470166 Using Microfluidic Device to Study Rheological Properties of Heavy Oil

Monday, November 14, 2016
Market Street (Parc 55 San Francisco)
Kiarash Keshmiri, Chemical and Material Engineering, University of Alberta, Edmonton, AB, Canada, Saeed Mozaffari, Chemical Engineering, Virginia Polytechnic Institute and State University, Plamen Tchoukov, University of Alberta, Haibo Huang, Reservoir and Geosciences, Alberta Innovates Technology Futures and Neda Nazemifard, Chemical and Material Engineering, University of Alberta

Using Microfluidic Device to Study Rheological Properties of Heavy Oil

Microfluidics is an emerging technology that deals with flow of fluid in micro-scale channels [1]. Microfluidic chips are used as a good representative of porous media to evaluate dynamic aspects of fluid flow at pore-scale [2]. There are few works on application of microfluidic chips on heavy oil and bitumen and understanding of their pore-scale rheology [3]. There are some advantages of their application such as direct visualization of phenomena, reduced consumption of samples, low cost of fabrication, and accurate controlling of operating condition [4].

Capillary action drives fluid motion in microchannel without external driving forces. Capillary driven flow refers to spontaneous movement of interface due to curved liquid-liquid or gas-liquid interface [5]. Fluid viscosity, pore geometry, wettability, and surface tension are important parameters that influence the capillary filling kinetics. Capillary filling speed in rectangular microchannel is evaluated by classical Lucas-Washburn-Riedel (LWR) equation [6].

  Where r is the hydraulic radius, σ the air-fluid interfacial tension (IFT), θc the fluid advancing contact angle, and μ the viscosity of the fluid. Based on the equation, there is a linear relation between position of advancing liquid and square root of time. In this study, glass etched microchannels with depth of 10 µm and width of 40 µm were used. Capillary filling speed of methanol, ethanol, and solutions of bitumen in heptol (80:20) are experimentally monitored using inverted microscope with a digital charged coupled device (CCD) camera (Figure. 1). As illustrated in Figure. 1, there are six parallel microchannels on each chip which enable us to conduct several experiments with the similar experimental condition. This is important for repeatability of the data and having average values for each run.

For all samples linear relation between propagation distance and square root of time was found as expected in the case of Newtonian fluids. Theoretical viscosity of each sample was calculated with the assumption of constant contact angle which was then compared with experimental bulk viscosities. It is noteworthy to mention that in our previous work [3] capillary filling kinetics of bitumen solutions in nanochannel (depth ~ 47 nm) was investigated where theoretical results were significantly deviated from experimental values specially for higher concentrations of bitumen samples. It seems that sharp variation of advancing contact angle and interface shape is the reason of deviation (Figure 2). In fact, advancing contact angle is completely different from bulk contact angle and considering a constant value is not a reliable approach for high viscosity fluids. Therefore, classical model failed to explain filling kinetics of high viscosity fluids in the nanochannel. These findings further suggest that channel size affect the wettability, where decreased wettability in nano-scale separations leads to large deviation between theoretical and experimental results. On the other hand, experimental results of microchannels were in good agreement with classical model. Microchannels have the same size of real pore and pore throat that make them suitable for fluid flow study in porous media.

All in all, nanochannels were not suitable for monitoring of heavy oil and bitumen flow while microchannel enables us to study capillary filling kinetics of the high viscose fluids. Filling kinetics of viscous fluids in micro-scale require more study in order to have better prediction of real porous media structure.                                            


[1] D. Sinton, Energy: the microfluidic frontier, Lab Chip, 2014, 14, 3127–3134

[2] M. P. Rossi, H. Ye, Y. Gogotsi, S. Babu, P. Ndungu and J. C. Bradley,” Environmental Scanning Electron Microscopy Study of Water in Carbon Nanopipes”, Nano Lett., 4 989–993 (2004).

[3] S. Mozaffari, “heology of Bitumen at the Onset of Asphaltene Aggregation and its Effects on the Stability of Water-in-Oil Emulsion”, M.Sc Thesis, University of Alberta, (2015).

[4] JC. McDonal, DC. Duffy, JR. Anderson, DT. Chiu, H. Wu, OJ. Schueller, GM. Whitesides, “Fabrication of microfluidic systems in poly(dimethylsiloxane)”, Electrophoresis. 21(1) 27-40 (2000).

[5] J.N. Kuo, Y.K. Lin, Capillary-Driven Dynamics of Water in Hydrophilic Microscope Coverslip Nanochannels, Japanese Journal of Applied Physics, 51 (2012).

[6] E. W. Washburn, "The Dynamics of Capillary Flow," Physical Review, 17 p. 273 (1921).

Figure. 1. Schematic of experimental setup

Figure. 2. Capillary filling of 40% bitumen diluted in heptol (8:20) [6]


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See more of this Session: Poster Session: Fluid Mechanics (Area 1J)
See more of this Group/Topical: Engineering Sciences and Fundamentals