The underwater wellhead centering technology and its application on the semi-submersible drilling platform

The stability of subsea wellhead is very important for safe and successful drilling operation on semi-submersible drilling platform and would be influenced mainly by the factors,well structure,cement job quality of surface level and oceanic condition,etc.The failue of any factor mentioned above could damage the stability of subsea wellhead and cause the subsea wellhead inclined severely and wellbore abandoned.In order to reduce the economic loss and resume the normal operation after the well hole is inclined,it is neccessory to center the inclined subsea wellhead.This article describes the job procedure,technologic characteristics and notabilias for subsea wellhead centering of YC 13-8-1 well in the west of the South China Sea.Through the practical operation,a set of subsea wellhead entering techology has been obtained and it can be referred on similar trouble removal in the future offshore drilling.