And then there’s the EPA study on Encana Corp.’s Pavillion play in Wyoming. After homeowners complained there, the EPA undertook a study and released a preliminary report concluding that some chemicals associated with fracking had migrated into well water.
The industry – and some scientists – question the EPA’s conclusions, saying it had no baseline data for the state of the water prior to drilling, and that the government scientists had essentially found hydrocarbons in hydrocarbon-bearing areas.
The agency is reviewing the criticism and expected to come out with a final report later this year.
While the industry insists fracking itself is safe, industry officials concede shoddy drilling, cementing, and casing techniques can lead to leaks of methane and frack fluid.
To guard against that, Talisman Energy Inc., for example, uses two or more layers of cement and steel casing to fortify the well and protect groundwater.
“That’s the real issue that regulators should be focusing on – the integrity of well design and then the integrity of well completions,” said Paul Smith, executive vice-president of Calgary-based Talisman, a company that has placed big bets on shale gas development.
While industry claims that there has been no evidence of fracking fluids contaminating groundwater, they can’t make the same assertion with regard to methane, the basic component of natural gas that has been blamed for tainting well water in dozens of cases.
Another Duke University study sampled 68 wells in Pennsylvania and New York State and found elevated methane levels that, on average, were 17 times higher than normal. However, Mr. Jackson acknowledged that the team had no sample of well water prior to drilling, and therefore could not say conclusively whether the methane was naturally occurring or had gotten into the water as a result of the drilling and fracking.
The team is now back at work, using chemical techniques to trace the origin of the methane to determine whether it is naturally occurring in the water or has migrated from deeper in the earth.
Talisman’s Mr. Smith insists that any methane found in water wells is there naturally, and dismisses dramatic scenes of homeowners setting aflame their tap water.
“The old lighting the tap [water on fire]trick – people have been able to do that a hundred of years in Pennsylvania, way before any industry oil and gas exploitation activity took place, because of the naturally occurring methane levels in different parts of Pennsylvania,” Mr. Smith said. “That’s nothing new to people.”
Talisman has drilled over 500 shale natural gas wells in North America and the company’s water tests have shown no evidence of increased methane levels owing to its activity, he said.
A major cause of concern is contamination from the wastewater retrieved from the well during drilling operations. The waste flow is a combination of “flow-back” water, which had been injected into the well, and “produced” saline water from the shale formation.
The returned water often contains high levels of suspended solids and arsenic, and exhibits high levels of radiation. A number of researchers have raised concerns about high volumes of wastewater overwhelming the capacity of local treatment facilities, or being clandestinely dumped in local streams and rivers.
The University of Texas report concluded that the potential risk from naturally-occurring contaminants is a “major concern.”
Energy companies are boosting efforts to re-use water when fracking, as a way of dealing with waste streams and to cut down on demand for fresh water supply.
One technique for disposing of wastewater is to re-inject it back underground, a practice that has raised concerns about resulting earthquakes.
On Friday, the Ohio Department of Natural Resources concluded that two tremors in December were caused by activities at re-injection sites that accept wastewater from neighbouring Pennsylvania. The state imposed new rules on re-injection operations. But Ohio did not ban the activity. Instead, it released new safety rules and vowed to monitor the companies to ensure they follow them.