My Mom and Proof of Reasonable Risk Associated with Hydraulic Fracturing


Often faced with one of her children’s’ tortured explanations, my mother would quip, “well, anything is possible.” In the same breath, she would quickly add, “but is it likely?” With regard to hydraulic fracturing, and the recent, largely unsupported claims associated with seismicity, I would add, “even if it is possible, is the risk significant/”

With high volume, horizontal hydraulic fracturing, let’s first understand the process – the three stages of the process — and then ask if some part of that process contributes to seismicity. If so, which part, and is the risk significant?

First, modern hydraulic fracturing involves piping several hundred thousand gallons of water (containing added biocides and surfactants in small volume), with sand deep into the earth several thousand feet below the surface, and under sufficient pressure to crack subsurface rocks and cause the release hydrocarbon gas and an oily material that can be refined into gasoline. (Because we are here only analyzing the latest published fear related to seismicity, the biocides and surfactants do not really matter.) Clearly, the energy in the water and sand is calculated to crack the subsurface rocks, but that part of the process is significantly measured and controlled. Historically, subsurface rock was fractured with a stick of dynamite – a process that was largely uncontrolled. Dynamite may be the source of anecdotes associated with seismic activity, but no longer.

Then the water and sand are pumped out of the hole, returning with the hydrocarbons and in very brackish water. Indeed, the deep subsurface conditions involve significant concentrations of salt (saline) at greater concentrations than found in the sea. And, while thousands of gallons of water were hydraulically pumped into the subsurface under pressure at the initiation of the process, the recovery process involves removing a great deal more material including very brackish water. The volume of water removed is significantly more than was introduced, and there is no indication that this removal part of the procedure increases the potential for seismic activity.

In some instances, that removed material is placed in settling ponds, and the water evaporates leaving a mess. Some criticize this part of the process as creating migrating dead zones. Other times, this removed material is re-injected into the ground near the hydraulic fracturing well site, or trucked off-site to deep injection wells in places like Ohio.

The United States Geological Service recently has made a statistical connection to increased seismic activity and increased hydraulic fracturing, but the service is also quick to point out that the matter needs more study.

Thus far, there is no evidence that the initial process of introducing water and sand to the subsurface creates any significant risk of seismic activity. Indeed, the evidence developed thus far is to the contrary. The volume of material introduced in a well at the initial stage of the hydraulic fracturing process just is not that significant.

Calibrated pumps are used to remove the material from the hole and, the process is well managed. The removal process is controlled, and even though a great deal more material is pumped to the surface than was introduced. Removing the material – even so much more of it – is not thought to cause any significant risk to increased seismicity.

Because no causal connection to seismicity has been established with either the introduction or removal phases of what is popularly referred to as fracking, scientist are now focusing on the waste disposal activities associated with the use of deep injection wells. On the one hand, the use of settling/evaporation ponds may involve other concerns, but seismicity is not one of them.

Deep injection wells are not new, indeed, the process is recognized and fairly well understood. Waste is pumped deep below the earth’s surface into that inhabitable area. The problem may be – it is still hypothetical and under study – that the sheer volume of material being injected into the earth’s crust is significant, and that this process may be creating conditions of instability and seismicity.

So far, however, most of the reported seismic activity is not noticeable at the surface. And, it has been observed only with very sophisticated, new instruments. Perhaps more importantly, we only learned about potential additional seismicity because scientists are now studying seismicity possibly related to hydraulic fracturing. As with the simple conundrum, if no one heard the tree fall, did it? The corollary, just because we now recognize very insignificant seismicity because we are looking for it, does not mean it was not occurring before we began listening for it. We simply may never have known of the earlier frequency.

Regulators in the oil, gas and waste industries have long suspected a potential correlation with deep injection wells and seismicity. Indeed, in places like Illinois, the deep well injection process is prohibited at the well head under the Illinois Hydraulic Fracturing Act – effectively removing all risk of seismicity associated with hydraulic fracturing in Illinois.

Regardless, almost all of the observed seismic activity presents no significant risk. The concept of an acceptable risk is a topic for another day. Suffice it to say there is a risk every time you drive a car, enter an elevator or turn on a light switch.

At this point, let the scientists analyze the problems and define the risk for us before we over react. Indeed, it is possible that hydraulic fracturing increases the risk of seismicity when water and sand is introduced at the beginning of the process. It is just not likely. Similarly, it is possible that the extraction of material from the boring may cause or create seismicity, but that too, is not very likely. Finally, it is possible that using deep injection wells may create an increased risk of seismicity, but in places like Illinois that practice is prohibited, and there is no likely risk of increased seismicity in Illinois. And, in those other states, let’s let the scientists tell us what we need to do to possibly modify the process – but only if modification of the process is necessary.

As my mother would also admonish, “don’t throw the baby out with the bathwater.” She would have been a good lawyer.