Modeling of asphaltene aggregates structure and deposition

A method is presented for deposition behavior prediction of asphaltene aggregates formed under shear in turbulent flow. Shearing experiments were performed in a Couette device with light and heavy crude oils and their blends. Aggregates investigated have a common fractal dimension of 1.75 and are formed by microaggregates (effective monomers) of a radius of 1.2 pm. The deposition velocity rapidly decreases with the viscosity increment. Depicted as a function of the aggregation number it shows a minimum for the aggregation number being in the range 10-100. The ratio of deposition velocities in light to heavy crude oils increases from about 4, as calculated for effective monomers, to about 40 for aggregation number equal 100. Deposition velocity of bigger asphaltene aggregates is substantially underestimated if modeled as compact particles of the same mass. (C) 2015 Elsevier B.V. All rights reserved.