Global bitumen and heavy-oil resources are estimated to be 5.6 trillion bbl, with most of that occurring in the western hemisphere. In the past decade, significant advances in the development and production of these resources have occurred by way of the critical integration of geology, geophysics, engineering, modeling economics, and transportation.

Bitumen and heavy-oil deposits are mainly unconsolidated sands bound together by biodegraded bitumen. In the case of the world's largest oil-sand and heavy-oil deposit, located in western Canada, the oil sands occur in deposits of low sedimentary accommodation on the distal side of a foreland basin. Hydrocarbons were derived from Mississippian Exshaw and/or Mesozoic source rocks. The hydrocarbons migrated eastward several hundred kilometers to accumulate and become biodegraded on the shallowly buried, low-temperature, northeastern margins of the basin. The hydrocarbons accumulated in tidally influenced fluvioestuarine sediments, midchannel bars, brackish bays, bay-head deltas, and tidal flats. Elsewhere, in another major global heavy-oil resource, the Oficina Formation in Venezuela was similarily deposited in fluvioestuarine to deltaic settings.

Current in-situ oil-sand development focuses on steam-assisted gravity drainage (SAGD) technology and, to a lesser degree, cyclic steam stimulation (CSS). Other emerging technologies being piloted include in-situ combustion, electrothermal dynamic stripping, and passive heating-assisted recovery methods. Water supply and disposal is an ongoing critical component for the mines and in-situ development. In the surface mines, hydrotransport, typically using recycled and brackish water, has major requirements for water, whereas fresh to saline water is used to generate steam for the in-situ bitumen heating. The development of oil sands requires a delicate balance between resource extraction regulatory systems, environmental issues, and long-term sustainability. In areas of in-situ SAGD development where overburden is shallow, cap rock integrity is also critical to prevent steam escape from mixed hydrocarbon and steam chambers into ground and surface waters. For surface mines, experimental new bacterial-remedial biotechnology shows promise for reducing sedimentation time of fines and toxin removal from tailings ponds. Thus, to cost-effectively develop oil-sand resources of the world, it is critical that technological innovation continue to develop to minimize environmental impacts and to more efficiently develop these strategic resources.