Deepwater drilling and production has been in existence for decades, and with it, station keeping philosophies and technologies have evolved with time and experience. In years past, moorings were designed purely with robustness and simplicity in mind, dropping anchors as rigs arrived on location, with the expectation to weather the storms, but now, with increased strengths seen in tropical rotating storms (TRS), ice floes, and deeper operating water depths, more sophisticated mooring components have been developed. Chain has yielded ground to wire and synthetic ropes. Stockless anchors have been replaced with piles, gravity installed anchors, and sophisticated high holding capacity (HHC) drag anchors. The connecting hardware has become "smart," evolving from kenters and c-links to sensor and sonar-equipped remotely releasable systems.
The main drivers for this evolution have been environmental – extreme metocean events, corrosion, wear and fatigue – from the floater to the seabed and below.
This paper will present how "dumb steel" mooring systems have evolved into sophisticated and detailed engineered foundations that span miles of ocean real-estate, while allowing for a new level of vessel mobility that reduces risks to people and assets.