Monday, May 9, 2016

What About Those Earthquakes?

In a comment on another blog post, Ed asked what I thought about the earthquakes in Oklahoma.

Before I give my opinion about whether I think there is a relationship between fracking and the recent earthquakes, I should give a little background.  Except for a petroleum engineering class I took in college, I don't have any education or direct experience working in the oil and gas industry. 

On the farm, there are pipelines running everywhere (in the recent boom, two new ones were built across a couple of pastures), back in the boom of the '70's a well was drilled on almost every 80 acres, and my grandparents, aunts, and parents own a portion of the mineral rights under the farm.

From what I know, the wells drilled in the '20's were shallow (1000 feet deep?), the wells in the '70's were deeper (around 5000 feet deep), and the recent wells were almost all directional (going down about 5000 feet, then running horizontal for about a mile).  Because the oil is in shale formations, all the wells were hydraulically fractured after drilling, and all the wells produced salt water that was disposed of in disposal wells.  If I had to guess, I'd guess that there was as much or even more drilling activity and production in the seventies as there was in the recent boom.

The recent earthquakes in Oklahoma started back in 2006 before the oil boom and started happening in my local area (where I live) about two years ago. There isn't as much drilling activity or as many disposal wells around the area where I live, but there was about a month or two when the earthquakes came all the time.  The biggest was probably around a 4.0, but most of them were small 2.0 type of earthquakes. The small ones feel sort of like the way the house shakes when there's a close thunder clap or if a large truck drove by the house. The larger ones feel like you'd think an earthquake would feel with the ground slightly "rolling", but it wasn't big enough to be alarming.

According to the geological websites I looked at, most of those earthquakes typically originated from 30,000 feet deep.

I never saw a good explanation for how injecting water into a disposal well that was around 5000 feet deep could cause an earthquake to originate from a faultline that was 30,000 feet deep.  From what little I know about hydrology, the water would tend to go upward towards the surface of the earth after being disposed of in the well.

To make a long story short, oil wells have been drilled in almost the same basic way since the oil fields opened up in Oklahoma, earthquakes have happened in the past in Oklahoma, the people blaming the oil/gas industry for earthquakes have a long history of blaming the oil/gas industry for anything and everything, and I don't see how anything that happens at 5000 feet underground can have an effect at the 30,000 feet deep mark.

So based on those thoughts, I'm not convinced that fracking or disposal wells caused the recent earthquakes, but I could be wrong, and I know that a ton of people will disagree with me.

16 comments:

  1. I guess up to watching this show, I always thought that fracking was to blame but according to the report (60 Minutes), fracking is not to blame. According to the research, the disposal wells are causing the blame. They said that disposal wells are drilled much deeper than the oil layer so as to not contribute to polluting the oil or making it harder to retrieve. Instead, the wills are drilled very deep down to a porous layer right above the layer that contains all the faults. They use this layer for it's ability to hold vast amounts of the brine. However, scientists now believe that the brine is seeping down into the fault layer and the water pressure is pushing apart the faults and that has caused all the earthquakes. They said Kansas was experiencing the same and did a reduction in the number of brine disposal wells and the earthquakes started immediately decreasing.

    It all sounded plausible to me. They even had a map showing all earthquakes of 3.0 and greater superimposed on a map showing all disposal wells and the images were almost exactly the same. But I have never experienced and earthquake and don't live in Oklahoma so I thought perhaps I should ask someone who does.

    On the surface of things if this were true, stopping the quakes would simply be finding a way to dispose of the brine. However, they pulled a beaker of 'oil' out of a well and it appeared that about half of it was brine and 2/5 of it gas and the remaining 1/10 was oil. That is a lot of brine to dispose of without causing some sort of ecological disaster.

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    1. The waste water is injected into a deeper layer than the oil producing layers, but it's nowhere as deep as 30,000 feet deep which is where the earthquakes that I experienced originated from. It just doesn't seem to make sense to me that any injected water could migrate downward from an upper level to such a great depth in enough volume to cause earthquakes like that.

      I do know that after a while you become much more sensitive to the smaller earthquakes and start to notice them more than you used to. According to most of what I've read, there have been numerous earthquakes in Oklahoma in the past, so it's possible that there were small earthquakes in the past that I just didn't notice because I wasn't "calibrated" to feel them.

      Some sort of connection with the recent earthquakes to the New Madrid fault always seemed to me like it might be worth investigating, but I never saw any local reporting at all along those lines.

      Besides all that, all I know is that we still need oil and natural gas, I'd rather not have a bunch of earthquakes happening if it can be helped, some people are always going to think the oil and gas industries can do no wrong, and some people are always going to blame the oil and gas industry for everything.

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    2. At least in my experience (which may not reflect the conditions everywhere), disposal wells are usually converted oil wells. That is, the waste fluids are injected back in an area of the field that's no longer productive and used to help flood the oil out to the producing wells. At least that's the norm around here.

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    3. I'm a little fuzzy on the details, but there's a disposal well a few miles from the farm that I think was drilled specifically as a disposal well.

      From the road, it looked like a horizontal drilling rig, but I don't know the depths it went to but it seems like it was drilling for longer than most other rigs spent drilling wells.

      Even with all the drilling activity and that disposal well, I don't think any earthquakes happened around the farm which is one reason I question whether waste water disposal is the main reason for earthquakes.

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  2. I had to google it but the layer waste water is pumped too is the Arbuckle layer which starts 7000 feet down. The layer underneath with the faults they call the crystaline basement ranges from 16,000 to 20,000 feet deep.

    https://news.stanford.edu/2015/06/18/okla-quake-drilling-061815/

    I wonder if there are several layers of fault material where two different types of earthquakes can be occurring.

    At the end of the day, I have a love hate relationship with the oil industry. We need them and therefore have to accept some bad things as a result (if indeed they are causing it) but it would certainly be nice if someday we weren't reliant on oil.

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    1. It's an awful long way from 7000 feet deep to the 16000 foot depth, I'd think it would take an astronomical amount of water to reach that depth and a lot of time for the water to reach those depths.

      The way I see it, if the world was less reliant on oil, it would just be reliant on something else, that's the way it's always worked and that's the way it will work in the future.

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  3. I should have been more specific. The Arbuckle layer into which the brine is evidently pumped starts at 7000 and goes down to 16,000. I'm guessing one would want to drill down somewhere in the middle to be able to pump the most water.

    You are right about being reliant on something else if it wasn't oil. My hope would be that we aren't reliant on something else that another country has control over. Perhaps is someone would develop the pocket fusion reactor so we all had our own personal battery that provided us with all the energy needed for our daily lives. The drawback is that the chinese would probably have the patents for the components.

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    1. Hydrocarbons are probably as close as the human race is ever going to get to having a cheap, versatile, readily available, and affordable energy source.

      It's funny that so many people hate the very thing that makes their lives possible.

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    2. While it puts me in the contrarian camp, as somebody who started off with a career in the energy (coal/oil) sector, and who then has worked for many years in the legal sector but with a close connection to industry, I agree with you on the odd nature of people sometimes detesting the things that make their lives possible, but I actually disagree on the future of petroleum and more particularly on coal. It's been interesting to watch.

      It is a matter of economics, of course, which is partially driven by supply, and by the cost of production. The boom we saw was driven by both, but the extent to which the recent boom was a mix of 1960s/1970s technology with brand new technology is really remarkable. The boom would not have happened without new technology and drilling methods. It also, however, wouldn't have happened without a price that made that worthwhile. Indeed, as surprising as it may seem, the boom in North America didn't even last long enough for the really new high tech rigs to really be fully deployed here, so there was plenty of tech left to apply. The rigs were largely the old type, rather than the new type.

      Setting aside the cause of the crash, however, new technologies are coming on in big ways that impact the energy sector. Where this is really hitting now is with coal. My state produces a lot of coal, and coal is now in a flat out economic depression. I don't think it's ever coming back. Indeed, years ago an executive for a major coal producer which was getting out of coal told me "coal is dead". A large part of that is due to North American coal consumers switching over to natural gas, and those consumers are never going back to coal.

      I note that as it seems to me that globally we're entering into a new era in regards to fuel. Coal is passing. Petroleum isn't yet, but some major coal producers are now anticipating a large reduction in demand coupled with an end to cost effective production. Saudi Arabia seems to be amongst those. We won't cease petroleum production in the foreseeable future, but as electrical power begins to come in, in new ways, I suspect that we'll increasingly see electric motors replace petroleum ones in many applications. The technology isn't there yet, but its starting to arrive. Just this past week I passed Tesla dealer in Salt Lake City that had a charging station just like a gas station. That'll start being more common.

      That anticipates a lot of technological advancements, both on the production and consumption end, but I think they're coming.

      Also on the consumption end, it seems that for some reason price no longer operates the way it once did, which reflects some sort of change in younger consumers in this area. They aren't enamored of driving the way that we older folks were, and therefore drops in price don't spur on the production of bigger vehicles, etc. The market seems saturated now, the way the market for Coca Cola, etc., is.

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    3. I don't think that there are still large amounts of petroleum out there just waiting to be found. I think that it's going to be difficult or almost impossible to come up with suitable replacements for everything that is currently made out of oil and natural gas anytime soon.

      Almost all of the wells drilled that I saw were horizontal wells. From one location, they were drilling up to 4 different wells going north and south up to a mile horizontally. With a vertical well it would have taken four wells (I think?) to equal each horizontal well. It was a pretty impressive operation to see those drilling rigs running, and at the peak of the activities I could see at least thirteen of those drilling rigs running at night from the farm.

      You'd think that you'd have also seen those sort of drilling rigs in WY.

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    4. We did have that type of drilling in Wyoming, but what I meant is that there are highly automated drilling rigs now that are fairly high tech. We didn't see many of those.

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  4. This topic is interesting to me because, prior to my being a lawyer, I was a geologist (that career having evaporated in an oil crash) and I've worked a lot on oil and gas matters as a lawyer.

    Anyhow, fracking isn't new, which is one thing to keep in mind. When all the reports about fracking causing all sorts of ills started surfacing I was very skeptical, and I remain at least somewhat skeptical, as the technology has been used for decades. I think what brought it to people's attention is that horizontal drilling opened up fields that were previously not all that productive and they then became so, with the aid of fracking. As some of these fields are in areas of the country that haven't seen much oil production for years, and in the intervening years people have moved near or onto the fields, its brought all of this to the attention to a lot of people for the first time.

    Having said that, a petroleum engineer that I know well down in the southwestern part of the country, and who is part of the industry, is convinced that the fracking is causing the Oklahoma earthquakes. As I know and respect him, I can't discount that. If this is correct, it has to be fluid displacement that's causing it. Or so I thought. I see here that the quakes started prior to the boom.

    Earthquakes, for what is worth, do come in cycles. That too makes sense. As stressed is released by one quake, it builds in another. It all seems immediate to us, as it's outside of our life experience. But to the planet, a period of several hundred thousand years means nothing at all.

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    1. From what I know and remember. the earthquakes started around 2006 with a lot of tiny ones that only seismic instruments could detect and a bigger one in 4.0 range causing some damage to a couple of older homes in central Oklahoma.

      The oil "boom" started going around 2008 with a few horizontal wells being drilled, and between 2011 and 2014 was the peak of drilling activity locally. Production and the disposal of the waste water from that production has held steady or went up since that 2014 drilling peak.

      Most of the earthquakes I experienced were back in about 2014, and they came in "clusters" with one after another for a day or so, then there would be a cluster of earthquakes in another part of the state. It could get on your nerves when they were happening, but they were relatively small and didn't damage anything.

      I can't remember the last time I've felt an earthquake, oil production and waste water disposal is still at the same levels as it was in 2014, so it still doesn't make sense to me that the waste water disposal was or is causing all the earthquakes. If waste water disposal was causing earthquakes, I'd think that they would still be happening as frequently as they were before because as far as I can tell they're still disposing of waste water.

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  5. I see you folks received a 5.0 one by Stillwater.

    Around here a 5.0 earthquake would be noticed, but not regarded as really bad. But that's not true everywhere, in part due to the nature of local construction. I hope you folks came out okay.

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    1. I felt the one that hit Cushing last night, but we're far enough away that I could just barely feel the ground sort of "roll up and down".

      The biggest one that's been close was the one that was somewhere around a 4.2 with the epicenter a few miles away, and I could easily see how a 5.0 might cause some damage.

      It's been almost two years since I've felt any significant earthquakes, which probably means they'll start up again in a few days.

      I'm guessing that Wyoming has earthquakes due to the seismic activity in the Yellowstone area, but I've never really associated earthquakes with Wyoming. It's funny how that works.

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    2. We actually have a lot of earthquakes and over half the state is seismically active. Yellowstone, of course, has a large number, but the rest of the state gets them as well. Of the several that I've felt, all were from faults in the Laramie Range a long ways from Yellowstone but quite near where I live. The most noticeable one happened when I lived in Laramie which was about 150 miles from the epicenter. It was noticeable due to the poor construction of the building I lived in at the time. That one damages some buildings in Ft. Collins, a further 50 miles away.

      The house that I live in now received a crack in the drywall from the last one, which was about 4.5 or so. It sounded like a truck had hit the house.

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