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Miscible displacement fronts of shear thinning fluids inside rough fractures
The miscible displacement of a shear-thinning fluid by another of same
rheological properties is studied experimentally in a transparent fracture by
an optical technique imaging relative concentration distributions. The fracture
walls have complementary self-affine geometries and are shifted laterally in
the direction perpendicular to the mean flow velocity {\bf U} : the flow field
is strongly channelized and macro dispersion controls the front structure for
P\'{e}clet numbers above a few units. The global front width increases then
linearly with time and reflects the velocity distribution between the different
channels. In contrast, at the local scale, front spreading is similar to Taylor
dispersion between plane parallel surfaces. Both dispersion mechanisms depend
strongly on the fluid rheology which shifts from Newtonian to shear-thinning
when the flow rate increases. In the latter domain, increasing the
concentration enhances the global front width but reduces both Taylor
dispersion (due to the flattening of the velocity profile in the gap of the
fracture) and the size of medium scale front structures
Dispersion enhancement and damping by buoyancy driven flows in 2D networks of capillaries
The influence of a small relative density difference on the displacement of
two miscible liquids is studied experimentally in transparent 2D networks of
micro channels. Both stable displacements in which the denser fluid enters at
the bottom of the cell and displaces the lighter one and unstable displacements
in which the lighter fluid is injected at the bottom and displaces the denser
one are realized. Except at the lowest mean flow velocity U, the average
of the relative concentration satisfies a convection-dispersion
equation. The dispersion coefficient is studied as function of the relative
magnitude of fluid velocity and of the velocity of buoyancy driven fluid
motion. A model is suggested and its applicability to previous results obtained
in 3D media is discussed
Experimental study on stability and rheological properties of aqueous foam in the presence of reservoir natural solid particles
The authors would like to acknowledge the school of engineering at the University of Aberdeen and University Technology Malaysia (UTM) to provide required materials and facilities to complete this research.Peer reviewedPostprin
Modeling Strategy for Injectivity in SWAG Processes
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How to Model Condensate Banking in a Simulation Model to Get Reliable Forecasts? Case Story of Elgin/Franklin
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Influence of Micro-mixing on the Size of Liposomes Self-Assembled from Miscible Liquid Phases
Ethanol injection and variations of it are a class of methods where two
miscible phases---one of which contains dissolved lipids---are mixed together
leading to the self-assembly of lipid molecules to form liposomes. This method
has been suggested, among other applications, for in-situ synthesis of
liposomes as drug delivery capsules. However, the mechanism that leads to a
specific size selection of the liposomes in solution based self-assembly in
general, and in flow-focussing microfluidic devices in particular, has so far
not been established. Here we report two aspects of this problem. A simple and
easily fabricated device for synthesis of monodisperse unilamellar liposomes in
a co-axial flow-focussing microfluidic geometry is presented. We also show that
the size of liposomes is dependent on the extent of micro-convective mixing of
the two miscible phases. Here, a viscosity stratification induced hydrodynamic
instability leads to a gentle micro-mixing which results in larger liposome
size than when the streams are mixed turbulently. The results are in sharp
contrast to a purely diffusive mixing in macroscopic laminar flow that was
believed to occur under these conditions. Further precise quantification of the
mixing characteristics should provide the insights to develop a general theory
for size selection for the class of ethanol injection methods. This will also
lay grounds for obtaining empirical evidence that will enable better control of
liposome sizes and for designing drug encapsulation and delivery devices.Comment: 11 pages, 14 Figure
Evaluation of CO2 and Carbonated Water EOR for Chalk Fields
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