Newer is not necessarily better, at least when it comes to gas well leakage.
A study published this week of gas wells in Pennsylvania shows that the newer, less conventional, fracking wells leak up to ten times more than the older traditional wells.
The findings also suggest that leaks of methane could be a problem for drilling across the nation, said study lead author Cornell University engineering professor Anthony Ingraffea.
The team of scientists analyzed more than 75,000 state inspections of gas wells done in Pennsylvania since 2000, and found that leak rates had increased since unconventional fracking wells appeared on the scene in 2006.
The researchers found the following:
- Wells drilled before 2009 had a leak rate of about 1 percent (most of these being traditional, “drill straight down” wells).
- Newer traditional wells had a leak rate of about 2 percent.
- New frocking wells had a leak rate of about 6 percent.
- In certain regions of the state where fracking has been intense, the leak rate was as high as 10 percent both before and after 2009.
The scientists don’t know the size of the leaks or why exactly the leak rate had increased. Ingraffea’s main comment was:
Something is coming out of it that shouldn’t, in a place that it shouldn’t.
Pennsylvania regulatory officials said that gas leaks are now on their way down, since peaking in 2010. That is due to a relatively new emphasis on proper cementing practices. Furthermore, Morgan Wagner, a spokesman for the state environmental agency, said since 2011 the state had focused more making leak protection efforts “more stringent.”
Energy industry officials attacked the study, saying the scientists measured the wrong thing. Chris Tucker, spokesman for industry-supported group Energy In Depth, wrote in an email:
The trick these researchers are pulling here is conflating pressure with leakage, trying to convince folks that the mere existence of the former is evidence of the latter.
Scientists not involved in the study, even pro-drilling scientists, say the findings indicate there is plenty of room for improving drilling safety.
To read the study: Assessment and risk analysis of casing and cement impairment in oil and gas wells in Pennsylvania, 2000-2012