Sea Technology

DEC 2018

The industry's recognized authority for design, engineering and application of equipment and services in the global ocean community

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Page 23 of 52 December 2018 | ST 23 iXblue Phins Subsea & Rovins Inertial Navigation Systems (INS) have been chosen by TechnipFMC and Fugro to provide accurate and reliable navigation information for the highly complex Kaombo ultra-deep-water offshore project. Located 140 km off the coast of Angola, the Kaombo project is one of the biggest ultra-deep offshore development in the world. Reaching depths of 1,950 meters, the six fields of the project cover a surface of 800 km2 and are connected to two FPSO (Floating Production Storage and Offloading) vessels via 300 km of subsea pipelines, making it one of the largest and most complex subsea well system for a single project. This high complexity in terms of size and duration of the project (over 2 years), as well as the extreme temperature and pressure conditions due to the depths involved thus required the use of sea- proven inertial navigation technology that is both reliable and cost-effective. iXblue FOG (Fiber-Optic Gyroscope) inertial navigation expertise was therefore selected by TechnipFMC and Fugro, who chose the Phins Subsea and Rovins INS to provide highly accurate and reliable position, heading and attitude to the WROVs conducting the challenging subsea operations. iXblue Rovins INS, that now provides a position accuracy of 0.1% of the Traveled Distance, was thus mobilized on the construction vessel to conduct various operations such as umbilical lay, flying leads, jumper and spool installations, as well as installation of 500 structures on the seabed. "In support of Fugro FineTrack, our field proven solution using its own Kalman filter, iXblue INS provides a robust positioning reference. This strong combination provides our surveyors and clients with excellent subsea navigation." Explains Hans Vink, Project Manager at Fugro. iXblue Phins Subsea INS, that equipped TechnipFMC Deep Blue pipelay vessel's WROV, also played a crucial de-risking role during CTL (Cut To Length) operations, in case of third-party LBL transponder failure within the second-end FLET (Flowline End Termination) target box LBL array. Indeed, by providing high positioning performance (now 0.05% of the Traveled Distance), iXblue Phins Subsea INS, tightly coupled with a DVL (Doppler Velocity Log), was able to greatly reduce the dependence to full LBL position, allowing for accurate positioning of the WROV even with only one remaining functional transponder within the second-end FLET array (see figure below). An essential advantage for this project, without which LBL transponder failure would have led to lost vessel time and higher operational costs, as a LCV (Light Construction Vessel) would have had to come replace the faulty transponder, while the pipelay vessel would have been in stand-by. "Accurate and efficient subsea positioning requires the use of Inertial Navigation Systems. INS not only enhance acoustic positioning but also allow a drastic reduction of the LBL interrogation rate thus removing the need for transponder replacement. iXblue Phins and Rovins have perfectly supported our WROV's operation all over the 2-years ultra-deep offshore operation." States Elie Jelelaty, Operation Manager at TechnipFMC. ยข iXblue navigation expertise chosen for Kaombo ultra-deep-water offshore project sponsored by iXblue Flowline route Laying corridor USBL CTL area LBL +/- 15 m Phins / DVL Sparse LBL aided positioning Full LBL aided positioning when available +/- 2.5 m FLET target box

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