Three-dimensional Prediction of Stress Distribution Above a Salt Diapir - Application to a Deepwater Hydrocarbon Exploration Well

Drilling through critically stressed faults is a major risk when drilling wells for hydrocarbon exploration of production. To minimize drilling risks, fully three-dimensional geomechanical modeling of a prospect offshore NW Africa was performed ahead of drilling. Modeling was performed in ELFEN, a finite element and discrete element software package, and constrained by the present-day three-dimensional geometry of the prospect, predicted pore pressure, modeled porosity-depth relationships, and estimates of grain density for the different lithologies modeled. These were used to derive vertical stress at each location due to overburden and resulting horizontal stress. Modeling indicated that faulting in the area is linked to steady state creep of the underlying salt and therefore not related to regional tectonic stress (faults are not critically stressed). Drilling confirmed the prognosis of limited or no major stress perturbation of the fault at the drilled location.