In this study, the asphaltene deposition was modeled during natural depletion process. The Langmuir and Toth adsorption models were used to investigate the monolayer and multilayer asphaltene adsorption phenomena onto core surfaces, respectively. A computer program was written to solve the equations with numerical method and the genetic algorithm technique was used to optimize the model parameters. The results showed that the model based on the Toth adsorption theory was more accurate than other model with respect to the reported experimental data. The objective function values equal to 0.0042 and 0.0708 for modeling based on the Toth and Langmuir adsorption models, respectively. These results confirmed the multilayer asphaltene adsorption onto core surfaces. The sensitivity analysis showed that the surface deposition mechanism had the highest effect and the diffusion mechanism had the lowest effect on the asphaltene deposition process during natural depletion in a core sample.
Keywords: Asphaltene, Adsorption, Deposition, Genetic algorithm, Natural depletion.