The Role That Offshore Rigs Can Play After Being Decommissioned

Everything comes to an end at one point or another, that’s just the way of life. Offshore oil platforms are no exception to this. Once they stop producing oil or gas on an economically viable level, they’re decommissioned. You’re then left with a big platform in the middle of the ocean. Typically, not much that can be done with it. At least, not until you realise their environmental potential… The team here at TriStone Holdings Ltd wanted to explore the marine potential of these floating megaliths in a little more detail.

What Is An Offshore Rig?

First, though, we better explain what an offshore rig is for those that don’t know. Unlike their onshore oil field counterparts, offshore oil and gas rigs are giant free-standing platforms situated in the middle of the sea, from which untapped crude oil and natural gas reserves can be drawn up from beneath the seafloor. To find out about offshore drilling in more detail, read our previous blog post on the topic, here!

How Can These Platforms Help Ecosystems?

The natural world is a remarkably adaptable thing. Time and time again, it does things that amaze scientists and the layperson in equal measure. Unlike the US, where artificial reefing has been commonplace since 1984’s National Fishing Enhancement Act, most decommissioned European offshore infrastructure has traditionally been brought onshore since the OSPAR Commission’s decision in 1998.

There have, however, been a few exceptions. These exceptions, known as ‘derogations’, were granted only if there were significant obstacles preventing a rig’s removal. These remaining large platforms are few and far between, but they’ve proven to develop into their own ecosystems; active offshore rigs, too, seem to be providing similarly vibrant habitats.

Evidence has previously been delivered, for instance, showing that man-made structures (offshore platforms) have created a new kind of hard substrate ecosystem within the North Sea (where a large proportion of the world’s offshore activities take place). There’s also growing evidence that the impacts of these ecosystems aren’t solely localised to the area immediately surrounding the platforms, either.

The platforms that have been studied are thought to have supplied larval colonies of both coral and mussel species to downstream ecosystems, as well. In other words, these man-made structures are becoming less and less ‘man-made’ the more time passes.

Why Coral?

The naturally hard surface of the support foundations anchoring these platforms to the seabed floor are ideal for corals to grow on. The free-swimming coral larvae attach themselves to the rig, seeing it simply as another hard rock on which to anchor. These coral reefs provide the basis for subsequent species to flourish.

What’s The Alternative To Leaving These Rigs?

When an offshore well is decommissioned, normally, it’s a complicated and expensive task that involves cementing the wells (“plugging” them) and experts across many (often diametrically opposed) industries believe that conversion is a better option than complete rig removal. In fact, some estimates have said that off the coast of California, for instance, adopting a conversion-based strategy could save upwards of $1 billion!

What Species Are Using The Offshore Rigs?

The greater the diversity and complexity of the artificial reefs that are built up, the greater the variety of species one might expect to be find making use of them. Sticking to the Californian theme for a moment and we also find that the marine habitats constructed around the platforms of the Golden State have the highest secondary fish production of any marine habitat ever studied! A huge number of interesting species have been found around these offshore platforms, including:

  • Rockfish
  • Sea lions (lionfish)
  • Garibaldi (a fish known for its incredibly bright orange appearance)
  • Tuna
  • Mussels
  • Oysters
  • Crabs
  • Cabezon (fish)
  • Barracuda
  • Sharks
  • Seals
  • Whales

The Future

With so many offshore platforms worldwide, we can expect to see a greater uptake of these so-called “rig-to-reef” programmes being adopted by countries as time goes on. Providing ecologically stimulating environments for a huge number of species, it seems a no-brainer to us here, at least, when compared with the intensive and expensive process of simply removing the rig.

Contact Us

So, if you’d like to find out more about our (onshore) portfolio and acquisitions, then get in touch! Contact TriStone Holdings Ltd today on 0800 055 7079 or by emailing us at [email protected]


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