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US pipeline conversions, gas flow reversals raise safety concerns

New Orleans (Platts)--22 Nov 2013 219 pm EST/1919 GMT


In the rush to accommodate shifting US natural gas supply patterns, there are worries that pipeline safety could get short shrift in companies' plans to reverse flows or switch to oil and liquids transportation, particularly as federal standards do not specifically address such changes, observers say.

"We're in the era of multi-billion-dollar projects," Richard Kuprewicz, president of pipeline safety consultant Accufacts, told this week's Pipeline Safety Trust annual meeting in New Orleans.

And that can lead to what he calls the "Space Shuttle syndrome," in which the "pressure to launch can overcome safety considerations."

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"Pipelines are undergoing a fundamental rebalancing" in North America as large volumes of shale gas come online, he said. And converting an older gas pipeline to a new purpose, such as carrying natural gas liquids from the Marcellus Shale south to the Gulf Coast or reversing the flow of traditional Gulf-to-Northeast pipes, "is faster and cheaper" than building new pipes.

One example is the Bluegrass Pipeline, a joint venture of Williams and Boardwalk Pipeline Partners that would involve construction of a new NGL pipe out of West Virginia and Ohio, along with the conversion of Boardwalk's Texas Gas Transmission system between Kentucky and Louisiana from gas to NGLs.

"You've gotta get rid of the NGLs, you can only put that stuff in the transmission lines for so long," Kuprewicz said of the quandary faced by existing gas carriers in the liquids-rich Marcellus and Utica shale plays. "It's hot, it's high-Btu, and it can really cause a problem for these transmission lines. They don't like taking that risk," he added.

"Existing regulations are weak or moot regarding these conversions, and from a public perspective, whether it's landowners, citizens, state or local governments, they're not getting enough transparency" about the projects, Kuprewicz said.

He pointed to a "disconnect" between safety issues and routing at the federal level. The US Federal Energy Regulatory Commission "is not a safety agency -- they can impose safety issues, but their primary purpose is commerce. And they don't have a lot of say [regarding routing] on liquids lines," he added.

FERC issues construction certificates and regulates rates for gas pipelines, but its jurisdiction over NGL and crude oil pipes is limited to ratemaking.

The integrity-management rules that frame safety regulation at the Pipeline and Hazardous Materials Safety Administration -- an agency within the Department of Transportation -- do not adequately cover the issues surrounding conversions, Kuprewicz said.

Operators performing such conversions should carefully consider how pressures will change along portions of their pipelines, and how that will change their assessments of crack threats and manufacturing defects.

"You'd better have the right kind of tool or hydrotest to assess those threats," he said.

David Johnson, a technical consultant to Energy Transfer, laid out a host of operational and safety changes operators will make as they convert pipelines. Energy Transfer is involved in a project to convert 574 miles of its Trunkline Gas pipeline from gas to crude oil along a path from Illinois to Louisiana, as well as separate project to convert some 82 miles of intrastate gas pipeline in South Texas to carrying liquids out of the Eagle Ford Shale.

Such converted pipes will still need to comply with PHMSA regulations for whatever product they are carrying, including corrosion control and pressure tests. The operating history of the line will be important in the new assessment, Johnson noted.

In addition, the conversion from gas to oil or liquids involves the installation of different types of pumps rather than compressors, and those pumps are electric-powered rather than gas-powered, so electricity may need to be permitted along the route, Johnson said, adding that new types of meters must also be installed.

Operationally, the leak-detection systems are vastly different, and the assessments for threats such as internal and external corrosion will change, as will assessments of material and construction anomalies, he said.

Pipeline valves are also different in gas and liquids carriers -- in the type of valves, their location and spacing and how they are installed, Johnson said. A liquids line requires a slower, "soft close" to prevent hammering on the pipeline, for instance.

At FERC, the pipelines will file for abandonment of the current facilities, which involves public comment and the publication of an analysis and decision by the agency.

Alan Mayberry, deputy associate administrator for field operations at PHMSA, echoed those prescribed changes involved in pipe conversions and flow reversals.

Such projects "are dealt with in integrity-management plans," he told the audience. He also cited changes in control room management, the need for new spill response plans, risk assessments and operator qualifications.

Just because the process of shifting from one product to another is not specifically addressed in the regulations, it does not mean those pipelines are not covered by some federal and state rules, Mayberry added.

He noted that PHMSA is stepping up its regulatory role in new pipeline construction, particularly with greater notice requirements, and said guidelines for flow reversals, service conversions and product changes are being developed at PHMSA.

--Stephanie Seay, stephanie.seay@platts.com
--Editing by Mark Davidson, mark.davidson@platts.com; Keiron Greenhalgh, keiron.greenhalgh@platts.com

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