NSF PR 00-23 - April 14, 2000
This material is available primarily for archival
purposes. Telephone numbers or other contact information
may be out of date; please see current contact information
at media
contacts.
Researchers Find Key to Spurring Methane Conversion
Microbiologists Derek Lovley and Robert Anderson of
the University of Massachusetts at Amherst have found
that bacteria living just below the earth's surface
can be coaxed to rapidly convert oil to methane gas
in oil-rich soil. Their findings, which are spelled
out in a paper in the April 13 issue of the journal
Nature, could change the way the oil exploration
industry operates. The research is funded by the National
Science Foundation (NSF).
Petroleum engineers often hit pockets of methane when
exploring for oil. According to Lovley, specialized
microorganisms that live deep in the earth break down
oil to its simplest form, and the result of that process
is what we call "natural gas," or methane. Underground
pockets of explosive gas are oil-exploration hazards
because they generally are contiguous to valuable
oil reserves.
In the summer of 1999, Lovley and Anderson examined
the site of a contaminated aquifer where crude oil
had spilled, 30 feet below the surface of the earth
near Bemidji, Minnesota. With the help of a grant
from NSF's Life in Extreme Environments Program, they
studied anaerobic metabolic processes of microbes
living in and around the oil spill. The contamination
had changed the composition of the microbial community
from what was normally found in the Minnesota soil
to something similar to what would be found near oil
reservoirs. Unlike soil found much deeper in the earth,
however, there was no sulfate in this soil. Until
Lovley and Anderson's study, sulfate was thought to
be a necessary ingredient in the process microbes
use to break down oil.
"We know that microbial processes found in shallow
environments are also common to deeper environments,"
explains Lovley, "We study microbes at shallow levels
because it's hard to sample them down as deep as the
oil reserves."
The researchers incubated the sediments in the laboratory
under conditions that mimicked those found in the
subsurface of the earth. Surprisingly, as soon as
Lovley and Anderson added the oil component hexadecane
with a carbon-14 tracer to the sediment, methane gas
carrying the tracer was produced "without a lag."
The two concluded that the microbes in the soil were
converting the hexadecane and other oil components
in the soil to methane gas, in the same way deep-dwelling
microbes might complete the methane process in a natural
environment.
"We found that, contrary to what was previously believed,
it's not necessary to have sulfate present in order
for microbes to produce methane from oil," says Lovley.
"This is important because significant amounts of
sulfate are not usually found in oil reservoirs. This
finding is very useful, with a potential for widespread
application to the petroleum industry." In some cases,
he said, it might be beneficial to use microorganisms
to convert the oil in reservoirs to methane because
methane is easier to extract than oil.
Adds Lovley, "When we better understand the conditions
under which microorganisms convert oil to methane,
we should be able to better predict where explosive
deposits of methane will be located. This should make
oil exploration a bit safer."
**NSF is an independent federal agency which supports
fundamental research and education across all fields
of science and engineering, with an annual budget
of about $4 billion. NSF funds reach all 50 states,
through grants to about 1,600 universities and institutions
nationwide. Each year, NSF receives about 30,000 competitive
requests for funding, and makes about 10,000 new funding
awards.
For instant information about NSF, sign up for the
Custom News Service. From the toolbar on NSF's home
page, (http://www.nsf.gov),
sign up to receive electronic versions of NSF news,
studies, publications and reports. Follow the simple
sign-on procedures that guide you to your choices.
Also see NSF news products at: http://www.nsf.gov:80/od/lpa/start.htm,
http://www.eurekalert.org/, and http://www.ari.net/newswise
|