1. A method for creating a facies probability cube comprising the steps of: generating a S-grid which is representative of a subsurface volume containing facies, the grid including layers of cells and columns of cells; determining vertical facies proportion data for the layers of cells; defining boundaries on an areal depocenter map to create depocenter regions in which respective facies are likely to occur within the S-grid; determining horizontal facies proportion data for the columns of cells utilizing the boundaries of the depocenter regions so that the proportion for each facies ranges from a maximum value at a facies depocenter for each respective depocenter region to a minimum value located laterally from the facies depocenter; and integrating the vertical facies proportion data with the horizontal facies proportion data to create a facies probability cube in which the cells are assigned probabilities for the occurrence of facies.