Water comes from the ground as a by-product of oil production from unconventional reservoirs. During the coming decades, this will theoretically counter the need to use freshwater for hydraulic fracturing operations in many of the United States’ large oil-producing areas.
But while other industries, such as agriculture, might want to recycle some of that water for their own needs, water quality issues and the potential costs involved mean it could be best to keep the water in the oil patch. That is the takeaway from two new studies led by researchers at The University of Texas at Austin.
“We need to first maximize reuse of produced water for hydraulic fracturing,” said Bridget Scanlon, lead author on both of the studies and a senior research scientist with the UT Bureau of Economic Geology. “That’s really the message here.”
The first study was published in Environmental Science and Technology on February 16. It quantified for the first time how much water is produced with oil and natural gas operations compared with how much is needed for hydraulic fracturing. The authors also projected water demand for hydraulic fracturing needs and produced water over the life of the oil and gas plays, which span decades. A play is a group of oil or natural gas fields controlled by the same geology.
The second study was published in Science of the Total Environment on February 3. It assessed the potential for using the water produced with oil and natural gas in other sectors, such as agriculture. The study showed that current volumes of produced water are relatively small compared with irrigation water demands and will not solve water scarcity issues.
The two studies can help inform significant public policy debates about water management related to oil and natural gas production in Texas, Oklahoma, New Mexico, and other parts of the United States, according to Scanlon.
“The water volumes that are quoted vary widely,” Scanlon said. “That’s why we did this study. This really provides a quantitative analysis of hydraulic fracturing water demand and produced water volumes.”
Dealing with water issues has become increasingly challenging with oil and natural gas development in unconventional shale reservoirs. Operators need significant amounts of water to hydraulically fracture shales to produce oil and natural gas, which can be an issue in areas where water is scarce.
And large quantities of water are brought up from the reservoirs as a by-product of production, posing a whole new set of issues for how to manage the produced water, particularly as science has shown that pumping it back into the deep subsurface is linked to seismic activity in some regions.