Thanks to hurricanes Katrina and Rita in 2005, and Ike and Gustav in 2008, Chevron suffered damage to 30 platforms, 18 caissons and 325 wells.

Lew Dennis, US offshore decommissioning manager for Chevron, led the company’s Hurricane Restoration Team and says it can be a challenge just appreciating the scale of the damage.

“The intensity of these storms far exceeded the design criteria that these older platforms were built to,” he said. “We had damage on one of our deep-water structures that indicated that there were waves over 80 feet high, and just twisted a W36-inch beam like it was a pretzel.”

From the huge restoration program spanning 2005 to 2013 (supported from 2007 by Veolia’s marine support vessel, the Swordfish, pictured), Chevron has distilled six high-level lessons, which Mr Dennis shared at DecomWorld’s 5th Annual Gulf of Mexico Decommissioning & Abandonment Summit in Houston in March.

1. The sheer scope of the damage, and its cost

Mr Dennis said the seven-year effort has consumed more than eight million person hours. At one time, the HRT had over 40 dedicated staff.

The cost of removing toppled platforms and wells proved to be six to 10 times higher than undamaged assets, Mr Dennis said, adding that the most costly platform location far exceeded $100 million.

Meanwhile, insurance covered only a fraction of the total loss, he said.

2. The risks of hurricane restoration

“This is probably some of the highest-risk work that we do in this industry,” he said.

It’s hard to get a clear picture of what’s on the ocean floor, and divers have to work amidst sharp, tangled debris with poor visibility.

And among the thousand-fold repetition of tasks, complacency was a constant danger.

“Having really detailed procedures and going by the book on every step of every task... Really,” he said, “believe it or not, unloading the groceries is a big deal, especially when you do it seven years running, day in, day out.”

The challenge, he said, was “to not let the crews get complacent and to always be looking for ways to improve... because your safety record is a combination of being lucky, and being good.”

3. Specialized technology

Mr Dennis said that the unprecedented amount of damage drove the industry and Chevron’s business partners to refine and develop new technology that has now become an enabler for the entire industry.

One example was Versabar’s heavy-lift vessel, the VB 10,000, which, when used with “the Claw” for deck recovery, led to a major reduction in diver exposure to risk.

In one tranche of work involving the recovery of five decks in the East Cameron area, this equipment led to a 90% reduction in diver exposure, he said.

It also allowed a step change in efficiency: “We went from weeks basically to days in picking up these decks. It just took a whole number of steps out of the equation,” said Mr Dennis.

Remote operated vehicles (ROVs) and autonomous underwater vehicles (AUVs) were also helpful in modelling the toppled structures before divers were put at risk.

Lockheed Martin’s AUV, the Marlin, was especially impressive, he said, in building 3-D models. (See story here.)

Hydraulic cutting tools eliminated the need for underwater burning, which Mr Dennis said was the second biggest killer of commercial divers in the world.

Increasing the use of hydraulic tools also increased the risk of hydraulic fluid spills, so Chevron had to institute a program of spill-reduction controls, which worked, Mr Dennis said.

4. The right skills

A project of this urgency and scale requires dedicated teams covering all necessary facets, including drilling, well intervention, heavy lifting, logistics, diving, and health, safety and environment (HSE), Mr Dennis said.

Most importantly, the people have to be good: “You can’t start out with on-the-job training, you’ve got to start with very experienced people,” he said, adding that Chevron asked retirees to come and help. These people were instrumental in setting up many elements of the program.

Mr Dennis emphasized that strong financial discipline was crucial.

“Even for a corporation as large as Chevron, at the end of each quarter and the end of each year I could look at Chevron’s earnings and see the impact the team had had, good or bad, depending on how good we were in our forecasting.”

5. Integrating platform deck and jacket reefing

Mr Dennis said the team encountered so many fish in and around toppled decks and jackets that capturing useable images of the structures was sometimes difficult.

He said further work should be directed at leaving toppled decks in place, which he said could find support among stakeholders in favour of extending the Rigs-to-Reefs program.

6. Embedding the lessons

Because Chevron was a “learning organization”, next time it would start at the level of knowledge afforded by this program, Mr Dennis said.

The use of ROVs and AUVs to minimize diving was one aspect, he said.

“The way this project was approached initially was, oh, we’ve got to have a whole bunch of divers to go out and look at these toppled structures. We wouldn’t be doing that in the future. We’d need divers eventually but we’ll be approaching the project initially with... building some very... detailed 3-D models before we put divers at risk down there.”

As well as capturing images, ROVs and AUVs were doing things: cutting, rigging and removing.

“We’re capturing all of our lessons electronically... and archiving them,” he said.

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