Deliberating on ‘downers’: the hidden legacies of two fierce ladies
  from: Offshore Engineer
  by: Jennifer Pallanich
  Wednesday, April 09, 2008

Hurricanes Katrina and Rita left their marks on more than just the coast. They knocked over many platforms in the Gulf of Mexico. Kicking off this month’s decommissioning special, US editor Jennifer Pallanich talks to companies about the methods they’re using to decommission damaged wells and platforms.

Decommissioning. It doesn’t increase production. It requires resources. It carries some risks. And it costs money.

‘When a platform is still standing proud, it costs substantially less to remove than a platform lying on its side,’ says Alan Vando, Tetra project execution manager, heavy lift. Industry estimates put the price increase at a factor of 10 while the US Minerals Management Service (MMS) estimates a 15% additional premium for removing a felled platform.

Damaged offshore platforms – sometimes referred to as downers – were fairly uncommon in the Gulf of Mexico until hurricanes Katrina and Rita cut a wide swath of damage in 2005.

Toppled platforms were ‘not a normal occurrence before Katrina,’ says Jerel Gilmore, vice president at well abandonment and decommissioning specialists Twachtman Snyder & Byrd (TSB), recently acquired by Proserv.

A lot of operators had downers after, though. According to MMS figures, of the 4000 structures in the GoM, 3050 were in the path of at least one of the storms. Of those, 117 were downed and 52 others sustained extensive damage.

While there was some pollution from the hurricanes, says MMS acting regional director Lars Herbst, there were no significant pollution releases.

The hurricanes threw into sharp relief the spirit of cooperation that tends to follow disasters.

‘It required multiple vendors. It required different technologies. It just depended on the situation you found yourself in,’ says Brent Boudreaux, InterAct PMTI’s director of marine operations and a decommissioning specialist. ‘Nobody had that one solution that fixed everything. There was a lot of collaboration. Everyone needed someone else’s help to get to that next step.’

First, the operators needed to call on decommissioning specialists, of which there are more than a few in the GoM.

Vando says while any decommissioning project includes a host of tricky spots, the angle of a downed platform further complicates the job.

‘The first challenge is figuring out what is what and where it’s at, and then it’s identifying what major structural components need to be cut away in order to access it,’ he says.

Getting data about the downer can take days or weeks, depending on the method used: a diver or shooting sonar to take a cloud of data points and then using the details to generate a model of the damages. While there may be a few holes in the data gathered by divers, Gilmore says, side scan sonar can supplement the information. From that information, decommissioning companies can create a 3D model of the facility.

‘We could view how much damage there was,’ says Esau Velazquez, TSB’s senior project manager. The beauty of the 3D model, he adds, is that it allows one to ‘see the big picture from far away with different angles.’

With the model in hand, it is possible to draw up a plan.

‘How do we begin to plan the remediation, the abandonment? How do we make the area safe from pollution?’ Gilmore asks. He notes the plan inevitably changes as the details that didn’t show up during the survey become apparent.

While the fundamentals of decommissioning don’t change, Velazquez says, certain approaches may change when dealing with something like a downer. The goal, of course, is to prevent or control pollution. If there’s a leak, he adds, it’s vital to identify which well is leaking and secure it.

Gilmore says the basic diagnostics in determining how to handle a well include figuring out whether the well is still under pressure, whether there are hydrocarbons in the tubing, and whether one can pump from the tree to flush out the hydrocarbons. In fortunate cases, the well is already dead, making it safe to cut. At the other end of fortune, it may be necessary to hot tap to relieve pressure before pumping in fluids and cementing.

‘It all depends on how badly this is damaged,’ Velazquez says.

The angles that come into play with a downer may mean another step: it might be necessary to cut a section of the jacket to gain access to the wellhead. ‘Those structures don’t fall cleanly,’ Vando says. They fall as a mass. ‘That presents significant hazards and exposures to divers as well.’

Diving crews often survey a structure and prepare the platform for cutting, which provides access to the lifting location. ‘It’s all really diver-related activity to prepare the structure to be lifted,’ Vando says, adding the company performs an engineering analysis to ensure the structure is sound enough to be lifted.

Since the well must be vertical before it can be plugged, that’s the main trick facing P&A experts.

‘You have to have vertical access to the well,’ says Huey Kliebert, TSB’s vice president, downhole services.

That’s where it gets difficult. Limited access to the wellhead may mean a tubular has to be cut, and from the angle most of these tubulars have been left, they’re dropping. ‘Getting the well vertical is a challenge because you don’t find clean pipe,’ Kliebert says.

He says the company has had to go to 60ft below the mudline to find clean vertical pipe, an effort that required a mass excavation device for dredging. For that, TSB called on Circle Technical Services, now a sister company in the Proserv Group, to supply excavators.

The objective is ‘to minimize the amount of material that we remove so that we don’t have structural integrity issues,’ says Mike Shouse, Tetra senior project engineer, subsea intervention. Doing so, he adds, also reduces the amount of straight pipe necessary from the mudline up.

Only after the gaining access and ensuring the well isn’t polluting, and finding vertical pipe can the basic decommissioning work begin.

‘Now you have a normal well so you can attempt to plug the well in a traditional fashion,’ Kliebert says.

Response

Of industry’s level of post-hurricane activities: ‘All that can be done is being done.With the large number of facilities that were toppled, the number of resources . . . is stretched pretty much to the max right now,’ Herbst says.

The MMS’ own response to the damage from the hurricanes is to re-examine its regulations and see where changes can be made to help prevent damage from future hurricanes. The MMS plans to incorporate API Bulletin 2INT-EX into the removal regulations, Herbst says. No timeline has been set out for this.

One focus, he says, will revolve around removing all facilities in a timely manner, namely within one year of the lease terminating.

Additionally, he says, the MMS issued at the beginning of August a safety alert recommending operators review and evaluate their inventory of non-producing wells and facilities to determine future utility and level of threat posed to the environment and human safety. MMS recommends that operators reference the guidance of API Bulletin 2INT-EX – Interim guidance for assessment of existing offshore structures for hurricane conditions – when conducting these evaluations. Plans should be implemented for removal of these structures beginning with those that pose the greatest threat. The MMS also plans to send out a notice to lessees regarding idle iron, Herbst says.

Adapting, modifying, refining

Despite the mad rush to take care of wells damaged by Katrina and Rita, there seems to be a lag in new abandonment technologies. Only once the well is vertical is it possible to follow up with the additional plugs, barriers and seals that the MMS requires. New technology in those fields is welcome, decommissioning experts say.

‘There have been incremental refinements to existing technologies,’ Vando says. ‘None of the equipment that we’re using is brand new.’

Blowout Tools is working to develop a multistring hot tap process to allow tapping into all strings at once through one rig rather than sequentially, according to TSB. That alone could save one to seven days in the abandonment process, sources say, in addition to its efficient and diver-friendly approach.

For brute cutting, two companies are making names for themselves, according to TSB. Gulfstream Services makes hydraulic equipment and has developed a shear cutter that can cut multistring conductors and 36in tubulars. Prime Marine has developed a concrete construction shear and modified it for the oil industry to allow cutting up to 48in platform legs.

Other companies, such as Wild Well Control, Eaton Oil Tools,Wachs and NCA are modifying precision cutting methods to work hydraulically underwater while being run from the surface.

‘It’s a much safer application. Divers install the cutters, then leave the area while personnel on surface control the cutters hydraulically,’ Kliebert says. Superior Wellhead and Wood Group both have subsea wellheads that are used on remediated downers, according to TSB.

Boudreaux sees the industry drawing on many of the mentioned improvements for more widespread use. ‘Some of this technology can be used in our day-to-day decommissioning activities . . . to make those operations safer, more efficient and cost effective,’ he says.

Some tools are still needed. In intervention, Shouse says, various tools are needed, adding the combination of two or three of those applications into one unit would be helpful. ‘Ideally our objective is to develop an integrated tooling package that would accomplish those things with one tool.’

Tetra is working closely with tooling vendors to develop other applications, says Neil Crawford, Tetra general manager – Applied Technologies Group, adding there’s ‘no magic bullet for this work’.

From panic to planning

Boudreaux rues that the industry didn’t learn all it could from Hurricane Andrew in 1992, which slowed the recovery from Hurricanes Katrina and Rita. ‘It was almost like this hadn’t ever happened before,’ he says. ‘It was a huge learning curve, and it still is a learning curve.

‘After the storms, every functional piece of equipment was highly in demand,’ he adds.

Clay Wilkins, regulatory supervisor for ATP Oil & Gas, notes decommissioning activities draw from the same pool of resources and equipment as installations and workovers, so operators may wait lengthy periods of time to get equipment. For example, he says, ATP waited over a year for access to a 230 class liftboat. Because of the wait, he says, operators attempt to use the equipment or resources on as many projects as possible. He says ATP has performed well P&A, pipeline abandonment or platform removal nearly every day for the last two years.

The initial rush has tapered off, and the difference time makes, Boudreaux says, is that operators and decommissioning companies are better aware of the damage.

‘They’re more focused on planning rather than in the panic mode,’ he says. ‘Production was the priority. Now that production is restored to a reasonable level, you have some time to sit back and plan how to execute these abandonments.’

The planning, of course, depends on the situation found at each platform site and the number of wellheads. Typical planning for abandonment runs three to six months, Boudreaux says. And a well toppled inside a jacket well bay area could take 15-25 days to plug, depending on the condition of the wellheads, whether there’s a bend and the presence of pressure, he adds.

It doesn’t matter whether one uses an anchored or DP spread, he says: ‘Either way you slice it, you’re going to spend 15 to 25 working days plugging a well.’

Decommissioning experts hope operators will P&A wells while they’re still vertical. At minimum, the first bottom plug should be placed in inactive wells before another hurricane approaches, Kliebert urges.

Boudreaux expects oil companies to be more proactive about abandonment because of the pinch to the purse strings from the hurricanes.

There’s a hope that ‘they’ll plug these wells as they die and not wait for the whole platform to die,’ he says. While it may not be cost-effective to plug each well as it dies, it’s less risky to the environment to do so, he adds.

That seems to be the case as far as Tetra is concerned, where Vando says Tetra’s DB-1 and Arapaho heavy lift vessels are both busy with scheduled decommissioning work.

‘You have a lot of junk iron out there waiting for the day the entire field ceases production. I have a feeling the process has been accelerated to mitigate liabilities. Operators have decided they may not be structurally sound enough to survive another hurricane,’ Vando says.

Most, he adds, are proceeding according to the MMS deadline requirements, but others are on an accelerated schedule. ‘The majority of work the heavy lift group here [at Tetra] has been doing is not recovery of toppled platforms. Instead, there has been a vast acceleration in removal of existing structures as oil companies accelerated their programs to minimize risk of damage from future hurricanes.’

TSB’s Kliebert believes some operators are waiting for pricing to come down to do any work that is not immediately required under certain government regulations. ‘But hurricane season comes every year,’ he says.

Boudreaux expects hurricane-related work to continue at least three to four more years, especially when factoring in planned decommissioning activity. That feeds into the question of employment. ‘My biggest worry is hiring: “Can I get the guys to do this work?”’

The day another hurricane rolls through the GoM, operators won’t have the same panic as in 2005, he predicts. ‘They’ll have some confidence that we can go out there and take care of the problems.’

And if the industry has learned nothing else from the fierce ladies Katrina and Rita, Boudreaux urges all involved in decommissioning activity to electronically and accessibly ‘document what you’ve done on a project like this.’ OE

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