On Saturday, January 26, a well drilled to the Utica formation, about 14,000 feet deep, communicated with several shallow wells, the deepest of which was drilled to about 3,000 feet. This is bad.
The well, drilled by CNX, and called the Shaw 1G, was being fracked. Pressure dropped suddenly and the workers stopped the fracking process. They discovered something blocking the wellbore. There doesn’t appear to be any information about where exactly the blockage is. That could be important because the blockage could indicate a failure in the casing. If there’s a failure in the vertical portion of the casing, that would explain why this well is communicating with much shallower wells. The casing failed and fracking fluid pushed out into the formation or formations that the shallow wells are producing from.
If, instead, there’s a failure in the horizontal portion of the casing, that means that fracking fluid propagated up through 11,000 feet of rock. The Marcellus Shale lies at around 5,000 to 7,000 feet deep in most areas of West Virginia That would mean that the fractures created through the fracking process in a Marcellus Shale well could potentially reach the surface and could certainly find their way into water wells.
The likelihood that the fractures pushed up through 11,000 feet of rock is low. Fracking has been going on for long enough now that it’s hard to believe that under normal circumstances this kind of thing would happen. There just aren’t any reports of it happening. There have been reports of water wells being ruined and of shallow wells being stimulated by fracking, however. Maybe this happens more often than we think, we just don’t realize what’s going on.
Update: The Pittsburgh Post-Gazette is reporting that there are now nine wells impacted by the problem. Interestingly, none of them are in line with the horizontal path of the well. It runs southeast, and the nine wells are to the north, west, and east. Additionally, the other Marcellus Shale wells in the area are not affected. This almost certainly means that the casing in the vertical portion of the well failed and allowed pressure to flow into a formation that all nine of the affected wells are producing from.