Duke Study Finds Fracking Wastewater is Mostly Brines, not Fracking Fluids

Duke University’s Nicholas School of the Environment published the findings of a study analyzing flowback and produced waters from hydraulically fractured unconventional oil and gas wells.  The study found that only 4-8% of the flowback and produced waters is composed of returned injected hydraulic fracturing fluids, and the majority of the return of injected hydraulic fracturing fluids occurs within the first few months after the initial fracturing.  The remaining 92-96% of the flowback and produced waters comes from naturally occurring formation brines.  

The study demonstrated that, while much of the public fear surrounding fracking is based upon the composition of the fracturing fluid, most of the fracturing fluid is in fact retained in the shale deep underground.  Thus, the probability of negative environmental impacts from fracturing fluids is low, particularly after several months of operation.  The authors expressed concern with the salinity and chemical composition of the flowback and produced waters generated from the formation brines, including varying levels of salts, heavy metals, naturally occurring radioactive elements, and other contaminants such as ammonium and iodide.  This composition limits the beneficial reuse of the wastewater without advanced treatment technologies. 

The study is based upon data collected from unconventional oil and gas wells in the Bakken formation in North Dakota, the Marcellus formation in Pennsylvania, the Barnett and Eagle Ford formations in Texas, the Haynesville formation in Louisiana and East Texas, and the Niobrara field in Colorado and Wyoming.  The study is titled “Quantity of flowback and produced waters from unconventional oil and gas exploration,” and is published in the peer-reviewed journal Science of the Total Environment.

Please contact us if you would like more information about the study.