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Thursday, October 11, 2012

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

October 9, 2012 | 1:00 AM
By Scott Detrow and Yan Lu

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. Read More: