A common method of extracting oil by injecting large amounts of water into old wells is coming under scrutiny by Michigan environmental groups.

The technique, known as water flooding, has been around for decades. But like many nonconventional means of oil recovery, it is becoming more economically viable as prices rise, and there is little information on exactly how much water is being traded for the oil that's produced.

Energy extraction is placing increasing pressure on the nation's water supply, according to a new report by the World Policy Institute. While agriculture accounts for 80 percent of the nation's water consumption, energy extraction accounts for much of the remaining 20 percent.

"The competition between water and energy needs represents a critical business, security, and environmental issue, but it has not yet received the attention that it deserves," Diana Glassman, a co-author of the report, said in a statement.

In Monitor Township, Mich., near Bay City, the Muskegon Development Co. is proposing a project to recover additional oil in what's known as the Kawkawlin Field by flooding old wells with up to 42,000 gallons of water a day from Lake Huron. That would last for up to eight years, requiring some 122 million gallons of water.

Township trustee Terry Miller, who also heads the Lone Tree Council environmental group, believes the impact of water use for energy has fallen under the radar of government leaders and the general public. He sees secondary recovery as a practice that has bypassed laws like the international Great Lakes Compact, meant to protect the basin from large water withdrawals.

The water amounts for the Kawkawlin project are relatively small by industrial standards, and don't meet the thresholds for extra regulations under the compact, according to Hal Fitch, assistant supervisor of wells for the Michigan Office of Geological Survey.

Larry Organek, an engineer for the Michigan Office of Geological Survey, said the state Department of Environmental Quality isn't keeping records of how much water is being used in total for the more than 50 secondary recovery projects currently in operation in the state.

Lack of oversight

Miller says that lack of oversight is exactly the problem.

"How many of these projects are going on, and how much nickel and diming of our water resources is occurring without anybody's knowledge for the most part?" Miller said.

The Michigan Environmental Council, an umbrella group of more than 70 state organizations, shares Miller's concerns about secondary recovery.

"The industry is pursuing riskier options like this because the easiest oil reserves have already been extracted," said Energy Program Director David Gard.

"In a sense, we are getting more desperate to keep our gas tanks full. This means pressure to expand production from older wells will only intensify. We need to make sure this doesn't happen at the cost of damaging our most precious natural resources."

U.S. oil production relies heavily on secondary recovery via water flooding, according to a 2009 report by Argonne National Laboratory.

The technique requires an average of eight gallons of water for every gallon of crude oil that's recovered.

In 2005, domestic onshore recovery operations in the U.S. required an estimated 1.2 billion gallons of injection water to produce 146 million gallons of conventional crude oil, according to the Argonne report. By comparison, U.S. agriculture uses about 100 billion gallons in a typical year.

The World Policy Institute report, "Water-Energy Nexus," found that emerging oil and alternative fuel sources consume much more water than conventional oil. For instance, petroleum from the Canadian oil sands extracted via surface mining techniques can consume 20 times more water than conventional oil drilling, and biofuels can require thousands of times more water than gasoline.

In addition, natural gas produced by hydraulic fracturing, or "fracking," consumes seven times more water than conventional gas extraction, but roughly the same amount of water as conventional oil drilling.

Michigan regulators recently approved rules that will require fracking operations to report the amount of water they recover from wells.

Big potential

According to an order granted by Fitch for the Muskegon Development work, there are 85 producing wells where the Kawkawlin project would take place, and more than 84,000 barrels of oil are left to be recovered using water injection.

"When you drill up a field, you might get 30 percent of the oil out of the reserve," Fitch said, "so 70 percent is left behind. If you undertake secondary recovery, you can recover maybe another 20-25 percent."

Secondary recovery using water has been going on in other parts of the Kawkawlin Field for about 15 years, according to Organek. The water line extension would allow for the third phase of the project.

Michigan regulators say the practice of secondary recovery using water has been growing in the state, or is at least becoming more economical, in the wake of $4-a-gallon gas prices, and crude oil prices above $100 a barrel.

"As the price of oil increases, these projects become more likely," Organek said. "They are capital intensive in the beginning, but as with a lot of other projects, as the price of oil moves up, they become more economical."

A major concern about secondary recovery projects is that none of the water is available again for drinking. State and federal permits for the Michigan project, for instance, don't require the water to be treated once it becomes contaminated with crude oil.

Fitch acknowledges water used for secondary recovery is "lost to the hydrologic cycle."

"It is what we could call a consumptive use of water," he said. "You have to balance that against the benefits of additional oil production."

Jeff Kart is a freelance writer based in Bay City, Mich. He's been covering the Great Lakes and environmental issues for more than 10 years.