MODELLING ASPHALTENE DEPOSITION IN TURBULENT PIPELINE FLOWS

Asphaltene deposition is one of the important problems of oil production that requires an accurate predictive modelling. We developed an asphaltene deposition model in a pipeline. The model is based on data, which are obtained by experiments performed in a Couette device, where the inner cylinder rotates, and deposition on the outer wall is studied. A detailed theoretical analysis of an applicability of a Couette device for imitation of the asphaltene deposition in a pipe flow is presented. The model developed is based on first principles and consists of the two major modules: (1) a sub-model describing the particle size distribution evolution in time in a Couette device, and along a pipe; (2) a sub-model for calculating the particle transport to the wall. A population balance model is employed for modelling the particle size evolution. A concept of the critical particle size is introduced; only particles that are smaller than the critical size can deposit. The model developed contains only three parameters that are determined experimentally using a Couette device. The model of asphaltene deposition in a Couette device allows accurate describing the deposit mass growth in time. Performance of the deposition model for a pipeline with the coefficients obtained by a laboratory Couette device is also illustrated.