Potable Reuse of Produced Water: Part 1
Defined by the United States Department of the Interior’s Bureau of Reclamation as “water that exists in subsurface formations [that] is brought to the surface during oil and gas production,” produced water has long had the potential to become a resource rather than a disposed waste byproduct. Yet high costs and underdeveloped technologies have largely limited that potential. However, that hasn’t stopped regulators from gradually placing stricter regulatory restrictions on produced water disposal across several regions of the U.S. Additionally, environmental concerns about the “long-term and short-term effects of the disposal of produced water on soil, ground-water, and streams” have become more pronounced.
The latest produced water numbers (PDF) come from 2012 — published by the Ground Water Protection Council in April 2015 — and provide insight into produced water volumes and usage in the U.S. The Council estimated in 2012 nearly 20.6 billion bbl of produced water were generated onshore by the oil and gas industry, with about 93 percent of it getting reinjected underground and just 0.6 percent (likely more) of it being “put to beneficial reuse” such as for drilling and fracturing fluids, irrigation, or dust and ice control on roads.
However, if regulations and environmental concerns are so prevalent, then why is the amount of reused produced water still so low? The answer is a complex one, requiring insight into aspects such as water properties, budgets, available technology, research, and public opinion. Looking at a typical extraction company’s produced water management plan, we find that it must be developed with the long term in mind and take into account all previously mentioned variables. As a result of high water salinity, fixed budgets, and a preponderance of expensive technologies, potable reuse of produced water may simply not be an option for most extractions. Yet the incentive to further existing desalination and filtration techniques to make them more effective and cost-friendly remains strong.
In the second part of this article about reusing produced water, we’ll take a closer look at the variables affecting water management plans and how produced water may further develop as a resource rather than a waste product.