Groundwater Quality and Fracking: Current Understanding and Science Needs

Soeder, Daniel

Groundwater Quality and Fracking: Current Understanding and Science Needs

Presented on Tuesday, December 4, 2018

Daniel Soeder, South Dakota School of Mines & Technology

Over the past two decades, shale gas and tight oil development have opened up vast new reserves of fossil energy in North America. However, the drilling and hydraulic fracturing or “fracking” processes that are necessary for the production of these resources pose risks to groundwater.

A consensus view developed from two NGWA workshops held in 2014 and 2017 identified two primary risks to shallow aquifers from fracking: 1) stray gas associated with shale wells, and 2) groundwater contamination from surface spills of frack chemicals and produced fluids. Induced seismicity from the disposal of fracking wastewater down underground injection control (UIC) wells is an additional risk, but does not directly affect shallow groundwater. A lack of data on the true environmental risks of fracking is driving unsupported arguments on both sides of the issue.

Several field studies have provided evidence that gas or frack fluid do not migrate upward from hydraulic fractures into overlying aquifers. Groundwater and surface water contamination is typically caused by surface spills and leaks of frack chemicals and produced fluids, both at production sites and UIC wells. Stray gas in groundwater has been statistically linked to shale gas wellbore integrity problems, although the specific causes of wellbore integrity failures have not been identified.

Data gaps and science needs include a lack of pre-drilling baseline data, ongoing challenges gaining access to field sites and data from industry, uncertainties about the origins and migration pathways of stray gas, and the introduction of new frack chemicals with unknown degradation pathways and breakdown products. Non-standardized sampling and analytical methods make comparison of results from different studies challenging. A consensus recommendation from the workshops was to improve data-sharing, and develop standardized methodologies.

MP3 Presentation Slides

Daniel Soeder

South Dakota School of Mines & Technology

Dan Soeder is the new Energy Resources Initiative director at South Dakota School of Mines & Technology in Rapid City. He was previously a research scientist at the U.S. Department of Energy (DOE) National Energy Technology Laboratory in Morgantown, West Virginia, from 2009 to 2017, where his focus was on gas shale. He came to DOE with 18 years of experience as a hydrologist with the U.S. Geological Survey in the Mid-Atlantic region and on the Yucca Mountain Project. Prior to that, he spent a decade performing production research on tight sandstone and shale at the Gas Technology Institute in Chicago, and two years as a DOE contractor on the Eastern Gas Shales Project, where he recovered and characterized shale drill core. He holds BS and MS degrees in geology from Cleveland State University and Bowling Green State University in Ohio.

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