Figure 3. Cross section composed of potentiometric surface or head values for upper Morrowan reservoirs. The standard brine gradient (0.465 psi/ft) was used for the head calculations. Head values for overpressured reservoirs exceed the topographic elevation. In contrast, potentiometric head values for underpressued reservoirs are less than topographic elevation values. The disparity between these values is further evidence to support the integrity and longevity of pressure seals in the Anadarko basin.