The ability of surface-treated silica nanoparticles to stabilize oil/water emulsions
presents us with many interesting avenues of study. The goal of this research is to assess
the ability of a dispersion of specially surface-treated nanoparticles to stabilize an
oil/water emulsion of prescribed internal structure created by flow within a fracture. We
hypothesize that for a set of conditions (nanoparticle concentration, salinity, aqueous to
organic phase ratio) a critical shear rate exists. That is, for flow rates that exceed this
critical shear rate, an emulsion can be created.
Flow experiments were conducted within fractured Boise sandstone and cement
cylinders. The Boise sandstone core (D = 1 in and L = 12 in) was cut down its length and
propped open to a specific aperture with beads. The fracture was saturated with dodecane
then displaced with nanoparticle dispersion, and vice versa while pressure drop across the fracture was recorded. Class H cement cylinders (D = 1 in and L = 3 in) were allowed to
set, then failed in compression to create a rough-walled fracture along their length. These
fractured cement cylinders were then sealed and encased in epoxy to isolate the fractures.
CT scans of the encased fractures were used to determine the aperture width, which is
utilized when calculating the shear rate inside of the fracture maintained during an
experiment. A dispersion of surface-modified silica nanoparticles and decane were coinjected
into both the Boise sandstone and cement fractures and the pressure drop was
measured across the fractures at a variety of shear rates. The effluent of each experiment
was collected in sample tubes.
Observation of the effluent and pressure drop data both support our hypothesis of
emulsion generation being possible once a critical shear rate has been reached. Alteration
of the injected phase ratio and increased residence time of the two phases inside of a
fracture both affect the amount of emulsification occurring within the fractures.
Increasing the residence time of both phases within a fracture allows for more
opportunities for emulsification to occur, resulting in a greater amount of emulsion to be
generated. Injection of high or low volumetric ratios of nanoparticle dispersion to organic
phase results in little amounts of emulsion generation; however, between the nanoparticle
dispersion to organic phase ratios of 0.25:1 and 2:1 significant amounts of emulsion are
generated. / text
| Identifer | oai:union.ndltd.org:UTEXAS/oai:repositories.lib.utexas.edu:2152/ETD-UT-2011-05-3226 |
| Date | 12 July 2011 |
| Creators | Roberts, Matthew Ryan |
| Source Sets | University of Texas |
| Language | English |
| Detected Language | English |
| Type | thesis |
| Format | application/pdf |
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