روح اله فاتحی

Asphaltene precipitation affects the formation by reducing the porosity and permeability. In this communication, the permeability reduction because of Asphaltene precipitation in granular porous media is modeled using pore-scale simulation. To this end, pore-scale geometry of a granular porous medium is used and governing equations are solved numerically by an improved version of weakly compressible Smoothed Particle Hydrodynamics (SPH). Based on the results of pore-scale simulation, a model is proposed for the permeability change of a single cell (grain) in the porous media. In this model, there are two parameters; final to initial permeability and characteristic time of precipitation that are evaluated through pore-scale simulation. Then, the proposed model is averaged through an up-scaling process to lead to a macro-scale relation which independently of the changes in the porosity predicts the time evolution of the permeability reduction. Experimental procedure have been conducted in a synthetic porous medium made of slim tube, which was filled with glassy beds. Different flood test carried out at different temperatures and injection rates to test the volume ratio of oil to solvent. A predictive model is developed to assess the permeability reduction via asphaltene precipitation. The main assumption for the model is based on the theory of deep bed filtration and the relationship between damaged and initial permeability, which is function of the porosity change with asphaltene deposition. The developed model simulates the permeability reduction in flooding tests using a computer code. The model provides good fit from the experimental data, which is an indication to the reliability of the developed model.