No, not the hairy cryptid with large feet and reclusive temperament, but rather Chevron’s massive extended tension-leg platform (TLP) in the Gulf of Mexico which was expected to go into production later this year and produce up to 75,000 barrels of oil per day. The massive project hit a setback late last month when 6 of the 16 “tendons” designed to anchor the platform to the sea floor sank in approximately 5,200 feet of water. The Bigfoot platform is reportedly being towed to more secure waters while this incident is investigated.
We took a look at satellite AIS and does appear the rig has returned slightly shallower water. Not exactly sure why they took such a long trip down south around May 11, but we do know they have been contending with a strong Gulf Loop Current this year, which also delayed operations. AIS data copyright – exactEarth/ShipView.
The reports also state that the Bigfoot platform was not connected to any wells and no fluids were released, which sounds plausible given our understanding of the process of installing a TLP. But how exactly does an TLP work? Well according to Rigzone.com:
While a buoyant hull supports the platform’s topsides, an intricate mooring system keeps the TLP in place. The buoyancy of the facility’s hull offsets the weight of the platform, requiring clusters of tight tendons, or tension legs, to secure the structure to the foundation on the seabed. The foundation is then kept stationary by piles driven into the seabed. The tension leg mooring system allows for horizontal movement with wave disturbances, but does not permit vertical, or bobbing, movement, which makes TLPs a popular choice for stability, such as in the hurricane-prone Gulf of Mexico.
If that is a little too technical, check out this promo video from a company that does these installations. In particular, fast-forward to 3:48 and you can see how the tendons have “tendon support buoys” to keep them afloat until they are attached to the structure and the platform is cranked down into the water to hold it in place.
The fact that something went wrong with the flotation of multiple tendons before the platform was even put into production is a reminder that things can always go wrong, and when it comes to deepwater oil drilling, the stakes are very, very high. Chevron has admitted that this setback will make it impossible to reach their goal of starting production by the end of 2015.