Parts of the United States have seen a sharp uptick in the amount of seismic activity over the past few years. These earthquakes are generally small in magnitude—in many cases incapable of being detected without sophisticated instrumentation—but their frequency is rising at an alarming rate. As the EIA reports, an increase in earthquakes east of the Rocky Mountains is particularly concerning, and seems to be centered on the state of Oklahoma. This new phenomenon is being linked with the storage of drilling wastewater in old oil and gas wells:
More earthquakes in these areas have coincided with the increase in oil and natural gas production from shale formations. Seismic events caused by human activity—also known as induced seismicity—are most often caused by the underground injection of wastewater produced during the oil and natural gas extraction process.
Before 2009, Oklahoma might have experienced one to two low-magnitude earthquakes per year. Since 2014, Oklahoma has experienced one to two low-magnitude earthquakes per day, with a few instances of higher magnitude (between magnitude 5 and 6) earthquakes that caused some damage.
Those readers familiar with the America’s many productive shale basins might be wondering why earthquakes are spiking predominantly in Oklahoma—after all, producers are storing wastewater from fracking in many of the country’s other shale hotspots. According to the EIA, Oklahoma’s stratigraphy is vulnerable to the seismic stresses induced by wastewater storage in wells:
In addition to the increased use of wastewater injection related to oil and natural gas production in the region, the geologic conditions in central Oklahoma are conducive to triggering seismic activity. The rock underlying the formations where disposal water is being injected in the region has existing faults that are susceptible to the changing stresses caused by fluid injection. Without these geologic conditions, induced seismicity would be much less common. For example, induced seismicity in the Bakken region of North Dakota and Montana is relatively rare.
On the one hand, this comes as something of a relief, because it suggests that the strong connection between fracking and earthquakes isn’t an existential problem for the most important energy development in the United States in a generation (or more). The problems Oklahoma is now facing don’t necessarily apply to the rest of the country.
Moreover, storing wastewater from oil and gas drilling in old wells isn’t the only option for shale companies. A cottage industry has cropped up to try and make recycling that wastewater economical, and some firms are looking at ways to frack shale rock without water at all. Then, too, there’s the option of storing this effluent in above ground ponds. These might not be the first choices of the shale industry, but it’s important to note that alternatives exist—and Oklahoma regulators are pushing the state’s drillers to employ them en masse.
This is a serious issue. It’s the most damning indictment of the shale industry that we’ve yet seen, and it’s a problem that demands a solution. We have a good grasp on what’s going wrong in Oklahoma’s shale fields, but now it’s time to fix it.
Source: The American Interest
About Oklahoma Minerals Founder GIB KNIGHT
Gib Knight is a private oil and gas investor and consultant, providing clients advanced analytics and building innovative visual business intelligence solutions to visualize the results, across a broad spectrum of regulatory filings and production data in Oklahoma and Texas. He is the founder of OklahomaMinerals.com, an online resource designed for mineral owners in Oklahoma.