A method for getting oil out of tarry sands could reduce the costs and lower the greenhouse-gas emissions associated with its extraction.
New technology for extracting oil from oil sands could more than double the amount of oil that can be extracted from these abundant deposits. It could also reduce greenhouse-gas emissions from the process by up to 85 percent. The technology was developed by N-Solv, an Alberta-based consortium that recently received $10 million from the Canadian government to develop the technology.
Canada’s oil sands are a huge resource. They contain enough oil to supply the U.S. for decades. But they are made up of a tarry substance called bitumen, which requires large amounts of energy to extract from the ground and prepare for transport to a refinery. This fact has raised concerns about the impact of oil sands on climate change. The concerns have been heightened by plans to build a new pipeline for transporting crude oil from the sands to refineries in the United States.
Most oil sands production currently involves digging up oily sand deposits near the surface and processing the sludgy material with heat and chemicals to free the oil and reduce its viscosity so it can flow through a pipeline. But 80 percent of oil sands are too deep for this approach. Getting at the deeper oil requires treating the bitumen underground so it can be pumped out through an oil well. The most common technique in new projects involves injecting the bitumen with steam underground. But producing the steam means burning natural gas, which emits carbon dioxide. And the oil that’s pumped out is still too thick to flow through a pipeline, so it has to be partially refined, which emits still more greenhouse gases.
N-Solv’s process requires less energy because it uses a solvent rather than steam to free the oil, says Murray Smith, a member of N-Solv’s board of directors. The solvent, such as propane, is heated to a relatively low temperature (about 50 °C) and injected into a bitumen deposit. The solvent breaks down the bitumen, allowing it to be pumped out along with the propane, which can be reused. The solvent approach requires less energy than heating, pumping, and recycling water for steam. And because the heaviest components of the bitumen remain underground, the oil that results from the solvent process needs to be refined less before it can be transported in a pipeline.
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