Oil Sands 101

Summary

Oil sands, also known as tar sands, consist of sand, clay, and water mixed with bitumen, a highly viscous form of crude oil. Due to its thick consistency, bitumen cannot be extracted using conventional drilling techniques. Instead, methods like open-pit mining and in-situ extraction, including steam-assisted gravity drainage, are employed to extract and process the bitumen. While oil sands offer a large potential oil supply, they come with significant environmental concerns, such as high carbon emissions, water usage, and land disturbance. Despite the challenges, oil sands remain an important source of energy and petroleum products.

Takeaways

• 😀 Oil sands, or 'tar sands,' are a mixture of sand, clay, water, and bitumen (heavy crude oil).
• 😀 Bitumen is highly viscous and does not flow unless heated or mixed with lighter hydrocarbons.
• 😀 Conventional drilling methods cannot be used to extract bitumen due to its thick, sticky nature.
• 😀 Open-pit mining is used when bitumen is located within 75 meters of the surface, where large clumps of oil sands are mined and processed.
• 😀 In-situ extraction methods, like Steam Assisted Gravity Drainage, are used for deeper bitumen deposits, involving the pumping of steam underground to liquefy the bitumen.
• 😀 After extraction, bitumen requires upgrading to make it similar to conventional oil, suitable for refining into common petroleum products.
• 😀 The two largest oil sands reserves are found in Northern Alberta, Canada, and Venezuela.
• 😀 Oil sands have a high energy density, making them a versatile fuel for transportation and the production of petroleum-based products like plastics.
• 😀 Oil sands extraction is more carbon-intensive than conventional crude oil production, resulting in higher greenhouse gas emissions.
• 😀 Environmental concerns include heavy water use, tailings ponds storing contaminated water, and land disturbance due to mining operations.
• 😀 Oil sands production costs are higher compared to conventional oil sources, making it a more expensive method of oil extraction.

Q & A

What is oil sands, and what does it contain?

Oil sands, also known as tar sands, are a mixture of sand, clay, and water that contains bitumen, a type of extra heavy crude oil. Bitumen is highly viscous and does not flow unless heated or mixed with lighter hydrocarbons.

Why can't conventional drilling techniques be used to extract bitumen from oil sands?

Conventional drilling techniques cannot be used on bitumen because it is too viscous to flow and sticks to the sand grain in which it is found.

What are the two main methods used to extract bitumen from oil sands?

The two main methods used to extract bitumen from oil sands are open-pit mining and in-situ extraction (which means 'in place').

How does open-pit mining work to extract bitumen?

In open-pit mining, large clumps of oil sands are shoveled into trucks, taken to crushers, and mixed with heated water to separate the bitumen from the sand. The extracted bitumen is then sent for further processing.

What does the in-situ extraction method involve?

In-situ extraction involves pumping steam underground through horizontal wells to liquefy the bitumen, which can then be pumped to the surface. This method is used when bitumen is located more than 75 meters below the surface.

What is the process called to make bitumen usable like conventional oil?

The process of upgrading bitumen to give it properties similar to conventional oil is called upgrading.

Where are the largest oil sands reserves in the world located?

The two largest oil sands reserves in the world are located in Northern Alberta, Canada, and Venezuela.

What are some of the environmental challenges posed by oil sands development?

Environmental challenges include higher carbon emissions due to production techniques, heavy water use from freshwater sources, contamination of tailings ponds, land disturbance, and the higher cost of oil sands production.

Why are tailings ponds problematic in oil sands mining?

Tailings ponds are problematic because they store wastewater contaminated with pollutants from the oil sands mining process. This water cannot be naturally recycled back into the ecosystem.

How does oil sands production compare to conventional oil in terms of carbon intensity?

Crude oil derived from oil sands is more carbon-intensive than conventional crude oil due to the higher greenhouse gas emissions associated with the production techniques used in oil sands extraction.