Selecting an appropriate Equation of State to model asphaltene precipitation in compositional wellbore/reservoir simulators is still unclear in the literature. Recent studies have shown that PC-SAFT is a more appropriate model for asphaltene precipitation compared to the commonly used solid model. The main objective of this paper is to compare the solid model and PC-SAFT in both static and dynamic asphaltene modeling. Through fluid characterization, the capabilities of both models are compared to reproduce precipitation experimental data.

The results show that both solid model and PC-SAFT are capable of accurate modeling of asphaltene precipitation. Although matching process using PC-SAFT is much easier, solid model is also able to reproduce the experimental data with the same quality as PC-SAFT, if it is tuned properly. The simulations showed that PC-SAFT is superior to solid model in terms of accuracy for extrapolation when the experimental data are not available for the simulation conditions (i.e. variation in temperature, pressure, and fluid composition in the reservoir/wellbore). However, both models are applicable for interpolation when the experimental data covers the range of simulation condition. The wellbore simulations show that although the trend of asphaltene deposition is similar for both models, solid model overestimates the amount of asphaltene precipitation and deposition in the wellbore compared to the PCSAFT model. On the other hand, since PC-SAFT uses an iterative procedure for finding the density roots, phase equilibrium calculation, and consequently, the simulation procedure takes much more computational time when PC-SAFT is used.

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