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Revolutionising riser and conductor cleaning in the splash zone

OceanTech’s remotely operated Clamp Access Tool (CAT) with built-in cleaning functions offers an array of benefits, including significant time savings, improved safety, and riser and conductor cleaning according to specific inspection needs.

Offshore oil and gas structures, wind turbine foundations, and fish farming nets, barges, and structures require regular maintenance. This includes cleaning, inspection and potential repair. If left unchecked, splash zone conditions can result in various problems, including:

  • Accelerated corrosion on exposed surfaces
  • Unidentified risks related to material strength and/or fatigue
  • Marine growth, such as algae and mussels, up to three inches thick
  • Bacterial, viral, and parasitic infections in fish farming

The potential for a neglected problem to turn into an expensive issue is considerable. For example, plant failure and unplanned maintenance account for nearly half of overall efficiency losses in offshore oil and gas.

Using conventional methods, such as divers and remotely operated vehicles (ROVs), for manual cleaning of risers and conductors is time-consuming and risky. Waves and structure-induced currents in the splash zone make manual cleaning and maintenance operations difficult. Unfavourable weather conditions during the winter months also mean a fairly limited time window.

OceanTech’s remotely operated Clamp Access Tool (CAT) with built-in cleaning functions enables offshore operators to perform riser and conductor cleaning efficiently and safely in an environmentally friendly manner. The CAT has also a track record for executing work during the autumn and winter months.

Clamp access tool with built-in cleaning functions

At OceanTech, we provide remotely operated robotic solutions for cleaning marine growth and removing corrosion prior to inspections and maintenance work. We use all types of cleaning systems and methods, including ultra-high-pressure water cleaning and innovative nozzle technology for cleaning both pipe structures and other more intricate structures. Our CAT with built-in cleaning functions enables offshore industries to rough clean risers and conductors in minutes rather than hours. Additionally, the tool does not depend on cranes, support vessels, divers, or ROVs.

The OceanTech team in Trondheim, Norway, developed this innovative solution to revolutionise offshore cleaning operations. By combining tailoring, off-the-shelf subsea equipment, and a modular approach, we can easily develop and add extra functions according to client needs. We can also adjust the cleaning tool according to the range the client needs to complete the cleaning job. While the tool weighs between a few hundred and 1,000 kilograms, depending on the version, we can still adapt it to specific riser and conductor widths.

Significant time savings and HSE benefits
Compared to conventional methods using divers and ROVs, our cleaning method offers several distinct advantages:

  • No ROV’s or divers needed
  • Significant time savings
  • Reduced likelihood of accidents and personal injuries
  • No support vessels or crane vessels needed
  • Reduced greenhouse gas emissions
  • Less dependence on weather and favourable splash zone conditions

Using conventional methods, cleaning risers and conductors in the splash zone can take hours to complete. With our solution, you can complete a rough clean of the structure immediately above (+20 feet) and below (-50 feet) the waterline in only minutes. The tool saves you considerable time while cleaning according to the specific requirements of the later inspection and repair work.

A second advantage is the reduced likelihood of accidents and personal injuries. OceanTech’s robotic solutions for splash zone operations do not require any offshore divers. There is no manual handling as required when using divers: all of our splash zone tools allow unmanned working close to structures in the harsh splash zone environment. Our solution is also environmentally friendly, reducing emissions by decreasing the need for support vessels.

Lastly, the CAT enables you to perform cleaning operations throughout the year. While weather conditions generally restrict splash zone operations, our cleaning tool minimises these impacts, and works well during the winter months.

Holistic approach to splash zone operations

The built-in high-pressure (<500 bar) washer is usually sufficient for rough cleaning of risers and conductors, but you can also attach scrapers and brushes to our access tools. For even higher pressures, an additional topside unit is necessary, with a hose that runs down to the working area. Our experienced engineering team can recommend cost-effective pump solutions that serve your cleaning needs.

OceanTech is a one-stop shop, offering solutions for all splash zone operations, including cleaning, inspection, repair work, and modifications to underwater structures. Our services include:

  • Visual inspections and non-destructive testing (NDT) services
  • Pulsed eddy current (PEC) wall thickness measurements
  • Any repair work in the splash zone, including corrosion protection, wrapping repairs, pipe repairs, fairlead repairs, and riser replacements
  • Modifications to underwater structures, including riser guide frame modifications, cutting and removals, and installations of new structures and reinforcements

In addition, we can handle all rigging and lifting activities, including lift plans and calculating suspension points as part of the total scope of work. We have strategic partners, who also help with providing specially trained personnel for our operations.

Our holistic approach to splash zone operations means we can deploy cleaning systems and methods that correspond to the specific requirements of subsequent operations. Cleaning operations in the splash zone are often followed by either inspections or repair work, and too much or too little cleaning can result in unnecessary use of both time and money. At OceanTech, we can see the full picture from the outset, optimise all operations, and ensure smooth communication between all stakeholders involved in related operations.