||"Smart water," a type of seawater, could help meet energy demands by boosting oil extraction by as much as 60 percent, scientists say.
Credit: Trevor MacInnis
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Researchers in Norway report
that injecting a special type of seawater called “smart water” into certain
low-yield oil wells may help boost oil extraction by as much as 60 percent. The
study could help meet rising energy demands and provide consumers with some
financial relief at the gas pump in the future, the scientists suggest. Their
findings are scheduled for the Sept. 10 issue of ACS’ Energy & Fuels, a bi-monthly journal.
In the new study, Tor Austad and colleagues note that more than 50
percent of the world’s oil reserves — billions of gallons of oil — are trapped
in oil reservoirs composed of calcium carbonate, rocks that include chalk and
limestone. Scientists now inject seawater into chalk-based oil wells to boost
oil extraction, but researchers do not know if the method will work for oil
wells composed of limestone, a tough material known for its low oil-recovery
rates — usually less than 30 percent, but in some cases less than 5 percent.
To find out, the scientists collected core samples from Middle East oil reservoirs composed of limestone and
soaked them in crude oil for several weeks. They then prepared batches of
so-called “smart water,” seawater formulated with sulfate and other substances
to improve seawater’s ability to penetrate limestone. In laboratory studies,
they showed that irrigating the limestone samples with “smart water” led to the
same fundamental chemical reactions that occur in chalk. Upcoming experiments
will verify if the efficiency in oil recovery is comparable to the observations
in chalk, the scientists note. — MTS
News release from American Chemical Society (ACS) on September 8, 2008.