Earthquake link triggers tougher drilling permit conditions

Shale gas rig

COLUMBUS — The  Ohio Department of Natural Resources is creating new, stronger permit conditions for deep oil or gas drilling near faults or areas of past seismic activity.

The new policies, announced April 11, are in response to recent seismic events in Poland Township (Mahoning County) at a well owned by Hilcorp Energy Company, that show a probable connection to hydraulic fracturing near a previously unknown microfault.

ODNR reported that a series of 11 earthquakes ranging in magnitude from 2.1 to 3.0, occurred near the Hilcorp Energy Co. drill site at the Republic Services Carbon Limestone Landfill starting March 10.

Seismic monitors

New permits issued by ODNR for horizontal drilling within three miles of a known fault or area of seismic activity greater than a 2.0 magnitude would require companies to install sensitive seismic monitors.

If those monitors detect a seismic event in excess of 1.0 magnitude, activities would pause while the cause is investigated.

If the investigation reveals a probable connection to the hydraulic fracturing process, all well completion operations will be suspended.

ODNR will develop new criteria and permit conditions for new applications in light of this change in policy. The department will also review previously issued permits that have not been drilled.

Hilcorp reaction

In a written statement, Hilcorp Energy Company said it is currently reviewing ODNR’s latest announcement regarding drilling permit conditions.

While it’s too early to understand how the newly introduced conditions impact its Ohio operations, Hilcorp said it remains committed to public safety and acting in a manner consistent with being a good corporate citizen in the communities where they operate.

Public safety

“While we can never be 100 percent sure that drilling activities are connected to a seismic event, caution dictates that we take these new steps to protect human health, safety and the environment,” said ODNR Director James Zehringer.

“Not only will this reasonable course of action help to ensure public health and safety, but it will also help us to expand our underground maps and provide more information about all types of seismicity in Ohio.”

Industry reaction

The Ohio Oil and Gas Association emphasized the series of earthquakes was a rare event and the public should not assume that is a common event with the oil and gas development.

“We believe the seismic activity experienced in Poland Township was a rare and isolated event that should not cast doubt about the safety of hydraulic fracturing, a process that has been conducted on more than one million oil and gas wells in the U.S., including 80,000 in Ohio, since the 1950s,” said Thomas E. Stewart, executive vice president of the Ohio Oil and Gas Association in a written statement.

The association is hoping stiffer regulations won’t curtail the industry’s development.

“We will thoroughly review the recommendations provided by the Ohio Department of Natural Resources, but will only support measures based on sound, scientific principles and practicality,” said Stewart.


Meanwhile, David Hill, a consulting geologist for the Ohio Oil and Gas Association, confirmed that the microfault in Poland Township had not been mapped, but said it will be studied for years and geologists will be able to learn a lot from the well site.

Hill said most faults in Ohio are inactive, which is why earthquakes in Ohio are rare.

He added that it took a specific set of events for the earthquakes to happen in Mahoning County, and, statistically, there is only a very low chance for an event like this to happen.

“You have to have a very specific set of parameters for an event like this happen,” said Hill. “Remember there are over 800 horizontal wells drilled in Ohio.”
“In modern society, we don’t eliminate risk. We manage it. We have to or we would never move forward,” said Hill.

800 wells drilled

More than 800 wells have been drilled in Ohio’s Utica and Marcellus shale play, including as many as 16,000 hydraulic fracturing stages from those wells.

Regarding the seismic events in Mahoning County, ODNR geologists believe the sand and water injected into the well during the hydraulic fracturing process may have increased pressure on an unknown microfault in the area.

Further hydraulic fracturing at the site is suspended, but the company will be permitted to recover resources from five of the previously drilled wells located on the pad. This is also expected to have the effect of reducing underground pressure and decreasing the likelihood of another seismic event.

Consortium created

Under ODNR’s lead, Ohio has joined a consortium of state regulators dedicated to learning more about seismic activity, especially as it relates to oil and gas activity.

The members of this consortium are currently working with the Interstate Oil and Gas Compact Commission and Groundwater Protection Council to share information and knowledge.

The working group also hopes to draw upon current and future research to develop common procedures for how to monitor for seismic activity and respond if activity occurs.

“ODNR’s directives are a sensible response to a serious issue that regulators across the country are closely examining,” said Gerry Baker, associate executive director of the Interstate Oil and Gas Compact Commission.

Seismic network

The Ohio Seismic Network, coordinated by ODNR and operated by various partners, began recording seismic events in 1999. Before that time, the recording of seismic events varied from distant machines and felt reports.

Ohio has a history of seismic activity, and since the network was established, Ohio has experienced 109 events greater than 2.0 magnitude.

Data from the Ohio Seismic Network will be used as part of the new application review process.

A map of underground seismic faults and past seismic events is available at


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