Although I haven't been able to speak to anyone personally connected to this incident yet, I suspect that a new well impacted an older well in the general vicinity. This happened quite often in the ANF area where there are many old oil wells that were not known about and when a new well was drilled to the same approximate depth it expressed itself at the surface from the old well. Records for these old wells are very limited or nonexistent. Old "preact" wells were never cemented and were usually plugged prior to any regulations with what was called a brush plug. My opinion is that legacy wells are the number 1 concern causing methane migration.
Hopefully, Shell and the DEP can locate the exact location of the old well, put a drilling rig over top of it, clean the old well out to total depth and plug and abandon the well using modern technology and methodology. When they do that, the migration issue will be stopped and the new well can produce safely and within the regulations. If Shell cannot plug the old well effectively, they may be required to plug their well that is found to have effected the old well.
Understand that when the old well is plugged, the methane migration issue should stop and any methane that got into the aquifer will dissipate and eventually stop.
I know of this happening at least 3 times in southwest PA and the problem is corrected when the old well is located and plugged properly.
Oh and this is a good lesson to all the folks that claim their water wells have been fraced into. If you introduce well fracing pressures to a shallow water well this is how it would express itself. There would be no doubt in anyones mind that the water well was affected by fracing.
