Integrated pore pressure, potentiometric, and geologic data in the Anadarko basin demonstrate the existence of a basinwide, completely sealed overpressured compartment, called the megacompartment complex. All reservoirs within this complex exhibit pressure gradients that exceed the normal gradient of 10.515 kPa/m (0.465 psi/ft). These reservoirs have produced large quantities of natural gas, particularly from the Pennsylvanian Red Fork and Morrowan sandstones.

This megacompartment complex is enclosed by top, basal, and lateral seals. The top seal zone, which is located between 2290 m and 3050 m (7500 and 10,000 ft) below the surface, is relatively horizontal, dips slightly to the southwest, and appears to cut across stratigraphy. However, the diagenetically enhanced basal seal is stratigraphically controlled and seems to coincide with the Devonian Woodford Shale. The complex is laterally sealed to the south by a vertical cementation zone associated with the frontal fault zone of the Wichita Mountain uplift and by the convergence of the top and basal seals along the eastern, northern, and western boundaries.

The interior of the complex is subdivided into a myriad of smaller compartments with distinct pressure gradients. In addition, local overpressured compartments are present outside the megacompartment complex in normally and near-normally pressured regions.