Dangers of old wells
Abandoned wells can leak natural gas, oil and brine. Some of those hazards can be a nuisance; others can be very serious, as these examples illustrate:
LEAKING GAS & FLUIDS
Pennsylvania’s Department of Environmental Protection identified several incidents since the late 1990s where pressure changes caused by the hydraulic fracturing of new wells caused gas and fluids to leak from abandoned wells.
McKean County, late 1990s: Natural gas vented from an abandoned well at a rate of more than 100,000 cubic feet per day after hydraulic fracturing operations at a nearby well.
East Vandergrift, Westmoreland County, 2008: After hydraulic fracturing at a conventional gas well, a large amount of natural gas seeped into the ground from a buried abandoned well that remained unidentified. The gas came within 8 feet of a home.
French Lick Creek, Tioga County, 2012: A hunting cabin’s water well overflowed and gas bubbles were found in a nearby stream in an area where several wells were being drilled and fracked.
Greene County, 2014: About 1,000 gallons of oily material — similar to a type of clay used in well plugging and drilling — was pushed out of an abandoned well while a new well was being fracked. The material flowed into a stream that supplied a cattle farm.
In 1985, natural gas leaked into a Ross Department Store in Los Angeles and caused an explosion that injured two dozen people. The gas seeped into the building through a geological fault and an abandoned well.
A U.S. Geological Survey report in 1988 found that brine leaking from abandoned wells had polluted an aquifer near West Point, Kentucky. The aquifer supplied drinking water to 50,000 people and Fort Knox. Several water wells were closed.
— Shane Hoover
Warning signs of an abandoned well
Abandoned oil and gas wells are found in yards, fields, streams, cemeteries, parks, and even under buildings and houses in large urban areas. Here are some signs of an abandoned well:
A large diameter pipe or wellhead is sticking out of the ground.
Grass and other plants won’t grow in an area.
A persistent odor of crude oil, natural gas or rotten eggs.
Well water contaminated by saltwater, marked by increased hardness or resistance to freezing.
Well water contaminated by oil, which may appear as a rainbow sheen on the surface.
Well water contaminated by natural gas. Signals include pressure surges, bubbles in the water and the odor of natural gas at the tap.
Signs of an abandoned oil or gas well should be reported to state authorities.
— Source: Ohio Department of Natural Resources