FIGURE 2.15. Based on the assumption that the zone near the well is permeated with mud filtrate, the Archie equation is used to compute Sxo, the filtrate saturation of this flushed zone. Sxo is used to compute moveable and residual hydrocarbon saturations. PfEFFER 2.0 generates a moveable oil plot consisting of bulk volume water, bulk volume fluid, and porosity. Difference between BVF and BVW represents the moveable hydrocarbons saturation.