Crude Bitumen

ST98

This section provides an overview for crude bitumen:

Crude bitumen is extra-heavy oil that in its natural state does not flow to a well. It occurs in sand (clastic) and carbonate formations in northern Alberta. Crude bitumen and the rock material it is found in, together with any other associated mineral substances other than natural gas, are called oil sands. For administrative purposes, the geological formations and the geographic areas containing the bitumen are designated as oil sands areas (OSAs). Combined, these areas occupy an area of about 142 000 square kilometres (km2; 54 000 square miles). Other heavy oil is deemed to be oil sands if it is located within an OSA. Since some bitumen within an OSA will flow to a well, it is amenable to primary development and is considered to be primary crude bitumen in this report.

Depending on the depth of the deposit, one of two methods is used to recover bitumen. North of Fort McMurray, crude bitumen occurs near the surface and can be recovered economically by open-pit mining. In this method, overburden is removed, oil sands ore is mined, and bitumen is extracted from the mined material in large facilities using hot water. At greater depths, where it is not economical to recover the bitumen by mining, in situ methods are employed. In situ recovery takes place both by primary development, similar to conventional crude oil production, and by enhanced development. Cyclic steam stimulation (CSS) and steam-assisted gravity drainage (SAGD) are the two main methods of enhanced development whereby the reservoir is heated to reduce the viscosity of the bitumen, allowing it to flow to a vertical or horizontal wellbore.

This section includes crude bitumen production, upgrading, and disposition of both upgraded and nonupgraded bitumen. Nonupgraded bitumen refers to crude bitumen that is sold without further processing. Typically, it is blended with a lighter-viscosity product (referred to as a diluent to meet specifications for transport through pipelines). Upgraded bitumen refers to the portion of crude bitumen production that is upgraded to synthetic crude oil or other petroleum products. Most upgraded bitumen is used by refineries as feedstock.