The earthquakes just keep coming. Four days after a 4.7 magnitude earthquake was recorded southwest of Cherokee, a 4.4 magnitude earthquake was recorded Monday near Hennessey and Tuesday a 3.0 magnitude quake sprang up about 40 miles southeast of Norman, capping off a run of 23 earthquakes of magnitude 3.0 or higher in a seven-day period.
In response to Thursday’s quake, the Oklahoma Corporation Commission released a plan calling for two disposal wells to stop operations and for many others to cut down in volume.
Oklahoma Geological Survey Director Jeremy Boak said it’s a smart move because he said there’s a clear link between disposal wells and seismic activity in Oklahoma and he would like to see a balanced approach that allows scientists and policy makers to gather more information.
Jack Dake, a land manager for Baron Exploration Company, said the OCC’s measured approach is a good one, but may not be worth the trouble. Make, who has been in the industry since 1978, doesn’t believe that human activity is responsible for Oklahoma’s uptick in quakes and believes the commission may be taking action just to take action.
“The commission was one of the first groups to look at earthquake causation and to consider whether or not oil and gas activities were a factor,” Dake said. “The commission has reason behind what they’re doing, but it’s not proof. This is simply to see if, and that’s a big if, if it’s related and perhaps there is no more prudent effort that the OCC can institute than what they’ve done, but as of today, to the best of my knowledge and belief, no one knows whether this means anything or not, other than they feel like the commission is doing something.”
The commission’s efforts are focused on injection disposal wells.
According to Boak, about 95 percent of the water being injected into disposal wells is formation water — water that was already present in the ground prior to fracking operations.
“The water that comes out is ancient seawater,” he said. “It’s been sitting there for millions of years, getting more concentrated all the time to the point where it’s saltier even than Dead Sea water which is already toxic to you by itself, in addition to, of course, the generated petroleum in there … So, it’s not good stuff. You have to dispose of it.”
Boak said for years, the best destination for that waste has been the Arbuckle group sediment, because of its immense depth and distance from groundwater. Now, Boak said the high volume of injection water is producing earthquakes. It’s fracking related, but he said the fracking itself is not the problem.
“The most ardent anti-frackers will insist that because the particular play being worked in is a fracking play, that fracking causes those earthquakes,” Boak said. “But there are plays that are water rich that don’t get fracked, or get fracked in much less serious ways and it isn’t the fracking itself that causes the earthquakes. It’s taking the produced water from the formation and trying to dispose of it somewhere deep, which is the best thing to do, except in this case it leaks.”
Everyone agrees that the water must be disposed of, but the best method is still a debate.
If disposal sites with a “good bottom seal” could be identified, Boak said the problem would be solved.
“We’re going to have to find ways to inject less water per month into the deep Arbuckles. One way to do that is to find another formation,” Boak said.
The downturn in oil prices may have been the best tool for curtailing the volume. Less production means less injection. Less injection means fewer quakes, according to Boak. If oil prices pick up again, he said we could see the number of quakes continue to rise.
The OCC has taken steps to control injection sites, but Boak said the real issue is finding a balance. To this point, he said it’s hard to tell with clarity what is driving the reduced injection volumes — the economy or the OCC’s efforts.
“We’re just beginning to get our hands on how that localization takes place and what it might tell us on how many wells we might have to throttle back on,” he said.
And while he’s been a geologist since 1970, he said this is a new problem, one that he and his colleagues intend to carefully unravel. With so much data to analyze, it’s no easy task.
“We understand the physics of earthquakes pretty darn well … but trying to figure out the reduction that we need to manage and how to do it most effectively is the challenge,” he said. “I’d love to get to the point to where we can predict the next magnitude 4.0 earthquake. We’re not to that point … I’m concerned about the latest pulse of earthquakes. We need to watch … We’re just beginning to get a handle on these patterns. It’s a big job and it takes time. I don’t think a wholesale stoppage is the right way to go. I think the targeted approach that OCC has been taking is effective. As long as they’re responding quickly, I think we’re doing useful things to try and scale it back until we have a better angle on how to completely control it.”
Ultimately, Dake said he doesn’t see the need for any more control through regulation. He said earthquakes are normal and just because there’s an increase doesn’t automatically point to human activity as a cause.
“To have periods of quiet and significant periods of activity is normal,” Dake said. ” … The Pacific Rim has been experiencing increasingly significant activities, both earthquakes and volcanoes, for at least the past 10 years. Recently, San Ramon, California experienced 583 earthquakes in three weeks, five times their previously recorded high. There are no injection wells near San Ramon. Boston had an earthquake (Tuesday) and Connecticut has been experiencing earthquakes in 2015. There are no injection wells there, either.”
This article was written by Mack Burke from The Norman Transcript, Okla. and was legally licensed through the NewsCred publisher network.