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State nearing requirement for baseline water testing before new oil-gas drilling

Nov 8, 2013 - By Mead Gruver, The Associated Press

The Wyoming Oil and Gas Conservation Commission is poised to require the companies that drill for oil and gas in the state to first test nearby water wells and other water sources for pollution.

The purpose is to document the condition of those nearby water sources and, if any contamination turns up later, help state regulators determine the origin of the pollution.

That could come in handy in a place like the Pavillion gas field. Drilling has occurred there for decades, but homeowners say their well water turned foul only within the past several years. State and federal officials continue to try to sort out the cause.

State officials posted the latest version of the proposed new baseline testing rules on the commission website Thursday. The commission, which regulates oil and gas development in the state, will discuss and possibly vote on adopting the rules Tuesday.

John Robitaille with the Petroleum Association of Wyoming said the new rules shouldn't be a problem for petroleum companies because many of them already are doing such tests.

"We're probably 10 years too late on permitting something like this. For many years, our member companies have been doing exactly what has been required on their own, voluntarily," he said.

Under the rules, companies would need to sample and test within a year prior to beginning to drill a single well or the first well on a multi-well pad. Three more rounds of testing would be done starting at least a year after installation of the well's production casing.

Companies would test all water wells or other water sources within a half-mile radius of the drilling site, up to four such wells or water sources.

The rules specify for what the companies are supposed to test, including bacteria, hydrocarbons, BTEX compounds, naphthalene and dissolved gases.

Environmental groups have said they generally support the rules. Among them is the Wyoming Outdoor Council. Spokesman Chris Merrill called it a "first line of defense" against groundwater contamination.

"The governor and the oil and gas commission deserve a lot of credit for developing a scientifically valid groundwater testing program," he said.

A state task force made up of representatives of the governor's office, State Engineer's Office and Wyoming Department of Environmental Quality developed the rules and recently sought public comment on an earlier draft. One last-minute change lowered the amount of dissolved methane that would trigger follow-up testing from 10 milligrams per liter to 5.

Water becomes a fire or explosion risk at 28 milligrams per liter. At 5 milligrams, the company would have to test to see if the methane is thermogenic or biogenic. Biogenic gas comes from bacteria and other living organisms. Thermogenic gas is fossil-fuel methane that typically originates from deposits deep underground -- the type of gas targeted for development.

Thermogenic gas occurs naturally in groundwater but can indicate a problem with gas from a production zone getting into groundwater. Studies have shown relatively few water wells in Wyoming with 5 milligrams or more of dissolved methane, said Jerimiah Rieman, Gov. Matt Mead's natural resources policy adviser who headed up the baseline testing task force.

"We weren't going to cause a great burden and do a bunch of additional analysis if we go down to 5 mg per liter," Rieman said.

Under the rules, the well owner, state oil and gas supervisor, and Department of Environmental Quality director would all need to be notified within 24 hours if the gas were thermogenic. They also would need to be notified if dissolved methane exceeded 10 milligrams per liter or increased by more than 5 milligrams between sampling periods.

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