Lightning a Threat to Salt Water Disposal Tanks

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Lightning a Threat to Salt Water Disposal Tanks

At disposal facilities, brine and oil residue are stored in tanks, where the oil is skimmed off the top.  Brine is then injected into the ground. This necessary practice has come under fire from lightning strikes. Since the Bakken boom began, lightning has been linked to the cause of multiple fires involving salt water disposal tanks, according to officials.

Salt water disposal tanks, which are generally constructed of fiberglass, are more prone to catching fire if struck by lightning. The reasons tanks catch fire experts say are because of the volatile gasses that collect in them from the oil residue mixed in with the brine and their fiberglass and other construction components.

What’s the Solution?

The logical answer it seems would be to build the tanks out of more lightning resistant material. However, industry experts caution that isn’t cost effective. For instance, steel tanks, which would be better suited to a lightning strike, are subject to the corrosive nature of the brine. Fiberglass tanks are much better suited to corrosion, and last longer.

Another more cost effective solution is to fortify the fiberglass tanks to make them resistant to lightning strikes. These fortifications are costly, but not nearly as costly compared to the damage caused by a direct hit from a lightning strike.

Despite the risk, some companies in the oil patch are willing to hedge their bets that a lightning strike will not hit their storage tank. But the simple truth is lightning wins the match every time when it hits a susceptible tank.

Lightning Protection for Fiberglass Tanks

Without adequate grounding and bonding, lightning can ignite fiberglass tanks that store produced saltwater. Metal piping, thief hatches, bull plugs, vent valves, and level transmitters sit isolated on top of the tanks, and lightning electromagnetic fields can induce voltage stress on these metal bodies. Without adequate grounding and bonding, arching can occur between metal bodies and ignite the vapor cloud or even induce in-tank fires.

Static electricity in one form or another is a phenomenon of nature and often results in electrostatic discharges that can cause fires and explosions similar to lightning. The flow of volatile produced water generates static along the wall surface and on the surface of the fluid. The internal surface of fiberglass tanks acts as an insulator and allows static charges to accumulate. Dedicated measures are required to enhance static neutralization within the tanks without inserting any metal body that can hold a charge or become a source of streamer during lightning events.

Fiberglass tank fires can be avoided using Petro Guardian’s engineered approach to grounding and bonding. Contact the team@petroguardian.com to find out how you can improve the integrity of your grounding and bonding.