Figure 1. Pressures in Morrow-Springer clastics, Oklahoma and much of the Texas Panhandle, on base map of Morrow-Springer thickness. A-A’ is cross-section in Figure Figure 2.

Figure 2. Southwest-northeast cross-section, Anadarko basin, showing interval characterized by overpressures.

Figure 3. Pressure regimes of Anadarko basin, on base map of base Morrow structure.

Figure 4. Structural cross-section of Cement anticline, Caddo and Grady counties, Oklahoma, showing interval of overpressures, which seemingly are elevation-dependent.

Location of anticline shown in Figures 3 and 7.

Figure 5. Fluid compartments in pre-Meramec formations, Anadarko basin and environs. Meramec is Mississippian in age.

Figure 6. Areal extent in western Oklahoma, Texas Panhandle, and western Kansas of potentiometric surface of +1400 feet in pre-Meramec formations, encompassing area where potentiometric surface in pre-Meramec is +10,500 feet.

Figure 7. Detailed distribution map of area with potentiometric surface in pre-Meramec of +10,500 feet.

Figure 8. Detailed distribution map of compartments in the area within 60 miles of Oklahoma City.

Figure 9. Southwest-northeast cross-section to Oklahoma City field, showing compartments in Pennsylvanian to Cambrian strata.

Figure 10. Seminole sag, where nearly one billion barrels of oil have been produced from underpressured reservoirs. Location shown in Figure 5.

Figure 11. Permian salt basin, from West Texas – New Mexico to western Kansas – eastern Colorado.

Figure 12. West-east cross-section (New Mexico – Texas – Oklahoma) of Permian evaporates and associated pressure regimes.

Figure 13. Palo Duro basin and related sedimentary provinces, showing boundary between fluid compartments.

Figure 14. Mississippian-Wolfcamp underpressured area, Permian basin, West Texas. Potentiometric surface is 1700 feet.

Figure 15. West-east cross-section, J M field, Crockett and Val Verde counties, Texas, showing the difference in elevation of the potentiometric surface (+2500 feet) across a major fault and position of potentiometric surface of +1700 feet (above Woodford Shale). Location of field in Figure 14.

Figure 16. Diagrammatic cross-section of Midland basin and Eastern Shelf, through Howard Glasscock field, showing underpressured compartments.

Figure 17. Distribution map of normal pressures and underpressures, southeastern New Mexico, and location of Bough “C” fluid compartment (within the compartment of underpressures  (left). Pressure-depth plot of numerous data taken within the underpressured compartment and the plot for the Bough “C” compartment (right).

Figure 18. Detailed map of pressure regimes, southeastern New Mexico, including the Bough “C” compartment within the underpressured compartment.

Figure 19. Structural contour map, on St. Peter Sandstone, Illinois basin, with boundary separating salinities of less than 25,000 ppm from salinities of greater than 50,000 ppm.

Figure 20. Map of potentiometric surface decline (in feet), St. Peter Sandstone, 1864-1958, in northern Illinois.

Figure 21. Distribution map of the northern Michigan fluid compartment.