Page 106: of Offshore Engineer Magazine (May/Jun 2014)

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Pipelines

Abaqus FEA helps

INTECSEA deliver durable pipe solutions for deepwater oil producers. Kip Hanson reports.

It’s all in the pipeline:

Transporting sour hydrocarbons more reliably t’s not that the world is running out environments for decades. By metallurgi-

Making the weld stronger than the pipe of oil. The problem is getting to what cally bonding a thin layer of corrosion Pipe sections are manufactured in

I remains of it, at a price that consum- resistant alloy (CRA), typically 316L or lengths of about 12m, called pipe joints. ers can swallow. A September 2013 oil Alloy 625, to the inside of C-Mn struc- These joints are then girth welded market report from the International tural steel pipe, a robust combination together end-to-end to create a pipeline.

Energy Agency (IEA) said that global of strength and corrosion resistance is For mechanically-lined pipe, each CRA demand for oil and liquid fuels will formed. joint is slid inside a carbon steel joint rise to 93MMb/d in 2014, an annual However, clad pipe suffers from and plastically expanded in the radial increase of more than 2%. This comes long lead times and high cost. Sherif direction to ensure a tight ft between at a time when most experts agree the El-Gebaly, lead pipeline engineer at the carbon steel and the liner. The ftted days of “easy” oil are over. Petroleum INTECSEA, a global company within the CRA joint is shorter in length, leaving a companies are now forced to drill in WorleyParsons Group, says that clad pipe distance of about 50-150mm at each end; areas deeper and more remote than ever can cost 10 times that of regular C-Mn this gap is flled with a weld overlay of before. Steel. “An alternative is CRA mechani- a CRA material, bonding the CRA layer

In the case of deepwater production, cally lined pipe using a weld overlay at to the carbon steel pipe and enabling the this means very high and unpredictable the ends,” he says. “This is both easier joint-to-joint girth weld to be performed. pressures coupled with severe tempera- and quicker to manufacture, presenting “Girth welds are critical,” said ture gradients both inside the pipe and cost savings of 30% over clad pipe.” INTECSEA global technology director out. Worse, the wellstream fuids coming However, concerns over the weld over- Philip Cooper. “Some of these installa- from these depths are increasingly sour, lay to liner interface joint have prevented tion vessels are running a million dollars a corrosive witch’s brew containing high wide use of CRA mechanically lined a day. The weld joints are inspected prior levels of hydrogen sulfde, CO , and vola- pipes due to the technology readiness to lowering the pipe into the sea, and if 2 tile organic compounds that make short level (TRL) not meeting operator require- repairs have to be made at this point, it work of regular carbon steel pipe. The ments. INTECSEA has been working to can seriously impact production rates.” oil industry has responded with calls for resolve and increase the confdence in Regardless of how much pipe gets better pipeline material. CRA mechanically lined pipe for use in laid in a day, environmental and safety

Clad pipe has been used in high-strain harsh environments. considerations mandate zero tolerance

May 2014 | OE oedigital.com 108 000_OE0514_pipelines1_intecsea.indd 108 4/19/14 10:45 PM