Asphaltene is one of the heavy components of crude oil that can precipitate out of oil with changes in pressure, temperature or oil composition. This precipitate can deposit in reservoir rock, pipeline or other processing facilities and cause lots of problems. Asphaltene deposit can reduce permeability and cause wettability alteration in rock reservoir and ultimately affects oil production and its economical efficiency. All proposed remediation techniques have proven costly and not highly effective, so prevention becomes the most beneficial way to counteract the problem. Revelation of the deposition mechanism and determination of the parameters are necessary in order to devise reliable prevention strategies. In this project modeling of asphaltene deposition in porous media was done and its consequences were investigated. At first, in order to model asphaltene deposition in porous media the weight percent of precipitated asphaltene was calculated as a function of pressure using one of the thermodynamic models in constant temperature and composition. Then system of equations containing continuity equation of oil and asphaltene, Darcy equation and asphaltene deposition model in porous media, was solved using numerical methods. Finally the parameters of model were regulated by using optimization methods and experimental data. The results show that among different deposition mechanisms in porous media, surface deposition is the most important one and unlike the other two mechanisms (entrainment and plugging) needs no precondition to occur.For Iranian oil sample after injection of about 3 pore volume, permeability reduces to 0.7 of its initial value. The dominant mechanism in this case is surface deposition. According to sensitivity analysis by changing surface deposition coefficient from 0.0001 to 0.001 s -1 , the ratio of permeability to its initial value changes from about 0.9 to about 0.4. The asphaltene deposition leads to permeability reduction y changing media wettability to oil-wet. Key words : Asphaltene , modeling ,deposition , precipitation , porous media
