Abstract

Knowledge of horizontal stress orientation can be utilized for addressing issues related to wellbore stability in any fault regime. Inclined wells drilled in the direction of minimum horizontal stress tend to be more stable in a normally faulted basin compared to those drilled in any other directions. Further, they also have the advantage of cutting through the natural fractures as these fractures tend to align themselves with the direction of maximum horizontal stress. On the contrary, inclined and horizontal wells drilled in the direction of maximum horizontal stress are likely to be more stable in a strike-slip fault regime or thrust fault regime. Well stimulation jobs like hydro- fracturing are preferred in the direction of maximum horizontal stress as all the induced fractures eventually tend to align themselves in this direction and fracturing in other directions will unnecessarily increase the tortuosity. Likewise, in unconsolidated sand reservoirs, initiation of sanding starts in the direction of minimum horizontal stress and hence if the perforations are carried out in the direction of maximum horizontal stress only (oriented perforation), the problem can be postponed for some time. We can therefore say that knowledge of the orientation of horizontal stresses is not only important for well planning, it is equally important for well completion.