Earthquakes such as the one that forced a wastewater disposal well in Youngstown, OH, to be closed at the beginning of the year can be avoided if oil, natural gas and service companies are more knowledgeable of the local and regional geology.
"The primary way to avoid these things is to understand the local regional geology," Julio Friedmann, chief energy technologist at Lawrence Livermore National Laboratory, told NGI's Shale Daily. "If there are pre-existing ancient faults close to your injection site, then the risk of induced earthquakes goes up."
Friedmann -- who served as keynote speaker at the United States Energy Association's (USEA) "Future of Fracking Technologies" conference in Washington, DC, on Thursday -- emphasized that hydraulic fracturing (fracking) doesn't typically lead to large earthquakes, but injection wells could potentially induce small ones, like the 4.0-magnitude temblor that hit Ohio on Dec. 31.
"An induced earthquake of magnitude 4.0 is large, but on the earthquake magnitude scale it's tiny," Friedmann said. "It feels kind of like a truck driving by in most places. In Ohio it was stronger because you have an old and strong crust there, but the fact is 4.0 is not a big earthquake and typically does not lead to infrastructure damage.
"Sometimes induced earthquakes can be large, and that's why it's important to do your homework and understand these risks."
At issue is a wastewater well owned by Youngstown-based D&L Energy Inc., which state regulators allege is responsible for a series of seismic events that began in March 2011 and ended on New Year's Eve. The Ohio Department of Natural Resources (ODNR) ordered Northstar Disposal Services LLC, the well's operator, to halt operations at the well on Jan. 1 (see Shale Daily, Jan. 4).
"We've been doing wastewater injection in this country for years and typically do not have those kinds of earthquakes," Friedmann said. "In Ohio, we've been injecting into deep formations for 50 years. This isn't something new and we know how to do this. This particular case was one in which a little foresight may have prevented that kind of an event.
"There are deep faults [in Ohio] that are well understood and mapped. The Ohio Geological Survey has known about them for a long time, as have professors at Ohio State [University] and so forth. Knowing the presence and the orientation of those faults can help oil and gas companies and service companies avoid these kinds of earthquakes."
Friedmann lauded oil and gas companies for the increasing use of recycling and improvements in cleaning and processing, thereby reducing the amount of fracking fluid generated from their operations. "Those are good steps to start with, but ultimately one should expect to require large volumes of water to be disposed of," Friedmann said. "The best way to do that is through deep injection."
Asked if he thought the seismic activity would subside in Youngstown, Friedmann said, "I'm sure it already has. [But] if they continue to inject the volumes of water at the same rate, they can expect more trouble. If they were to change location or reduce the volume and rate of injection, then the chance of earthquakes would go down a lot."
Friedmann added that he thought the industry would take the necessary steps in responding to events such as the Youngstown quakes, which received significant media attention. "I think the companies involved are fully aware now of these issues and I'm sure are coming up with reasonable measures [to solve them]," Friedmann said.
Vince Bevacqua, spokesman for D&L, could not be reached for comment Friday. D&L said shortly after the disposal well's shutdown that it would pay for a study to determine the cause of the seismic activity (see Shale Daily, Jan. 11).
Last year regulators in Arkansas established a moratorium on wastewater disposal wells in an area of the Fayetteville Shale after similar quake activity was reported there (see Shale Daily, July 29, 2011; March 4, 2011).
The ODNR said quake activity began in the Youngstown area on March 17. Four seismometers operated by Columbia University recorded a 2.7-magnitude earthquake on Dec. 24 in addition to the Dec. 31 quake. The agency added that the two quakes over the holidays were 330 feet apart and occurred at a similar depth, about 12,000 feet.