Turning 'Cold Molasses' Into Gold

Oil Sands Shows No Sign of Abating.

The all-out action in Canada’s oil sands shows no sign of abating.

But oil sands are a whole different breed of cat from other types of oil deposits, and recovering the oil and converting it into something of value to meet consumer and industrial needs is no ordinary oil field operation.

The Canadian oil sands, often referred to as tar sands, are actually deposits of bitumen, which is a thick, gooey type of crude oil – it’s been compared to cold molasses at room temperature.

Image Caption

Canada Oil Sands — Foster Creek
An aerial view of the Foster Creek's heavy oil in-situ oil sands SAGD (steam-assisted gravity-drainage) operations.
Photo courtesy of EnCana

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The all-out action in Canada’s oil sands shows no sign of abating.

But oil sands are a whole different breed of cat from other types of oil deposits, and recovering the oil and converting it into something of value to meet consumer and industrial needs is no ordinary oil field operation.

The Canadian oil sands, often referred to as tar sands, are actually deposits of bitumen, which is a thick, gooey type of crude oil – it’s been compared to cold molasses at room temperature.

Considerable upgrading is required before it can be refined to produce a useable fuel.

The Alberta Department of Energy (ADOE) defines bitumen in the technical sense as a “tar-like mixture of petroleum hydrocarbons with a density greater than 960 kilograms per cubic meter; light crude oil, by comparison, has a density as low as 793 kilograms per cubic meter.”

In fact, the heavy, viscous oil must be heated or diluted with lighter hydrocarbons before it can even flow through pipelines, according to the ADOE.

The Process

Canada’s oil sands, which are located in the province of Alberta, account for one of the two largest sources of bitumen in the world, according to the ADOE. The other is Venezuela.

Depending on depth of the resource, either open pit mining or in-situ (in-place) techniques are used to recover the bitumen. To produce one barrel of oil via mining, two tons of oil sands must be dug out, moved and processed and then returned to the open pit for reclamation.

Equipment such as cranes and dump trucks that are required for the mining procedure are bigger than big. In fact, the huge trucks that transport the sand to be processed reportedly weigh in at 360 tons when empty.

Once the oil sands are mined, they are broken up by crushers and sent to an extraction plant where the bitumen is separated out to be moved to the upgrading facility. Following the upgrading procedure, the bitumen ultimately is converted into diesel fuel and synthetic crude, which is transported by pipeline to refineries to be converted into a number of products, including gasoline, jet fuel and home heating oils.

In-situ recovery techniques are used where the sands are buried deeper than 200 feet, which applies to about 80 percent of the resource, according to Greg Stringham, vice president of the Canadian Association of Petroleum Producers.

The in-situ methods include cyclic steam stimulation and steam-assisted-gravity-drainage, which entail thermal injection via vertical or horizontal wells, solvent injection and CO2 methods, depending on the in-situ techniques being used.

The bitumen separation occurs in the ground, so it’s sent directly to the upgrading facility by pipeline.

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