Asphaltene deposition phenomena are investigated both theoretically and experimentally. A Couette device, where the inner cylinder rotates and particles deposit on the outer wall, is used for laboratory studies of the deposition process. The modeling approach, recently proposed by the authors (Eskin et al.1), is improved. The deposition model is composed of the sub-models describing asphaltene agglomerate growth and their transport to the wall. The agglomerate growth model is simplified without reducing its accuracy and the more accurate model of particle transport to the wall is employed. According to the deposition model, tuned by the experimental data, only sub-micron asphaltene particles can deposit on the pipe wall and only a very small fraction of particles touching the wall sticks to its surface. Those phenomena are explained based on an analogy between the deposition and water in oil emulsion stabilization by asphaltenes, and on an analysis of interaction of asphaltene molecules. The deposition model performance is illustrated by modeling of oil production, accompanied with asphaltene deposition, from a cylindrical reservoir through vertical tubing. The calculations (see figure below), performed for a reservoir depleting over time, demonstrate an excellent visual agreement with the filed data reported in literature2.
1. Eskin D., Ratulowski J., Akbarzadeh K., Pan S. Modeling Asphaltene Deposition in Turbulent Pipeline Flows. Canadian Journal of Chemical Engineering. 2011 (in Press).
2. Haskett CE and Tartera M. A practical solution of the problem to the asphaltene deposits – Hassi Messaoud Field, Algeria. Journal of Petroleum Technology. 1965; April: 387-391.