Yemisi Izuora/Agency Report
Total and its partners on the Kaombo field offshore Angola have decided to use the Sonardyne Fusion 6G technology Long Base Line (LBL) acoustic positioning network, following its successful use on Total’s Egina field offshore Nigeria.
Fusion is Sonardyne’s sixth generation (6G) LBL technology platform, specified globally for its ability to meet the most stringent of subsea survey and construction positioning tolerances. Due to its wideband 2 digital signal architecture, common tasks such as template installation, touch-down monitoring and spool piece metrologies can be completed quickly, efficiently, and precisely regardless of the water depth.
The exceptionally fast deployment of Fusion 6G at Kaombo was attributed in part to the extensive project planning workshops hosted by project partner Technip in France. Attended by teams from Total, Technip and Fugro, together with personnel from Sonardyne’s Survey Support Group (SSG), the sessions were used to review the full scale of the operation and consider the most efficient and cost-effective configuration of the LBL transponder frame network.
The campaign to deploy, calibrate, and make ready for work the field-wide array of transponder frames, was completed in just 31 days using the seabed component of a Fusion 6G system. This was half the time budgeted for, a figure that is thought to have set a new unofficial record for this scale of operation.
Covering an area of around 1,300 sq km, Kaombo lies in water depths up to 1,750 meters. Development of the field will involve the drilling of 59 subsea wells, connected by over 290 km of subsea lines leading to two FPSOs. The majority of subsea construction work is scheduled for 2016-2017, which will be supported by the permanent transponder frame network. First oil for the initial FPSO is expected in 2017.
Deciding the quantity, specification and location for each transponder within a seabed array is crucial to the success of any LBL project. As the contractor for the Kaombo SURF (Subsea, Umbilicals, Risers and Flowlines) package, Technip conducted the LBL array planning themselves, a process that involved confirming that there was clear line of sight between neighboring transponders and modelling acoustic network coverage at specific locations. By using the same specialist software as the SSG, Technip survey team was able to then share their proposed array design with Sonardyne for verification, thereby further increasing confidence in the plan prior to mobilisation.
At Kaombo, the investment in time spent planning acoustic operations onshore was rewarded with a highly successful offshore LBL campaign.
