Anti-recoil control design using a hybrid riser tensioning system in deepwater drilling

摘要

A riser data logging system can be installed on the riser top to provide real time information of the riser, instead of or in addition to relying on sensors installed on a tensioner. The riser recoil detection system can thus be made independent of any motion of the vessel. This logging system can feedback the riser top acceleration, velocity, position, and the wire-line tensions into a controller. By comparing the acceleration difference between the riser top and the vessel body, the controller can provide more reliable and faster detection of events occurring on a vessel, potentially detecting the condition within one second. If the acceleration exceeds a certain limit, the electrical tensioners are able to reduce the wire-line tension nearly instantaneously, providing a much more effective anti-recoil control that conventional hydro-pneumatic tensioners.