After at least a dozen earthquakes hit an area of northern Oklahoma in less than a week, the state commissions that regulate Oklahoma’s oil and natural gas industry asked some injection well operators to reduce wastewater disposal volumes.
In last year alone, there were more than 900 earthquakes in Oklahoma.
And just this week three earthquakes of magnitude 4.0 or higher were recorded in the northwestern part of the state and felt not only here in Wichita, but also as far away as Wisconsin. The quakes have been linked to and are occurring in areas where massive amounts of wastewater from oil wells are pumped back into the ground. The water is a byproduct of oil and gas production.
“The problem is that the coincidental evidence is so strong it’s hard to say that it isn’t somehow related, but there still is not a smoking gun you can point to and say, ‘Aha! That is the reason,'" says Jon Callen, president of Edmiston Oil in Wichita.
Callen says that there is also speculation that stopping the disposal too quickly could have a negative outcome.
“The concern is that if you were injecting water into the ground at a certain rate under certain pressures and you shut that off suddenly, you could create a new environment that, from that sudden pressure change, could cause an immediate reaction from that drastic change," he says.
Callen says Oklahoma and Kansas have had similar problems with increased seismic activity, but until now each state was attacking the issue differently.
“Kansas has already started to request and cause reductions in water injection," he says. "Oklahoma is just now getting around to starting that.”
The major difference is that Kansas has taken legal action requiring reductions in daily disposal volumes. As of right now, Oklahoma is asking companies to reduce amounts voluntarily. Callen says the injection of wastewater into disposal wells isn’t new. In fact, his company has been doing it since the 1950s.
"But ours are not the long horizontals in the sense [that] we’re taking the water out of the ground and we’re putting it back where we found it," he says. "We’re just letting the oil settle out and selling the oil. It hasn’t been a problem until we got in the new horizontal wells and the fracking.”
But it isn’t the fracking that causes the problem. Callen says that part is a one-time event.
"You frack a well and you’re on the well for less than a week doing that. It’s more likely the handling of the wastewater that comes out after you separate the water and the oil that you produce, and put the water back in that’s causing the problem," he says.
Sometimes the wastewater from fracking is transported and injected into wells elsewhere for disposal. The United States Geological Survey (USGS) reports that the number of recorded earthquakes in Kansas has risen substantially since 2013, when there were four recorded quakes. In 2014, there were 127, the majority of them in Harper and Sumner counties. And in March of 2015 the Kansas Corporation Commission (KCC) issued an order limiting the wastewater disposal in those counties to 25,000 barrels per day per well.
That impacted roughly 74 wells, says Ryan Hoffman, director of the oil and gas conservation division for the KCC. He says 23 additional wells, identified as being in areas of seismic concern, were also subject to harsher restrictions. They also had limits on the pressure that could be used for disposal.
“From that time until September 15, which would have been 180 days, the wells in that area were limited to 8,000 barrels per day," Hoffman says. "And that was to give staff and KGS time to monitor and make any further recommendation to the commission.”
Roughly three months after the order became effective there were 87 fewer earthquakes than the same timeframe prior to the restrictions. There were also 47 fewer quakes of magnitude 3.0 or larger.
The commission chose to extend the observation and monitoring period for another 180 days, and they’re getting ready to decide for a third time whether the restrictions and monitoring should continue.
“The way things stand now, the commission has asked staff to make their recommendation actually in the middle of February so that if there’s any response they’ll procedurally have enough time to make an order by the middle of March," Hoffman says.
He says that most of the companies operating the wells were compliant, but one company, SandRidge Energy, filed an intervention in April of 2015 preserving their right to appeal the order because it impacts their economic interests.
“To reduce disposal of saltwater you have to reduce your production, so it would definitely impact their ability to make money, because their only option would be to either spread out where the saltwater is going, take it to multiple wells, or produce less of the water, which means they’re also producing less oil," he says.
Hoffman says SandRidge has thus far complied with the reduction order and has yet to request a hearing. The company has reportedly objected similarly to reducing waste water disposal at its wells in northern Oklahoma.
And while the downward trend of seismic activity originating in Kansas can be viewed as positive news, the Kansas Corporation Commission says the results are not conclusive. According to the United State Geological Survey, many, if not most, of the tremors felt in Kansas lately have originated in Oklahoma.
Follow Abigail Wilson on Twitter @AbigailKMUW.
To contact KMUW News or to send in a news tip, reach us at firstname.lastname@example.org.