Unified Model to Predict Asphaltene Deposition in Production Pipelines

Asphaltenes are heavy-molecular-weight condensed aromatic fractions present in crude oil along with saturates, resins, and aromatics. Asphaltene particles start precipitating when the phase stability is affected by the change in pressure, temperature, or composition. The asphaltene particles may affect fluid properties as well as the production rate due to contraction of the flow lines simultaneously. It is important to develop a robust model to accurately predict the deposition behavior at a wide range of operating conditions. Therefore, by considering possible precipitation, aggregation, and deposition mechanisms, a unified model has been developed in this study. Experimental data in the literature are used to verify the model performance, and results showed a good agreement with the data. Furthermore, this model is used to analyze the effects of flow rate, pipe size, and particle size on the deposition rate and the thickness profile. Moreover, the diameter of the pipe was scaled up to analyze the effect of deposition on fieldlike conditions. Based on the results, the thickness of deposit increased sharply in the first few days, signifying the importance of the early detection of asphaltenes. Despite its simplicity, the model proved its capability to predict asphaltene deposition at different operating conditions.