In April 2025, Ocean Installer and Oceaneering successfully completed a significant collaborative project for a major life extension project offshore Angola.
The initiative aimed to replace nine risers and one umbilical that analysis had identified as potential failure points on a floating production, storage, and offloading (FPSO) vessel.
The joint agreement enabled the successful execution of the work scope including removal, installation, connection and pre commissioning activities supported by surface and saturation diving and ROV services for a major operator as part of life extension projects in the region.
The project had to be completed within a tightly constrained client shutdown window.
The deepwater scope, at 1,500-meter water depth, also needed strategically planned diver intervention down to 150 meters to disconnect and reconnect the risers safely and efficiently. Additionally, the interdependencies between the topside scope and construction work on the vessel (including saturation diving and surface diving) had to be methodically planned in order to optimize the execution.
Collaboration between Ocean Installer and Oceaneering teams was essential to ensure the successful coordination of all activities to minimize the offshore campaign duration and reduce the client’s overall cost.
The consortium implemented an integrated delivery model, combining offshore construction and subsea execution activities including diving.
A configuration that enabled efficient vessel management throughout the project reduced the overall vessel requirements and helped shorten the overall offshore execution window.
The consortium’s engineering teams planned and controlled the removal and installation sequence including riser recovery, gooseneck spool change outs, and subsequent riser and gas lift umbilical installations to minimize offshore campaign duration and interface risk. The consortium coupled this with in-country support, including personnel deployment, logistics coordination, and local procurement, to maintain schedule assurance and ensure safe, compliant execution throughout.
The project faced several operational challenges, including a significant schedule impact caused by manta ray sightings, which required divers to maintain a mandatory 30‑minute standby after each sighting.
Deepwater conditions and the complexity of mobilizing a modular saturation system onto a consortium partner vessel added further logistical demands. Additionally, the large volume of personnel movements required precise coordination to maintain safety and minimize delays throughout the campaign.
Despite these challenges, the campaign demonstrated strong operational performance and collaboration, executing a complex scope with a substantial team of offshore personnel, and global teams from Ocean Installer and Oceaneering. High-quality task and diving plans underpinned safe and effective operations execution, while exceptional diver efficiency and a steep learning curve drove continuous improvement, enhancing productivity throughout the project. Notable achievements include:
The project was delivered safely, efficiently, and ahead of schedule, reinforcing Ocean Installer and Oceaneering’s commitment to operational excellence.
The scope included the removal of nine risers from the FPSO, installation of replacement risers and a gas lift umbilical, and the removal and reinstallation of nine gooseneck spools.
Through meticulous planning, robust engineering, and seamless execution, the team restored FPSO production earlier than expected, while maintaining zero Lost Time Incidents. This achievement not only minimized downtime for the client but also extended the FPSO’s operational life well beyond its original design, ensuring continued asset integrity and production reliability.
Collaboration played a critical role in this success. The close cooperation between Ocean Installer and Oceaneering not only reduced the number of vessels required, it also streamlined operations.
The Result?
A safer and more efficient campaign that delivered measurable value to the client and demonstrated the power of integrated solutions in overcoming complex subsea challenges.
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