Assessing Technical and Economic Recovery of Oil Resources

Table 2 provides the model comparisons, with the ultimate oil recovery fromthese five sample oil fields scaled to field level. While oil recovery calculations forindividual projects vary somewhat, the results are that overall the two models provide anexcellent match of the aggregate oil production from the five fields.Table 2. Comparison of Compositional Model Simulation and CO2-PROPHETModel SimulationCompositionalModel SimulationCO2-PROPHETModel SimulationField/UnitField LevelOil Recovery(MMB)Field LevelOil Recovery(MMB)% DifferenceBetweenModelsSeminole (San Andres Unit) 696 569 (18%)Wasson (Denver Unit) 1,054 1,064 1%Wasson (Bennett Ranch Unit) 172 179 4%Vacuum (Grayburg/San Andres) 529 577 9%Robertson (San Andres) 83 83 -Total 2,534 2,473 (2%)C. Technically Recoverable Resources from the MPZ and ROZ. Eachmodel, the full-scale compositional simulator and CO2-PROPHET, provided estimatesof 2.5 billion barrels of technically recoverable resources from applying CO 2 -EOR to theremaining oil in-place in the combined MPZ and TZ/ROZ in the five study fields, Table3. Of this, 1.4 billion barrels are from the TZ/ROZ and 1.1 billion barrels are from theMPZ in these five fields.CO 2 -EOR of the MPZ is underway in four of the five study fields, accounting for0.65 billion barrels of past oil production and current reserves. After subtracting this oilproduction and reserves, the incremental oil resource from the MPZ would be 0.44billion from the MPZ, Table 4.4-6 February 2006