Macrodispersion in stratified porous media

A methodology has been presented by which field data on spatial variations in the hydraulic conductivity and local dispersivity may be utilized to determine the macrodispersion coefficient tensor of the formation. This technique has been applied to an idealized stratified formation, and the relative importance of several nondimensional parameters that influence the macrodispersivity have been studied. It has been shown that for flows parallel to the stratification the macrodispersivity may be several orders of magnitude greater than the local dispersivity. This effect is significantly reduced as the flow direction is rotated. In utilizing the macroscopic advection-dispersion equation, it has been shown that the macrodispersion coefficient may be dependent on grid scale, source location, and flow direction, although scale and source dependence will generally disappear as the grid scale becomes very large.