9 Investigates: Recycling Injection Well Wastewater
LUBBOCK, Texas - Never has there been so much pressure on Oklahoma's oil and gas producers to reduce the amount of wastewater they're injecting underground.
With disposal wells now overwhelmingly linked to the state's earthquake explosion, there is a growing effort to find something else to do with wastewater, other than just pump it deep into the earth.
One possible solution may lie out here, in West Texas.
In this part of the Lone Star State, rainfall is scarce. When farmers plant their crops, they don't always know where the water to grow them will come from.
"Yeah," said Katie Lewis, "my husband and my father farm."
Katie Lewis understands the vicissitudes of family farming. With a PhD in soil science, Lewis understands better than most what works and what doesn't work, when it comes to producing a successful crop, which is, perhaps, what made her uniquely qualified to lead a recent Texas A&M research project.
"The purpose of the research," Lewis explained, in a recent interview, "was to use locally produced oil and gas water to irrigate crops."
That's right, produced water -- the briny wastewater that comes up from the depths with the oil and gas -- being used to water crops.
With the support of Energy Water Solutions and two local energy companies, Anadarko Petroleum and Gibson Energy, 50,000 barrels of such wastewater were trucked last spring to Texas A&M's Pecos research station. There, it was treated to remove most of the salt and heavy metals.
Then Lewis and her team took over. In early June, 2015, they planted ten acres of cotton as part of the controlled experiment.
"We had two irrigation treatments," explained Lewis. "One was 100 percent well-water, and the second one was the blended water, and it was four parts well-water to one part the treated produced water."
Irrigation with produced water is already established practice in some places -- California, most notably. But that's because the produced water there contains far less salt, and requires minimal conditioning before it can be re-used for farming.
On the other hand, experts say produced water from formations in parts of Texas and Oklahoma is five or six times saltier than seawater. Re-using this wastewater is, therefore, more challenging, and has caused producers to pay attention to research like the kind Lewis conducted.
"Not only are they paying attention," said Chad Warmington, "a lot of those companies are leading the way."
Warmington, President of the Oklahoma Oil and Gas Association, says many producers already recycle their wastewater.
"Primarily the recycling that's going on," said Warmington, "is taking that water that comes back up, the produced water, and conditioning it to the point that we can re-use it in other parts of the operation."
Although re-using wastewater for production can create efficiencies, Warmington says, generally, it's still cheaper for most producers to inject the water into a disposal well. And he points out that in some parts of the state, where seismicity has not increased, injection still is the safest method of disposal.
But Warmington says producers understand the current push to recycle.
"I think the tradeoff for less earthquakes is worth it," Warmington stated.
In addition to production and irrigation, experts in produced water say options for re-use include thermoelectric power generation and, with enough treatment, even public water supply.
Kyle Murray, a hydrologist with the Oklahoma Geological Survey at the University of Oklahoma, says the key in all of these re-uses is making it economically viable for the participants, which means the producer and end-user need to be close to each other.
"Location is really the key," said Murray, "if we have produced water, and we have a need for clean water in the same area, we can make it work."
"The potential is there," agreed Katie Lewis.
Lewis's irrigation experiment worked--better than she expected. She says there were no statistical differences in cotton lint yield, "and that, of course, was our primary objective," Lewis said.
What's more, Lewis said, "the cotton that was being grown under the treated produced water looked healthier -- it was greener."
Lewis sees benefits to both farmers, for whom water will always be a precious commodity, and oil and gas producers, who need new ways to dispose of the water they produce.
Lewis says more research is needed, however, and, to her dismay, no additional funding was made available this year, so her plans to try different blends of well-water to treated water will have to wait.