Corrosion is a huge issue for the oil and gas industry. Carbon steel equipment reacts with carbon dioxide (CO2) and hydrogen sulphide (H2S) that occur in producing conditions. It will also react with oxygen present in water injection systems. The result? Over time, the walls of equipment get thinner, caused by weight-loss corrosion, and may be perforated if there is localised corrosion.

What’s more – the worst corrosion can often be in the less high-profile systems. At Wood Group Intetech we see operators worldwide plagued by corrosion in their water injection equipment. Why? It’s difficult to maintain excellent oxygen removal from water.

Non-flowing “dead-legs” can be another problem area. Low flow conditions encourage the proliferation of microbial species. The species metabolise sulphate ions into various other sulphur species like H2S – just as animals metabolise oxygen to carbon dioxide to get energy – causing localised corrosion of the steel.

But it’s not only fluid –handling equipment that is affected, it’s a global infrastructure issue too.

A recent NACE study estimates the global cost of corrosion at US$2.5 trillion in 2013. The equivalent to approximately 3.4 per cent of global GDP.

Corrosion carries more than just a financial cost; leakage of fluids also results in major health, safety and environmental risks. Corrosion damage must be continuously risk-assessed to ensure inspection efforts are focussed.

It’s important to be proactive in prioritising corroding equipment items. Repairs can then be planned before catastrophic failure. Better still, actions can be taken to reduce the rate of corrosion and extend equipment life. Sorted. Or is it?

There’s plenty the oil and gas industry can do to combat the issue of corrosion. In my next blog, I’ll detail solutions including how to select the right materials for life of field and how to control corrosion if it sets in.