Marcellus Shale drilling is driving a boom in the construction of wastewater disposal wells in Ohio, despite the oil and gas industry push to reuse the water that flows back up after hydraulic fracturing.
In Ohio, 16 new wells are under construction to take waste "brine" from oil and gas wells. Seven have been granted permits but have not yet been drilled, according to figures provided by the Ohio Department of Natural Resources. An additional 20 applications for new brine wells are under review.
Taken together, the wells under construction, permitted and applied for would represent a 25 percent increase over the 172 active wells currently accepting drilling and fracturing waste.
In Pennsylvania, there are only five such wells in operation. But two more permits are under review, according to U.S. EPA officials, one in the west of the state in Venango County and the other more central in Clearfield County.
Two disposal wells permitted near Corry, about 40 miles southwest of Erie, aren't yet receiving waste because their permits were appealed by neighboring landowners.
Waste disposal is the less-well-understood side of oil and gas production, but it was pushed into the spotlight by fears that treatment plants didn't properly treat the radiation-laced brine before releasing it into streams. Then, as Pennsylvania regulators clamped down on allowing treated wastewater into rivers, a New Year's Day earthquake was linked to an injection well just across the state line in Youngstown, Ohio.
The website of the Marcellus Shale Coalition, which represents drillers in Ohio, Pennsylvania and other states, says that "in the Appalachian Basin, flow-back is almost entirely recycled and reused to fracture additional wells."
Pennsylvania Department of Environmental Protection Secretary Michael Krancer told a congressional committee in December that about 80 percent of the brine from hydraulic fracturing is used on another frack job.
"Recycling rates across the Marcellus continue to tick positively upward as technologies evolve and become more widely available," said Travis Windle, spokesman for the Marcellus Shale Coalition. "These advancements represent a huge environmental success story. And while more and more flowback and produced water is recycled each day, EPA-permitted injection wells play an important role in the broader water management process, especially as it relates to drilling fluids."
Though less than 8 percent of the brine, used fracturing fluid and drilling waste from Pennsylvania Marcellus wells is injected into disposal wells, that's up from a little more than 6 percent in 2010. And state records show that the total amount of waste being sent to injection wells has gone up nearly 500 percent since 2010.
In Pennsylvania, waste injection wells are regulated by EPA, while in Ohio they're regulated by state officials.
Some in industry have said Pennsylvania's geology is unsuitable for underground injection, while state officials have said the best areas of the state for injection are being used for gas storage. But EPA scientists, along with some academics, say Pennsylvania's geology is just as suitable as the rest of Appalachia. There are 30 oil and gas brine wells in the four Ohio counties that border Pennsylvania.
Nationally, EPA records show there are a little more than 150,000 "Class II" injection wells associated with oil and gas. According to the U.S. Geological Survey, about 40,000 of those are disposal wells. The rest are wells where water is used to dislodge oil and gas and "enhance recovery" of the minerals. Underground injection is also used to dispose of radioactive waste, hazardous waste, mining fluids and carbon dioxide.
U.S. Geological Survey officials have pointed to injection as a likely cause of a "remarkable" increase in earthquakes across the middle of the country (EnergyWire, March 29).
Oil and gas producers are exempt from a federal environmental law designed to prevent industrial waste injection wells from triggering earthquakes (EnergyWire, March 22). States can adopt stricter regulations on injection wells, as Ohio is doing for future wells after the Youngstown quake.
The Ohio rules order well operators to submit more comprehensive geological data when requesting a permit to drill and require tracking of wastewater.
Other states have not followed suit, but EPA is drafting suggestions for state regulators to minimize earthquakes caused by waste injection (EnergyWire, March 15).
And a National Academy of Sciences panel is studying how oil and gas production and other types of energy production can lead to man-made earthquakes. NAS officials are hoping to release that report this summer.