It’s tough to wean the world off its reliance on fossil fuels. Despite the global push towards cleaner, sustainable energy sources, estimates point to the current demand of 100 million barrels of oil per day. Moreover, green economies still need fossil fuels—they’re used as building blocks for other materials such as plastics.
Where there’s room for improvement, however, is in the crude oil extraction process. “Being able to extract 20 percent more oil from oil reservoirs worldwide will translate to billions of barrels of oil,” said Dan Daniel, a Research Scientist at A*STAR’s Institute of Materials Research and Engineering (IMRE).
Recent advances in nanotechnology have created a buzz in the field, with nanoparticles hypothesised as being a viable means of drawing out more oil trapped within porous rocks. Suspensions of silica nanoparticles, also known as nanofluids, are thought to alter the wettability of oil reservoirs, thereby enhancing the oil recovery process. However, until now, there has been no robust way of measuring just how much nanofluids help.
A*STAR researchers from IMRE and the Institute of Sustainability for Chemicals, Energy and Environment (ISCE2) dove deeper into this topic using innovative visualisation approaches. The team, in addition to Daniel, also comprised Shidong Li, a Research Scientist with the then Institute of Chemical and Engineering Sciences at A*STAR, together with Ludger Paul Stubbs, who was formerly at ISCE2 and now a Senior Research Scientist at A*STAR’s Singapore Institute of Food and Biotechnology Innovation (SIFBI).
The researchers used an array of microscopy techniques to visualise and quantify the effects of nanofluids in oil extraction simulations. They found that adding even trace amounts of nanoparticles to oil droplets improved the surface wettability and reduced the adhesion of oil to rocks by over 400 times.
Silica nanofluids reduced the contact area between oil droplets and simulated rock (etched glass) by forming a thin film of nanoparticles (NP) and water between the two surfaces.
© A*STAR Research
Daniel likens these effects to doing a load of laundry. “Just as detergent molecules allow us to dislodge dirt and oil from our clothes, nanoparticles greatly reduce adhesion of oil to rocks, allowing us to extract oil from the rock network more easily.”
The findings demonstrated that silica nanofluids could improve oil recovery rates by eight percent under laboratory conditions, a process that the team plans to optimise for use in industry settings.
“By understanding the mechanism by which the nanoparticles enhance extraction processes, we are now planning to perfect our nanoparticle 'recipe' for even better oil recovery,” said Daniel.
The A*STAR-affiliated researchers contributing to this research are from the Institute of Materials Research and Engineering (IMRE) and the Institute of Sustainability for Chemicals, Energy and Environment (ISCE2).
