ON THE GULF OF MEXICO -- Five years after the nation's worst offshore oil spill, the industry is working on drilling even farther into the depths beneath the Gulf of Mexico to tap large deposits once thought unreachable. Opening this new frontier, miles below the bottom of the Gulf, requires engineering feats far beyond those used at BP's much shallower Macondo well.
But critics say energy companies haven't developed the corresponding safety measures to prevent another disaster or contain one if it happens -- a sign, environmentalists say, that the lessons of BP's spill were short-lived.
These new depths and larger reservoirs could exacerbate a blowout like what happened at the Deepwater Horizon rig at the Macondo well. Hundreds of thousands of barrels of oil could spill each day, and the response would be slowed as the equipment to deal with it -- skimmers, booms, submarines, containment stacks -- is shipped 100 miles or more from shore.
Since the Macondo disaster, which sent at least 134 million gallons spewing into the Gulf five years ago today, federal agencies have approved about two dozen next-generation, ultra-deep wells.
The number of deep-water drilling rigs has increased, too, from 35 at the time of the Macondo blowout to 48 last month, according to data from IHS Energy, a Houston company that collects industry statistics.
Department of Interior officials overseeing offshore drilling did not provide data on these wells and accompanying exploration and drilling plans, information that The Associated Press requested last month.
But a review of offshore well data by the AP shows the average ocean depth of all wells started since 2010 has increased to 1,757 feet, 40 percent deeper than the average well drilled in the five years before that.
And that's just the depth of the water.
Drillers are exploring a "golden zone" of oil and natural gas that lies roughly 20,000 feet beneath the seafloor, through a 10,000-foot-thick layer of prehistoric salt -- far deeper than BP's Macondo well, which was considered so tricky at the time that a rig worker killed in the blowout once described it to his wife as "the well from hell."
Geophysicists estimate oil companies can unleash Saudi Arabian-like gushers at these unprecedented depths from fields capable of yielding up to 300,000 barrels of oil per day.
Temperatures and pressures -- the conditions that make drilling so risky -- get more intense the deeper you go. And the ancient salt layer brings extra wild cards.
Technology now allows engineers to see the huge reservoirs beneath the previously opaque salt, but the layer is still harder to see through than rock. And it's prone to hiding pockets of oil and gas that raise the potential for a blowout.
"It's not rocket science," said Matthew Franchek, director of the University of Houston's subsea engineering graduate program. "Oh, no, it's much, much more complicated."
By comparison, the Macondo well did not involve drilling through salt, and the "play" -- an industry term for a reservoir -- lay about 13,000 feet under the seafloor. The drillers aboard the Deepwater Horizon rig were teasing oil from prehistoric sludge dating back 23 million years, whereas the hydrocarbons in what's called the Lower Tertiary zone are found in rock formations that go back 66 million years.
One post-Macondo engineering study found that the Macondo well rated a 3-plus on a 5-point scale of complexity. Thirteen wells in the 5 category had been drilled by the start of 2010.
The study also noted that Macondo was only the 43rd complex deep-sea well in the Gulf when it blew out. In that context -- one blowout out of 43 similar wells -- the industry cannot say it has a good safety record when it comes to complex deep wells, said David Pritchard, a Texas petroleum engineer who did the study.
Geoff Morrell, a BP spokesman, said his company has vastly improved its safety culture. "Ultimately, the proof is in the results, and our safety metrics since the spill put us in line with or leading the industry," he said.
After the 2010 explosion aboard the Deepwater Horizon drilling rig -- which engulfed the high-tech platform in flames and killed 11 men -- oil, natural gas and toxic sludge poured into the Gulf for 87 days as regulators, industry and the White House struggled to contain the offshore disaster. President Barack Obama's administration ordered a six-month halt to deep-water drilling but lifted it sooner under pressure from the industry and Gulf Coast officials.
A blowout in deeper water, farther from shore and containing even larger amounts of oil, would pose major challenges.
"We're setting the stage for the next Macondo blowout, and even worse," said Richard Charter, a senior fellow with the Ocean Foundation and a longtime industry watchdog.
The industry and regulators acknowledge the difficulties encountered at these new depths.
"Going to greater depths, greater pressures, does present greater challenges," said Stephen Colville, president and CEO of the International Association of Drilling Contractors. "We have this desperate need for energy, and we have to go after it wherever it is."
BP PLC remains at the vanguard of ultra-deep exploration, and with its "Project 20K," it is developing the tools to handle the extremes of these deep reservoirs. The project's name is a reference to the 20,000 pounds of pressure per square inch the equipment must withstand.
Other companies, among them Chevron Corp., Statoil, Shell Oil Co. and ConocoPhillips, are developing these deep fields with the blessing of federal authorities.
"We believe absolutely that it is safe to drill these reservoirs," said Lars Herbst, the Gulf of Mexico regional director of the Bureau of Safety and Environmental Enforcement, the agency that oversees offshore drilling.
Since the BP spill, regulators and the industry publicly have said increasing safety is now a top priority. And they've taken a number of steps to make offshore drilling safer -- including developing better cleanup equipment, hiring more inspectors, demanding tougher safety audits and setting better standards for drilling.
Last week, the Department of Interior released long-waited proposed changes for blowout preventers calling for changes that in theory would resolve flaws with those now in use. The rules, if adopted, would take effect in another five years at the earliest.
Meanwhile, drilling is resuming to pre-Macondo levels, and the number of reports about drilling trouble is again creeping up. Bureau of Safety and Environmental Enforcement records show drillers have been hit by a steady string of "well losses," reportable incidents when a drilling operation temporarily loses control of a well. Since the Macondo blowout, 22 such incidents have been reported to authorities.
The loss-of-well-control incidents occurred in both shallow and deep waters.
Information for this article was contributed by Jeff Donn of The Associated Press.
A Section on 04/20/2015