Bridget Scanlon

Bridget Scanlon, senior research scientist at the Bureau of Economic Geology, authored a study that found unconventional gas and oil production uses about the same amount of water as conventional production. Scanlon’s results will aid future economic and policy studies about the environmental impacts of unconventional energy production methods like fracking.

Photo Credit: Xintong Guo | Daily Texan Staff

A study led by a UT researcher found that the amount of water used for unconventional gas and oil production, such as hydraulic fracturing, is about the same as is used for conventional production. 

The study, published on Sept. 18 online in the “Environmental Science & Technology Journal,” was led by Bridget Scanlon, senior research scientist in the Jackson School of Geosciences.

“We’re using more water for hydraulic fracturing because we’re producing more oil using hydraulic fracturing,” Scanlon said. “It is not because hydraulic fracturing is more water-intensive per unit of oil production.” 

Scanlon said she decided to conduct the study to answer existing questions about the vulnerability of unconventional gas and oil production because of water shortages and the use of hydraulic fracturing.

“There is a concern about using water, especially in times of drought,” said Kristine Uhlman, research engineering/scientist associate. “With this research, people can understand that the method for generating energy is not necessarily what’s causing more water use.”

According to Uhlman, hydraulic fracturing, fracking, is a process in which liquids are injected into fractures of rocks to extract natural gas and oil. Conventional oil and gas accumulates in reservoirs and is extracted through the use of conventional, vertical wells. Unconventional oil and gas is trapped in dense rock, typically shale, and cannot be extracted except through the use of unconventional, horizontal wells. Uhlman said the unconventional oil production method has been useful to reach unconventional oil. 

“Unconventional oil and gas production is helping the United Sates be energy independent,” Uhlman said. “We have enough energy to sustain ourselves because of this new unconventional development of unconventional oil and gas.”

Scanlon said the results of this study could be used in future economic and policy studies about environmental impacts of unconventional energy production. She said the research was based on a well-by-well analysis of water use in hydraulic fracturing and used a number of different databases. 

She looked at thousands of wells used for conventional and unconventional oil and gas production and came up with ranges of how much water is used to construct them. They found the same amount of water is used for both methods.

“The difference is not how much water is used, but when it is used,” Uhlman said.

Uhlman said that this study could provide people with a better understanding of the relationship between water and energy.

Research scientist associate Robert Reedy and research scientist Jean-Philippe Nicot, both with the Jackson School of Geosciences, also contributed to the study.

(Illustration by Colin Mullin)

A new study found that regions in Texas and California have experienced severe groundwater depletion over the last century due to unsustainable irrigation techniques.

Bridget Scanlon, hydrogeologist in the Bureau of Economic Geology at the Jackson School of Geosciences, published a study in May on water depletion levels in the High Plains regions across Texas, Kansas and Nebraska and the Central Valley region of California. These two regions combined produce a large portion of the nation’s food supply. According to the study, Scanlon compared data from NASA’s Gravity Recovery and Climate Experiment satellites as well as ground-based estimates from well water data in order to determine the level of depletion across these regions. Over the last century, a disproportionate concentration of depletion has occurred in Texas and California, Scanlon said.

“I started focusing my research on impacts of irrigation and water resources when I realized that irrigation consumes 90 percent of freshwater resources,” Scanlon said. “These two regions have accounted for 50 percent of groundwater depletion in the last century.”

Robert Reedy, a research engineering and scientist associate in the Bureau of Economic Geology and co-author of the study, said the results of the research should be interpreted within a bigger picture.

“The food supply is not in danger,” Reedy said. “Agriculture would not go away in the case of depleted water. Productivity would decrease, so it would shift the balances, and prices would certainly go up if a certain supply went down. Part of the whole thing is just to see where all of this is headed.”

Scanlon said one of the most significant findings was the concentration of water depletion in specific parts of the Texas and Kansas areas in the High Plains region, which showed that water depletion was not uniform across one area.

“Most people think the High Plains aquifer is all the same type of system and everything is the same across the aquifer, but with this study we have really shown that spatially it’s quite variable,” Scanlon said. “About 35 percent of the depletion is focused in 4 percent of the land area, so in order to better manage it, we need to understand that.”

In California’s Central Valley, a complicated piping system has allowed areas to the south with less rainfall to be replenished with surface water from northern areas that receive more rain, Scanlon said.

“In California it’s a little bit different,” Scanlon said. “There’s a lot of rain in the Sacramento region but in Bakersfield to the south, the rainfall rate is much lower. California developed a large pipe infrastructure to transfer surface water between regions.”

Despite the effectiveness of the pipe structure, which takes surface water from rainfall, a similar system in the High Plains region would not be viable, Scanlon said. In addition to the process being expensive, Scanlon said Texas does not have all the infrastructure California has and it would be a much more involved process to transfer surface water to areas in need.

Changbing Yang, a research associate in the Bureau of Economic Geology, said there will be significant repercussions if more efficient and sustainable systems aren’t put into place in the High Plains.

“Bridget Scanlon’s study over groundwater depletion in the High Plains and Central Valley regions is significant,” Yang said. “In the High Plains, groundwater yield will decrease by two times if we continue to irrigate it as we have been.”

Part of finding the bigger picture in terms of regional agriculture is realizing that many people are unaware that they may be affected, Reedy said.

“The way the food market is set up in the country, a lot of people are unaware of the whole chain of events and everything that goes into it,” Reedy said. “Different groups of people are aware of certain aspects of what’s going around them in the world and others just don’t hear or understand some aspects of everyday life. Farmers are living on the land and doing the work and sometimes even they don’t know what’s going on except maybe in their own region.”