Drilling in the Cusiana field, located in the tectonically active foothills of the Casanare region of Colombia, has proved to be extremely difficult. One major contributor to the operational difficulties is poor hole conditions, which often lead to stuck pipe. However, experience has shown that performance improves when drilling updip of the major faults and bedding; downdip and crossdip well trajectories are the most problematic. Stress modeling of the geological cross sections indicates that the principal stresses in the Cusiana field may be rotated significantly from the vertical and horizontal. After adjusting a conventional wellbore-stability analysis to allow for stress rotation, a reasonable match is obtained between prediction and field experience on the issue of stability variation with hole trajectory for wells drilled in the region.