In Pennsylvania's gas drilling boom, newer and unconventional wells leak more often than older and traditional ones, according to a study of state inspection reports for 41,000 wells.
The results suggest that leaks of methane could be a problem for drilling across the nation, said study lead author Anthony Ingraffea, a Cornell University engineering professor who directs an environmental activist group that helped pay for the study.
The research was criticized by the energy industry. Marcellus Shale Coalition spokesman Travis Windle said it reflects Ingraffea's “clear pattern of playing fast and loose with the facts.”
The Marcellus shale formation of plentiful but previously hard-to-extract trapped natural gas stretches over Pennsylvania, West Virginia and New York.
The study was published on Monday by the Proceedings of the National Academy of Sciences.
A team of four scientists analyzed more than 75,000 state inspections of gas wells done in Pennsylvania since 2000.
Overall, older wells — those drilled before 2009 — had a leak rate of about 1 percent. Most were traditional wells, drilling straight down. Unconventional wells — those drilled horizontally and commonly referred to as fracking — didn't come on the scene until 2006 and quickly took over.
Newer traditional wells drilled after 2009 had a leak rate of about 2 percent; the rate for unconventional wells was about 6 percent, the study found.
The leak rate reached as high as nearly 10 percent for wells drilled horizontally before and after 2009 in the northeastern part of the state.
TribLive commenting policy
You are solely responsible for your comments and by using TribLive.com you agree to our Terms of Service.
We moderate comments. Our goal is to provide substantive commentary for a general readership. By screening submissions, we provide a space where readers can share intelligent and informed commentary that enhances the quality of our news and information.
While most comments will be posted if they are on-topic and not abusive, moderating decisions are subjective. We will make them as carefully and consistently as we can. Because of the volume of reader comments, we cannot review individual moderation decisions with readers.
We value thoughtful comments representing a range of views that make their point quickly and politely. We make an effort to protect discussions from repeated comments either by the same reader or different readers.
We follow the same standards for taste as the daily newspaper. A few things we won't tolerate: personal attacks, obscenity, vulgarity, profanity (including expletives and letters followed by dashes), commercial promotion, impersonations, incoherence, proselytizing and SHOUTING. Don't include URLs to Web sites.
We do not edit comments. They are either approved or deleted. We reserve the right to edit a comment that is quoted or excerpted in an article. In this case, we may fix spelling and punctuation.
We welcome strong opinions and criticism of our work, but we don't want comments to become bogged down with discussions of our policies and we will moderate accordingly.
We appreciate it when readers and people quoted in articles or blog posts point out errors of fact or emphasis and will investigate all assertions. But these suggestions should be sent via e-mail. To avoid distracting other readers, we won't publish comments that suggest a correction. Instead, corrections will be made in a blog post or in an article.