It is well known that the equivalent gridblock permeability obtained by the scaling-up procedure from fine gridblocks depends on the boundary conditions. In the literature, most boundary conditions considered represent a "linear" flow pattern, while in reservoir simulation, "radial" flow plays an important role and is related directly to well production forecasts.

In this paper, we will show the need for a specific treatment of the scaling-up procedure in the vicinity of wells due to the "radial" flow pattern with a high pressure gradient. On reservoir field scale, two types of flow should be considered: (1) the "linear" flow pattern, which usually represents a low pressure gradient region; and (2) the "radial" flow pattern, which usually represents a high pressure gradient region. The determination of the equivalent absolute permeabilities by "radial" flow patterns is discussed in this paper. The scaled-up parameters consist of transmissibility and numerical productivity index (PI).