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