Tag Archives: decommission of oil drilling platforms

The Leaky Oil Pipelines on Our Seafloor

Federal officials aren’t adequately monitoring the integrity of 8,600 miles of active oil-and-gas pipelines on the Gulf of Mexico’s seafloor, and for decades have allowed the industry to abandon old pipelines with little oversight, a new report to Congress shows. The Government Accountability Office report faults the Interior Department’s offshore oil-safety regulator’s reliance on surface observations and pressure sensors, rather than  subsea inspection, to monitor for leaks.

The report urges the regulator, the Bureau of Safety and Environmental Enforcement (BSEE), to resume work on a long-stalled update to pipeline rules. BSEE currently requires monthly inspections of pipeline routes in the Gulf by helicopter or marine vessel, to look for oil sheens or gas bubbles on the surface to determine whether a pipeline is leaking. By comparison, the bureau’s Pacific office requires subsea pipeline inspections, in part because of seismic concerns, on its much smaller network of 200 miles of active pipelines.

The GAO also found that BSEE and its predecessors allowed the oil industry to leave thousands of miles of decommissioned pipelines on the seafloor rather than incur the cost of raising them back to the surface. Federal regulations allow BSEE to permit operators to decommission pipelines in place, cleaning and burying them in the seabed. The GAO found that the agency doesn’t ensure standards are followed, even as it allowed 97% of the miles of decommissioned pipelines taken out of active use in the Gulf since the 1960s—nearly 18,000 miles—to remain in place.

BSEE also has failed to fully consider whether decommissioned pipelines represent a hazard to navigation and commercial fishing, like trawlers that can be damaged by snagging equipment on undersea pipelines, the report said. Eighty-nine trawlers reported damage from snagging on oil-and-gas equipment between 2015 and 2019, the report found.

BSEE’s failure to inspect decommissioned pipelines also means officials don’t have a complete record of which equipment has been properly cleaned and buried, or whether hurricanes and underwater landslides have moved buried pipelines, potentially creating navigation hazards and environmental damage. A buried 9-mile pipeline segment was swept 4,000 feet out of place by Hurricane Katrina, the report said.

BSEE also allowed oil producers to leave in place some 250 decommissioned “umbilical lines” that carry electricity and hydraulic power to subsea equipment, the report said, over objections of some Interior officials who were concerned that these lines often contain hazardous chemicals that could leak over time as the equipment degrades.

Excerpt from Ted Mann, U.S. Needs to Better Monitor Oil, Gas Pipelines in Gulf of Mexico, Report Says, WSJ, Apr. 19, 2021

Gambling with the Environment: Shell’s Decommissioning Plans in the North Sea

Giant oil firms have spent more than four decades pumping billions of pounds worth of oil from the seabed. But now decommissioned rigs in the North Sea are at the centre of an environmental storm with an oil giant under intense pressure to rethink plans to leave some of the platforms in the sea.

Several hundred oil drilling platforms in the waters off Scotland are due to be decommissioned over the next three decades as they approach the end of their operational lifetime.  Due to the cost and difficulty of dismantling the structures – each of which can be as tall as the Eiffel Tower – Shell proposed removing only the topside of its four Brent platforms, leaving the huge concrete legs in place.

A natural gas platform in Norway. Almost all of the 600KT structure will be submerged.

That resulted in the controversial suggestion that oil mixed with sediment in 42 out of 64 concrete storage cells – each up to 66 feet in diameter and 200 feet high, around the height of the Scott Monument in Edinburgh – should remain on the seabed. These could remain for up to 500 years after the platforms have been decommissioned.

Chevron oil platform

The plans have raised alarm in some quarters over the impact of leaks from the estimated 11,000 tonnes of raw oil and toxins remaining in the base of the four Brent installations – Alpha, Bravo, Charlie and Delta, all put up in the East Shetland basin in the 1970s.  It has emerged that a report of an expert evaluation group commissioned by the Dutch government has provided a critical analysis of the position and recommends a clean-up be carried out as agreed more than 20 years ago in international treaties.   See Brent Decommissioning Derogation: An evaluation. The special treaty known as Ospar, which was adopted in 1992, states that rigs, including their contents and pipelines, must be removed from the sea after decommissioning.

The experts said that removing all contaminated materials “presents the most certain solution”.  They say staying true to Ospar “not only avoids passing on potential problems to future generations” but also prevents “large amounts of negative public attention as was the case in the decommissioning of Brent Spar in the 1990s”.  When Shell proposed sinking the Spar oil storage buoy in 1995, it prompted protests by Greenpeace, petrol boycotts in Germany and a falling share price. The company was eventually forced to back down and find a more environmentally friendly plan.

In October 2019, Greenpeace activists from the Netherlands, Germany and Denmark boarded two oil platforms in Shell’s Brent field in a protest against the plans. They scaled Brent Bravo and hung banners saying “Shell, clean up your mess!” and “Stop Ocean Pollution”.

The 2019 report revealed that an earlier independent review group(that took place in 2017)said that a “leave in place” solution with appropriate navigational markers and safety zones gave “a risk in relation to shipping impact that Shell regarded as acceptable”.  The report added: “However, although the estimated probabilities of a collision may be low on a per annum basis, the consequences could be catastrophic and result in major injury and loss of life or serious marine pollution.”

Excerpts from North Sea oil decommissioning: pressure grows on Shell to back down, the Herald, Oct. 20, 2019