Noble has strict H2S safety procedures |

Noble has strict H2S safety procedures

John Colson
Post Independent Staff
Glenwood Springs, CO Colorado

Noble Energy, the company dealing with elevated levels of hydrogen sulfide gas at gas wells in western Garfield County, has strict safety protocols for dealing with the toxic gas, according to a company official.

Stephen Flaherty, community relations director for Noble Energy, said the company makes sure its wells are “a controlled environment” with alarms and safety procedures designed to minimize the danger to workers.

All company employees wear monitors while working on well pads and other facilities where H2S either has been detected or is considered a possibility, and well workers are trained in the procedures to follow should H2S be detected.

The gas detection monitors are keyed to sound off if they sense H2S at a concentration of 10 parts per million (ppm) or higher.

If a monitor sounds an alarm, Flaherty said, “the first thing that happens is immediate evacuation of the well pad and notification of the person in charge.”

After drilling or other operations are shut down, contractors come in to find the source of the H2S leak and fix it.

Once the leak is fixed, the company injects biocides and other compounds into the well to neutralize the H2S.

“We are treating down-hole,” he emphasized in explaining the chemical treatment.

These operations are conducted by specialists wearing protective gear, including self-contained breathing apparatus.

Monitors are erected around the work site during such operations, set to alert the crew if H2S is detected.

Flaherty, along with Stuart Ellsworth, engineering manager for the Colorado Oil and Gas Conservation Commission, have stated that H2S dissipates quickly in the atmosphere and is not considered a threat to neighboring homes.

Flaherty noted that the COGCC rules prohibit drilling wells less than 150 feet from an occupied dwelling.

Ellsworth recently told attendees at a Garfield County Energy Advisory Board meeting that H2S will dissipate into the atmosphere within 60 feet of a well pad.

At that same meeting, retired engineer Bob Arrington of Battlement Mesa argued that, because H2S is heavier than air, it could form a plume and pool into gullies or other low spots.

Ellsworth said Arrington’s scenario is possible, but he rejected the idea that an H2S plume could hold together over a longer distance and endanger neighboring residents.

Flaherty said there may be times when small amounts of H2S can escape to the outside atmosphere, such as when tanks are opened for testing of the contents, or during well servicing activities later in the life of a well.

It was following a procedure known as “swabbing,” a well-servicing technique for clearing blockages from the well bore, that Silt Mesa resident Carl McWilliams said he inhaled H2S in 2009 while working on a Noble rig and got seriously ill.

McWilliams’ claim was later found credible by the Occupational Safety and Health Administration, which fined his employer, the Canadian contractor Lonkar Services US.

Flaherty said that the same protocols that are followed now were in place in 2009, but he noted that Noble does not supply equipment or training to subcontractors.

Compliance with Noble and OSHA guidelines, he said, is something that is left to the subcontractors to do on their own.

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