In fields operated by ONGC in India, the horizontal stress orientations were determined using logging tools to help optimize the trajectory of future wells in any fault system (Tiwari, 2013). Figure 21 summarizes the different fault systems in which wells can be drilled. In a normally faulted system, the preferred drilling direction for inclined or horizontal wells is the minimum horizontal stress direction. The resulting wellbore tends to be more stable, thus requires lower mud weight and lower cost. Whereas, in a strike-slip or thrust fault system, the preferred drilling direction for inclined or horizontal wells is the direction of the maximum horizontal stress. | In fields operated by ONGC in India, the horizontal stress orientations were determined using logging tools to help optimize the trajectory of future wells in any fault system (Tiwari, 2013). Figure 21 summarizes the different fault systems in which wells can be drilled. In a normally faulted system, the preferred drilling direction for inclined or horizontal wells is the minimum horizontal stress direction. The resulting wellbore tends to be more stable, thus requires lower mud weight and lower cost. Whereas, in a strike-slip or thrust fault system, the preferred drilling direction for inclined or horizontal wells is the direction of the maximum horizontal stress. |