Yesterday the “Great Fracking Debate” took place at EGU2013 and I tuned in via webstream for the royal rumble of good vs. evil that was sure to take place. I have to say I was a little disappointed (not really) because the tone of the debate was very respectful and sophisticated. I guess if I want to see a good verbal sparring match I’ll have to head over to Parliament and take in a question period. The panellists speaking were: Tom Leveridge from the Energy and Climate Change Select Committee at House of Commons, UK; Brian Horsfield from the Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Germany; Jesús Carrera from the Department of Geosciences, Institute of Environmental Assessment and Water Research, Spain and Jurrien Westerhof from Greenpeace, Austria.
The discussion ranged from talking about how much the world needs fossil fuels and the hydrogeological implications of contamination all the way to the environmental and energy policy and the political will needed for fracking to become practicable in Europe. Overall the debate was a little light on the science and a bit heavy on the policy for my taste. However, it is obviously critical to discuss the politics of fracking since the science is merely a tool to inform the ultimate political decision and is not itself able to determine what is right or wrong. To that end there was a good bit of discussion on the future energy needs of the UK and Europe and if fracking was a necessary tool in order to provide for the energy needs of future generations. Furthermore, the panelists made some excellent points about the need for basic science in this issue and how by continuing to study the impacts and develop more effective ways to extract shale gas we can open the door to a whole new resource for the world and not just Europe or the US. If you would like to watch the entire debate it is archived here.
Since the science wasn’t really discussed I thought I’d throw out this primer to fracking and how it works. Enjoy!
Why are we fracking?
The first question that we should ask, before discussing what fracking is, is why are are we using hydraulic fracturing and what are its benefits. It’s an undeniable fact that the world is highly dependent on fossil fuels for energy, particularly natural gas and oil. However, our thirst for fossil fuels has led to the depletion of most of the easily accessible reserves around the world. This means that oil and gas companies, in their quest to meet demand, are developing new technologies and exploring new regions that were previously overlooked. One new source of natural gas is in shale. Most oil and natural gas is produced in shales due to their high organic content and subsequent heating during lithification (turn to rock). This heating produces oil and natural gas that slowly migrates from the shale into other rocks where it is trapped in what, until recently, were conventional reserves. Oil and gas recovery in the past focused on looking for places where oil and gas was trapped. However, the depletion of these reserves has forced us to look elsewhere, such as in the source rocks like shale, primarily for natural gas and coalbed methane. In theory this sounds great, similar to the old adage: why get an apple from the basket when you can get one from the tree, but in practice things are a little more difficult. The reason for this is that shale is made of very, very fine mineral grains. The natural gas that we would like to recover is trapped in the tiny pore spaces between these grains making it almost impossible to extract. In order to overcome this, the oil and gas industry has been forced to develop new technologies to enhance recovery. One of the most successful, but controversial, is fracking.
What is Hydraulic Fracturing (Fracking)??
The simplest answer to “what is fracking” is that it is a process in which fluids (more on that later) are injected into a borehole to increase pressure. This results in the rock at the bottom of the borehole fracturing. This allows us to recover resources that are hard to get more efficiently.
|What is fracking? (Source: EPA Hydraulic Fracturing Study Plan,November 2011 - used with permission)|
A good analogy is to think of a common scenario you likely tried as a kid. Imagine you have a juice box and instead of sucking on the straw (which represents the borehole) you blow into it instead. Most often this increase in pressure results in juice spraying out to top of the straw. However, one day you blow particularly hard, so hard that the sides of your juice box spit open and you experience catastrophic juice spillage on your favourite pants (not that this actually happened to me or anything…) However, the point is that this increase in pressure inside your juice box resulted in the sides splitting. Fracking works on the exact same principle. When the fracking liquid is injected into a drill hole the pressure on the surrounding rock goes up substantially If the pressure continues to rise we can cause the rock to fracture. As I mentioned above the permeability of shale is very low and therefore just drilling the well is not enough to recover the gas efficiently. In order to increase recovery we have to increase the permeability. Artificially creating fractures is the way we do so.
What gets injected?
Unfortunately, only the oil companies know the exact answer to this question. However, we do know that the mixture is mainly water with numerous chemical additives.
|EPA Hydraulic Fracturing Study Plan, November 2011 – used with permission|
Obviously there is a laundry list of chemicals that may be incorporated. It is worth noting that it would certainly not be beneficial to ingest any of these substances or to find them in groundwater. In fact, some of these chemicals can be toxic at ppb levels meaning that even the most minor contamination can have huge consequences. Furthermore, this is by no means a full list. The above chart is merely and example of some the chemicals you might expect to find in a fracking fluid. The fracking fluid that is used for each well is tailored specifically for that rock formation being targeted in order to maximize recovery.
What are the environmental effects?
One of the most controversial issues with fracking is the potential for environmental harm that may result from the practice. Some of these include surficial spills of the fracking fluid at the well site, contaminating groundwater either through subsurface migration of the fluid, infiltration from a spill, leaking around a bad well casing, or even earthquakes from the injection of the fluids. Furthermore, fracking requires large amounts of water and also produces large amounts of waste water. The problem created by getting this much clean water and then disposing of the resulting waste water also has potential for large environmental impacts on water sources such as local groundwater reserves in terms of both depleting and contaminating them.
|EPA Hydraulic Fracturing Study Plan, November 2011 – used with permission|
As of now, the impact of fracking is still being studied and moratoriums on drilling and fracking exist in many states and provinces in the U.S. and Canada. To date there have been numerous studies on the environmental impact of fracking and it is essential that these studies be performed in order to truly gauge the impact fracking could have at a particular site.
That is all for now. I realize that I have not addressed some of the more complex issues surrounding fracking. My intention was not to omit any piece of information, but to provide a basic primer about what fracking is and the issues surrounding it. For more detailed information or information about a particular site I encourage you to do more research. Thanks for reading.
Finally, what are your opinions on fracking? Is it a necessary evil? Or is it evil at all? Do you think we can be trusted to frack responsibly? I would love to hear other peoples thoughts on fracking.
US Environmental Protection Agency: http://water.epa.gov/type/groundwater/uic/class2/hydraulicfracturing/index.cfm
US Environmental Protection Agency Hydraulic Fracturing Study Plan: http://water.epa.gov/type/groundwater/uic/class2/hydraulicfracturing/upload/hf_study_plan_110211_final_508.pdf
Note: This post was originally published at my pre-EGU blog on November 5, 2011. However, after recently watching the Great Fracking Debate at EGU2013 I thought I might do a re-post.