Posted on 10/18/2013 4:58:51 AM PDT by thackney
In late August, French oilfield services firm Technip announced it had been awarded a contract by Shell Offshore Incorporated to lay the world's deepest gas pipeline.
The work will be part of Royal Dutch Shell plc's 100 percent-owned and operated Stones project, which will see a production facility installed under 9,500 feet of water in the Walker Ridge area of the U.S. Gulf of Mexico – some 200 miles from New Orleans. So far, the world's deepest production platform is at the Independence project in the eastern Gulf of Mexico.
"What we're trying to do is open up a new development play in the Gulf of Mexico: the Paleogene development. So, Stones is really pushing that deepwater frontier. We've pushed it a bit with Perdido and we're looking to push it even further with Stones," Curtis Lohr, Shell's project manager in charge of the Stones development, told Rigzone in a recent phone interview.
Stones was discovered in 2005 and is estimated to hold more than two billion barrels of oil equivalent. After the final investment decision to go ahead with developing the field was made in May of this year, the first phase of development will see peak production of 50,000 barrels of oil equivalent per day (boepd) from more than 250 million barrels of oil equivalent (MMboe) in resources.
The first phase will see two subsea production wells tied back to a floating storage, production and offloading (FPSO) vessel. In later phases, Shell plans to add six more wells.
"The Stones development consists of a mid-sized Suezmax-size FPSO with an eight-well subsea system. We'll have eight wells in Phase One, with the first two wells available for first oil in 2016," Lohr said.
The subsea development will include the usual subsea trees at the well locations, as well as a gathering manifold, umbilicals and risers.
"The umbilicals and risers will bring the oil and gas up to the FPSO for processing. They'll be attached to a disconnectable buoy on the FPSO. A disconnectable FPSO has the advantage of being able to safely avoid the hurricanes that frequent the Gulf of Mexico," Lohr said.
"The gas is exported with a pipeline; the oil is exported with shuttle tankers, like a typical FPSO development."
Lohr said that the greatest challenge for the team managing the project is where Stones is located.
"As oil operators, if we could get these developments in shallower waters, it would be great. Stones is where it is, so 9,500 feet of water is quite deep water making Stones the world's deepest production system once installed.
"For the gas pipeline, the ultra-deepwater results in high tensions pulling on the FPSO buoy. On the seafloor, there is an escarpment, so when I talk about 9,500 feet of water that's where the wells are located but the top of the escarpment just north of the Stones development is in 7,500 feet of water. So you've got this 2,000-foot rise that the gas pipeline has to traverse across.
"On top of that, if you look at the details, there are seafloor furrows, which are basically large bumps on the seafloor where the pipelines are being laid, so those are pretty challenging … The gas pipeline will be fitted with VIV [vortex induced vibration] suppression to make sure we don't have any fatigue issues. And then, obviously, we have to design the wall thickness of the pipeline to span those seafloor furrows."
The fact that Stones is an ultra-deepwater development means that during the installation phase there will be very little room for error. For example, installing the gas pipeline – a task that is expected to take 45 days – has to be done carefully because it would have to be re-laid in the event of any damage.
"You've got to get it right the first time, which is true of any deep-water development," Lohr said.
Installing the world's deepest gas pipeline and production system will not be the only milestones for the Stones project. Lohr pointed out that Stones will be the first time a steel lazy-wave riser is connected to a disconnectable FPSO turret/buoy.
"Shell has successfully executed previous projects with steel lazy-wave risers (that's not anything new to us) and SBM – the FPSO contractor – has delivered several disconnectable FPSOs, but to put the two together is a first for the industry," he said.
With all of this going on, Shell sees the Stones project serving as a template for future ultra-deepwater projects.
"We definitely see Stones as an enabler for future growth. There are other potential developments that look a lot like Stones. So if we unlock Stones, I think we can unlock a lot of other developments in the Gulf of Mexico as well," Lohr said.
Offshore installation at the Stones project is scheduled to begin in late 2014.
Incredible (and exciting) stuff.
WOW is the only thing I can say right now.
oBAMA has not blocked this yet”
9500’ : 8300’ deeper than the saturation dive I participated in back in 1982 to prove we could repair the Statoil pipeline crossing the Norwegian Trench.
I think this is all ROV work at that depth.
Correct, using “Echo Scope” mounted to ROV
And that’s where the Big Oil profits go.
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