Asphaltene, which exists in crude oil, is a high molecular weight, polar component. It is widely believed that asphaltene may precipitate and plug pores of reservoir rock and induce wettability alteration for the changes in oil composition, reservoir pressure and temperature. Therefore, alphaltene precipitation in the pores of oil formation definitely leads to formation damage and wettability alteration. The mechanisms caused asphaltene precipitation have been researched in labs and the key factors to effect the precipitation have been well understood, but prediction for its quantitative damages for oil formation, wettability alteration and their effects on percolation performance are still uncertain. In this work, a mathematical model considering asphaltene precipitation and wettability alteration is presented and an oil field scaled numerical simulator is developed to predict for asphaltene precipitation problems in the development of oil field. The simulation results show that the porosity and permeability in the vicinity of production wellbore decrease dramatically for asphaltene precipitation. The water-cut increases for the increase in the effective permeability of oil phase and the decrease in the effective permeability of water for the wettability alteration induced by asphaltene deposition onto the pore surfaces.

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