oliezanden

Oliezanden are naturally occurring mixtures of sand or sandstone with bitumen, a dense, viscous form of crude oil, along with water and clay. The bitumen content varies by deposit and is often too viscous to flow at ambient temperatures, which classifies oliezanden as an unconventional hydrocarbon resource. The oil is typically recovered and processed to produce usable crude.

Extraction and processing: Shallow deposits are commonly mined with heavy equipment; the ore is then processed to separate the sand from the bitumen. In deeper deposits, in-situ methods such as steam-assisted gravity drainage (SAGD) or cyclic steam stimulation (CSS) are used to reduce viscosity and enable extraction through wells. Recovered bitumen is upgraded to synthetic crude oil and then refined.

Geography and reserves: The largest accumulations are in Alberta, Canada, with major parcels in the Athabasca, Peace River, and Cold Lake regions. Smaller deposits exist in other countries, and ongoing exploration seeks to expand recoverable resources.

Environmental and economic aspects: Oil sands development is energy-intensive and requires large amounts of heat and water. It raises greenhouse gas emissions per barrel relative to conventional crude, and poses land-use and water-management challenges, including tailings ponds. Industry participants advocate reclamation programs and advances in water recycling. Oil sands contribute significantly to regional economies and global oil supply subject to market and policy conditions.