Effects of Make-Up Torque on the Sealability of Sphere-Type Premium Connection for Tubing and Casing Strings

The present investigations on sealability evaluation for tubing and casing premium connections depend the FEM with testing. This paper proposed a theoretical model to evaluate of sphere-type connection based make-up torque, which combines Hertz contact pressure von Mises yield criterion calculating elastic–plastic distribution sealing interface adopts gas obtained from Murtagian’s experimental results deducing capacity. With model, effects additional torque key parameters, including width, average capacity, were analyzed compared. show that closely influenced parameters’ variation index energy theory should be recommended other than interface. For improving sealability, controlled accurately ensuring enough width but proper lager sphere radius selected reducing risk sticking.