14 DAY TRIAL // A method of combining fluids of different viscosities to create an in-situ mixing tool for other liquids is the latest invention from the Massachusetts Institute of Technology (MIT). The achievement could have significant repercussions for the oil industry and other chemistry-based sectors.
For example, one of the most important problems that many technological processes cannot handle is the inability to mix fluids in very small places. One such case is when engineers try to extract the oil that has been trapped inside porous rocks.
The chemical reactions that are needed to do so are so tremendously complex that they cannot take place properly in the limited space they are offered. What MIT experts are proposing is the utilization of “viscous fingers” in such situations.
These are structures created at the boundary between two fluids of different viscosities. Scientists with the MIT Department of Civil and Environmental Engineering (CEE) recently look a closer look at these interactions, and somehow managed to turn them into an usable tool.
“Getting two fluids to mix in a very tight space is difficult because there’s not much room for a disorderly flow,” explains the MIT ARCO associate professor in energy studies, Ruben Juanes.
“But with two fluids of highly contrasting viscosity, the thinner fluid naturally creates disorder, which proves to be a marvelously efficient means of mixing,” adds the expert, who was the principal investigator on the new research.
The work was funded by the Italian energy company Eni. Details of the method were published in the May 12 online issue of the esteemed journal Physical Review Letters. Interestingly, the team also found that the speed at which the less-viscous fluid is introduced into the other one is important too.
The speed at which the process called viscous fingering is mixing the two fluids together is directly dependent on this speed. This provides potential users with an additional means of tailoring the parameters of the reactions to their specific needs.
“It’s been known for a very long time that a low-viscosity fluid will finger through the high-viscosity fluid. What was not known is how this affects the mixing rate of the two fluids,” Juanes explains.
“For instance, in the petroleum industry, people have developed increasingly refined models of how quickly the low-viscosity fluid will reach the production well, but know little about how it will mix once it makes contact with the oil,” the expert concludes.