A methodology was developed to determine residual saturations in a reservoir from fluid contact measurements and to forecast future contact movement. The methodology is based on the remaining volumes of fluid in the reservoir. At any given time, the remaining volumes of fluid (oil, gas and water) can be determined from known pore volumes, fluid contacts and saturations. The remaining fluid volumes can also be determined from material balances. The volumetric and material balance calculations are equated to solve for either the unknown saturations or the location of the fluid contacts. To apply the method, production, injection, pressure, fluid property, pore Volume versus depth and initial fluid contact data are required. The methodology was demonstrated on the Westerose D-3 Pool. Residual saturations were determined to be: S-wt = 6%, S-gc = 4%, S-orw = 25% S-org = 16% S-gt = 23% and S-orwg = 13.5%. A history match of the historical contact level, for the Westerose Pool was obtained with an average absolute deviation of 2.0 m, which was within the measurement error. Contact movements were also forecast from 2000 to 2003. While there were no reported contact measurements in this period, the observed decline in oil rates was consistent with the predicted oil zone thickness.