Nav: Home

Increased flow of groundwater after earthquakes suggests oil extraction applications

June 28, 2006

SANTA CRUZ, CA--The most obvious manifestation of an earthquake is the shaking from seismic waves that knocks down buildings and rattles people. Now researchers have established a more subtle effect of this shaking--it increases the permeability of rock to groundwater and other fluids.

The enhanced permeability caused by seismic shaking could potentially be harnessed to help extract oil from natural reservoirs, said Emily Brodsky, assistant professor of Earth sciences at the University of California, Santa Cruz.

"Permeability governs how fluid flows through rocks, whether it's water or oil, so this has practical implications for oil extraction," Brodsky said.

Brodsky is coauthor of a paper describing the new findings in the June 29 issue of Nature. The first author is Jean Elkhoury, a graduate student who worked with Brodsky at UCLA, and the other coauthor is Duncan Agnew of UC San Diego.

The study was based on two decades of data from the Piñon Flat Observatory in southern California, where researchers from UCSD's Scripps Institution of Oceanography maintain an extensive geophysical observatory.

"It's probably one of the best-monitored pieces of land anywhere on Earth," Brodsky said.

The monitoring includes records of fluctuating water levels in wells. The water levels fluctuate in response to tidal effects similar to oceanic tides. In this case, the gravitational effects of the moon on the solid Earth squeeze and stretch the rocks in the crust, forcing water in and out of the wells from the surrounding rocks. The speed of the response in a well depends on the permeability of the surrounding rock.

"We know the tidal strain very well, so we can measure the lag between the imposed tidal strain and the response in the well to get a precise measure of the permeability of the rock," Brodsky said.

The researchers analyzed the data in relation to earthquakes and saw a striking correlation. "Every time there's a big earthquake in southern California, the permeability jumps. We saw this in two different wells for more than seven different earthquakes," Brodsky said.

After an earthquake, the rock surrounding the wells became as much as three times more permeable to groundwater, she said. Furthermore, the size of the increase in permeability was proportional to the peak amplitude of the shaking. The changes were transient, with permeability returning to the original level within a few months after an earthquake.

The oil industry might be able to exploit this phenomenon by using "vibroseis" trucks to send seismic waves into the ground. Currently used for seismic imaging studies, vibroseis trucks vibrate at a particular frequency for a prolonged period.

"If we understood the physics of the permeability enhancement well enough, the vibrations could be tuned to increase the flow of oil," Brodsky said.
-end-


University of California - Santa Cruz

Related Earthquake Articles:

From where will the next big earthquake hit the city of Istanbul?
Scientists reckon with an earthquake with a magnitude of 7 or greater in this region in the coming years.
Dissection of the 2015 Bonin deep earthquake
Researchers at Tohoku University's Department of Geophysics, have been studying the deep earthquake which occurred on May 30, 2015, to the west of Japan's Bonin Islands.
The search for the earthquake nucleus
Where a tectonic plate dives under another, in the so-called subduction zones at ocean margins, many strong earthquakes occur.
Better understanding post-earthquake fault movement
Preparation and good timing enabled Gareth Funning and a team of researchers to collect a unique data set following the 2014 South Napa earthquake that showed different parts of the fault, sometimes only a few kilometers apart, moved at different speeds and at different times.
The maximum earthquake magnitude for North Turkey
The Istanbul metropolitan region faces a high probability for a large earthquake in the near future.
Double dose of bad earthquake news
A team of researchers, including one from the University of California, Riverside, has discovered that earthquake ruptures can jump much further than previously thought, a finding that could have severe implications on the Los Angeles area and other regions in the world.
Discovery of hidden earthquake presents challenge to earthquake early-warning systems
Seismologists at the University of Liverpool studying the 2011 Chile earthquake have discovered a previously undetected earthquake which took place seconds after the initial rupture.
Babe Ruth and earthquake hazard maps
Northwestern University researchers have turned to an unusual source -- Major League Baseball -- to help learn why maps used to predict shaking in future earthquakes often do poorly.
Earthquake rupture halted by seamounts
Experts expected for some time that one of the next mega earthquakes occurs off northern Chile.
Catastrophic landslides post-earthquake
In the last few months, it has once more become clear that large earthquakes can solicit catastrophic landsliding.

Related Earthquake Reading:

Quakeland: On the Road to America's Next Devastating Earthquake
by Kathryn Miles (Author)

The Great Quake: How the Biggest Earthquake in North America Changed Our Understanding of the Planet
by Henry Fountain (Author)

Earthquakes (True Books: Earth Science (Paperback))
by Ker Than (Author)

National Geographic Kids Everything Volcanoes and Earthquakes: Earthshaking photos, facts, and fun!
by Kathy Furgang (Author)

Earthquake Terror (Puffin Novel)
by Peg Kehret (Author)

I Survived the San Francisco Earthquake, 1906 (I Survived #5)
by Lauren Tarshis (Author), Scott Dawson (Illustrator)

Earthquakes (Let's-Read-and-Find-Out Science 2)
by Dr. Franklyn M. Branley (Author), Megan Lloyd (Illustrator)

Soil Liquefaction During Earthquakes (Engineering monographs on earthquake criteria, structural design, and strong motion records)
by I. M. Idriss (Author), R. W. Boulanger (Author)

Earthquakes (Smithsonian-science)
by Seymour Simon (Author)

The San Francisco Earthquake: A Minute-by-Minute Account of the 1906 Disaster
by Open Road Media

Best Science Podcasts 2018

We have hand picked the best science podcasts for 2018. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Hacking The Law
We have a vision of justice as blind, impartial, and fair — but in reality, the law often fails those who need it most. This hour, TED speakers explore radical ways to change the legal system. Guests include lawyer and social justice advocate Robin Steinberg, animal rights lawyer Steven Wise, political activist Brett Hennig, and lawyer and social entrepreneur Vivek Maru.
Now Playing: Science for the People

#495 Earth Science in Space
Some worlds are made of sand. Some are made of water. Some are even made of salt. In science fiction and fantasy, planet can be made of whatever you want. But what does that mean for how the planets themselves work? When in doubt, throw an asteroid at it. This is a live show recorded at the 2018 Dragon Con in Atlanta Georgia. Featuring Travor Valle, Mika McKinnon, David Moscato, Scott Harris, and moderated by our own Bethany Brookshire. Note: The sound isn't as good as we'd hoped but we love the guests and the conversation and we wanted to...