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A game-changer in weld inspection: Our partnership with ConocoPhillips on a new crack detection robot

By using OceanTech’s eddy current welding inspection robot in a life extension project, ConocoPhillips Skandinavia realised a cost saving of $1.9 million compared to conventional solutions.

Decommissioning an offshore platform is complex and expensive. Extending the life of a platform can be cost-effective, profitable, and environmentally responsible for exploration and production (E&P) companies. As advancements in technology make it possible to recover oil and gas from previously inaccessible reservoirs, operators increasingly look for alternatives to maximise the value of their investments.

ConocoPhillips operates the Ekofisk C platform in the North Sea. The platform was originally installed in 1974 with an expected 20-year lifespan. However, due to ongoing maintenance and upgrades, the platform has continued to operate beyond its original design life. Life extensions require approvals from relevant authorities. While requirements vary across jurisdictions and offshore structures, they commonly include safety systems, environmental protection measures, and the platform’s structural integrity.

In the latest platform life extension project at the Ekofisk C platform, ConocoPhillips consulted with OceanTech. The company required inspection data for its structural integrity analyses.

Structural integrity inspections in the splash zone

A structural integrity analysis of an offshore platform involves evaluating the ability of jacket structures and structural components to withstand loads and stresses over time. Typically, an evaluation of the platform’s structural design encompasses:

  • An analysis of the platform’s materials
  • The load-bearing capacity of various components
  • The anticipated environmental conditions at the platform’s location

Inspection data is required for a comprehensive structural integrity analysis, and we can use several inspection techniques to obtain these offshore:

  • Visual inspections check the structure for any sign of damage.
  • Non-destructive testing (NDT), such as ultrasonic thickness measurements, pulsed eddy current (PEC) thickness measurements, and Alternating Current Field Measurement, detect cracks, corrosion, and defects in structures and components.
  • Corrosion monitoring uses sensors and other devices to monitor the corrosion rate over time.
  • Fatigue monitoring identifies areas that may be susceptible to fatigue failure.
  • Strain gauging involves installing strain gauges on structures or equipment to measure stress in critical areas.
  • Cathodic protection measurements and monitoring determine the effectiveness of the cathodic protection systems, such as sacrificial anodes that protect structures from corrosion.

Inspections in the splash zone using divers or remotely operated underwater vehicles (ROVs) can be challenging. The murky and turbulent conditions of the splash zone can restrict visibility and pose safety risks to divers. Inspections in this environment also require specialised equipment and personnel, which can be expensive using ROVs. Additionally, the currents and waves in the splash zone can make it tricky for ROVs to maintain proper positioning during inspections.

For ConocoPhillips’ Ekofisk C life extension project, it was particularly important to inspect potential cracks in the platform’s structural welds safely and efficiently.

Raising the bar for structural weld inspections

OceanTech’s innovative robotic solutions for inspections in the splash zone are ideal for verifying the integrity of any structure in life extension processes. All our tools and techniques avoid the use of divers, remotely operated underwater vehicles (ROVs), and support vessels, offering the following key benefits:

  • The fixed, stable platform enables the deployment of sensors, cameras, probes, and other inspection tools that would be impossible to use with divers and ROVs.
  • Compared to using divers or ROVs, our inspection solutions provide improved safety, significant cost savings, and reduced carbon emissions.
  • Our robotic solutions for splash zone inspections also provide higher-quality inspections due to their consistency, accuracy, and efficiency.

The oil and gas industry is moving towards robotics and automation to improve safety, efficiency, and cost-effectiveness. ConocoPhillips contracted us to develop a remotely controlled eddy current weld inspection robot and inspect the welds in the main nodes of the Ekofisk C platform’s jacket structure. The development process involved iterative design and testing, which we carried out in close cooperation with ConocoPhillips and DNV. Following a technology qualification process led by DNV and fulfilling the requirements of DNVGL-RP-AP203, we successfully deployed the inspection robot at ConocoPhillips’ Ekofisk C platform.

The inspection robot raises the bar for weld inspections in the splash zone. It controls the position of an eddy current probe that scans for cracks in welds on submerged tubular structural members. It can also rotate around the brace and hold position without slipping when subjected to hydrodynamic loads. We use our vertical access tool and a manipulator arm to deploy and position the robot on the structure. This allows for safe and highly accurate inspections in hazardous environments like the splash zone.

How it works: Watch our explainer video here.

Achieved zero HSE incidents and cost savings of $1.9 million

The inspection robot enabled us to complete inspections of 20 welded joints over 28 days at the Ekofisk C platform. There were no HSE incidents or accidents, and the robot worked efficiently and accurately.

In fact, according to estimates from ConocoPhillips, they achieved cost savings of $1.9 million compared to using divers and support vessels. Based on the inspection data and subsequent structural integrity analysis, the Norwegian authorities have extended ConocoPhillips’ production licence.

Currently, we are enhancing the robot through a collaboration between ConocoPhillips, DNV, and the renowned research institute SINTEF. The innovative project aims to enable the eddy current probe to operate autonomously using cameras and laser systems. These advancements will further improve the reliability of the inspection data.