Case Study: Offshore Riser Inspections with an Underwater ROV

Remotely operated vehicles (ROVs) are becoming indispensable tools in offshore operations, providing vital capabilities for underwater inspections, surveys, and maintenance. These underwater robots are particularly valuable for common offshore jobs such as riser inspections, where operational conditions often present significant challenges.

In this case study, we examine how Deep Trekker's PIVOT underwater ROV was successfully and effectively utilized by Orion Inspection and Consulting Services for riser inspections in offshore environments, offering insights into the advantages of using advanced underwater robotics for such critical tasks.

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Riser Inspections in Offshore Environments: Challenges and Requirements

Flexible risers are crucial components in offshore platforms, used for transporting oil and gas from subsea wells to the surface, as well as re-injecting water and gas. These structures are subjected to harsh conditions such as extreme weather, corrosion, and the presence of strong currents.

Conducting thorough and accurate inspections of risers and accessories such as bell mouth, bend stiffener, and others, is essential for ensuring their integrity and minimizing operational downtime. However, riser inspections are often complicated by environmental factors, such as wave swells and underwater currents, which can hinder traditional inspection methods, and make diver-based approaches difficult or impossible.

ROVs quickly detect corrosion, misalignment, and damage in subsea cables and pipelines—without costly downtime or diver risk.

Deep Trekker PIVOT ROV: A Solution to Challenging Offshore Conditions

Deep Trekker's PIVOT ROV was chosen for a riser inspection operation on a Floating Production Storage and Offloading (FPSO) unit in October / November 2022. This operation required the vehicle to navigate the challenging "splash zone" - the area where waves and swells create turbulence. Unlike other smaller ROVs that had previously struggled to pass through these waves, or the larger work class models that cannot operate within that zone, the PIVOT was able to break through the surface swell and reach the production risers without difficulty.

This capability is a key advantage of the PIVOT ROV, which is designed for stability and performance in dynamic environments. The PIVOT's robust design, combined with its ability to manage lateral currents, allowed it to complete the riser inspections even in challenging weather and current conditions, demonstrating the vehicle's exceptional reliability for underwater operations. Also, although not used on this deployment, the PIVOT has the flexibility to be equipped with NDT sensors, making it a more complete tool for this activity.

Overcoming Environmental Challenges: Performance in Rough Conditions

The inspection was conducted with currents up to 3 knots, a challenging condition for any underwater ROV. Despite lacking a Doppler Velocity Log (DVL), the ROV maintained stability, which was essential for accurate inspection of 14 production risers at depths of up to 30 meters. The vehicle’s ability to fight lateral currents and maintain a steady position allowed the inspection to proceed without significant delays.

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The PIVOT ROV was also able to operate during stormy conditions, including lightning, further showcasing its resilience in adverse environments. The strong currents alone would have already prevented divers from entering the water, and combined with lightning, highlighted the unique advantage of using ROVs for such tasks.

The underwater ROV completed the inspection in just three hours, with a single battery charge - a testament to its efficiency and operational capacity.

Real-World Application: Advancing Offshore Inspections Through Diverless Operations

As part of Diverless Programs spearheaded by asset owners that aim to improve safety in offshore operations by reducing the requirement to put people in the water where it can be avoided, the PIVOT ROV has proven to be an ideal solution for riser inspections. These programs emphasize safety and productivity, seeking alternatives to traditional diver-based methods. The successful execution of the inspection in challenging conditions marked a significant achievement in this initiative.

Felipe Oliveira, CEO of Orion, who oversaw the operation, noted,

“On this specific operation, we were told that smaller ROVs had tried to perform this inspection but were unable to pass through the wave area. The PIVOT, however, managed to navigate the environment and carry out the inspection successfully, even under currents of 3 knots within its first deployment.”

The client was extremely satisfied with the results, and the operation was repeated successfully in March 2024, with future missions also scheduled.

Benefits of Using Deep Trekker ROVs for Riser Inspections

The PIVOT ROV's ability to navigate harsh offshore environments provides several benefits:

Operational Efficiency: The PIVOT completed the inspection of 14 production risers in just three hours, minimizing operational downtime.
Safety: By replacing divers, the underwater ROV contributes to safer operations, particularly in challenging conditions.
Reliability: The vehicle’s performance in strong currents, waves, and lightning highlights its robustness and reliability for offshore inspections.
Cost-Effectiveness: Reducing the need for divers and scaffolding minimizes the cost of operations, while the ROV’s quick turnaround time ensures a higher rate of productivity.

The Future of ROVs in Offshore Inspections

As offshore operations continue to expand, the demand for advanced underwater robots like Deep Trekker’s PIVOT ROV will only increase. The ability of underwater ROVs to conduct thorough inspections under difficult conditions provides significant advantages over traditional methods, improving both safety and efficiency. The case study of Orion’s work highlights how ROVs can transform offshore inspections, offering an effective and reliable solution for critical riser assessments.

The integration of ROVs in offshore inspections is not just a trend but a shift toward safer, more efficient, and more cost-effective operations. With continued innovation in underwater robotics, the future of offshore inspections looks increasingly promising.

Ask us about using ROVs to inspect the risers, hull, and water tanks on your offshore platform.

Deep Trekker’s Expert Guidance and Custom Solutions

Our team consists of highly skilled professionals with extensive industry experience, dedicated to assisting you in integrating submersible robots into your operations seamlessly. Whether your project involves pipeline and infrastructure inspections, water tank maintenance, salvage operations, underwater surveys, search and recovery missions, aquaculture operations, environmental monitoring, marine research, or other specialized applications, we are equipped to cater to your unique requirements and objectives effectively using our state-of-the-art underwater ROV solutions.

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Secure Your Deep Trekker Underwater ROV Today

When you're ready to secure your very own Deep Trekker vehicle, contact us and we'll be happy to provide you with a customized quote tailored precisely to your requirements. Incorporating Deep Trekker ROVs into your underwater operations ensures unmatched safety, efficiency, and success.