A New Technique in Reducing the Numerical Dispersion During Miscible Displacement Process

Diffusion and mechanical dispersion are two important mixing mechanisms of fluids flowing through porous media. They are two major factors affecting the size of mixing zone and concentration profiles while injecting a miscible fluid to reservoir. The summation of these two parameters is called physical dispersion or simply called dispersion. Solving diffusivity equation to find pressure and saturation of each phase in grid blocks always has got some source ofnumerical error which is called numerical dispersion as it has the same effect of dispersion in diffusivity equation. Reducing the numerical dispersion which is the truncation error of the finitedifference form of the convection-dispersion equation is the key to study the effect of diffusionand dispersion in miscible processes. A synthetic 2-D Model has been generated to study the weight of numerical dispersion in predicting the concentration profile during a miscible displacement. According to diffusivity equation, the grid shapes have been defined depending on the front velocity of grids’ positiotion to reduce the numerical dispersion of the system.

Keywords:

Dipersion , Numrical Dipersion , Diffusivity , Recovery Factor , Miscible Displacement