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.

Reef site High Island 389, in Galveston’s Flower Garden Banks National Marine Sanctuary.Photo from Chris Ledford / Texas Parks and Wildlife Dept. Artificial Reef Program.

Requirements on decommissioning in the US Outer Continental Shelf (OCS) have existed before any lease was ever signed for hydrocarbon exploration in its federal waters. Passed on 7 August 1953, the Outer Continental Shelf Lands Act (OCSLA) defines the OCS as “submerged lands [under US jurisdiction] lying seaward of state coastal waters (3mi. offshore).” The Secretary of the Interior was also made responsible for “the administration of mineral [which is defined as oil, gas, sulphur and others] exploration and development of the OCS.”

In 1954, one year after the creation of the OCSLA, Lease OCS 0404, the first lease ever to be issued in the US OCS, was granted for a five-year lease on property off Louisiana in the US Gulf of Mexico. At that time, the US Energy Information Administration places total offshore oil production at 133,000bo/d. Then covered in Lease Section 6, the ljjessees had one year upon expiration or early termination of the lease to remove “all devices, works, and structures.”

“As long as we’ve been leasing and installing facilities on the federal OCS we have had a decommissioning mandate on every single one of them,” T.J. Broussard, chief, Environmental Enforcement Branch of the US Bureau of Safety and Environmental Enforcement (BSEE), says, explaining that even minor structures must abide by the same decommissioning mandates.

“We didn’t want taxpayers to be liable for having to remove components that were put in place by the operators, or by the people under Right-of-Use-and-Easement or Right-of-Way agreements,” he says.

US oil production rates have changed: It is about ten times what it was in 1954, with the US EIA placing offshore oil production at 1.3MMbo/d in 2013. However, in terms of decommissioning regulations, not much else has changed since that time. Now covered under Lease Section 22, lessees still have one year to remove everything – “to pull the topside, remove the jacket assembly and remove any other obstructions on the seabed that could have occurred during your lease operations,” as Broussard explains.

Decom in the GOM

According to BSEE’s most recent data, there are currently about 2600 facilities —from floaters and jacketed platforms down to caisson/well protectors—in the Gulf of Mexico. Based on the number of permits received, Broussard expects removal in 2014 to follow the trend of the last few years, with about 200-250 facilities due to be removed from the Gulf.

“The rate varies because not only do you have operators whose leases are ending under the regulatory timeframe of one year, but you have operators who choose to remove platforms for financial or other reasons,” Broussard explains.

When it is a simple, standard decommissioning for even a four- or six-pile jacketed facility in the shallower waters on the OCS (300ft or less), decommissioning can be made quick work, with Broussard saying that a project without issues could be pulled out in a week or two.

Multiple factors influence how quickly the facility can be decommissioned, from how complex the project is down to the working order of the tools.

“I’ve seen it be as quick as two days,” he says. “Or I have seen a four-pile structure can take a month because cutters weren’t working, or because the operator wanted to use explosives and animals wouldn’t leave area.”

Another factor: water depth, and, most especially, the complexity of the projects necessary to operate in such depths.

Marine life in reef site High Island 317. Photos from James Sinclair / BSEE. 

The Gulf of Mexico, which the US Environmental Protection Agency (EPA) identifies as the world’s ninth-largest body of water with a mean water depth of 1615m, is home to the world’s ultra-deepwater projects. As an example, what will be the world’s deepest production facility is located in the Gulf of Mexico. Shell’s Stones oil and gas development sits 320km off the coast of New Orleans in approximately 2900m of water; its first phase is due to enter production in 2016 through a US$1 billion floating production storage and offloading unit.

The EPA says that waters deeper than 3000m account for 20% of the water in the entire Gulf of Mexico.

Mooring and anchor facilities are used in deepwater projects that need removal. Divers or remote-operated vehicles (ROV) are required to unfasten equipment from the seafloor, which can affect the length of time of the decommissioning.

“Some of the deepwater facilities, like spars and tension leg platforms, are installed on the federal OCS in multiple pieces as they are commissioning. In certain cases it is more difficult to decommission it and take it apart because it was made to be installed in one primary manner,” he says. “[For] a large facility like a spar—once you decommission it, it’s a large piece of steel you have to do something with.”

While a material barge can be used to unload and shuttle facility pieces back to shore in shallow water projects—of which BSEE has seen more than 3000 removed since the start of the OCS program—it’s not that easy in deepwater.

What arrived via barge for commissioning cannot always be reloaded onto one during decommissioning, so it a barge might have to be deballasted and towed back in for scrapping. In addition, particular severance tools and vessels are needed that are not as readily available as the derrick barges or material barges used in shallower waters.

On top of that, Broussard says the ROVs employed might require a separate vessel on deepwater removals.

“[Deepwater decomissionings] require a lot more upfront planning on behalf of the operator,” Broussard says. “For deepwater projects operators will be in our office 1-2 years, if not longer, in advance to go over their primary plan, or look for any problems or things BSEE would like them to focus on.”

Decommissioning is not the only option in the Gulf of Mexico. The secondary option is less of removal option than one of renewal: reefing programs.

Reef site High Island (HI) 376A. HI is one of 18 existing Rigs to Reefs sites along Texas’ coasts.  Photo from Chris Ledford / Texas Parks and Wildlife Dept. Artificial Reef Program..

Rigs to Reefs

The final disposition, that is, how the materials will be removed, must be included on a lessee’s permit application. Beyond decommissioning, operators can also choose to donate their facilities to a reefing program, which began to crop up after the National Fishing Enhancement Act of 1984.

Around that same time, which coincided with the first wave of offshore structures needing decommissioning in the 1970s-1980s, the Mineral Management Service (MMS), as BSEE was known then, conducted studies that found that the jackets on these facilities were “durable, stable, and complex. Biological ecosystems developed on them over time when doing resource extraction,” Doug Peter, Rigs to Reefs coordinator for BSEE, explains.

Among the Act’s findings were that “US fishery production annually falls short of satisfying US demand,” and that “properly designed, constructed, and located artificial reefs in waters covered under this title can enhance the habitat and diversity of fishery resources.”

This act “prompted the states to develop for artificial reefs programs,” Peter says. “The MMS followed suit shortly thereafter and allowed departures from the normal removal of platform after their use of extracting oil and gas.”

After some trial structures were towed to Florida for reefing between 1982 and 1983, Rigs to Reefs was formalized as a program in 1985. The two states with the majority of structures in their waters created programs first: Louisiana’s state program began in 1986, with Texas following in 1990. The other states that channel into the Gulf of Mexico also started programs throughout the 1990s.

While there are copious structures ribboning the Gulf’s waters, not all of them make the cut for a federal or state reefing program. Peter places the number of structures reefed to date in the Gulf of Mexico at 455.

There are a lot of single-pile caissons and structures in shallow water in the Gulf of Mexico that would automatically be disqualified from Rigs to Reefs on size alone. While the Gulf of Mexico is known for its deepwater, the US EPA says that the waters of the continental slope are just 200-300m. Rigs to Reefs also generally requires a three-pile structure at minimum. If a structure is in an area with other conflict uses, it also would not be able to be reefed.

Just like the reefs themselves, the process is a delicate one, where a missing piece could cause the entire process to crumble. “There are a number of things that actually determine if a structure is suitable, and there are also the dealings between the state program and the operator that own the structure. Any one of those puzzle pieces could make or break the reefing of a structure,” Peter says. “There’s a lot of intricacies to this, so not every structure is suitable. It also requires buy-in from the operator that owns the structure because it’s ultimately their decision whether they want to participate in the state program. The state program has to accept liability of the structure that’s actually being reefed.”

BSEE’s Rigs to Reefs program evaluates suitability, and then turns it over to the state program to cooperate on final placement. The size of the reefing area varies, with Peters offering the examples of an average size of a reef site off Texas being around 40 acres, while Louisiana’s average reef sites are around 360 acres.

Site composition also varies. Dale Shively, artificial reef program leader for Texas Parks and Wildlife Dept. says there are many options at the program’s disposal. “Sometimes we can present scenarios where it works out better than [the companies] originally thought,” he explains, urging companies not to be “closed-minded” when looking at disposal options. “We can work with the US Army Corps of Engineers and the US Coast Guard to see if a shallower clearance is available... We can perform a partial removal, in which the platform base stays in place on the ocean bottom with the top next to it; topple it in place; or tow the platform to an existing reef site.”

As far as permitting is concerned for reefing programs, Broussard says that, “only a few components on the permit are different. We want to ensure that the facility or jacket assembly is compatible with the program and won’t introduce any additional impacts or issues when it comes to the OCS. We don’t want it to break loose and damage infrastructure, and we don’t want it to have any contaminants.”

Peter points out that these facilities can sometime offer the marine life more than Mother Nature herself: the reefed structures offer high relief, meaning that they extend further in the water column than the natural structures.

“There’s quite an ecosystem that develops around some of these structures,” Peter says. “They provide stable, durable, complex habitats that allow things to thrive that wouldn’t be there because of the sand and mud bottom in the bottom of the Gulf.”

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