Oklahoma’s Clear Link Between Earthquakes and Energy Boom

Oklahoma officials this week said oil and gas activity was the likely cause of the stunning increase in earthquakes in the state. In an interview with Yale Environment 360, Oklahoma geologist Todd Halihan talks about what has caused this growing problem and what can be done about it.

Over the last few years, Oklahoma has experienced a stunning increase in the number of earthquakes. Since 2008, quakes of magnitude 3.0 or greater have hit that state 600 times more frequently than the historic average. Despite peer-reviewed studies to the contrary, Oklahoma’s state government had continued to express skepticism about the link between this seismic boom and the increase in the amount of wastewater from oil and gas operations being injected underground.

Todd Halihan
Todd Halihan

That official skepticism ended this week with the announcement by the Oklahoma Geological Survey that wastewater injection wells were, indeed, the “likely” cause of “the majority” of that state’s earthquakes.

Geologist Todd Halihan, a professor at Oklahoma State University, welcomed that announcement. Halihan, who sits on the Oklahoma Governor’s Coordinating Council on Seismic Activity, has examined the impact of injection wells on seismic activity and compared the state’s reluctance to accept the prevailing science to the Dust Bowl era, when warnings of that disaster went unheeded.

In an interview with Yale Environment 360, Halihan outlines some possible ways that the abnormal seismic activity in Oklahoma might be tamped down. But he also explains why he believes the problem has no quick or easy fixes.

Yale Environment 360: For a number of years, Oklahoma’s state government expressed official skepticism regarding the link between injection wells and induced seismicity. So what’s your reaction to the Oklahoma Geological Survey’s announcement that the rise in the number of earthquakes there is very likely attributable to injection wells?

Todd Halihan: It’s nice that the state is aligned with the peer-reviewed research. In terms of my discussion on the problem, I talk about peer-reviewed research and I try to provide the facts from a neutral perspective. As I’ve given those talks, it’s been very funny when people try to figure out which side of the issue I’m on. I’ve been very confounding to people because I’m actually neutral — or I try my best to be. I just present the facts and what the options are. So I’m relieved that there’s now an alignment between the peer-reviewed literature and the state’s official statement.

e360: You said that, in your efforts to get the state to align with that peer-reviewed work, you sometimes felt you were talking about climate change and not earthquakes. How so?

Halihan: One thing is the belief that until we are 100 percent certain we shouldn’t take any action that would affect the economy. If you’ve got a plane with smoke coming out of it, you’re probably going to take some action. You’re not 100 percent certain it’s going to crash, but you probably want to step back and look at it. So it’s the same thing for the energy industry and the folks here. Yes, we’re not 100 percent sure that you’re causing earthquakes. But the problem for me that I saw was that even while we had a lot of seismic activity, people were applying to drill right in the center of it. You can understand from an economic perspective they’ve got an investment. But for folks to then say, “I realize there’s a problem going on, there’s uncertainty going on, but I would like to just keep going as fast as I can. I want to keep adding to the problem because I’ve got a business plan.” And that’s the limit that I reached — plowing forward in the face of uncertainty when there’s a pretty negative side effect. I don’t think that’s necessarily an appropriate way to have the industry move forward.

The other thing is people saying that I’m obviously looking to do fundraising for my research. I’ve purposely not written a grant to ask for money to look at earthquake issues, so that I have not been a funded researcher. It’s a common accusation against climate scientists, and we giggle because none of us know a rich climate scientist. We also don’t know any rich seismologists that are working on earthquake issues.

e360: That limit you say you reached may have been the point when you started making analogies to the Dust Bowl era and the unheeded warnings about that disaster.

Halihan: When I was a kid learning about the Dust Bowl there was a sense, “Wow, they didn’t know anything back then, I pity those poor people they didn’t have science.” And then when I moved to Oklahoma I learned that actually there were people from the [agricultural] extension offices speaking with farmers, saying “You guys can’t do this, this is a really bad

There’s a built-in uncertainty because we’re basically running an industrial-scale wastewater facility.’

idea.” And the science was ignored.

e360: Wastewater that’s injected underground can rupture or loosen existing faults, resulting in seismic activity. That’s something that was established decades ago. What research in Oklahoma is still needed to adequately characterize the seismic risk these wells might pose? Do we need to know more about the faults in Oklahoma?

Halihan: There’s a built-in uncertainty because we’re basically running an industrial-scale wastewater disposal facility that we didn’t characterize in terms of how it was functioning as a whole originally. This happened in freshwater issues back in 1980s when we were doing most of that regulation on a per-well basis. We’d look at a farmer who wanted to pump 400 gallons for his irrigation well, and we did lots of regulations based on that and then each guy applied for a different permit. But then you started realizing if you had 1,000 wells, that it didn’t really work. You had to look at how the whole thing is interacting and understand the whole system to be able to regulate it. And so now if you look at the various states that manage their groundwater systems, I don’t know of any of them that are managing on a per-well basis. But on the oil and gas side, we’re still doing that. It’s a per-well basis, it’s not a system basis.

And so when you have 1,000 disposal wells operating at the same time, you start asking questions like, “At this point right here I’d like to know what happens when we have monthly averages of what they injected.” You actually don’t have the data to solve the problem. You either would have to increase the data density tremendously for each location, or you’d have to start managing in an alternate way.

e360: The Oklahoma Corporation Commission, which regulates the oil and gas industry in the state, reviews injection well permits for, amongst other things, proximity to faults. It also monitors pressure and volume data for wells in areas of concern. And it recently required some well operators in an area with the deepest injection formation to prove they’re not injecting into the granite so-called basement level, which is prone to faults. So what’s your take on how adequate or not those protocols are?

Halihan: There’s a bit of history there because the protocols were developed to keep the very salty water from getting into the freshwater aquifers and contaminating them. The original methodology for getting rid of the water was to put it in the stream and we just sent it on its way. So an injection well became a much better option because we didn’t put all that salt into the streams and destroy the surface water. The primary concern was whether the material we’re injecting will come back up to the surface. All the protocols were built for that. Very commonly, when those wells were built, they would drill through the thick rock at the basement level. What you would typically do is drill all the way through it. The easiest way to know you’d made it through was that you would start to see granite come up. Then you’d stop.

Where you’re trying to protect freshwater, that protocol works great. In the event of seismicity, attaching it to the rocks below it — in the basement rocks in that granite — that’s a really bad idea. When those fluids try to go into the basement [level], there’s basically nowhere to go, and it changes the pressure along those faults. But we didn’t have seismicity when we first developed all these protocols. So what the Oklahoma Corporation Commission has said is we have to match both objectives now. If you’ve gone down into those rocks, you’re going to have to plug back, which means I’m going to go put in concrete or other material to seal that bottom portion of that well off so the water can no longer directly feed into the basement rocks.

e360: But since the Oklahoma Corporation Commission instituted this monitoring system, most of which started in December 2013, it’s my understanding that seismicity has only increased in the state. So where do

Whatever the state government has asked for, the industry has said, ‘Ok, we’ll do that.’’

we go from here? What does the science tell us about some things that can be done at this point to mitigate induced seismicity?

Halihan: You can lower injection rates. There’s some evidence suggesting you don’t just want to turn off all of them. That might be a riskier thing to do. So you want to lower them down and slow the whole process down. I’ve looked at whether you can go into a seismically active fault and drain off some of the pressure and try to lock it back up again. That experiment’s never been done. But that’s a potential. We could go in and remediate them by draining excess fluid out of that particular location we’re really concerned about.

e360: And there are areas of higher risk, depending on which way the fault is oriented. In addition to pressure and volume, that could be another factor that a regulatory agency could look at, right?

Halihan: From a regulatory perspective, you could say we know this fault has the correct orientation to be more likely to slip. So therefore you can’t do this or that around there. The other scenario is a company says, “Ok, we looked around. We did not detect any faults. We put in our well and now a new fault has been detected that didn’t show up until it started moving.” And so what do you do from a regulatory perspective? You’ve already allowed the well to be there and they’ve already spent the money.

But whatever the state government has asked for, the industry has said, “Ok, we’ll do that.” I don’t know of any case where any company ever said, “We’re not doing that.” People talk as if the industry’s out to get somebody. If the state says. “We think it’s a good idea that you guys spend X amount of dollars and do that to this well,” the industry has done those things.

e360: So maybe the state’s not asking enough of the industry?

Halihan: Right. The question is how do they ask it, and in which way do they ask it, and which is the most useful thing to ask, in the context of the uncertainty of the problem.

e360: An Oklahoma state representative, among others, has called for a moratorium on disposal wells in the most problematic parts of the state. Are there areas that are simply too risky to operate a well in?

Halihan: There are several levels of what you define as risk. There’s the risk that you cause a major earthquake and you have a lot of liability and damage things and potentially have done harm to folks. There are companies operating on a very high technical level, and then you have the backyard oil barons. And having those two guys being tagged together as “that industry” makes it really difficult when you say we’d like to move forward in sensible ways. There are companies that are moving forward with an entire tribe of technical folks behind them looking at everything they do, and then folks that are saying, “I want to put a well here because I’ve got a drill rig and I’ve filled out my forms right.” That setup is probably the riskiest.

e360: You sit on the governor’s Coordinating Council on Seismic Activity, which is charged with organizing state resources related to Oklahoma’s increase in seismic activity. What are some priorities for you as a member of that council?

Halihan: The council’s charge is to coordinate. And one of the things that was missing was communication. So the council set up a website that recently launched. That way there’s an easier, centralized way to get stuff out to the public to say, “Here’s what’s going on, here’s what people are doing.”

e360: If you were going to apply for funding for a study on this issue, what would you want to look at?

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Halihan: The Arbuckle Formation is a really thick carbonate rock that is really good at absorbing water. It’s distributed over a huge portion of the state. So when we then look at a way to make water go away from a particular point, it’s really good at it. … We need to understand how those fluids are moving. And we don’t have a good handle on that.

So there are two things to study. One is, how does that piece of rock actually function on a system basis down there? They operated it for a long time, and it didn’t have earthquakes. But now it’s seismically active. We don’t have a good handle on where those fluids are going and how fast and in which directions do they head away from those wells. And if you had X number of wells in the same location, how do they interact? We don’t really have a lot of data on that because we’ve been managing on a per-well basis. It would be great to know that information, and the companies would love to know that information.

e360: In the last few years, the amount of wastewater injected underground in Oklahoma has shot up about 35 percent. Is anyone talking about alternatives to well injection, such as treating the water?

Halihan: When you’re treating things that are 150,000 parts per million, you still end up with fluids that you have to dispose of. You’re getting some clean water out of it but you start getting to where it’s financially unviable to do other things. So there’s the question of whether we’re going to have to ask if that formation is too wet to produce. And we can think about how to deal with the water that’s already there. All those questions are happening at the same time someone’s got a big loan for the things they’re doing to produce that oil. So it’s not a purely academic pursuit.

e360: What keeps you up at night with regards to this issue?

Halihan: My house is sitting on faults, and I sit up at night because my bed is shaking.

e360: So you have a dog in this fight.

Halihan: I have a very scared dog in the fight. He jumps up in my bed and decides I’m going to save him.