In late 2021, a major operator identified a failure of the diverter block blind flange on two water injection trees at one of its fields offshore West Africa. To avoid pulling the trees and to support safe, continued production, the operator contracted a team of technology and service providers to develop an intervention and repair solution.
Oceaneering was initially tasked with executing the offshore scope, including vessel and ROV support, as we were the incumbent provider of inspection, maintenance, and repair (IMR) services to the client. The scope grew, however, enabling Oceaneering to demonstrate expertise in delivering bespoke, engineered solutions that meet exacting requirements.
The project’s tooling was developed by another provider, but Oceaneering engineers played a key role in the process. Their expertise was essential in confirming ROV operability and suitability of the newly developed tools for the intended application and was used to execute comprehensive 3D simulations of the subsea operations prior to full tool development.
Oceaneering’s team completed the initial 3D simulations using Vortex Studio software., leveraging models of the tools in a 3D environment in conjunction with models of the subsea trees, and under conditions that mimicked the subsea operations. Oceaneering used this information to confirm the tools’ compatibility with the tree, highlight any potential clashes, and to support the development of the tooling from an operational point of view.
Oceaneering was also able to introduce efficiencies by completing early intervention scopes of work during windows of opportunity on the already-contracted vessel. In June 2022, the offshore team removed counterbalance weights on the trees to gain access to the blind flanges and captured data confirming the true condition of the fully exposed components.
We also used an advanced survey spread installed on Oceaneering’s Millennium ROV to complete photogrammetry modelling of the tree. The images were overlapped over the onshore mockup frame that was built to test the bespoke tooling, confirming the accuracy, and assuring the providers that subsea operations could be executed as intended. Additionally, the photogrammetry models were used in a virtual reality environment, enabling designers and engineers to better understand the challenge.
The team completed a second intervention to further prepare the tree for the main campaign. This involved removal of a post used to support electrical flying leads using Oceaneering standard tooling with minimal bespoke equipment, allowing for a cost effective and efficient solution.
Upon successful manufacturing of the tools, Oceaneering completed factory acceptance testing (FAT) and factory integration testing (FIT) at the manufacturer’s site.
The tools were shipped to Oceaneering’s facility in Stavanger where they spent four weeks undergoing intense site integration testing (SIT), replicating the offshore sequence of operations, and enabling an appropriate methodology to be produced.
Post SIT and using Oceaneering’s expertise in international logistics, the tools, including a full suite of spares for redundancy, were shipped to Oceaneering’s facility in Luanda, Angola. The tools underwent site receival testing (SRT) to confirm functionality after arrival in country. The tools and offshore team mobilized from Luanda transited to the field and successfully performed the repair of the first tree within a ten-day window.
The operation's efficiency was a result of exceptional planning and thorough testing performed before the campaign. Leveraging learnings, the Oceaneering team completed a similar scope of subsea intervention on the second tree in seven days. After successful intervention and confirmation of renewed water injection capabilities in April 2023, the tools were returned to shore, prepared for storage, and are available should any similar future intervention be required.
Working with the client and another technology provider, the Oceaneering team helped quickly restore water injection functionality, allowing the well to be back online on a significantly faster timeline than that of a tree replacement, enabling production to restart, ensuring continued production for the operator.
Oceaneering demonstrated engineering expertise by using available technologies to plan, test, prepare, and capitalize on opportune windows to complete early intervention campaign work that provided a better overall understanding of the components’ condition. This approach not only saved vessel days for the operator, but de-risked operations with forward-thinking planning and advanced technology solutions.
Ready to Learn More?
Explore our Subsea Engineered Solutions capabilities.
Contact Us
Our team of experts is ready to help you get started.
Oceaneering offers best-in-class products and solutions, backed by unparalleled quality, reliability, and global support. Fill out the inquiry form to start a conversation today.