Bitumen and heavy oil are difficult to extract from reservoirs because they are thick and do not flow easily. There are several methods of extraction, one of which uses carbon dioxide-rich gas injections which helps liquify the bitumen for easier extraction, while presenting opportunities for sequestration of carbon dioxide in the reservoir.
Before companies pump CO2 into reservoirs they need to first determine how the CO2 and oil will behave under specific pressures and in specific rock formations. Dr. David Sinton, a professor of mechanical and industrial engineering at the University of Toronto, and postdoctoral researcher Dr. Hossein Fadaei are using microfluidic chips to test the bitumen-gas interaction - a rapid, reliable approach that could be used by both researchers and the oil and gas industry.
Conventional methods of analysis are conducted using about .5 L of bitumen and a process that can take hours or even days for a single test result. Sinton and his colleagues use a small glass microchip to replicate a pore within a rock reservoir. The channels in the pore are 50 microns wide, or about half the diameter of a human hair. The device is initially filled with CO2 at low pressure and a small sample of bitumen is injected into the centre of the chip. High pressure CO2 is then injected at both ends of the chip and the swelling of the oil is measured over time.
“This takes 10 minutes and uses a nanoliter plug of sample. If you can do a test in a few minutes and perform many tests in parallel, that’s a lot cheaper,” he points out. “The experimental setup is also quite simple compared to existing methods.”