What is Oil Sands

 

Oil Sands video

Oil sands are deposits of bitumen, a heavy black viscous oil that must be rigorously treated to convert it into an upgraded crude oil before it can be used by refineries to produce gasoline and diesel fuels. Until recently, Alberta's bitumen deposits were known as tar sands but are now referred to as oil sands.

Bitumen is best described as a thick, sticky form of crude oil, so heavy and viscous that it will not flow unless heated or diluted with lighter hydrocarbons. At room temperature, it is much like cold molasses.

Oil sands are substantially heavier than other crude oils. Technically speaking, bitumen is a tar-like mixture of petroleum hydrocarbons with a density greater than 960 kilograms per cubic metre; light crude oil, by comparison, has a density as low as 793 kilograms per cubic metre.

Compared to conventional crude oil, bitumen requires some additional upgrading before it can be refined. It also requires dilution with lighter hydrocarbons to make it transportable by pipelines.

Bitumen makes up about 10-12 per cent of the actual oil sands found in Alberta. The remainder is 80-85 per cent mineral matter - including sand and clays - and 4-6 per cent water.

While conventional crude oil flows naturally or is pumped from the ground, oil sands must be mined or recovered in situ - meaning 'in place.' Oil sands recovery processes include extraction and separation systems to remove the bitumen from sand and water.

Alberta's oil sands comprise one of the world's two largest sources of bitumen; the other is in Venezuela.

Oil sands are found in three places in Alberta - the Athabasca, Peace River and Cold Lake regions - and cover a total of nearly 140,200* square kilometres.

Mineable bitumen deposits are located near the surface and can be recovered by open-pit mining techniques. For example, the Syncrude and Suncor oil sands operations near Fort McMurray, Alberta, use the world's largest trucks and shovels to recover bitumen.

About two tonnes of oil sands must be dug up, moved and processed to produce one barrel of oil. Roughly 75 per cent of the bitumen can be recovered from sand; processed sand has to be returned to the pit and the site reclaimed.

In situ recovery is used for bitumen deposits buried too deeply - more than 75 metres - for mining to be practical. Most in situ bitumen and heavy oil production comes from deposits buried more than 400 metres below the surface of the earth.

Cyclic steam stimulation (CSS) and steam-assisted gravity drainage (SAGD) are in situ recovery methods, which include thermal injection through vertical or horizontal wells, solvent injection and CO2 methods. Canada's largest in situ bitumen recovery project is at Cold Lake, where deposits are heated by steam injection to bring bitumen to the surface, then diluted with condensate for shipping by pipelines.

Other technologies are emerging such as pulse technology and vapour recovery extraction (VAPEX).

* using GIS software


Frequently Asked Questions about oil sands

Oil Reserves and Production brochure (2006)

Alberta's Oil Sands - Overview (2006 Production Year)  

Oil Sands Industry Update (2006 December)