Design And Analysis Of Floating Drilling Oil Platform Riser Tensioners

Oil drilling technology of China is still at a very early stage. In order to protect the oiland gas resources under the south China sea, to make our country a real world power, it isnecessary to narrow the spatial between our technology and other countries’. The guidelineriser tensioner system is installed on the floating drilling rig or semi-submersible platform tomaintain a pre-selected vertical tension in the riser. When the vessel is heaving and rollingdue to waves and wind, the guideline riser tensioner system will work as a pre-tensionerspring and keep tension in the marine riser.Based on the actual status and production level of China’s ocean engineering equipment，this paper has analyzed the structure and principle of the foreign riser tensioner, and designeda riser tensioner equipment. The tensioner has advantages of structure simple structure,complete function and economy applicable, and it also promotes the development of China’socean engineering equipment. The tensioner is based upon the structure of hydro-pneumaticcylinder and pulley block,and pulley puts four times stroke of hydro-pneumatic cylinder. Asthe transmission medium of the tensioner, high pressure gas can reduce frictional resistance inthe accumulator sealing link and can also reduce viscous resistance produced in oil movement.The main principle of tensioner is that thrust produced by hydro-pneumatic cylinder istransferred to marine riser using wire rope and oriented pulley, and provides vertical forcefor the riser tensioner.The guideline riser tensioner system mainly consists of the following parts：air pressurevessels, liquid-gas accumulators, tension hydraulic cylinder, tackle block, low pressure oiltanks, pipeline and control devices, etc. All the modules have been designed in detail.The mechanics analysis of the key components, such as pulley, supporting frame, etc, hasbeen analyzed by ANSYS Workbench software. To guarantee the reliability of the tensionsystem, convergence analysis of the results of the guideline riser tensioner has also beenanalyzed by ANSYS Workbench. At the same time, the paper also has analyzed the extrusionstress and shearing stress of the pulleys and axis on the math.The parameter design of the wireline, hydraulic cylinder, accumulators, air pressurevessels in the tensioner has been designed by using the experiential formula. The paper hasalso analyzed the hydraulic system of the guideline riser tensioner system in theory detailedly, in order to get several parametric curves. It is quite helpful for the improvement of thetensioning device or other follow-up work, by analyzing these curves.