backstop control design using a deepwater drilling riser hybrid tensioning system

摘要

A riser data profiling system can be installed on the riser top to provide real-time riser information instead of or in addition to sensors mounted on a tensioner. The riser kickback detection system can thus be made independent of any movement of the ship. This profiling system can provide as feedback the acceleration, velocity, riser top position and wire rope stresses for a controller. By comparing the acceleration difference between the riser top and the ship bottom, the controller can provide more reliable and faster detection of events occurring on a ship, potentially detecting the condition within one second. If acceleration exceeds a certain limit, electric tensioners are able to reduce wire rope tension almost instantaneously, providing much more effective anti-fallback control than conventional hydropneumatic tensioners.