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Highly Corrosive: Protecting Offshore Equipment


19 January 2011


Oil and gas companies are exploring in increasingly difficult environments as they try to maintain output. But inevitably this means that their equipment is increasingly at risk from corrosion, leading to ever greater demand for anti-corrosion services, reports Anthony Beachey.


The use of modern coatings and well-established cathodic protection techniques ensures that steel piping is resistant to corrosion, allowing many decades of service, and companies are exploiting new technology to prolong the life of pipelines and other offshore equipment even further. Magnetic flux leakage (MFL) and electromagnetic acoustic transducer (EMAT) technologies, for example, are now used on in-line inspection to provide detailed information about the internal and external problems associated with corrosion, cracking and disbondment of the external coating.

Nipping corrosion in the bud

Corrocoat, based in the UK, and a global leader in the development of high technology coatings and composites, provides a good example of the sort of growth being seen in the industry. For according to Clive Harper, Group Financial Director, the business has enjoyed growth of over 25%-30% during the 20 years that he has been with the company.

That rapid expansion is perhaps not surprising given that the cost of corrosion amounts to between 3% and 6% of GDP around the world, according to Corrocoat's UK managing Director Graham Greenwood-Sole.

Moreover, according to Wasco Energy, a Malaysian company, demand is likely to accelerate in the coming years because the majority of the world's offshore infrastructure is beginning to reach the end of its original design life, and "it is more important than ever to address corrosion control and asset integrity for offshore pipelines."

Wasco Energy supplies pipe coating solutions for the oil, gas and water industries in Asia and owns one of the worlds most advanced, fully-integrated, coating facilities. Wasco's Pipe Coating Division offers a comprehensive range of anti-corrosion coatings, flow assurance coatings, concrete weight coatings, and cathodic protection anodes.

"Wasco's Pipe Coating Division offers a comprehensive range of anti-corrosion coatings."

According to Wasco over the past 20 years, its cathodic protection systems have been designed to provide a more efficient and affordable alternative to traditionally installed anode systems. While traditional sacrificial anode systems are still the most efficient solution for certain new projects, aging infrastructure and new types of offshore assets (FPSO's, deep water fields) require the cathodic protection designer to be open to new ideas and methodologies in order to streamline installation and reduce overall project costs.

Investing in coating

Corrocoat started out as a service company repairing equipment affected by corrosion, but the founder and CEO Charles Watkinson became disillusioned with the quality of coatings and decided Corrocoat should develop its own. Watkinson's conviction that technology and innovation can solve any problem spawned a hugely successful Research & Development arm and today the company continues to invest heavily in R&D to keep ahead of the pack.

The company supplies a wide range of industries but oil, gas, marine and power are the company's key sectors. Being able "to carry out work successfully first time and every time is critical to its success in these areas", according to Greenwood-Sole.

Corrocoat now operates in 37 countries globally, supplying coating materials and carrying out the application of these coatings and associated engineering work. Mike Platt, Technical Services Manager, says the company supports licensees across the world by offering training courses in the UK or by providing technical on-site visits.

The company says it provides its operators with a great deal of information about the different types of corrosion, the importance of surface preparation and trains staff in the techniques of applying  coatings because, as Mr Platt points out, "if the coatings are not applied properly, corrosion can endure with potentially catastrophic consequences".

Corrocoat is keen to stress the environmental benefits of its products and services. All of its coatings are polymer based, which results in less use of solvent. But the real benefit, according to Mr. Watkinson is that "our coatings stop plants and equipment from being replaced, resulting in recycling and energy savings".

"Corrocoat is keen to stress the environmental benefits of its products and services."

Mr Greenwood-Sole adds that the company's philosophy is based upon looking for solutions that prevent corrosion, rather than replacing equipment and that this fits with the needs of customers, who are increasingly looking at lifecycle analysis.

Corrocoat has recently developed a technique that results in the uniform application of coatings on pipelines, which should boost demand for its services in the energy sector, while it is very confident of winning some large orders in the renewable power sector, among wave and wind projects."

Cathelco, based in the UK, claim to be world leading manufacturers of seawater pipework antifouling (AF) and hull corrosion protection (ICCP) systems for the offshore oil and gas industry. It claims to be using its experience to design hull corrosion protection systems for a new generation of offshore structures.

The company's current ICCP systems, for example, monitor electrical potential and regulate anode output to neutralise corrosive activity on hull surfaces, ensuring effective corrosion protection throughout the design life of the structure.

Cathelco have just announced that it is supplying a hull corrosion protection system for a floating production, storage and offloading unit which is being converted for Petrobras Netherlands who will operate it in the Roncador field off Brazil. The ICCP system consists of six 150amp anodes and two reference electrodes mounted port and starboard connected to a 900amp thyristor control panel placed at the forward part of the ship and a similar system at the aft of the vessel. Given that FPSOs can spend long periods away from dock, the anodes can be replaced, if necessary, while the vessel is at sea.

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