Perilous Pathways: How Abandoned Wells Can Contribute To Methane Migration Problems

INFOGRAPHIC

October 9, 2012 | 1:00 AM

By Scott Detrow and Yan Lu

Part 1: Why abandoned wells are a problem

Infographic: How abandoned wells can contribute to methane migration

Part 2: How many wells dot Pennsylvania, and why aren’t we plugging more of them?

Map: Known abandoned wells in Pennsylvania

Part 3: How to track down an abandoned well

Part 4: States don’t do much to regulate drilling near abandoned wells

Methane is a flammable, odorless gas that exists within underground shale formations. Because of the porous, intertwined rock formations that many parts of Pennsylvania sit on top of, the gas can naturally seep to the surface. Methane can be dangerous when it migrates into water wells or basements.

Orphaned and abandoned oil and gas wells create a natural pathway for methane to migrate from. The process can be accelerated when an active well is drilled into the same formation the abandoned well is tapped into. This occurrence — called “communication” — is extremely rare, but it can create major problems at the surface. A 30-foot geyser of gas and water that burst through the ground in Tioga County in June was likely caused by Marcellus Shale drilling near an abandoned well.

This graphic shows how methane gas can make its way from deep underground into a basement, water well or the ground.

STATEIMPACT REPORTING, GRAPHIC PRODUCED BY YAN LU

Comments

http://twitter.com/rakingmuck rakingmuck

I want to thank you for this excellent information. I have just returned from a trip to Philadelphia, where I grew up. I was stunned that NOT ONE PERSON knew what was happening in Louisiana or fraking in general. This information could save lives and I am spreading it throughout the Internet.
http://www.facebook.com/profile.php?id=100003701314172 Waterflaws Nom DeGuerre

Fracking os FAR MORE than just a methane migration problem, and has irreversible and essentially eternal consequences. PLUS, it’s also adding to our already perilous CO2 (methane is even worse!) problrms !!
Thuston in Houston

A key element of this issue is the phrase “improperly abandoned wells.” The problem is old wells which were not dealt with appropriately. Fracking is not the problem, per se, though this article and accompanying graphic suggests that the fracking action may trigger the impact of the original well which was not properly abandoned.
Jefferson Williams

As noted, this is a very rare event. As not noted, it is more or less a one time event and not a continual source of contamination as communication is cut off once the surface and conductor pipe are set. Further, the abandoned well in the graphic is quite shallow which is unusual for an oil well. The contaminating well has to be shallow or the methane would have trouble migrating up into the water well. Most oil wells (including abandoned ones) are not shallow. The mean depth of oil field worldwide is ~ 5000 feet deep.

In the comments below, I see someone beleives that gas wells emit so much methane into the atmosphere in the stages from drilling to putting the well on production that the outgassed methane negates the reduction in CO2 in the USA that has been acheived by switching power plants from coal to gas. I have seen that there are some academics out there who are making these claims in published articles. The problem with their claim is they assume that 85% of rigs out there don’t flare their methane whenever there is signifant gas coming uphole. I have been on hundreds of rigs and NOT ONCE did I encounter a rig that did not flare gas when gas was present. It is EXTREMELY UNSAFE not to flare gas when it is present and the oil industry has a very strong safety culture. I’m guessing the academics who wrote the paper(s) have never spent more than an hour on a rig.

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