Coffee at the neighborhood breakfast-hamburger joint can be problematic for this Oil & Gas Journal editor.
Years ago, the regulars at the coffee clutch table used to quiz this editor about "the real reason" behind what they considered to be high gasoline prices. Currently the debate has shifted to whether hydraulic fracturing is responsible for earthquakes.
The neighbors seem to have little interest in learning about wastewater injection wells and how waste disposal differs from fracturing. They are not alone in confusing fracturing with wastewater disposal. Some environmental groups have sued or threatened to sue over fracturing. These groups strive to make fracturing the scapegoat for numerous problems, including earthquakes, droughts, water pollution, and health issues.
The US Geological Survey maintains a "Myths and Misconceptions" page about induced earthquakes on its web site, found at earthquake.usgs.gov/research/induced/myths.php.
USGS starts its scientific fact list with a statement that fracturing is not causing induced earthquakes.
"Wastewater disposal is the primary cause of the recent increase in earthquakes" across Oklahoma and other central states, USGS said. Wastewater disposal wells typically operate for longer durations and inject more fluid than fracturing.
"Wastewater injections can raise pressure levels…and thus increases the likelihood of induced earthquakes," USGS said, adding this applies to some but not all disposal wells.
Mostly brine
A recent Duke University study concluded that naturally occurring brines-not fracturing fluids-account for most of the wastewater coming from unconventional oil and gas wells completed with fracturing.
Avner Vengosh, Duke geochemistry professor, noted the public's concerns about the danger of chemicals from industry wastewater getting into groundwater.
"Our new analysis, however, shows that these fluids only account for between 4% and 8% of wastewater being generated over the productive lifetime of fractured wells in the major US unconventional oil and gas basins," Vengosh said.
Most fracturing fluid injected into wells stays deep underground, he said. More than 92% of the flowback and produced water from wells is derived from brines.
Vengosh noted brines contain varying levels of salts, heavy metals, and naturally occurring radioactive elements. Duke researchers published their findings Oct. 14 in the Science of the Total Environment.
The Duke study considered wastewater generated from unconventional oil and gas wells in six basins: the Bakken formation in North Dakota; the Marcellus in Pennsylvania; the Barnett and Eagle Ford formations in Texas; the Haynesville formation in Arkansas, Louisiana, and East Texas; and the Niobrara in Colorado and Wyoming.
Water management
Resources for the Future (RFF) recently issued a paper on wastewater management in which researchers examined the lifecycle of water used in fracturing. They reviewed literature from industry, science, and regulators to develop a model for shale gas water and wastewater management.
RFF contemplated the role of oil and gas well operators, centralized wastewater treatment (CWT) plant planners and operators, environmental and public health regulators, and social planners. Different stakeholders have different objectives.
Producers seek to minimize water bills and wastewater management costs. CWT plant planners and operators seek to maximize revenue from selling reclaimed water and other recovered resources. Regulators want to minimize pollution.
RFF suggests future research might include:
• Inclusion of natural gas production revenue.
• Calculations involving road damage.
• Calibration of the model with a case study.
• Costs for various treatment technology and storage options.
• Technology-specific solid waste generation and water quality data.
• Devising a model that considers reclaimed water for different uses.
• Inclusion of more than one contaminant. The existing paper only studied total dissolved solids.
• Considering other resource recovery options for CWT plants.
• Inclusion of reclaimed water sources to supply water for well drilling and stimulation.
About the Author
Paula Dittrick
Senior Staff Writer
Paula Dittrick has covered oil and gas from Houston for more than 20 years. Starting in May 2007, she developed a health, safety, and environment beat for Oil & Gas Journal. Dittrick is familiar with the industry’s financial aspects. She also monitors issues associated with carbon sequestration and renewable energy.
Dittrick joined OGJ in February 2001. Previously, she worked for Dow Jones and United Press International. She began writing about oil and gas as UPI’s West Texas bureau chief during the 1980s. She earned a Bachelor’s of Science degree in journalism from the University of Nebraska in 1974.