Research And Design Of Flexible Hang-off Equipment For Drilling Riser

As one of the key equipment for floating drilling platforms,drilling riser connects subsea wellhead with platform and forms a channel from the brine for releasing drilling tools and retuning mud.When platform encounters typhoons and other extreme weather,we need to separate riser form LMRP and set riser into hang-off state then evacuate with the platform.The most commonly used methods are hard and soft hang-off now,the difference lies in the different boundary conditions at the top of the riser.Two methods have advantages and disadvantages,suit for different occasions.Aiming at the riser hang-off needs,the thesis designs a new riser hang-off equipment named flexible hang-off equipment.The new equipment makes hang-off operation easier,at the same time,it improves the riser's performance during hang-off and makes the operation safer.By reading relevant literature of riser hang-off and equipment used,the author understands the development of riser hang-off home and abroad.The author analyzes its working principle and characteristics and builds the flexible riser hang-off system combined with the riser's requirements to hang-off equipment.Considering the limited installation space and reliability of the hang-off equipment,the stroke of motion compensation cylinder is 1 meter,by 2 extended-range drive mechanism the stroke becomes 2 meters.Relying on the 2 meters' stroke,we control the heave motion of the riser to reduce the extreme acceleration of riser thereby improving the riser's performance during hang-off.The author complete detailed design of the flexible hang-off equipment with SolidWorks and assemble it into a complete three-dimensional model;The author finish strength check of key components relating to the integrity of the system's function with ANSYS and optimize the parts according to the analysis results;According to the hang-off load and other requirements,the author design the hydraulic system circuit and calculate parameters related,then complete component selection;The author calculate riser's performance during hang-off for different motion compensation scheme and select the comparatively best one.As a result,the mechanical structure of the flexible hang-off equipment is complete and reliable,the hydraulic circulate is complete and the riser's performance during hang-off is improved.