Lightning a threat to ND saltwater disposal sites

Published on NewsOK Modified: July 19, 2014 at 12:39 pm •  Published: July 19, 2014
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WILLISTON, N.D. (AP) — Three massive fires since the beginning of June have highlighted the threat lightning poses in the North Dakota oil patch, and in each case it was tanks that store the toxic saltwater associated with drilling — not the oil wells or drilling rigs — that were to blame.

The lightning-sparked fires destroyed the groups of silo-like storage tanks at the three locations, which are among more than 440 sites in North Dakota where so-called saltwater is stored before being pumped into permanent disposal sites miles underground. In each case, the fires burned for days, spewing noxious black smoke into the air and literally salting the earth.

Although disposal tanks aren't likely more susceptible to lightning strikes than similar structures that jut out over the prairie, their fiberglass components and combustible contents make it very likely they'll go up in flames when they are hit.

"You're creating the perfect mixture for ignition," said Bruce Kaiser, president of the Clearwater, Florida-based Lightning Master Corporation, which is one of several companies that provide lightning protection systems to oil field facilities. "Counterintuitively, it's the water tanks that blow up, not the oil tanks."

Also called brine, saltwater is a byproduct of oil production that is between 10 and 30 times saltier than seawater and that contains oil residue when it is put in the tanks, where gas vapors also collect. Companies allow the liquid to settle and separate, then skim and sell off the oil to pad their profits while injecting what remains into the ground.

Due to brine's corrosiveness, companies would have to replace their disposal tanks every few years if they were just metal, so they commonly use tanks made of or lined with fiberglass, which last longer.

Metal-only tanks would allow the electricity to pass through them and into the ground more easily than those with fiberglass, said John Jensenius, a lightning safety expert at the National Oceanic and Atmospheric Administration.

"Because fiberglass is more resistant to electrical charge movement, it's going to heat up. That's why you're seeing the fires," he said.

Despite the risks posed by lightning, North Dakota doesn't require companies to install any protections. Some do it anyway — the owner of tanks near the town of Ross that were struck June 27 estimates it will cost $2 million to replace them and clean up the site. But others apparently are unaware of the threat or are willing to take their chances to save money.

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