Permian Basin: the ground is sinking dangerously in the largest hydrocarbon field in the United States

If oil is the blood of the United States, then its beating heart is none other than the Permian Basin, whose name refers to the geological stage that contains the resource. Situated straddling two southern states (Texas and New Mexico), this territory, as large as 40% of mainland France (220,000 square kilometers), represents a quarter of the national production of black gold.

After a first phase of exploitation of conventional hydrocarbons in the industrial age, the region which saw the Bush dynasty prosper turned in the 2010s to so-called “unconventional” shale oil and gas, of which the Extraction requires fracturing the rock using pressurized fluids (hydraulic fracturing).

By analyzing satellite data, our colleagues from the Wall Street Journal (April 28, 2024) reveal that in a large area of ​​the Permian Basin where oil production has reached nearly three million barrels per day, the ground has subsided by 28 centimeters since 2015. Conversely, the earth has risen at the level of the wells where industrial wastewater is discharged, thus forming worrying “folds”.

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3.4 billion barrels of wastewater

“Unconventional hydrocarbons are characterized by a short operating life, requiring drilling ever further, even if it means weakening the subsoil of entire regions”already wrote in 2022 Laurent Carroué, general inspector of education, sport and research, director of research at the French Institute of Geopolitics – Paris VIII University (The unconventional hydrocarbon boom in the Permian BasinGeoConfluences).

The depth of the wells can range from a few hundred meters to 3,000 m deep, knowing that for a horizontal well, due to the nature of the rock, there are around thirty fracturing operations per kilometer of tube length. Each of these operations consumes on average 300 m3 of water, 30 tonnes of sand and 0.5% of chemical additives, detailed the French researcher.

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Once used, the water is then separated from the hydrocarbon. All that remains is to get rid of it… In 2013, during the shale boom, companies in the Permian Basin released approximately 382 million barrels of water, according to the analysis company B3 Insight cited by the Wall Street Journal (WSJ). Last year, they pumped about 3.4 billion barrels of water into disposal wells, roughly the amount of water New York City consumes in about five months, the article compares. .

Increase in earthquakes

If part of the wells are about a mile (1.6 km) below the surface, which is “practical and relatively inexpensive”the companies also injected a smaller portion of the wastewater to depths of about three miles (4.8 km), allowing them to dump more without affecting subsequent drilling. “But there’s a catchunderlines the WSJ. Water can cause deeply rooted faults to slide, creating earthquakes.”

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As a result, the number of earthquakes greater than magnitude 2.5 in the Permian Basin increased from 42 in 2017 to 671 in 2022 (B3 Insight cited by WSJ). At the end of 2022, a magnitude 5.4 earthquake in Reeves County, Texas, notably caused tremors felt as far away as Dallas, more than 700 kilometers away.

In addition to earthquakes, residents and scientists increasingly fear that wastewater will migrate into the “aging and uncapped wells that litter the Permian Basin by the thousands” and not “contaminate drinking water supplies”. Fluids could also rise to the surface, polluting ranch lands. A request on this subject must be considered by the Federal Environmental Protection Agency.