Slashdot Mirror
Did Fracking Cause Recent Oklahoma Earthquakes?
Hugh Pickens writes writes "Oklahoma is typically seismically stable, with about 50 small quakes a year — but in 2009, that number jumped up to more than 1,000 and on November 5 a 5.6-magnitude tremor rattled Oklahoma — one of the strongest to ever hit the state — leading scientists to wonder if the increasingly common use of fracking, the controversial practice of blasting underground rock formations with high-pressure water, sand, and chemicals to extract natural gas, may have put stress on fault lines. Human intervention has caused earthquakes before with one 'textbook case' occurring in 1967 in India, says Peter Fairley at IEEE Spectrum, when the reservoir behind the hydroelectric Koyna Dam was filled up. The added water 'unleashed a magnitude 6.3 quake' by placing stress 'on a previously unknown fault, killing 180 people and leaving thousands homeless.' Last week's earthquakes and aftershocks are centered in rural Lincoln County, in an area about 30 miles east of Oklahoma City and there are 181 injection wells In Lincoln County. But a recent study by Austin Holland, a seismologist with the Oklahoma Geological Survey, says that it's possible that hydraulic fracking caused a series of small earthquakes, peaking at 2.8, in an area south of Oklahoma City but doesn't believe fracking caused the big Nov. 5, 6 and 8 earthquakes comparing a man-made earthquake to a mosquito bite. 'It's really quite inconsequential,' says Holland."
Not only do I live in Oklahoma but my work bumps up against the energy/hydrocarbon industry. This is a subject that I know quite a bit about, in fact....
The answer is: No, No, and No.
For forever, Oklahoma has had small earthquakes like this. It is not uncommon as we sit on the Arkoma plate (little known fact: The Arbuckle mountains were the largest in the world....about 130 million yrs ago). I remember quakes as far back as I can remember and I can even remember the dumb local news outlets mistaking a B52 landing at night for yet another earthquake (circa 1991 or so). This is not a news story, rather, it is an opportunity for the anti-fracking crowd to push its agenda when the opportunity is ripe. Whether it has any basis in reality is quite a different question...
The quakes were centered almost in the middle of the state. Unfortunately for the anti-fracking crowd, all of the fracking in the state is going on in the Woodford Shale, which is South / Southwest of where the quakes occured (by a lot). While earthquakes being caused by fracking cater to our common senses, there just isn't ANY evidence that the two are linked. And I mean in that statistical "causation" way. *NO* regulatory agency, body, or otherwise has indicated otherwise.
Additionally, the Woodford shale deposit has been in active development for many many years. Fracking didn't just start there a few years ago. Try a decade or more.
While I never say never, I will only say that extraordinary claims require extraordinary evidence. And it's an extraordinary claim to suggest our fracking is starting earthquakes here in Oklahoma.
Most of the news around here (Oklahoma) is saying probably not. The seismologists that have been on are saying that, while the earthquakes were shallow, they were still far too deep to be caused by fracking.
Hmm...the big Oklahoma quake was 3.1 miles deep (the smaller quakes leading up to it were around 2.5 - 3.5 miles deep). Fracking wells are typically 1 to 4 miles deep.
The Woodford shale formation under Oklahoma ranges from 5000 - 12000 feet. (around 1 to 2.25 miles)
Sounds like it's in the same ballpark, I'm not saying that the fracking and earthquakes are definitely related, but I wouldn't call the quake "far too deep" to have resulted from fracking.
"Chemicals" do not describe WHAT they actually use. Includes Sodium Hydroxide or Caustic Soda.
Drain cleaner like Draino or Lye as it was formerly called. They are dissolving matter to create more passages.
This is besides the fracking debate. Asked why, the industry used "chemicals" and not the true names of the agents,
they said to hide their 'formula' contents.
The most abundant chemical used in fracing is water. This is the same water that your waiter serves you with your meal. It's not unusual for frac fluid to be 89% water by mass. I have been on a job that didn't use water. It used oil. When oil is used it's commonly lease oil. That means that oil was produced from the well, mixed into a fracturing fluid, and then pumped back into the well. However, the use of oil as a frac fluid is quite rare. The vast majority of frac jobs use water.
The second most abundant chemical used in fracing is sand. This is the same sand that you lie on while enjoying a day at the beach. I have personally mixed a frac fluid that was 73% sand. However, it's much too difficult to mix and pump at that concentration, so all frac jobs will be performed at a lower concentration of sand. There are substitutes that are sometimes used in place of sand. One such substitute has been tungsten carbide. However, the use of tungsten carbide in frac fluids is rare. Sand is much less expensive, so it's used in the vast majority of fracturing jobs. It's not uncommon to use a resin-coated sand in the last portion of the fracturing job. Coating the sand in resin helps keep it in the fracture so that it isn't produced with the oil.
The third most abundant chemical used in fracing is guar. This is the same chemical that your waiter serves in your salad dressing. It turns water into a thin gel. Gelled water is used in fracturing fluid because sand doesn't tend to settle out in gel as quickly as it settles out in water.
Those three chemicals are all that's necessary for many fracturing jobs. There are other chemicals that may be used. For example, sometimes a crosslinker is used to make the gel really thick. Crosslinkers can be toxic. However, any other chemical used will be used in low concentrations. If for no other reason, then to reduce costs. You can imagine how inexpensive water can be. Similarly, you can imagine how inexpensive sand can be. Guar can be expensive, but fortunately for the fracturing companies, very little is needed.
If sodium hydroxide is used, it's used to raise the pH. It's not used to create passages. If passages are desired, then they are created using hydrochloric acid. This is the same acid that occurs naturally in your stomach. Jobs that create passages in this manner are called acidizing jobs. It would not be usual to have a fracturing job and an acidizing job at the same time. The passages created by acid don't tend to collapse back down upon themselves. The passage created by hydraulic pressure does tend to collapse back down upon itself, so sand is pumped into the passage to keep the passage open for when the hydraulic pressure is removed.
The reason the industry uses the term "chemicals" IS to hide the formula. There is intense competition between the companies that provide fracturing services. The actual chemicals used is considered to be a trade secret. Therefore, as long as the fracturing companies continue to hide the true name then they are protected by law. If they were to reveal that name, then anyone would be able to provide the same service and that would drive the price they could charge downward. Of course, it's an open secret that water and sand are used. It's also an open secret that guar is used, but even so it's still used under trademarked names. Why? What reason do you think they have for concealing the true name of their agents?
~Loyal
I aim to misbehave.