Constraining the magnitude of vertical stress (S_v), or overburden pressure, is key in determining a region’s stress state and has implications for reservoir geomechanics and the potential for induced seismicity. Of the principal stress orientations (S_v, minimum horizontal stress [S_hmin], and maximum horizontal stress [S_Hmax]), S_v is the most straightforward to constrain using wire-line log data. The magnitude of S_v varies because of lithology and burial history, potentially causing local perturbations in the in situ stress field.

Previous studies on the state of stress in the Permian Basin use a constant S_v, relying on determination of S_Hmax and S_hmin, and yield an interpretation that the faulting regime transitions from normal faulting in the west to normal to strike-slip faulting in the east. Here, we present an interpretation of the spatial and depth variability in S_v trends in the Permian Basin based on density log integration. Where density measurements are absent, values are calculated from compressional velocity logs using a transform that is fit to local data. Notable variations include higher S_v gradient on carbonate platforms and shelves, where high-density carbonates are thicker and are found at shallower depths than in the basins. Within the basins, the magnitude of S_v gradient is as low as 1.06 psi/ft at depth. This work shows the potential for regional interpretations of S_v to gain insight into the effect of variations in S_v on state of stress.