Modeling of asphaltene deposition during oil/gas flow in wellbore

Abstract

Asphaltene deposition occurs in production lines and leads to a reduction in the production rate due to the contraction of the area. Besides, remedies to treat the deposition costs the industry a high expenditure because of the chemical and the physical removal techniques that may require a partial shutdown of the system. Therefore, it is crucial to accurately predict the rate of deposition to assist in minimizing and controlling this issue. To do so, factors contributing to the precipitation and deposition of asphaltenes must be accounted for, especially pressure and temperature. However, most models available in the literature assume a single-phase flow scenario to predict the thickness of asphaltene, which may lead to some discrepancies. Predicting pressure and temperature gradients in the wellbores during multi-phase flow using single-phase assumptions may cause a significant margin of error. In this study, a robust model is developed to predict the pressure, temperature, and asphaltene deposition simultaneously during multiphase flow in wellbores. The model predicts these variables with an acceptable margin of error when verified against experimental data available in the literature. It predicted the pressure against experimental data with a root-mean-square error of less than 1 psi for various flow patterns and the temperature profile with a root-mean-square error of 0.58 °F. Furthermore, a detailed analysis is conducted to investigate the effect of flow pattern, time, and gas flow rate on the thickness of the deposited layer of asphaltenes.