RTI International and Duke University are teaming up to determine whether the use of so-called “produced water” from oil wells for crop irrigation is safe.
And there’s a lot of this water.
Argonne National Laboratory has reported that more than 7.5 barrels of water were produced for every barrel of crude, according to a Reuters news report. A decade ago, more than 20 billions of such water was produced – and that was long before the broad expansion of the oil and natural gas industry into shale fields.
The study is being conducted for the U.S. Department of Agriculture’s National Institute of Food and Agriculture (NIFA).
“Concerns have been raised about the potential health impacts of consuming food irrigated with this water,” said Jennifer Hoponick Redmon, environmental health scientist at RTI who is co-project director. “Another concern is whether potential salts and heavy metals in the oil-produced water could over time hinder crop growth.”
What is ‘produced water’?
Produced water is a term used in the oil industry to describe water that is produced as a byproduct along with the oil and gas. Oil and gas reservoirs often have water as well as hydrocarbons, sometimes in a zone that lies under the hydrocarbons, and sometimes in the same zone with the oil and gas.
Oil wells sometimes produce large volumes of water with the oil, while gas wells tend to produce water in smaller proportion.
To achieve maximum oil recovery, waterflooding is often implemented, in which water is injected into the reservoirs to help force the oil to the production wells. The injected water eventually reaches the production wells, and so in the later stages of waterflooding, the produced water proportion (“cut”) of the total production increases.
The Pacific Institute and California State University-Bakersfield are also part of the project.
“While U.S. oilfield produced water production is projected to increase, beneficial irrigation use is hindered by a lack of publicly available, scientific evidence on its safety,” Hoponick Redmon said. “To promote sustainable food production, it is imperative that we strategically and scientifically evaluate ways to optimize our limited resources within the food-energy-water nexus in a safe way.”
RTI points out that “significant amounts” of this water already is used to irrigate crops in California.
The research team will evaluate the potential human health impacts and sustainability of using produced water from oilfields to irrigate crops,” RTI says.
“As severe droughts limit the availability of irrigation water in many U.S. watersheds, demand for alternative water sources increases.”