An oil well. Unconventional oil gets its name from how it is extracted, not from the composition of the oil itself.
Unconventional oil is oil obtained in a way that differs from the usual drilling method. There are many unconventional oils, including oil sand and shale rock, and the term applies more to how the oil is extracted than to the oil itself. In terms of efficiency, performance and environmental impact, unconventional oil is not as good as conventional oil. Conventional oil extraction is generating less and less oil, although many oil extraction companies are looking for alternative ways to obtain oil.
Kerogen is a material that originates from plants or animals and has been altered by bacteria. Unlike liquid petroleum, which went through extreme heat to become a conventional oil, kerogen did not go through this process. Through a heating process, kerogen is converted into an oil-like substance that can be used like normal petroleum. Shale rock, a type of sedimentary rock, contains large amounts of kerogen and is an unconventional method of obtaining oil commonly called shale oil.
Bitumen, more often called oily sand due to its texture, looks a lot like oil or tar, but it’s not. It is a semi-solid material that contains degraded oil and is largely composed of sand and clay particles. This method produces little unconventional oil, because 2 tons (1,814 kilograms) are needed for a barrel of oil. The most common way of extracting bitumen is by injecting steam into the oily sand, which reduces the viscosity of the bitumen and makes it easier to collect.
Heavy oil is unconventional oil that is similar to conventional oil but much heavier. This is because the lighter hydrocarbons found in conventional oil have broken down, leaving only a heavy substance. To extract heavy oil, diluents are added to reduce the overall viscosity so that the heavy oil can be pumped.
Thermal depolymerization (TDP) is a method that emulates nature and uses different raw materials for unconventional oil. Raw materials such as petroleum coke or tailings deposits are added to the TDP unit. Using extreme heat and pressure, the raw material is processed to create oil. The oil yield differs depending on the raw material.
Although unconventional oil offers different methods of obtaining oil, it presents environmental risks. Most of the materials used in unconventional oil drilling and extraction contain large amounts of toxic substances such as sulfur. The areas where unconventional oils come from are also generally more dangerous for workers.