With much of the easy-to-pump oil already extracted from U.S. oilfields, companies are increasingly going after the oil that remains stuck to the rocks in reservoirs. They typically inject steam or carbon dioxide into the reservoirs to thin the sticky oil so that it flows more easily. Researchers at Queens University in Ontario, Canada, have now found that a novel soaplike compound could make the process more productive.
The compound is a type of surfactant – a class of compounds that allow substances such as oil and water, which otherwise do not blend well, to form mixtures. Surfactants, which are used in materials such as detergents and paint, are widely known to increase oil production – by as much as 28 percent when pumped into reservoirs together with water, according to the U.S. Department of Energy. But they also pose a problem: once the oil-water emulsion is extracted from the reservoir, the oil needs to be separated. That’s complicated and expensive.
The biggest problem, says Eric Beckman, a professor of chemical and petroleum engineering at the University of Pittsburgh, is that the surfactant holding the oil and water together has to be deactivated. Currently, oil-water emulsions are broken using other chemicals or heat. “It would be much easier to simply turn the surfactant off,” he says, “so the emulsion simply falls apart and you can recover and reuse the surfactant if you want.”
This is exactly what Philip Jessop, associate professor of chemistry at Queens, made possible with the help of collaborators at Georgia Tech. They found a surfactant that they say can be switched on and off using carbon dioxide and air. Some companies have already expressed interest in the work, Jessop says. The researchers describe the novel properties of the surfactant, a type of amidine, in this week’s issue of Science.