Surfactant/foam transport: Some enhanced oil recovery processes and soil remediation processes are based on creating additional interfaces through the application of surface active materials called surfactants. These materials promote the "mixing of oil and water" by creation of nanostructures that can reduce the oil-water interfacial tension by a factor of 10E-4 and or solubilize oil into an aqueous phase containing dispersed surfactant aggregates called "micelles" They can also stabilize thin water films so that gas will flow as a dispersed "foam" phase that transports as if it is a highly viscous fluid.
Wettability in petroleum systems: Water, oil, and gas exists in porous rocks with a large specific surface area. The wetting and/or spreading of the fluids on the solid and/or fluids govern the ease of recovery of the hydrocarbons from the rock formation. Research is being conducted to understand fundamental mechanisms of wettability and to enhance the imbibition of water into carbonate rocks.
NMR fluid and rock properties: The petroleum industry uses nuclear magnetic resonance (NMR) well logging to evaluate the formation properties immediately after a well is drilled. Similar measurements are made in the laboratory with fluid and rock samples to develop the methodology to interpret the NMR signals.
Gas hydrates: Gas hydrates currently are important in the seafloor pipeline transportation of oil and gas, a potential natural gas source for the future, and have been a cause for climate change in the geological past.
Professor Hirasaki joined the Rice faculty after a 26 year career with Shell Development and Shell Oil Company. His research in fluid transport through porous media ranged from the microscopic scale intermolecular forces governing wettability to the megascopic scale numerical reservoir simulators for field-wide modeling. A reoccurring theme throughout this research is the dominance of interfaces in the determination of fluid transport processes. Fluids flow through rock and soil in pore spaces that are on the order of microns. The relative transport of phases and components are governed by the degree of wetting of the solid by the fluid phases and the sorption of species on the fluid and solid surfaces in addition to the usual transport coefficients such as viscosity and diffusivity.
Professor Hirasaki's research program is sponsored by an industrial consortium, USDOE, and industrial contracts.