Dispatch from the oil frontier

  • The Noble Clyde Boudreaux, a semi-submersible floating oil-drilling platform, sinks pilot wells in the ultra-deep waters of the Gulf of Mexico for Shell Oil. Image credit: Ed Keating
  • In the driller"â„¢s cabin, Shawn Dyke uses a joystick to direct a drill bit grinding through petroleum-bearing formations more than 4,8 km below the rig. Image credit: Ed Keating
  • Workers watch the drill string "“ interlocking 9 m, 270 kg sections of steel pipe "“ descend through the drill floor.
  • Below the drill floor, in an opening known as the moon pool, the drill string enters the riser, a conduit that extends down to the seabed. The slip ring collaring the conduit is connected to shock absorbers that keep the string taut as the rig rises and falls on the waves. Image credit: Ed Keating
  • Each 22,8 m section of aluminium riser weighs 14 tons "“ 33 per cent less than the steel risers used on other rigs. A layer of high-density foam adds buoyancy, further reducing weight once the riser is in place in the water. Image credit: Ed Keating
Date:30 April 2008 Tags:, , , , , , ,

To reach America’s most promising oil patch since Alaska’s North Slope, contributing editor Carl Hoffman flew 320 km south of Galveston, Texas, by helicopter, deep into the Gulf of Mexico. There, roughnecks on the latest high-tech drilling rig accomplish daily what was considered to be impossible just a decade ago: tap potentially vast petroleum reserves that lie beneath 2 400 m of water.

In the oil patch, the roughnecks say, it doesn’t rain and it doesn’t get dark; it might as well be Vegas. I’m in the deep waters of the Gulf of Mexico’s Alaminos Canyon, on a giant piece of floating steel and aluminium called the . And here, middle of the night though it may be, the Boudreaux is lit up like a truck stop as it threads a straw into one of the last, great untouched accumulations of oil in the United States, so far offshore that it’s hard against Mexican territorial waters.

Outside the window of a glass booth called the driller’s cabin, steel pipe is inexorably turning clockwise, controlled by techs wielding joysticks in ergonomic captain’s chairs. Since the rig started drilling in July 2007, the pipe has been turning 24 hours a day, seven days a week.

With its banks of computer monitors, gauges and controls, the room looks as high-tech as an airplane cockpit. The drill string, though, is anything but dramatic – just a thin cylinder of steel turning and slowly descending through a hole in the floor. “That’s where we eat,” the roughnecks say, meaning: That’s where we make our money.

When I walk outside and descend a series of steps and catwalks over the open space in the middle of the rig known as the moon pool, I realise it’s what you can’t see that’s remarkable. The water crashing against the in 1 m to 2 m waves is 2 400 m deep, a dynamic, constantly moving medium of swirling currents, cold temperatures and crushing pressure. Yet dangling from a hole in the drill floor above is that single slender thread – 2,4 km long – dropping down through the ocean. Untouched by human hands, it found a seabed target the size of a rubbish-bin lid, and it’s now boring through 4,8 km of mud, rock and salt, bending as much as 60 degrees off vertical, guided and steered by the drillers so far above and so far away they might as well be in another world.

A decade ago, drilling in water this deep was impossible. Of the nearly 4 000 active platforms in the Gulf, the vast majority stand in water less than 60 m deep. But that easy oil has long since been tapped. What remains lies on what’s known as the frontier: in water more than 1 500 m deep. Enabled by new technology and the rising price of oil, petroleum companies are using rigs like the to smash depth records in a rush to open the tap of what may be 56 billion barrels of oil.

There have already been successes. In 2004, Shell broke the record for the deepest producing field – the Coulomb, at 2 307 m – when it tapped a formation 230 km southeast of New Orleans. Two years later, in 2 100 m of water 430 km southwest of the city, Chevron successfully tested its Jack No 2 well in a field that may hold 15 billion barrels. That find alone could boost US reserves by 50 per cent. The , which is owned and operated by Noble, a Texas-based exploration and production outfit, is part of Shell’s latest record-breaking project – the Perdido regional development.

By 2010, Perdido will link three fields spread over 20 000 ha of seabed with the deepest production facility in the world. There are no public estimates yet on the size of two of the fields, Silvertip and Tobago, but geologists think oil and natural gas in the third, Great White, amount to the equivalent of 500 million barrels.

As the night passes, the drill bores on, the drillers sucking on plugs of snuff and spitting into cups as they monitor bit depth, bit weight and torque. At this point, the has already installed a 27 m long steel casing into the seabed and capped it with a wellhead and a 14,6 m-high tower of controls and hydraulic valves known as the blowout preventer. Then, 2 400 m of aluminium-alloy pipe in 22,8 m sections, known as the riser, was connected to the seafloor assembly.

The next step was to link 9 m sections of pipe into a drill string and thread it down the riser, through the seafloor assembly and into the casing. Once the bit at the end of the string has hit the bottom and started drilling, synthetic mud is sent down the riser to lubricate and cool the drill bit, keep the walls of the well from collapsing, and flush cuttings to the surface.

The 9 m sections of pipe descend at a rate of 30 cm every 40 seconds, so a new pipe must be added to the drill string every few minutes. Before the top section of pipe passes through the drill floor, a machine called an iron roughneck grabs the pipe and disconnects it from the top drive overhead. Another device, the pipe-racking handler, grabs a new section, slings it in place and tightens it together – and it’s all controlled with a few flicks of the wrist by drillers in the air-conditioned cabin.

This automation is in sharp contrast to the technology of earlier rigs, which required roughnecks on the drill floor and in the derrick to disconnect and connect sections of drill pipe by hand – a laborious, dirty and dangerous process. Ten years ago, it would have taken 75 days to drill a well 5 400 m deep; the crew can do it in two weeks.

In the driller’s cabin, talk fills the hours – of breeding racehorses, of guys getting stuck in airports in western Africa, of wives and kids back home. It’s an odd, bifurcated life: 12-hour shifts for 14 days on, 14 days off; hourly workers hit overtime after the first three-and-a-half days. New hires must spend two weeks on a shoreside rig to see if they can hack the schedule. But the ones who like it make the most of it. There’s a gym onboard and a flat-screen TV in every room, but the crew members mostly do just one thing, and that’s work. Still, it’s easier than it used to be. “We would work seven on and seven off,” says Raymond Allen, a big-boned, redheaded assistant rig manager from Jena, Louisiana who first went offshore in 1985. “When we went to 14, I thought I’d hate it, but turns out there’s half the travel time out to the rig and back.”

Still, the schedule can be tough on families. “Can’t just come home and take over,” says Alan Ricketson, 58, an assistant rig manager with silver hair and a white moustache. “You kind of have to ease your way into the household.”

Until the 1990s, most offshore drillers worked on rigs that were jacked up on long legs just off the beach, and they were easy to get to. But drilling in ultra-deep water kicks in a series of cascading complexities. “Every physical component of the rig has to change in deep water, and it’s all about logistics and size,” says Therald Martin, Noble’s drilling superintendent in the gulf.

In deep water, a rig can’t stand on the bottom, which means it either has to be anchored with dozens of kilometres of chain and cable, or float freely, held in place by GPS-guided thrusters. Deeper water means more drill string and riser stored on the rig, which means everything on it has to be bigger, with more storage room. Bigger means more people, which means more food, beds and helicopter shuttles. Bigger and deeper means more electrical power, which means more generators, which mean more fuel-storage capacity. And deeper means farther out to sea; the is 330 km south of Galveston, requiring every litre of fuel or heavy piece of machinery to be brought out on a 23-hour journey by ship. “If something goes wrong and the rig needs a part,” Martin says, “we’ll easily spend R1,4 million getting it out there.”

A few months ago, a middle-aged engineer suffered a heart attack; the has a three-bed infirmary but the worker needed immediate cardiac care. A helicopter flew two hours to pick him up and was halfway home when a second man’s ticker went on the blink. By the time both crewmen were safely in the hospital onshore, hours had passed and Noble was looking at a R210 000 helicopter bill.

Then there’s the ocean itself. At a depth of 2 400 m, the pressures are enormous – about 241 bar. No human hands can operate equipment on the seabed. That means remotely operated vehicles (ROVs) have to be able to work in those pressures, day in and day out. And the range of temperatures plays havoc with drilling mud. “It’s 6,6 degrees at the seabed and 135 at the drill bit,” says Ricketson, keeping an eye on the turning drill, “so that mud has to function at extremely high and low temperatures – only new synthetic mud can do that.”

The numbers are big. The hull is 82,6 m wide by 69,5 m long, and it soars six storeys above the waterline. It’s moored to the seafloor with almost 50 km of steel chain and cable attached to 16 anchors weighing 16 tons each. Noble is the first company to use aluminium risers, rather than steel, which cuts weight by a third. An inshore rig might be powered by one or two 1 100-kW generators; on the Boudreaux, six 2 600 kW monsters burn through 1 135 litres of diesel an hour supplying power to the rig, which carries 560 000 litres of fuel.

Two derricks and two drilling cabins allow the rig to drill and lay casing simultaneously. A motion sensor and 12 giant pneumatic shocks, each with 290 000 N of tension, maintain consistent pressure on the drill bit as the rig pitches and rolls. Every kilogram of equipment, from food to fuel, must be weighed and the rig’s ballast adjusted to keep it level, with a draft of 20 metres.

All this tech doesn’t come cheap. A typical offshore development in 30 m of water costs R700 million; just the test well for Chevron’s Jack No 2 cost R700 million, and the US Minerals Management Service estimates the cost of developing a deepwater field can exceed R7 billion. Shell won’t say what the Perdido regional development will cost, but Noble is charging Shell hundreds of thousands of dollars a day for its rig. Shell has already spent R3,8 billion on leases in the gulf – that’s just for the right to drill.

It’s 8 am; outside, there’s nothing but azure sea and sky and thick gulf humidity. In the dimly lit control van on the deck of the , Clay Groves is sitting in front of a bank of monitors, a joystick in each hand, manoeuvring the rig’s 186 kW ROV toward the sea floor. Ray Allen watches him work the controls. About the size of a standard minivan, the ROV is outfitted with mechanical arms that are virtually an extension of Groves’s.

As the ROV drops, the cameras show nothing but a gently falling snow of plankton, and then there it is – a grey moonscape, featureless except for the rectangular blowout preventer. Allen wants photos of the riser connection. “Can you get closer?” Groves manoeuvres the ROV in tight on the tree of gauges and hoses bathed in bright light. “Looks good,” he says. “No leaks, entanglements or debris.”

Groves flies over and around the stack, checks small glass-covered dishes that contain a ball on a bull’s-eye – verifying that the device is level. A translucent blob of a sea cucumber sails into view. “Look”, he shouts, “it’s a headless chicken!”

When the first hole was ready to be drilled, the ROV placed buoys in a 1,5 m square and guided the drill bit into the target with its mechanical arms. Although fibre-optic cables connect the blowout preventer to the rig, if they get cut or the device fails to work, the ROV can close the valves itself. Groves wiggles his hands, and I watch robotic pincers 2,4 km away reach for a valve handle.

“There’s almost nothing down there we can’t do,” he says, “and we see all sorts of cool stuff.” Later, as he raises the ROV to the surface, he plays back video he’s shot of huge rays ghosting through the deep and a squid dangling long pink tentacles.

Even though we’re on a floating steel island, it’s easy not even to notice the sunsets and dawns, the rain clouds scudding across the horizon, and the schools of fish swarming around the rig. It’s all big machines and noise, a warren of bright-white, air-conditioned, linoleum-floored hallways and windowless rooms, of hard hats and jumpsuits. Day or night seems the same; you lose track of time – at 3 pm or 3 am there’s always someone pumping iron in the gym, a few guys sipping coffee in the mess hall. You forget where you are, until you step out on to the smoking deck – a flat, steel place with a few aluminium benches – remove your hard hat and safety glasses, and realise you’re standing on a huge spigot in the middle of nowhere.

With luck, drillers like Ricketson and Allen will be out here for years to come. When the finishes the holes it’s drilling now, it will be moved a few kilometres to start a new set of wells. Then Shell will install a floating production facility called a spar over the site, and the wellheads from the three fields will be connected on the seafloor and then hooked up to the spar. Under so much water, there’s a huge amount of back pressure on the wells, preventing the oil from flowing up on its own. Instead, the oil will flow from the wellheads to concrete caissons sunk into the seafloor, where gravity and centrifugal force will separate the oil from the natural gas that is also found in the formation. The caissons will house 1 118 kW pumps to push the separated hydrocarbons to the surface.

Considering the technology and cost, it’s an audacious plan full of unknowns: hurricanes that will mean evacuation of the spar, or that could even destroy it; fluctuating oil prices; flow rates from sandy accumulations that might not measure up; complex wellheads and caissons and pumps that you can’t even touch, that have to function for years in cold and currents and crushing pressure. Proponents of peak oil – a theory that says we’re at, or near, the time when little new oil will be found, causing a rapid decline in petroleum production – argue that the action in the gulf is nothing but the last desperate gasps of a dying way of life.

Peter Jackson, a senior director monitoring oil industry activities at Cambridge Energy Research Associates, an independent think tank in Boston, disagrees. “The overall US supply is gradually decreasing, but that rate of decline will be slowed by contributions from deepwater reserves in the whole Atlantic basin, from the gulf to Nigeria, Angola and Brazil.” Jackson sees oil production reaching a plateau, rather than a sharp peak, but not for decades. “And that means we’ll have time to mitigate and make some plans and legislate, and that’s very different from saying there’s going to be a peak in, say, 2010, followed by a precipitous decline.”

And it’s hard not to argue with a simple fact: Shell and other oil companies aren’t spending billions of dollars without believing that it’ll pay off for years to come. “We’re putting all of our free cash into oil and gas development,” says Russ Ford, vice president of development for Shell. “We believe hydrocarbons will be there for a very long time. Nothing is going to knock down oil.”

Meanwhile, in the drilling cabin, Ricketson notices the bit’s torque is shooting higher, so he raises the string a couple of metres. Grey mud sloshes on to the drilling floor as he checks the data. Five minutes slip by, at R2 800 a minute. Back on dry land, people are filling up their petrol tanks, heating their homes, using their computers with petroleum-based plastic cases. Without ceremony, Ricketson calls out the command: “Return to bottom.”

Unlocking Perdido
The Perdido development, 320 km out into the Gulf of Mexico, will eventually tap three hydrocarbon fields beneath 2,4 km of water. Here’s how.
By Erin McCarthy

Launched in 1987 and recently modi ed for deepwater exploratory and production work, the Noble Clyde Boudreaux drills pilot wells that will de ne the extent of the Perdido hydrocarbon reservoirs. Some key features: dual drilling derricks that operate simultaneously in a tightly choreographed routine to cut typical drilling times in half; 16 mooring cables – four more than conventional platforms – that provide additional stability in hurricane-prone locations; and relatively lightweight rig-to-seabed aluminium conduits called risers that allow for moorings in ultra-deep water.

1. Risers
These tubes, which extend from the rig to pilot wells on the seabed, come in 22,8 m lengths connected by ball-and-slip joints that allow the assembly to bend as the rig moves in waves up to 6 m high. In addition to housing the drill string, risers funnel synthetic mud down to the drill bit, lubricating and cooling it.

2. Casing derrick
This 15-storey structure is used to assemble sections of the risers and drill string and to back up the drilling derrick. It is also used to run steel casing 27 m into the seafloor in preparation for drilling pilot wells. The casings prevent the upper walls of the wells from collapsing.

3. Drilling derrick
This 17-storey derrick connects the riser and drill string assemblies from the casing derrick and lowers them to the sea floor. Once the risers and drill string are in place, this derrick performs most of the rig’s drilling operations.

In 2010, after the Boudreaux has drilled 22 pilot wells to a depth of about 3 000 m, the rig will be towed elsewhere. A production platform known as a spar will then be anchored in the middle of the Perdido operation. The spar’s main function will be to collect oil and natural gas from the world’s most extensive deep-sea production facility – a vast infrastructure that can only be serviced by robots – and then deliver the hydrocarbons through twin pipelines to shore.

1 Christmas trees
These pressurised valve towers control the output of producing wells. Operators on the rig use remotely operated vehicles (ROVs) to turn valves on and off to allow oil, gas and water to flow into the manifolds, which collect hydrocarbons from several wells.

2 Caissons
Hydrocarbons are pumped from manifolds to these 106 m-long cylinders buried in the sea bed. Inside the caissons, gravity and centrifugal force separate hydrocarbons into oil and natural gas.

3 Production risers
Pumps in the caissons then send oil and natural gas up production risers to the spar. After water and impurities are removed, the hydrocarbons are sent back down to the ocean floor in separate pipelines that transport the oil and natural gas 320 km for additional onshore processing.


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