Chevron Corp. says it is applying lessons learned from last year’s Deepwater Horizon accident to make sure the drilling project regulators approved on Thursday will be the safest well possible.
The permit issued by the Bureau of Ocean Energy Management, Regulation and Enforcement lets Chevron return to a well it started drilling in 6,750 feet of water 216 miles off the Louisiana coast last year. Chevron was about 80 percent of the way to its goal total depth of 29,000 feet when the government banned deep-water drilling in June because of the oil spill.
Unlike four other deep-water projects that regulators have approved since the spill, Chevron’s Moccasin well is the first to tap a new reservoir from which oil or gas has not been produced, meaning there are potentially greater risks.
The approval came a day after investigators reported that the blowout preventer that should have averted last year’s disaster failed to fully sever and seal a drill pipe that had been rocked out of place by a surge of pressure in BP’s Macondo well.
The Hyrdril-made blowout preventer for Chevron’s project has two pairs of shear rams to cut the pipe in an emergency, while the one on the Macondo had one pair, said Gary Luquette, president of Chevron’s North American exploration and production business. Transocean’s drill ship Discoverer Inspiration will drill the well.
Chevron changed its well design from last year and will now use casing designed to handle the pressure of the capping procedure that finally stopped the Macondo spill. Earlier attempts to plug the well were hampered by concerns about the well casing’s integrity.
The extra efforts reflect the intense scrutiny the industry faces as it returns to the deep water. The scrutiny intensified this week when the ocean energy bureau released its investigation of the blowout preventer used at the Macondo well. It concluded the blind shear rams were unable to cut through drill pipe and seal oil and natural gas underground because that pipe had buckled and shifted off center.
Although the blind shear rams are designed to center the pipe and slash through it, the pipe at BP’s well had been pushed askew under the pressure of surging gas and was held out of place by separate components.
The blowout preventer report already has spurred fresh calls for the devices to be built with more powerful pistons and stronger shearing rams.
Although first made about 90 years ago, blowout preventers and their blades are constantly being refined.
“They are so much more powerful and much better designed” even than 15 years ago, said Donald Van Nieuwenhuise, a petroleum engineering professor who directs geoscience programs at the University of Houston.
But the hulking devices are highly standardized to meet American Petroleum Institute specifications and allow easy replacement of components, even across manufacturers.
The problem with an off-center drill pipe failing to cut cleanly is not new, said Saeid Rahimian, president of Robbins Myers’ fluid management group, which makes blowout preventers through its T-3 Energy Services unit.
“Getting pipe out of the way after a cut is a very real challenge,” Rahimian said. “It may seem like an easy thing to overcome, but it’s actually quite a complex system at work here.”
The industry has constantly updated blowout preventer technology as drillers continue to move into more challenging environments.
“But Macondo was a catalyst to take more drastic measures, to put things on a faster track,” Rahimian said, adding that there are different ways to approach the problem.
One is the “belt-and-suspenders” approach of using redundant shear rams in the same blowout preventer, as some contractors already do.
But there are weight, size and cost considerations for getting such redundant systems to work in all environments, Rahiminian said.
That’s why some in industry are also refocusing efforts on creating a better way of getting a clean shear.
National Oilwell Varco unveiled a low-force shearing tool last year designed to cut through 2 inches of solid steel in less than 30 seconds using blades that resembled a trident.
Rahimian said T-3 is working from scratch on new ideas, but creating a system that can handle the largest pipes with the least amount of force necessary is a tough challenge.
“It’s one thing to envision it. It’s quite another to design and test and actually manufacture it,” he said.