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.
Tim Stephens | EurekAlert!
Receding glaciers in Bolivia leave communities at risk
20.10.2016 | European Geosciences Union
UM researchers study vast carbon residue of ocean life
19.10.2016 | University of Miami Rosenstiel School of Marine & Atmospheric Science
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.
Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
21.10.2016 | Health and Medicine
21.10.2016 | Information Technology
21.10.2016 | Materials Sciences