Labortory studies of triaxial creep behavior on thick-walled hollow cylindrical salt rock specimens

Rock Salt belongs to the group of inorganic chemical sedimentary rocks, which is mainly composed of halite. Salt domes are considered as one of the most important oil traps. Drilling in the salt regions is associated with many problems. Challenging problems in drilling include trapping of the drill pipe string and reducing diameter of the wellbore. Convergence of wellbore’s wall in rock salts is mainly attributable to creep phenomenon. Creep is a time dependent phenomenon that occurs under constant stress. In this research, the effect of confining pressure, deviator stress, and strain rate on creep behavior of rock salt was studied. Furthermore, a mathematical equation was developed to estimate the strain rate in various stress fields. The results revealed that strain rate increases by increasing the deviatoric stress and confining pressure.