Modeling of asphaltene particle size distribution in well using DEM-CFD

In the present study, the agglomeration and fragmentation of asphaltene particles have been simulated in laminar using the simultaneous coupling of Discrete Element method and Computational Fluid Dynamics. A new coalescence model according to the nature of asphaltene has been proposed. Asphaltene flocs have been considered as irregular shape rigid object. Particle collisions and collision efficiency as well as the fragmentation of asphaltene flocs have been studied in details. Furthermore, the asphaltene particles growth and change in particle size distribution along with average fractal dimension changes have been investigated. During the flocculation of the asphaltene particles, the asphaltene particles grow slowly in the initial times. It can be explained by the agglomeration of primary particles and the formation of asphaltene flocs. In the middle time period, due to the collision of the flocs and the formation of large flocs, the growth of the asphaltene particles increase. At the late times, the fragmentations limit the floc growth, and eventually asphaltene particle size approximately reaches a constant value in the steady state. The lognormal distribution provides the best fit for the asphaltene PSDs which, according to previous studies, is also consistent with the nature of asphaltene. The results of proposed collision and fragmentation kernels based on simulation results are agreed well with previous studies.