April 05, 2018

Reuse of Produced Water Offers Energy Savings

By Natalie Rogers

New Mexico depends heavily on revenue generated by oil and gas extraction throughout the state, but significant environmental concerns remain about extraction and production, especially with regards to water use. Oil and gas production generates billions of gallons of what is referred to as "produced water", much of it with very high concentrations of dissolved solids, and much of it originates as fresh groundwater, a precious commodity in the desert southwest. Produced water is often stored or discarded as wastewater, but a new paper published in Volume 13, Number 2 of Environmental Research Letters by EPSCoR PhD candidate Katie Zemlick suggests there might be other economically-viable options for managing produced water. The paper, titled "Mapping the Energy Footprint of Produced Water Management in New Mexico," provides insight into the energy requirements of—and by extension, financial benefits to—the treatment and reuse of produced water. It is co-authored by EPSCoR faculty Janie Chermak and Bruce Thomson, EPSCoR graduate student Elmira Kalhor, Vince Tidwell of Sandia National Laboratories, and Jeri Sullivan Graham of Los Alamos National Lab (LANL). In 2016, Katie completed an EPSCoR Externship at LANL under the direction of Dr. Sullivan Graham that contributed to the research published in this paper.

For her research, Katie collected monthly production data over a ten year period from the New Mexico Oil Conservation Division from four locations around the state: the two largest oil and gas–producing basins—San Juan Basin in the northwest and the Permian Basin in the southeast—as well as Bravo Dome and the Raton Basin, both in the northeast. Then, she calculated the energy required for three difference scenarios: 1) freshwater pumping and transportation for hydraulic fracturing and disposal of produced water; 2) the energy required for transportation, treatment, and reuse of produced water from hydraulic fracturing; and 3) transportation and reuse of produced water for enhanced oil recovery. Results indicate that, regardless of location, the energy required for treatment and reuse of produced water is far less than conventional use and disposal of freshwater.

Reuse of produced water for hydraulic fracturing is not only more energy efficient than conventional management techniques, it also reduces both demand for scarce freshwater resources and use of disposal wells. By evaluating components of each management strategy individually, this work illustrates how the energy footprint of regional produced water management can be reduced. The advent of unconventional oil and gas recovery in the last decade highlights the need to understand existing water management in the industry, identify opportunities and strategies for improvement, and recognize that these dynamics are likely to change in the future.

2018 has been an eventful year for Katie so far—shortly after this paper was published, she successfully defended her dissertation, "Modeling the Interdependencies of Energy and Water in New Mexico: Historic Drivers, Hydrologic Impacts, and Energy Requirements." She will receive her PhD this May. Her paper is available as an open source publication. Read it or download it in its entirety here.