HARRISBURG - A published report says that Pennsylvania has an estimated 200,000 abandoned oil and gas wells, but knows the location of only a tiny fraction of them.
That's a potential problem for Marcellus Shale drillers that are trying to avoid crossing paths with the old wells.
StateImpact Pennsylvania reports that while it is rare for a modern drilling operation to intersect with an abandoned well, it does happen. A subsidiary of Shell Oil Co. was drilling in Tioga County last summer when a 30-foot geyser of methane gas and water erupted from the ground. That forced the evacuation of several homes until the leak was brought under control.
The gas most likely came from a shallow formation and made its way into an abandoned well drilled in 1932.