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Guest Post: Waterless Fracking?

The views expressed are those of the author and are not necessarily those of Scientific American.


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Propane Fracking vs. Water Fracking: Which is better (worse)?

With all the negative attention surrounding hydraulic fracturing, a process that stimulates shale plays but requires the use of millions of gallons of water, it is no surprise that companies are looking at alternatives.  One such alternative that has recently emerged uses gelled propane instead of water. According to GasFrac Services, a relatively new Canadian oilfield service company, this type of “[propane] fracturing can deliver economic and environmental benefits.”

But are there really environmental benefits, and is gelled propane safer than using water? As an engineer with some history in the oil and gas industry, I hope I can shed some light on this “proprietary innovation”.

Today, oil and gas companies use water for hydraulic fracturing because it is cheap, abundant (relatively) and safe (doesn’t explode). A typical frac job will require the use of about four million gallons of water, most of which will stay down hole, in the reservoir, permanently. The small percentage that flows back out of the well – called flowback water – must be treated and disposed of.

If these companies chose to use gelled propane, then these wells would use less water and produce less wastewater. This is a universally positive change, and particularly good in areas like west and south Texas where water supply is limited. Additionally, fracking with water can sometimes cause  formation damage, or damage to the reservoir, which can close flow pathways and prevent oil and gas from being produced.  Using gelled propane would likely reduce formation damage during the fracking processes, which means better overall recovery, and a more profitable well.

However, while the site specific water consumption could be greatly reduced, the impacts to the total lifecycle water consumption throughout the entire production pathway are not clear. There is a significant amount of water that goes in to producing and liquefying propane, so while you might not use much water at the well site, the total amount of water consumed could still be high.

Using liquid propane could also pose a safety risk. Propane, under normal conditions, is a gas. Liquid propane is a liquid because it is held under pressure. If there is a leak above ground, the propane could form a vapor cloud and explode, if there were any ignition sources nearby (a running vehicle, perhaps). This risk already exists because the natural gas that you are producing is a gas, as the name suggests, so the incremental risk may not be significant. GasFrac Services claims that they have multiple safety barriers, and insists the process is safe. However, regardless of their barriers, propane is still significantly more explosive than water so there is some added risk.

GasFrac mentions that the liquid propane is “gelled with proprietary chemicals”. In other words, we don’t know what they are putting in the propane. But, it is likely similar to the chemicals used in conventional fracturing. For those concerned with groundwater contamination by fracking chemicals, using propane does not eliminate the risk for water contamination, since you are still using chemicals. (By the way, just because it is a ‘chemical’ does not mean it is evil. Did you know that water is a chemical? So is oxygen. How about these scary sounding chemicals: phosphoric acid and potassium benzoate? These are ingredients in diet coke.)

One reason propane has not yet been used widely is because it is more expensive than water, and the benefits may not justify the costs. However, the GasFrac process is fairly new, and they have demonstrated some promising metrics, such as longer fracture lengths and higher production rates compared to water fracking, which means it might be more effective. If it is truly more effective, its use may become more common. But, if there are any significant safety incidents, the industry will avoid it, and stick with the tried and true water method.

The bottom line is this: There may be some benefits to gelled propane, one of the biggest being a decrease in on-site water consumption. If it is truly better, the industry will recognize that and we could see a shift away from such water intensive fracking methods. But perhaps what is more likely is that propane fracking be used in places where there are extreme water shortages. Otherwise, water fracking will likely continue to dominate.

About the Author:

Scott McNally is an energy engineer who has spent the past year working on national energy policy issues in Washington, DC. He has worked as an ORISE Fellow with the Department of Energy’s ARPA-E Program and an energy and climate researcher with the White House Council on Environmental Quality. Previously, Scott was a project engineer for Shell Oil Company and an environmental engineer for Valero. Scott has a B.S. in Chemical Engineering from the University of Texas at Austin, and is currently completing a Masters in Energy Resources Engineering at Stanford University. Scott was invited to be a guest blogger by Plugged In’s Melissa C. Lott. You can reach Scott via e-mail at scottmcnally at gmail dot com.

Photo Credit: Photo by Cliff Weathers and used under this creative commons license.

About the Author: Plugged In Guest Author - An energy research engineer who has worked in oil and gas, environmental engineering, renewable energy, and energy and environmental policy for the Obama Administration.

The views expressed are those of the author and are not necessarily those of Scientific American.





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  1. 1. FracMaster 4:14 pm 10/10/2012

    I have looked at Gasfrac in detail. I would not go onto a location where it is being used. With a water frac you can run for the hills and make it. I have had to do that on occasion. If a Gasfrac where to fail you are dead.

    Link to this
  2. 2. Traveler 007 5:18 pm 10/10/2012

    Fracking dangers have been horribly exaggerated, when have you had to run for the hills over fracking? Nothing to run from LOL

    Link to this
  3. 3. jpdickey 6:56 pm 10/10/2012

    If the propane produces longer fracture lengths, would this have any impact on the potential for small earthquakes to be triggered by the fracking?

    Link to this
  4. 4. jerryd 12:57 pm 10/11/2012

    The problen with propane is if it gets loose it is heavier than air so hugs the ground and spreads out making a very big expolsive event’\

    The problem with fracking isn’t fracking but the people, companies doing it. If done right rarely will be a problem but too many cheap out amd don’t seal the well casings well enough so HC’s, etc from one underground HC. etc sources leak into the water table, etc.

    The problem with fracking fluids is bad handling mostly by dumping, etc into the environment illegally mostly to save money.

    Link to this
  5. 5. scottmcnally 4:42 am 10/12/2012

    Hello everyone,
    Thanks for your comments.
    FracMaster – I agree with Traveler, in what circumstances have you had to run for the hills? I have been on site at a number of frac jobs, and I have never heard of anyone having to actually run away from anything.
    Jpdickey- I suppose maybe it might be possible that the tiny earthquakes triggered by fraccing could be slightly larger, but what you are referring to is called ‘induced seismicity’. I will point out though, that with over a million frac jobs behind us, there has never, ever been a major earthquake triggered by fracking. I’m not saying it is impossible, but it has never happened before. I think the biggest fracking induced earthquakes we have seen are on the scale of 2.0 or 2.1, which is mostly undetectable by humans. By comparison, the earthquakes that you would get from carbon dioxide sequestration would be more frequent and severe than from fracking.
    Jerryd – You are right that propane is heavier than air, but, it also comes out of the well. Propane is already present at most oil and gas wells, so this isn’t a new hazard – the hazard already exists. You are right, if done correctly, you will rarely have a problem. And you are also correct that wastewater handling is a concern. I haven’t heard any cases of companies illegally dumping though.

    Link to this
  6. 6. CherryBombSim 12:03 pm 10/12/2012

    Scott, please do not insult my intelligence with “Did you know that water is a chemical?”, etc. Some chemicals are harmless, some are dangerous.

    Also, earthquakes over 3.0 magnitude (can definitely be felt) have been caused by fracking operations. They are almost certainly caused by the waste disposal into injection wells rather than the actual frack, though. The frack itself doesn’t last very long, and the pressure is released. (People get excited about the amount of water used, but it is a one-shot deal.) Still, it is wise to be cautious near unstable areas and dams and such. I was an oil geologist for a number of years, and weird s**t DOES happen.

    Yeah, FracMaster is imagining drama.

    Link to this

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