The Very Real Problem of Fracking Wastewater
- U.S. shale oil wells generate 27–45 million barrels of toxic wastewater every day, with shale gas adding billions more gallons annually.
- Traditional underground disposal is polluting groundwater, reactivating old wells, and triggering earthquakes in Texas and Oklahoma.
- Oil companies like ConocoPhillips and Chevron now warn that wastewater could flood oil reserves and choke production unless alternatives are developed.
There's an old saying that I won't spell out completely, but which most readers will certainly have heard at least once in their lives, to wit: "Don't sh-- where you eat." It is an all-purpose warning about not pursuing incompatible activities in the same place, particularly activities that produce either physical waste or emotional complications.
In this case, the waste part is wastewater emitted by oil wells drilled into shale deposits, which must undergo extensive hydraulic fracturing (often called fracking) before the oil can be freed. What most people do not know is that for every barrel of shale oil extracted, three to five barrels of water laden with fracking chemicals and salt, toxic minerals, and radioactivity (from the deep rock) also come up, most of it water originally injected under high pressure to fracture the shale and release the oil.
Some 9 million barrels a day of shale oil is currently produced in the United States each day, according to the U.S. Energy Information Administration. That means between 27 and 45 million barrels of fracking wastewater is produced EACH DAY; in gallons, that's between 1.1 and 1.9 billion gallons. And, of course, multiply by 365 and you'll get yearly totals. That's a lot of wastewater, and it has to go somewhere, and that somewhere is starting to pollute underground water supplies and surface soil and water, and to interfere with oil production itself.
Mostly, this wastewater is disposed of underground, at first deep underground and now in shallower wells. The deep disposal began triggering earthquakes in Texas that were felt hundreds of miles away. Oklahoma has experienced a similar rise in earthquakes due to oil and gas wastewater pumped underground. Because of this, regulators started to move underground disposal to shallower depths, which led to other problems.
(Yes, shale gas wells produce lots of wastewater, too. The United States extracted an estimated 45.9 trillion cubic feet of natural gas last year, of which 79 percent came from shale wells requiring hydraulic fracturing. An estimated 0.8 and 1.3 gallons of water are produced along with the gas for every 1,000 cubic feet. That means between 29 and 47 billion gallons of wastewater from natural gas drilling needed to find a home last year. This may be an overestimate since some gas, called associated gas, is produced from oil wells.)
Groundwater used for human and animal consumption is being polluted by these shallower underground injections. So much pressure has built up underground that some old abandoned wells have sprung to life, spewing wastewater that comes to the surface through old well casings. The industry pretends to care about this, but generally fights landowners who complain and sue. But what the industry is really increasingly concerned about is that the wastewater is starting to break through to producing wells and compromise production. One major producer, ConocoPhillips, has warned that underground wastewater injections risk flooding out oil reserves. "Flooding out" means that water infiltrates into oil reservoirs from places where wastewater has been injected, complicating production or even making profitable production impossible as water comes to dominate extraction volumes.
If oil companies cannot find ways to dispose of the increasing volumes of fracking wastewater, they will have to limit production. Some of the wastewater is being treated, though there is concern about the level of toxic materials that remain in the supposedly purified discharge water. Underground injection is still the most widely used and cheapest method of disposal.
The call for developing alternatives to underground disposal now has an unlikely champion, oil major Chevron, a company at the center of the controversy over fracking wastewater disposal. The industry will need a solution soon, as water use is expected to balloon as the industry moves on to less oil-rich reservoirs that will require more fluid to successfully fracture wells. This is projected to lead by 2035 to a 39 percent increase in wastewater from the Permian Basin, the largest producer of shale oil in the United States.
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