Oklahoma drillers look to reuse produced water

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PERRY, Okla. (AP) - Oil and gas companies are burying an increasing amount of pipeline in the northern part of the state, but it isn’t just for high-priced crude. They’re also looking for efficient ways to transport and reuse expensive, toxic produced water.

The drillers are finding ways to mix the highly salty water with small amounts of fresh water to hydraulically fracture wells. Reusing produced water cuts down on the amount of fresh water and surface water drillers need for frack jobs, and pipelines are less costly than trucking.

In Perry, Devon Energy is starting to lay oil, natural gas and water pipelines in the same easement, a system it calls integrated facilities. The new method helps make the Mississippian-Woodford trend efficient and economical, said Mark Matalik, drilling engineering supervisor with Devon.

Coordinating the drilling schedules with the pipeline construction lets producing wells tap into the system, rather than using trucks to transport water, Matalik said.

Putting three lines together also makes negotiating with landowners simpler, said Tim Baker, pollution abatement manager for the Oklahoma Corporation Commission Oil and Gas Conservation Division. Operators are not required to obtain permits from his agency for pipelines that transport the briny produced water.

“This is all being driven by horizontal wells,” Baker said. “Operators are using a large amount of water to frack wells, and there is a lot of produced water initially, so there is more of an effort to use pipes than trucks.”

Devon began operating the integrated facilities in the second half of 2013, company spokesman Chip Minty told The Journal Record (http://bit.ly/1hSht5C ). Once the company determined that the oil field in north-central Oklahoma was economically viable, it began planning the infrastructure to transport crude and natural gas from the wellhead, he said. Soon afterward, Devon decided to include produced water pipelines as part of its infrastructure plans.

In the last three to five years, the industry has continued to develop ways to use salty produced water in hydraulic fracturing operations. That hasn’t always been the case, however. When the company began drilling in the Barnett Shale in the Dallas-Fort Worth area, it needed to use fresh water, Minty said.

“As we’ve moved forward through these years and tried to answer these questions about water conservation, we have learned how to complete these wells without fresh water and with certain amounts of saline,” he said.

Landowners benefit when oil, gas and produced water pipelines are buried in the same ditch, said Terry Stowers, an attorney and executive director with the Coalition of Oklahoma Surface and Mineral Owners. It may be more expensive to negotiate three pipelines in one easement than a single pipeline, but it’s better in the long run, he said.

“If they can put in same area, they minimize impact on the surface, and that is a great thing,” Stowers said.

In Devon’s case, the ratio of oil to produced water in the Mississippian-Woodford is, on average, about five barrels of water to one barrel of oil, Matalik said. However, in other parts of the Mississippi Lime formation it can be much higher, Stowers said. In some places, companies get about 49 barrels of produced water for every one barrel of oil.

The produced water pipeline system reduces the risk of spills, in addition to cutting costs, Baker said. Stowers said he is concerned about long-term maintenance of the saltwater pipeline system. If pipelines aren’t maintained 10 or 15 years after installation, they can leak, he said.

“If they are maintained properly, pipelines are by far the safest and most efficient way to move products,” Stowers said.

Minty said Devon uses polyurethane pipe to transport produced water, which doesn’t corrode or leak. The company also transports crude in steel pipes treated with catalysts to prevent corrosion, he said.

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