What is Oil Sand? Resources and History of Oil Sands

What Are Oil Sands? Understanding Tar Sands and Their Impact

Oil sands, also known as “tar sands,” are naturally occurring sedimentary deposits composed of sand, clay minerals, water, and bitumen. Bitumen is a dense, sticky form of petroleum that can exist as a viscous liquid or a semi-solid at room temperature. Typically, bitumen constitutes about 5 to 15% of the total oil sand deposit. While oil sands are a valuable source of crude oil, extracting bitumen presents significant technical and environmental challenges.

How Is Bitumen Extracted From Oil Sands?

The method of extracting bitumen from oil sands largely depends on the depth at which the deposits lie.

1. Surface Mining (Open-Pit Mining)

When oil sands are near the surface, large-scale open-pit mining is used. The process involves:

• Removing the overburden: Layers of soil and rock are cleared to access the oil sands.

• Mining: Large machines scoop the oil sands and load them onto trucks.

• Transporting to processing facilities: The sands are crushed and mixed with hot water and chemicals to release the bitumen.

• Separation: The bitumen is separated from water and sand, then diluted with lighter hydrocarbons to reduce viscosity.

• Pipelining: The processed bitumen is sent to refineries for further processing into usable fuels and petrochemical products.

Surface mining is effective for shallow deposits, but it is energy-intensive and can significantly disrupt the landscape.

2. In Situ Recovery

For deeply buried oil sands, surface mining is not feasible. Instead, in situ recovery methods are used. The most common is Steam-Assisted Gravity Drainage (SAGD):

• Wells are drilled into the deposit.

• Steam and chemicals are injected to soften the bitumen, making it less viscous.

• The heated bitumen is pumped to the surface for cleaning and dilution with lighter hydrocarbons.

In situ methods are less disruptive to surface land than mining but require substantial energy input and water.

History of Oil Sands Development

• 1920s: Canada began research on separating bitumen from oil sands, sponsored by the Alberta Research Council.

• 1967: The Great Canadian Oil Sands Company launched commercial production, producing roughly 12,000 barrels per day.

• 1930s (US): Government permits allowed oil companies to experiment with mining and drilling, but most projects failed due to environmental and logistical challenges.

Today, the Athabasca oil sands dominate global production, with open-pit mining used where oil is near the surface and in situ recovery for deeper deposits. Production fluctuates with global oil prices, as oil sands extraction is more costly than conventional crude production.

How Is The Oil Removed?

The method of extracting bitumen from oil sand depends on how deep the oil sands buried. When oil sands deeply bury, wells must drill to extract the bitumen. When the oil sands are close to the surface, they mine and transported to a processing plant for extraction. Are tar sands an important resource?

Most of the world’s oil sands resources are located in Alberta, Canada. The Alberta Energy and Utilities Board estimate that these contain about 1.6 trillion barrels of oil, about 14% of the world’s total oil resources. The largest deposit is Athabasca Oil Sands

Open Sky

The overburden remove at an oil sand mine, and large mining machines load the sand onto trucks that take it to a nearby processing facility. In the treatment plant, the oil sand crush and treated with hot water and chemicals to release the bitumen. The released bitumen is then separated from the water, mixed with lighter hydrocarbons to reduce its viscosity, and pumped through a pipeline to a refinery.

Production Per Drilling

Bitumen extract from deeply buried oil sands by drilling wells, known as “in situ recovery.” Several wells are prepared in the oil sand. Then the steam and chemicals pump into a well. The hot vapor and chemicals soften the bitumen, reduce its viscosity, and discharge it into extraction wells, where it pump to the surface. At the surface, the bitumen clean, mixed with lighter hydrocarbons, and pumped through a pipeline to a refinery.

Oil Sands Development History

Research on oil sands began in Canada in the 1920s. The Alberta Research Council sponsored the first research on the separation of bitumen from oil sand. Experimentation continued through the 1960s without significant commercial production. Before, in 1967, the Great Canadian Oil Sand Company began commercial production, producing around 12,000 barrels per day.

In the United States, government agencies granted permits to oil companies to open demonstration mines and drill on-site on government land in the 1930s. These projects resulted in smaller amounts of commercial production in California and Utah. However, most failed because they faced remote locations, difficult topography, and a lack of water.

The Athabasca oil sands of Canada have been the main source of commercial production. Open-pit minefields can be prosperous when oil prices are high but financially distressed when Oil prices are falling. They also face environmental concerns, including air quality, land use, and water availability.

Environmental Impacts of Oil Sands

The extraction and processing of oil sands have considerable environmental consequences:

1. Greenhouse Gas Emissions

• Oil sands production emits more CO₂ compared to conventional oil extraction due to energy-intensive processing.

• This contributes significantly to climate change concerns.

2. Land Disturbance

• Open-pit mining removes large areas of forest and soil, disrupting ecosystems.

• Reclamation efforts are costly and slow, often taking decades to restore the land.

3. Water Usage and Pollution

• Several barrels of water are required for every barrel of bitumen extracted.

• Tailings ponds, which store wastewater and residual bitumen, can contaminate local waterways and harm wildlife.

• In arid regions like Utah, water scarcity makes oil sands development particularly challenging.

4. Wildlife and Habitat Loss

• Mining activities disrupt habitats for fish, birds, and mammals.

• Fragmentation of ecosystems can lead to population declines and biodiversity loss.

Technological Innovations in Oil Sands Extraction

To reduce environmental impacts and improve efficiency, companies are investing in:

• Solvent-assisted extraction: Reduces steam use and lowers greenhouse gas emissions.

• Electric-powered mining equipment: Minimizes fossil fuel consumption.

• Water recycling technologies: Reduces freshwater use and tailings pond volume.

• Carbon capture and storage (CCS): Traps CO₂ emissions before they reach the atmosphere.

These innovations aim to make oil sands production more sustainable and economically viable.

Environmental Concerns

The extraction and processing of tar sands have several environmental impacts. These include: greenhouse gas emissions, land disturbance, habitat destruction for wildlife, and degradation of local water quality. In the United States, water issues are critical because known tar sands and shale deposits find in arid areas of Utah. Several barrels of water require for every barrel of oil produced.