Research investigates use of nanoparticles for advanced oil recovery
Brazil is a pioneering country in the exploration of oil in deep waters and a great quantity of this fossil fuel is stored in the porous space of carbonate rocks, especially in the pre-salt layer. These rocks are very heterogeneous and have complex pore systems, bringing great challenges to the extraction of oil and gas.
After drilling an oil or gas reservoir, the natural pressure inside it causes the contents to flow naturally to the surface where the fluid is collected and directed to a tanker. However, a few years after the opening of the well, the amount of oil extracted daily tends to decrease due to the drop in internal well pressure.
One of the ways to continue the exploration is by the injecting water or gas into the well, which helps in the transport of fluids and increases oil production, allowing it to be explored for several years. A more efficient way is, however, through the injection of surfactants, which facilitate the remobilization of oil, even in regions where water and gas have no further effect.
Recently, Tannaz Pak and collaborators from Brazil and the United Kingdom investigated  the use of nanoparticles to improve the advanced recovery of oil in carbonate rocks. By means of time-resolved X-ray microtomography, the research showed for the first time how oil droplets, retained in the pores of carbonate rocks, change shape when interacting with silica nanoparticles suspended in water, making it again available for extraction.
The group also demonstrated that nanoparticles are effective at much lower concentrations than those of substances normally used by the industry for petroleum remobilization, potentially lowering extraction costs.
The experiments were carried out in the UK. However, according to Nathaly Lopes Archilha, a researcher at the Brazilian Synchrotron Light Laboratory (LNLS) and one of the authors of the research, it is currently possible to perform the same experiments in LNLS.
The results can also assist in the removal of hydrocarbon-based contaminants in groundwater. Therefore, the researchers are already working on this new project at LNLS and the research will benefit immensely from the facilities of Sirius, the new Brazilian synchrotron light source, which is expected to open for users in 2019.
The new laboratory will have X-ray microtomography facilities capable of studying larger samples with better spatial and temporal resolutions. This will be essential to reveal the physics behind the processes under study and for the investigation of samples representative of the oil and gas reservoirs and groundwater resources.
Source:  Tannaz Pak, Nathaly Lopes Archilha, Iara Frangiotti Mantovani, Anderson Camargo Moreira & Ian B. Butler, The Dynamics of Nanoparticle-enhanced Fluid Displacement in Porous Media – A Pore-scale Study, Scientific Reports (2018) 8: 11148. DOI: 101038 / s41598-018-29569-2
The project was funded by the Royal Academy of Engineering through the Newton Funds.