Australia’s Total Marine Technology has been contracted to support the decommissioning of a Navigation Communication Control (NCC) Buoy at East Spar in the North West Shelf.
TMT will provide ROV operated cutting equipment, hydraulic power equipment as well as making some custom tooling to complete the work. The NCC Buoy was installed in 1996 and is now no longer required.
Some of the subsea tooling will be provided by TMT along with reelers, HPUs and Hydraulic control panels, and some tooling that TMT has custom built for this project. TMT will be working with sister company SapuraKencana Australia on the project. Operations will be based on the DP2 subsea support vessel SapuraKencana Constructor, which has two TMT operated ROVs on board.
The main body of the NCC Buoy is a steel tube 7.5 metres across and 17 metres long that is tethered to a gravity base in approximately 96 metres of water. The decommissioning process will involve attaching a hydraulic chain jack to the underside of the buoy that will be used to lower the buoy enough to remove tension on the guy wires that attach it to the gravity base. These wires will be cut and then the buoy will be raised to the surface. Then the buoy’s umbilical that was used to communicate with nearby wells can be cut and the ends capped to avoid any loss of fluids from the umbilical into the environment.
Decommissioning of the buoy is expected to have some challenges such as multiple concurrent operations with divers and ROVs working on the project. The project is expected to take about a week offshore and should be completed by the end of the year.