With decommissioning an inevitability, what to do with platforms once production ceases is a hot topic. Karen Boman surveys new ideas for life after production.
Once upon a time, it seemed that the only thing to do with aging offshore infrastructure was to rip it out. Yet, new ideas, such as leaving structures behind to encourage artificial reef development, or repurposing for education and tourism are under consideration.
 |
| An old platform’s possible new life. Image from Katerina Bounia. |
Katerina Bounia, associate and co-founder of Athens-based Arch-Interact Architects, has proposed such an idea for the entire Prinos fixed platform infrastructure, in the Gulf of Kavala, offshore Greece. The Prinos platform complex started production in 1981 at a rate of 30,000 bo/d; by 2013, production had declined to 1800 bo/d.
Through Bounia’s plan, based on thesis research she conducted at the University of Patras to foster ocean awareness and offer a new paradigm for platform reuse strategies worldwide, the platform complex would not only serve as an artificial reef that would become a home to marine life, but offer educational and research lab facilities, a scuba diving center, and a platform for concerts. The platforms would be renovated and the structural frame preserved though the plan, which would extend the urban network of the city of Kavala offshore.
The proposal would offer a chance for big companies to have a positive impact on the environment, Bounia said during a panel discussion on decommissioning at SPE Offshore Europe 2017 in September.
The scenario for repurposing the Prinos platform structure will remain a scenario, however, as the prospects in the Prinos basin in the Gulf of Kavala still contain over 35 MMbbl of recoverable oil, says Costas Ioannidis, plant manager for Kavala Oil, a subsidiary of Energean Oil & Gas. The main processing platform Delta of the Prinos platform complex (Alpha - Beta - Delta) will remain active as the recipient of the oil and gas produced from the main Prinos field and the surrounding satellite small fields via new small platforms (like the existing Alpha, Beta and Kappa) and new short submarine pipelines.
Recent studies and continuous inspection by DNV GL and maintenance by Kavala’s divers also have extended the life of the Prinos platforms to a new total of at least 50 years, Ioannidis says.
Kavala Oil gave Bounia drawings and data of the Prinos offshore platforms for her study as part of the company’s policy and Ioannidis’ personal philosophy of helping students and universities achieve their goals, Ioannidis says. However, “the time to convert the Prinos offshore structures into a casino or some touristic or fishing resort is still far away in the future,” Ioannidis says.
 |
| Prinos offshore complex. Photo from Energean Oil & Gas. |
Still, new ideas for decommissioning are needed as the global oil and gas industry faces a limited choice of removal processes and equipment for decommissioning. With 307 floaters, more than 9100 platforms, over 5000 subsea wells and thousands of kilometers of pipeline needing removal, the global oil and gas industry is facing a major wave of decommissioning, said Brian Jones, technical director, energy, at London Offshore Consultants UK, during the panel presentation.
The variety of installation types means that no standard fix is available for all offshore infrastructure in need of decommissioning, Jones said. Costs also will vary by region, with the biggest stemming from marine operations. The age and condition of most infrastructure also adds complexity to the removal process. Regulations in different regions also vary; in the North Sea, all platform infrastructure must be removed.
“The reality is that costs will be higher than estimates, which means that more competitive tendering will be required,” Jones added.
Jones sees some positive movement, with newer vessels such as the Pioneering Spirit now available to the market, and cutting methods better than explosives are also now available. One platform removal method, refloat, is not new, but is innovative. However, it does raise the risk of spiraling costs.
Rigs to reefs
The US currently has a program called Rigs to Reefs in place in the Gulf of Mexico to address abandoned fixed platforms. The US Bureau of Safety and Environmental Enforcement (BSEE) created the Rigs to Reefs program in response to public outcry over the loss of marine life that occurred when oil and gas platforms that had existed for years in the Gulf were removed in the mid-1980s.
The high costs of removing shallow water fixed platforms in the Gulf of Mexico has resulted in 1227 idle structures out of 3907 total structures being left idle, Bounia said during her presentation. The Rigs to Reef program has significantly lowered the costs of platform removal by cutting and toppling platform infrastructure onto the ocean floor, where they become reefs for marine life. The program not only has reduced removal costs per platform by US$800,000, or $4 million to date, but created income to help finance marine research. To date, 10% of Gulf of Mexico fixed platforms have been decommissioned through the program.
The growth in fishing activity from oil and gas platforms and support for the effective creation of artificial reefs off coastal states led the US Congress in 1984 to approve the National Fishing Enhancement Act. This legislation created the basis for establishment of a National Artificial Reef Plan and establishment of a reef permitting system.
Since 1985, BSEE has encouraged coastal states with artificial reef plans to repurpose oil and gas platform jackets into artificial reefs. BSEE requires oil and gas companies to decommission and remove oil and gas platforms from the Outer Continental Shelf (OCS) once a lease expires or operations cease. However, a platform can be exempted from these requirements if they qualify for reuse as an artificial reef.
According to BSEE, oil and gas platforms become habitats for marine life shortly after installation. Hundreds of different species of fish flock to these reefs, including red snapper, mackerel and some shark species, which drop in on the reefs at mealtimes. Coral, sponges, bryozoans, and clams are some of the invertebrate life found on the steel piles and jackets, creating the basis for undersea food webs.
All five US Gulf Coast states – Louisiana, Texas, Alabama, Mississippi and Florida – have specific state approved artificial reef programs. Through these programs, oil and gas platforms, concrete structures such as bridges, barges, vessels, and even military tanks, are deployed to serve as artificial reefs.
A fireworm at home on an old rig.
Photo from Chris Ledford, Texas Parks and Wildlife Department.
The majority of oil and gas platforms that have been turned into artificial reefs are located offshore Louisiana and Texas.
Louisiana has recycled 387 oil and gas platforms over the lifetime of its Rigs to Reefs program. These platforms have been deployed at 76 sites across the entire Louisiana coast, in water depths ranging from 102ft to 656ft, says Mike McDonough, Rigs to Reef program manager with the Louisiana Department of Wildlife and Fisheries.
Texas, through its Rigs to Reefs program, has repurposed 151 oil and gas platforms into reefs, which have been placed in at least 80 of 91 reef sites offshore Texas. The reef sites are situated in water depths ranging from 50ft to 925ft, though most are in 200ft to 300ft of water. The sites are scattered offshore the Texas coast, but mostly centered around the Outer Continental Shelf area known as High Island near the Flower Gardens, says Dale Shively, program leader for Texas Parks and Wildlife Department’s (TPWD) artificial reef program.
However, the number of platforms recycled into reefs since the 2014 oil price downturn has declined both in Texas and Louisiana. The projects can be expensive; in some cases, it might make more economic sense to scrap the platform, try and extend production life, or sell to a smaller company that can operate it more efficiently.
Over the next 10 years, Shively expects the number of platforms that could be turned into reefs to shrink as oil and gas companies focus on deepwater, or water depths over 1000ft. A debate is now occurring over whether leaving piles and jackets at this depth would serve any purpose. Marine life does exist at 1000ft that would use the infrastructure, but the amount of growth is lower than in 200ft of water, where sunlight can penetrate and foster growth of natural coral reef systems.
Shively says that TPWD also has seen the number of platforms offshore dwindle to less than 300. Once those are gone, TPWD will need other types of materials and a different source of finding to run Texas’ Rigs to Reefs program.
Further Reading:
Bringing decommissioning to life
Sarah Parker Musarra examines decommissioning in the Gulf of Mexico, and how these facilities can become fixtures in the surrounding marine life.
Subscribe
