A water treatment technology with chlorine dioxide at its core is gaining attention in the oil patch as an effective bacteria killer, fostering the reuse of produced water for frack jobs.

“Produced water has more food for bacteria, so you have to be diligent with bacteria control,” Warren Sumner, CEO of Austin-based Omni Water Solutions, told Hart Energy. “Chlorine dioxide is very effective at keeping produced water storage ponds clean, so it does help foster re-use of produced water.”

Recycling water used during fracking operations has become increasingly important for shale operators in an effort to reduce use of freshwater. Hydraulically fracturing a well requires the use of millions of gallons of water.

Omni Water Solutions, which announced Friday the launch of its STINGRAY line of chlorine dioxide treatment units aimed at controlling the bacteria during pressure pumping operations, has been using chlorine dioxide treatment units to treat both freshwater and reused water. The system combines chlorine dioxide with the company’s filtration systems to create usable frack fluids from produced water.

“This process can virtually eliminate the need to use fresh water for the majority of frack chemistries being used,” Sumner said, later adding the units were first deployed in Oklahoma in December 2014 and expanded to the Eagle Ford and Permian shale plays this spring.

The company recently formed an alliance with Weatherford, which highlighted the partnership in the company’s 2014 annual report released Thursday night.

“Through this partnership, operators are able to minimize the use and cost of freshwater resources, while reducing the complexities of local wastewater disposal and onsite wastewater trucking,” Weatherford said.

Q: How does it work?

A: Sumner: The units create chlorine dioxide and inject it into the water stream that is flowing through the frack equipment during a frack job. Before the frack starts, we test the water to determine how much bacteria is present so we can dose it properly. We also inject some chlorine dioxide in the working tanks to clean them before they get filled with the disinfected water.

During the frack, we are injecting chlorine dioxide into the water stream as it flows into the blender and goes downhole at 80 to 100 barrels per minute. We continuously monitor the results by testing water samples at various points in the process to be sure we have enough chlorine dioxide to kill bacteria that resides in the sand or prop pant as well as a
residual dosage to kill bacteria in the well bore.

Q: How does it compare to conventional biocides?

A: Sumner: Chlorine dioxide is more effective at killing bacteria than conventional biocides in many cases. In our testing of actual frack jobs we see more complete bacteria kill than conventional biocides in same area using same source water. One customer stopped using conventional biocides and will not use anything but chlorine dioxide. Other customers are telling us their wells have fewer corrosion problems and other production issues when they use chlorine dioxide, so the bacteria kill is immediate, but the benefits accrue over time.

Q: Why is type of technology/equipment important today?

A: Sumner: This type of equipment is doing a better job at eliminating scale and corrosion-forming bacteria than the conventional approach, often for less cost per barrel treated. Today most producers are using fresh water for fracture stimulation, but we see more producers moving toward re-use of produced water. Produced water works well when you kill existing bacteria and take away the food source that could support future bacteria growth.

So Omni’s chlorine dioxide units can work by themselves on freshwater sources or in tandem with Omni’s filtration technologies on produced water sources. Together, they enable oil and gas producers to achieve recycling goals with superior results.

Contact the author, Velda Addison, at vaddison@hartenergy.com.