Dynamics of Oil Dewetting and Two Phase Flow in Microchannels
Date
2018-01-08
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Abstract
The motion of three-phase contact lines (TPC), wetting dynamics, and fluid displacements in porous media have a wide range of engineering applications from coating and printing to agriculture, and subsurface flows. This dissertation investigates the early time dynamics of TPC and fluid movements in micro-channels related to subsurface oil recovery mechanisms.
First, the role of the surrounding fluid viscosity on wetting dynamics is investigated. Experiments are designed to visualize the spreading of an aqueous phase droplet on a glass substrate submerged in an oil phase. Experiments reveal that the TPC velocity is a decreasing function of ambient phase viscosity which is found, through a scaling analysis, to depend on both the spreading radius and the geometric mean of drop and ambient fluids’ viscosities.
Second, the effect of surfactants (sodium dodecyl sulfate: SDS) on the TPC dynamics is studied. In contrast to the dominance of viscous regime in pure water droplet spreading, two distinct early-time regimes are identified. The early time spreading dynamics, for the case of SDS added droplet, is characterized by the time exponents close to 0.5 and 1 before transitioning into the Tanner’s regime. Moreover, it is revealed that the SDS concentration has a non-monotonic effect on the early time dynamics. Increasing the SDS concentration initially retards the expansion of wetted area while accelerates the TPC velocity in the second regime.
Finally, the displacement of a viscous oil by an aqueous solution in a network of micro-capillaries is investigated. The effects of silica nanoparticles and various types of surfactants on the fluid-fluid interface evolutions and the heavy oil recovery are characterized using the microfluidic approach and 3D confocal imaging. Addition of untreated silica particles enhances the oil displacement efficiency by decreasing the thickness of the remaining oil film. In the presence of surfactants, the oil phase is divided into many smaller clusters that easily flow through the channels and enhances the rate of oil recovery. Ultimately, the presence of both silica and surfactants yields to the highest level of oil recovery as a result of coupled oil phase breakup and film thickness reduction effects.
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Keywords
Two phase flows, Microfluidics, Oil dewetting, Nanofluid, Drop spreading
Citation
Bazazi, P. (2018). Dynamics of Oil Dewetting and Two Phase Flow in Microchannels (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.