | Pembina Institute

Alberta Centre for Reclamation and Restoration Ecology

Water Matters 

Total-EP Canada

Canadian Energy Research Institute – Oil Sands Environmental Impacts
The Royal Society of Canada – Environmental and Health Impacts of Canada’s Oil Sands Industry
Alberta Government – Oil Sands Environmental Management

Alberta Energy: Oil Sands Sustainable Development Secretariat

Canada’s National Energy Board

IHS – The Role of the Canadian Oil Sands in the US Market
The Globe and Mail – Oil-sands link to health concerns
The Royal Society of Canada – Environmental and Health Impacts of Canada’s Oil Sands Industry


Canadian Oil Sands

Oil Sands Review




The Wall Street Journal

New York Times


Oil Sands Review

The Wall Street Journal

Huffington Post – Alberta Oil Sands Articles
Financial Post – Majority of oil sands ownership and profits are foreign, says analysis