Type the words water, fire and fracking into a YouTube search and you’ll get more than 30,000 videos about tap water bursting into flames. The cause is likely natural gas or methane.
Biogenic gas is nearly 100 percent methane. It occurs from bacterial activity in shallow aquifers. It has naturally leaked into water wells for a long time. But, some people fear fracking leads to more kitchen fireworks. If that’s true, it would be from a different type of gas – thermogenic gas – a gas that’s traced to oil and gas production.
Stephen Osborn is an assistant geology professor at California State Polytechnic University Pomona. He's studying water wells in Colorado. Last summer he collected 40 ground water samples in northeast Colorado in the heart of the oil and gas fields.
Osborn says the evidence doesn't suggest that thermogenic methane is polluting water wells.
"Wherever methane concentrations are high, greater than about one milligram per liter, it tends to be biogenic gas," he says. "There's really no evidence within our current data set to suggest that it's thermogenic gas, or the kind of gas that comes from deep in the basin, the kind of gas that companies are targeting for production."
The preliminary data in Colorado differs from a 2011 Duke University study that Osborn led. The results were published in The Proceedings of the National Academy of Sciences.
Researchers collected and analyzed water samples from 68 private groundwater wells in northeastern Pennsylvania and upstate New York. Some of those samples came from near active drilling sites, while others did not. Osborn says the concentrations of thermogenic methane in a lot of the homes sampled in Pennsylvania were much higher than the wells sampled in Colorado. He says he witnessed flammable faucets in Pennsylvania.
The oil and gas industry published a critique of the Duke study contending there were errors in the research.
Osborn says there are several reasons why thermogenic methane could pollute water in Pennsylvania, but not in Colorado. He says it may be a function of how the wells are drilled. Or it could be because operational procedures by gas companies differ by region. But, Osborn's current working hypothesis is that it's because the geology in each state is very different.
According to the Colorado Oil and Gas Conservation Commission (COGCC) 1,600 domestic water wells were sampled in Colorado from roughly 1990 to 2012. Thermogenic methane was found in 23 wells. Of those 23 cases, 12 were linked to a leaky oil and gas well.
The leaky wells have since been repaired to prevent methane migration into water. In the remaining 11 cases, leaks were not discovered, making it possible that thermogenic gas migrated to the water. However, COGCC says fracking chemicals were not found in any water samples.
Osborn will take more water samples in Colorado this summer to have a more comprehensive data set.
