Mechanical Simulation Analysis On The Lowering Process Of The Subsea Capping Stack

As one of the most effective equipment for offshore oil control and emergency rescue,the subsea capping stack can deal with sudden oil leakage accidents during offshore drilling under emergency conditions.The research on the installation process and mechanical simulation of wire rope and drill pipe during the installation of 3000 m subsea capping stack will effectively promote the process of localization of China’s first subsea capping stack from research and development to engineering application.In this paper,according to the complex environment conditions of the South China Sea,the installation processes of wire rope and drill pipe of 3000 m subsea capping stack were analyzed and compared.Then,Orcaflex software was used to establish the system model and simulate the two installation processes of 3000 m subsea capping stack in the South China Sea.A multi-body coupling system model of “installation vessel-wire rope-subsea capping stack” was established to study the stress of wire rope and the motion response of subsea capping stack.The whole lowering process is divided into three stages: entering water stage,splash zone stage and deep-water stage.By adopting the method of controlling variables,the influence of wind speed,current and wave height on the installation of wire rope of subsea capping stack was analyzed.At the same time,a multi-body coupling model of semi-submersible platform-drill pipe-subsea capping stack was established to simulate the whole process of lowering the drill pipe of3000 m subsea capping stack.Then the variation of stress,bending moment,rotation angle and inclination of drill pipe with time was studied,as well as the influence of different flow velocity,wave height and wave period on the lowering process of drill pipe of subsea capping stack.Through process analysis and installation simulation,it is recommended to install 3000 m subsea capping stack with wire ropes.