TVO’s proprietary BOP tethering technology was essential in completing a recent plugging and
abandonment (P&A) project in the UKCS, which concluded the first segment of a four-year,
multi-well subsea decommissioning campaign.
P&A on this well was challenging due to the well having a weaker 13-5/8” wellhead connection,
which was also inclined significantly above the normal tolerance. TVO’s tethering system was
installed to allow the wellhead fatigue to be managed with the rig BOPs installed and to provide
stability to the inclined wellhead during critical operations. This allowed the well P&A
operations to be successfully completed on this high risk well.
For nearly a decade, TVO has applied its subsea tethering technology to resolve wellhead
loading and fatigue issues for some of the most challenging operating environments. The basic
system configuration employs four polyethylene-based tethers anchored to foundations on the
seabed. The system arrests the motion of the BOP stack above the wellhead and transfers loads
to the tethering system, foundations, and seabed to substantially reduce wellhead cyclic stresses
and enhance fatigue life.
TVO has successfully used its unique BOP tethering technology for multiple applications from
initial development and workovers to decommissioning, supporting projects in the North Sea,
Far East, and South America. Today, the experts on the TVO team are applying their extensive
global experience to one of the largest decommissioning programs in the North Sea.
Although this campaign is extensive, with a significant number of wells remaining, the effective
P&A of this challenging well is a significant milestone and sets the stage for success for the
remainder of the decommissioning program.
