.... Examples of such riser systems are special purpose drill and workover risers which are exposed to high bending stress typically in the drill deck area or when passing the ball joint of a marine riser. Such systems are very sensitive to environmental conditions and therefore require continuous fatigue...

... between the sea floor and a floating drilling or production vessel. In essence, a marine riser extends the well at the ocean floor to the floating vessel. A completion or workover riser system is generally used to run the tubing hanger and tubing through the drilling riser and BOP into well bore...