North Dakota oil facility explosion and fire highlights lightning risk
09 July 2014
A July 7 lightning strike caused an explosion and fire that destroyed the saltwater disposal facility of an oil production well pad near the town of Alexander, North Dakota. The nine saltwater and two oil tanks on site were destroyed, according to McKenzie County Emergency Manager Jerry Samuelson.
The state's Department of Health said the incident led to the release of 2,813 barrels of saltwater and 649 barrels of oil. No injuries were reported.
Saltwater is a byproduct of shale oil production, is considered an environmental hazard and must be disposed of in special facilities. It is initially stored in tanks near the well head and the mixture of residual gas and oil it contains can give rise to an explosion risk.
In recent weeks, three of the North Dakota's 440 plus active saltwater disposal facilities have been destroyed by fires and explosions sparked by lightning strikes.
A June 1 lightning strike spilled 15 barrels of oil and 1,200 barrels of brine while another on June 27 spilled 580 barrels of oil and 1,800 barrels of brine, and clean up and reconstruction costs for the second incident are put at US$2 million.
Forum News Service quoted Samuelson as saying that lightning strikes at saltwater sites were a common occurrence because the tanks were built of fibreglass which created static electricity. Fibreglass tanks tend to be more prone to lightning strikes than steel tanks, but the latter are more prone to corrosion.
North Dakota does not require companies to install lightning protection systems on its oil field facilities.
The American Petroleum Institute has standards and recommended practices for companies to follow related to preventing ignitions caused by lightning, static and stray current. It also has recommended practices for lightning protection for hydrocarbon storage tanks.