TVO’s Hercules™ high-strength BOP tethering system makes it possible for a deepwater floater fitted with a dynamic positioning system to work safely in shallow water.
In a standard installation, four large, winged suction piles, designed for loading above the mudline, are positioned on the seabed to anchor the tensioners. The piles are installed by a construction vessel ahead of the rig’s arrival. The tensioners are lowered onto the suction piles from an installation vessel or from the rig and secured to the piles by an ROV. The BOP is then installed onto the well, and the ROV pulls the tethering lines from each tensioner to the BOP, where the lines are attached. With the lines in place, the ROV tightens the tether lines to secure the system on the wellhead.
Once the components of the system are connected, the system is passive. If a drift off or drive off occurs, any load increase transfers to the tensioners and suction piles, which hold the BOP in position and ensure well integrity is not compromised.
