A New Approach for Selection of Casing Seating Depths

Wellbore instability, especially in unconsolidated formations is one of the most significant problems during the drilling and imposes huge costs on drilling industry. Introducing the practical solution to decrease or eliminate these types of problems can significantly reduce the drilling time as well as drilling costs. The aim of this study is using geomechanical modeling of the well to determine the optimum casing points. For this purpose, the casing seating depths have been determined by considering the minimum allowable mud pressure obtained through geomechanical modeling as a safety margin of pore pressure. The obtained casing points have been compared with the conventional method which is commonly used in the drilling industry. Results show that, however applying this approach leads to increase number of the casings, it is less likely to occur wellbore stability problems such as breakout or breakdown during the drilling.