According to the National Oceanic and Atmospheric Association, between 2014 and 2017 more than 75% of the world’s tropical coral reefs experienced heat-stress severe enough to trigger bleaching, with 30% of them suffering mortality level conditions. As ocean temperatures increase (0.4–0.5 °C since the late 19th century), bleaching began to occur well beyond the cyclical El Niño events generally known for raising global temperatures. Although reefs can recover after brief bleaching events, scientists fear that sustained heat stress could cause the corals and the ecosystems they support (by providing shelter, spawning grounds, and protection from predators) to deteriorate and eventually die off.
Besides being marine nurseries – according to NOAA 25% of the ocean’s fish depend on healthy coral reefs – these natural structures also provide an array of “ecosystem” services (i) protecting the shoreline against storms and erosion, (ii) providing jobs for local communities (over half a billion people depend on reefs for food, income, and protection), (iii) offering opportunities for recreation, and (iv) being a source of food and new medicines. In other words, in their absence, (i) societies would need to rely on manmade seawalls which are expensive, less effective, and environmentally damaging to construct, (ii) certain fish and crustaceans would be deprived of a place to spawn and develop with likely effects in the food chain which would ultimately affect the food and income security of certain populations, (iii) thousands of reef tourism jobs and revenues (billions of dollars each year) would be at risk, and so much more. But all is not lost! The growing awareness of climate change has placed the environment high on the international political agenda and scientists are more motivated than ever to progress their understanding of marine habitats.
In this context, with natural reefs undergoing a rapid decline due to climate change and marine life finding refuge within the pylons of oil rigs, we thought useful to have a look at platform decommissioning and Rigs-to-Reefs programmes specifically as there are more than 12,000 offshore oil and gas platforms built on continental shelves worldwide with thousands due for decommissioning in the coming decades (over 2,000 projects by 2040). Driven by strict regulations, this growing market segment is likely to attract Earth Observation service providers – as developed below – in particular those already familiar with the oil and gas sector as analysed in the Copernicus Market Report (2016).
Building the case for Rigs-to-Reefs programmes
Artificial reefs have been used for centuries, but coordinated construction and design only started in the 17th century in Japan. The US, Japan and Italy frequently use artificial reefs for fisheries and mariculture with Japan leading the way in artificial reef research on efficiency and design. In Europe, artificial reefs were created as early as the 70’s and 80’s with Italy being at the forefront of European standards thanks to its dedicated scientific programmes and active stakeholder involvement (government level as well as fisheries). Over 56 artificial reefs have been created or are planned in the OSPAR Maritime Area (a mechanism by which 15 Governments & the EU cooperate to protect the marine environment of the North-East Atlantic) the majority of which is located in the Bay of Biscay and along the Iberian Coast. Nevertheless, reefing is not the immediate option for operators in the North Sea because of an overall negative perception which, in The Netherlands, led to the halting of the Noordwijk scientific reef project initiated in 1992 following strong opposition by fishermen.
Although not intended as artificial reefs from the onset, over the course of their service, some oil rigs may attract marine life and grow into ecologically important artificial reefs. Constructed out of corrosion-resistant steel that withstands breakup, rigs have a large, open structure that allows easy circulation for fish whilst also providing hard substrate for barnacles, corals, sponges, clams, etc. As a matter of fact, according to scientists, offshore rigs are some of the most bountiful human-made marine habitats in the world which is why certain countries (most notably the US) have reconsidered their decommissioning procedures, introducing the option of converting oil rigs into artificial reefs under Rigs-to-Reefs programmes. [For further reading on the history, practices, published science, and available information involved when considering the reefing option – with a focus on the US legislation – do have a look at this summary by Bull and Love (2019).]
Through the ecosystems they create, offshore platforms, like natural reefs, provide a number of economic benefits. Consequently, following increased interest and participation in fishing at offshore oil and gas platforms and due to widespread support for effective artificial reef development, the US Congress signed (in 1984) the National Fishing Enhancement Act which recognised the benefits of artificial reefs and encouraged states to draw up plans to turn defunct rigs into reefs. As per the US Bureau of Safety and Environmental Enforcement the benefits of Rigs-to-Reefs programmes are:
- For the environment, repurposing obsolete structures saves fuel emissions and enriches the marine life in the area.
- For oil and gas companies, repurposing obsolete structures saves them the costs of removing, transporting, and disposing of them onshore.
- For states, the artificial reefs attract marine life that enhance fisheries and contribute to the economy by attracting recreational and commercial fishing and diving.
- For divers and recreational and commercial fishers, artificial reefs create a rich diversity of marine life.
- For marine species, the artificial reefs provide habitat, shelter, food, and other necessary elements for biodiversity and a productive ocean (or even refuge in the case of certain overfished and critically endangered species as per the literature quoted below).
The five coastal states on the Gulf of Mexico – Alabama, Florida, Louisiana, Mississippi and Texas – all have Rigs-to-Reefs programmes and, to date, have converted more than 500 oil and gas platforms into artificial reefs. This model has subsequently been adopted by several other countries, namely Malaysia, Thailand, Brunei, whereas in others the debate is still ongoing (the North Sea countries and Australia).
Being heavily regulated – oftentimes excluding commercial fishing, particularly trawling, and in some cases recreational fishing too – various studies have described oil platforms around the world as de facto marine protected areas, making them the perfect refuge for a variety of species (as detailed in the below study excerpt). Schroeder and Love (2002) found that rockfish surrounding an oil platform were larger and greater in density compared with the populations at recreationally and commercially fished sites. In addition, eight offshore oil and gas platforms off southern California supported 430,000 juveniles of the highly overfished and IUCN Critically Endangered Bocaccio rockfish Sebastes paucispinis, accounting for 20% of the average annual number of surviving juveniles of this species. In these instances, the refuges provide much higher recruitment and survival rates than natural but fished nursery grounds (Love et al., 2006). In some regions, the exclusion of all vessels, including recreational and commercial fishers, can be legally mandated, and these “exclusion zones” vary in size between countries. Similarly, in the North Sea, the exclusion from fishing around offshore oil platforms that have been in place for decades, has resulted in a network of de facto MPAs (de Groot, 1982; Fujii and Jamieson, 2016). In Australia, the “petroleum safety zones” surrounding offshore platforms extend up to 500 m from the outer edge of any well or structure (Commonwealth of Australia, 2010), while the exclusion zone around a drilling platform in the Jubilee Field in Ghana is five nautical miles (Chalfin, 2018). In 2003, Mexico created an “area of exclusion” of 5,794 km2 around oil platforms in the Campeche region of the Gulf of Mexico (Quist and Nygren, 2015).
In other words, given the abundance of species they grow to harbour and potential services these new ecosystems could provide, Rigs-to-Reefs programmes are likely to gain traction, in particular through the scientific and advocacy work led by companies such as Blue Latitudes.
Decommissioning options and monitoring
When total removal is the legal requirement, decommissioning involves the plugging of wells, cleaning, capping and possibly removal of pipelines, removal of production equipment and removal of the structure. In the US, as of 1987, federal regulations required the use of National Marine Fisheries Service approved observers to perform biological monitoring at the explosive removal (explosives account for roughly half of all removals) of oil and gas structures in the U.S. Gulf of Mexico. Consequently, the Platform Removal Observer Program (PROP) was initiated to (i) protect sea turtles and marine mammals from the impacts of underwater explosives used in the platform removal process and (ii) assess the impacts of underwater explosives on these protected species. Program data indicate, approximately 2,860 structures monitored from 1987 to 2018 and only 13 sea turtles hurt under these regulations.
When, following extensive ecological evaluations and a series of permitting protocols, state authorities and the oil and gas companies agree that the best option is reefing, these structures are converted into an artificial reef using one of the three general methods 1) tow-and-place, 2) topple-in-place, and 3) partial removal:
- Tow-and-place involves severing the structure from the sea floor either using explosives or mechanical cutting techniques and then towing it to the selected reef for deployment.
- Topple-in-place also detaches the structure from the seabed. The detached structure is then toppled onto its side.
- Partial removal generally does not use explosives. The top portion of the structure is severed at a permitted navigational depth, typically 85 feet deep, and placed on the sea floor next to the base of the remaining structure.
In the US, once a structure is accepted into the programme and the formalities required of the oil and gas company are complied with, all title and liability are transferred to the state who will subsequently undertake all necessary monitoring activities, ensure maintenance and carry out marine conservation and education using the resulting donations (half of decommissioning savings go into the state’s artificial reef programme).
As for Europe, where the debate around Rigs-to-Reefs programmes is still ongoing, the assumption is that structures will be removed – almost all of the 129 installations decommissioned by 2012 were removed. This entails carrying out appropriate environmental assessments of the proposed decommissioning plans by evaluating the results of recent (within 5 years) environmental baselines/monitoring surveys around the installations to be decommissioned (DECC, 2011) – potentially a great opportunity for EO service providers given the extensive data archives available. Furthermore, due consideration is given to all foreseeable long-term impacts and emergency plans are drafted (e.g. oil release). As per the Habitats Directive, across Europe, it is required to consider whether the decommissioning will have a significant effect on species such as the cold-water coral Lophelia pertusa, and the reef-forming worm Sabellaria, which commonly grow on or near North Sea structures. There may be a requirement to conduct surveys to establish whether such species or habitats are present and to what extent (DECC, 2011).
The role of Earth Observation
As discussed, these environments (natural reefs), which act as nurseries for a large number of the species populating the ocean, are at risk due to climate change. Consequently, significant research and monitoring activities are being undertaken to progress our scientific understanding of them. A relevant, large-scale, project showcasing the use of EO in monitoring these structures, eReefs, is building the world’s largest reef forecasting and modelling program by combining satellite technology with powerful models and machine learning to develop the tools needed to save the Great Barrier Reef. The system can also model water quality in 3D across the entire reef using data from NASA and Sentinel-3 satellites. The dedicated website provides access to visualisations and aggregations of the eReefs hydrodynamic and biogeochemical models allowing easy access to the current and historic environmental conditions on the Great Barrier Reef. Similarly, the Sen2Coral project developed algorithms for mapping (habitat, bathymetry, water quality) and detecting change based on Sentinel-2 data to enable coral reef health assessment and monitoring. These tools were then made openly available to interested stakeholders in an effort to inform and mobilise them.
Given the variety of interplaying factors and the expanses to be monitored, the use of Earth Observation has clear benefits. At the broadest scale, remote sensing by satellite imaging can be used to monitor large scale parameters such as air pollution plumes, global sea surface temperatures, waves, marine animals, and phytoplankton blooms, as well as in the identification and tracking of major changes such as accidental releases of hydrocarbons (Brekke and Solberg, 2005). The fact that both the 10th edition of the 2020 Copernicus Masters and the Space Award were won by a start-up, Reef Support, using Sentinel-2’s multi-spectral imagery data to monitor aquaculture, beaches and coral reefs, speaks, in my opinion, to the importance of these environments and the market they could potentially generate.
Similarly, in the case of Rigs-to-Reefs, decommissioned sites and their surroundings are to be regularly monitored as required by law. Given the size of these areas and the costs and risks implied by regular monitoring, I believe there is scope for developing new solutions and technologies – soon to be investigated by 4 Earth Intelligence (4EI), a project intended to assess the feasibility of using space-based data to support the decommissioning of energy assets. The fact that these parks are usually managed by state entities (in particular in the US) facilitates things for potential interested parties as discussions, negotiations, formalities and compliance would be less fragmented than when addressing the open market. Fixed-point ocean observatories, strategically located in these areas, would support the ground-truthing of satellite data and potentially provide the background data necessary to distinguish changes relating to decommissioning from those driven by environmental variability (natural or anthropogenic). Further, machine learning and big data technologies – training machine learning models to process satellite imagery in order to identify specific phenomena and / or sudden changes – would result in the development of tools that would enable more regular and cost-effective monitoring not to mention that, in the event of sudden changes, where and if needed, these could trigger more timely and better informed interventions.
In conclusion, as the blue economy is on the rise – expected to grow from £1.9 trillion in 2018 to £3.2 trillion in 2030, there is plenty of room for ingenious players to disrupt the existing processes by developing smarter and more sustainable solutions. As demonstrated, Earth Observation, especially through the availability of free and open data, could be a trump card for players interested in exploring this sector.
[Should you be wondering what rig-based habitats may look like do check out this video]