The Pennsylvania Department of Environmental Protection (DEP) is investigating an EQT-operated unconventional gas well in Greene County after complaints from local residents who have experienced water contamination, among other issues.
The investigation began June 20th after EQT reported to DEP that it had received a complaint a day earlier from a property owner living near an EQT-owned unconventional well. The resident told EQT that water was spewing from a nearby abandoned conventional gas well, and that they had found sediment in their water. An emailed statement from DEP said EQT reported a “possible communication” between the unconventional well lateral being fracked and the abandoned well and stopped its fracking activities. The abandoned well had not been previously identified by DEP, the statement indicated. Further complaints followed from other residents who noticed changes in their well water.
Well communication, also called a “frac-out,” is not uncommon, especially in areas where new wells are being fracked near older, abandoned, or orphaned wells.
What exactly is a frac-out? The fundamentals of an unconventional gas well must be understood first. An unconventional gas well uses long lateral lines drilled thousands of feet out from the horizontal shaft to access natural gas in deep pockets of a shale formation. A combination of water, sand, and other chemicals are pumped into the rock formation through the lateral at high pressure to break, or fracture, the rock, releasing the gas, which is pumped back out of the well.
As these types of wells travel miles away from the surface well location, they can interact with other formations. Gas naturally moves through the path of least resistance, meaning that gas can travel if there are changes in the rock formation. A frac-out occurs when mismatched pressures cause the fracking liquid and gas to unintentionally come back to the surface via the path of least resistance.
Though common and often inconsequential, frac-outs can cause serious problems both environmentally and for human health, especially when in the vicinity of abandoned wells and residential homes.
DEP is in the early stages of its investigation of the water complaints, and is sampling and testing water, investigating gas wells in the area of the unconventional well site, and reviewing information from EQT.