Texas regulators limit oil and gas disposal wells in bid to reduce earthquakes in West Texas

A produced water tank sits at an injection well site outside of Odessa on Jan. 31, 2022. (Credit: Eli Hartman for The Texas Tribune)

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The state’s oil and gas regulatory agency last month suspended nearly two dozen permits that let companies inject saltwater water into the ground, a routine industry practice that regulators said has contributed to the rising frequency and magnitude of earthquakes in West Texas.

The permits are set to expire in early January. They apply to 23 disposal wells holding hundreds of thousands of barrels of produced water, a toxic brine found in the deep recesses of rock rich in crude oil.

Produced water flows up to the surface during crude oil extraction, and although amounts vary, drilling for oil can return enormous volumes of the liquid. A 2022 report found that Texas alone generated 3.9 billion barrels of produced water from oil and gas extraction.

The Railroad Commission of Texas, which regulates oil and gas in the state, instructed major companies — including Chevron, Cimarex Energy, BPX Midstream, NGL Water Solutions Permian, LLC, Blackbuck Resources and CPB Water — to no longer dispose of saltwater in Reeves and Culberson counties in an effort to reduce earthquakes in the region.

According to the Railroad Commission, seven earthquakes occurred in Reeves and Culberson counties in 2023. In November, the U.S. Geological Survey recorded a 5.2 magnitude earthquake in the region, which tied for the fourth strongest seismic event in Texas history. The process of injecting saltwater back into the ground “is likely contributing to recent seismic activity,” the Railroad Commission has said.

Storing produced water in deep underground rock formations is one of the few ways oil and gas operators can get rid of the contaminated, salty mixture. These wells lie in pockets of rock formations underground.

“The water has to go somewhere,” said Robert Trentham, a senior lecturer and geologist at the University of Texas Permian Basin, in an interview about seismic activity in the region. But when the chemical compound is pumped into wedges already full of water from previous injections, it increases the pressure above the surrounding rock, contributing to seismic activity, Trentham said.

Treating produced water for desalinization is an alternative to disposal wells, but it is less affordable. Oil and gas companies have also used produced water for hydraulic fracturing — or fracking — which consists of injecting water in high-pressure tanks to break up rocks and release crude oil and other reserves.

“The obvious thing that we’re all doing … is you try to recycle all the water you possibly can,” said Laura Capper, CEO of EnergyMakers Advisory Group, an oil and gas consulting firm. “Everybody’s pretty much doing that.”

However, the amount of water required for hydraulic fracturing only accounts for a fraction of the produced water that surfaces to the ground during crude oil extraction, leaving oil and gas operators with plenty of water they still need to get rid of.

It is unclear whether the companies whose permits lapsed will continue to rely on other saltwater disposal wells in the region.

“We’re on kind of a collision course with timelines,” Capper said, referring to an increased urgency among some oil and gas operators to find alternative methods to store produced water.

Capper added that she and other oil and gas operators are waiting on long-term guidance from the Railroad Commission. “We need to find a solution today,” she said.

In 2021, the Railroad Commission created a map that tracks earthquakes in the Permian Basin, which acknowledged the relationship between saltwater injection and the recurrent earthquakes in the region. The commission said it would continue to order companies to reduce their output of produced water “if injection is likely to be or determined to be contributing to seismic activity,” the Railroad Commission said.

The commission has since established a number of measures to reduce earthquakes, including expanding the seismic response map to include more saltwater disposal wells, capping the amount of produced water companies can inject into the ground and revoking well permits.

Scientists have said they are not sure whether reducing the number of saltwater disposal wells will diminish seismic activity.