OK Wastewater Disposal Wells Under Greater Scrutiny After Earthquakes

With all the earthquakes Oklahoma is experiencing, there has been a lot of talk about disposal wells and the correlation between the two. However, there are a lot of questions about what these wells are and what they do.

The Oklahoma Corporation Commission works closely with the Environmental Protection Agency (EPA) under the Safe Drinking Water Act to make sure disposal wells are safe, but that practice is now in serious question.

Injection wells are used for a lot of things, but right now the focus is on disposal wells. They are a type of injection well and at the center of a lot of attention.

“A disposal well is a well that is used to take oil and gas wastewater and put it into an underground formation that has been deemed safe by federal and state authorities for the storing of that water,” Oklahoma Corporation Commission spokesman Matt Skinner said.

There are about 4,000 disposal wells in Oklahoma, and about 1,000 of them are known as Arbuckle wells.

“Of those the ones that researchers say we really need to concentrate on when it comes to earthquakes are Arbuckle disposal wells,” Skinner said. “They dispose into the state’s deepest formation, which is called the Arbuckle.”

The largest part of wastewater comes from producing wells, but with that comes water from the formation.

“It’s very high in chloride, many times saltier than the ocean,” Skinner said.

According to hydrogeologists, water is injected through tubing and casing several thousand feet into the Oklahoma ground - more than a billion barrels a year. That amount is equivalent to all the water in Lake Thunderbird, two Lake Hefners or five Arcadia Lakes.

“While this technique has long been regarded as the Cadillac when it comes to protecting our fresh water, with the onset of earthquakes and the models that show the relationship between deep high water wastewater injection and earthquakes, you have to change what you mean by ‘safe,’” Skinner said. 

The Corporation Commission says two companies have challenged their well guidelines - Tulsa based company Marjo and SandRidge Energy.