Bitumen rheological properties reconciliation of "viscosity" measurements

The rheological properties of Athabasca bitumen were studied using an oscillatory parallel-plate rheometer at different shear rates at 250-330 K. Athabasca bitumen possessed complex phase behavior. It was a solid-like material up to 260-280 K and a non-Newtonian shear-thinning fluid over the balance of the temperature interval studied. The large range of shear rates applied led to 3 orders of magnitude variation in measured viscosity values at fixed temperature. A literature review of viscosities for Athabasca bitumen showed that location, depth of formation, and extraction procedures also affect the measured viscosity of bitumen. Two orders of magnitude variations arise even if the measurement method and temperature remain fixed. This is an abstract of a paper presented at the 8th World Congress of Chemical Engineering (Montréal, Quebec, Canada 8/23-27/2009).