Groundwater Protection Council report evaluates reuse potential for water produced by oil, gas wells

Oil and gas operators produce about 900 billion gallons of water from their wells per year, with about 55% of that disposed of by those operators.

But in an environment where a changing climate and growing populations are putting pressure on available freshwater supplies, operators and regulators alike are rethinking the economics and long-term sustainability of traditional produced-water management practices.

A report issued Monday by the Groundwater Protection Council evaluates those trends, promotes potential ways produced water might be appropriately reused and examines challenges associated with that goal.

A key question that must be answered, the report states, is whether reusing produced water in some parts of the country could be the right thing to do in cases where its beneficial use would outweigh costs to manage, treat, store and move produced water around.

Beyond costs, other factors that also must be considered include health and environmental risks and legal and regulatory matters involving ownership and liability issues.

The council involved about a half dozen top-level state regulators from Oklahoma, including Shellie Chard, director of the water quality division at the Department of Environmental Quality.

Chard served as the water quality co-chair for the study.

"Oklahoma is a national leader in addressing the importance of water, energy and environmental challenges, so having a voice in this report was critical to its success," she said. "The produced water report maintains that water reuse is possible and may be cost effective in some situations, which is important for drought susceptible areas of our state where the reused water makes fresh water available for drinking.

"This is an incredibly important step forward in water management."

The report’s summary notes the quality of produced water, which can include significant amounts of mineral salts, other organic contaminants, metals and radioactive materials, varies widely depending on where it is produced and from what formation it flows.

Because of that, treatment, risk management and regulatory strategies could vary.

The report consists of three modules. The first evaluates current legal, regulatory, and operational frameworks of produced-water management, (usually prescribed by the federal government through its discharge and injection programs and enforced by state environmental regulators).

The second evaluates seven oil and gas basins, seeing how and where produced water is reused by oil and gas operators. Operators need water, for example, to complete today’s horizontal wells and must handle the water that completed wells produce.

In cases where water is disposed, produced water is temporarily stored at a well site until it can be piped or trucked to a disposal well.

In cases where the produced water is reused by oil and gas operators, a significant amount is used for enhanced oil recovery operations or is treated so that it can be used to complete another well. In the latter case, it usually is piped or trucked to a treatment and blending facility before going into storage until it is needed.

The basin reusing the highest percentage of produced water, the report states, was the Appalachian, at about 67%. Reuse of produced water in all others, however, averaged less than 15%, the report shows.

The final module evaluates potential other ways produced water could be reused, and what types of research might be needed to get there.

It includes an overview of various treatment technologies that exist or are being actively researched today within academic, governmental, and industrial arenas and identifies hundreds of published, peer-reviewed studies and other reports that might help assess the possibilities by identifying knowledge gaps and current limitations.

In short, the report is described by the council as an effort to work with various stakeholders to evaluate opportunities and challenges associated with using produced water, as well as to make suggestions that policy makers, researchers, regulators, and others can use to address them.

Mike Paque, executive director of the Groundwater Protection Council, wrote in an introduction the council engaged geologists, engineers, lawyers, toxicologists, soil experts, public health experts, the petroleum industry and state regulators to create the report.

He noted participants reviewed thousands of papers and studies as they researched the topic and held dozens of meetings before writing, editing and producing the report.

He wrote the report "contains the most current information available about regulatory frameworks, produced-water use in oil and gas operations, and potential future uses of produced water outside of oil and gas operations.

"While we believe the report is exhaustive, it is by no means the final word with respect to produced-water reuse," Paque continued. "We expect future efforts to continue developing a more mature understanding of produced-water characteristics and reuse potential."