They are the paparazzi of geophysics.
Winthrop Professor David Lumley, the Woodside-Chevron Chair in Petroleum Geoscience and CO2 Sequestration, and Research Fellow Dr Jeffrey Shragge take what they describe as ‘snapshots' of the earth that cost about $10 million each.
The pictures are at the core of time-lapse imaging, a form of seismic monitoring that was pioneered at Stanford University in the 1990s, while Professor Lumley was doing his PhD there. It is one of the hottest fields of research in the petroleum industry.
Dr Shragge joined Professor Lumley at UWA after also completing his PhD at Stanford and wanting to expand his seismic imaging experience.
Images taken a year or even five years apart, below the surface of either the ocean floor or land rock layers, show the movement of fluids over time, including oil and gas, making it a valuable tool for pinpointing expensive ($50M) drilling locations and locating resources that have been bypassed.
"Yes, it's expensive technology," Professor Lumley said. "But when you consider the value of the projects - billions of dollars - it's worth it to the energy companies."
He said the ability to use the technology to identify the best places underground in which to store carbon dioxide or CO2 was also valued by the developers of the new offshore giant gas projects, including Chevron Australia's Gorgon fields.
"The geochemistry of these fields means that the methane gas that is brought up will be mixed with a lot of natural CO2 - which needs to be removed before it can be liquefied to form LNG and shipped to market.
"The companies don't want to simply vent the CO2 into the atmosphere, so they are keen to investigate carbon sequestration, or injecting and storing it in deep rock formations where it originated."
While Professor Lumley and his team are not employed by Chevron or Woodside, the energy companies have funded his Chair to encourage the research that they need. "They want the Centre to focus on the grand challenges and develop the technology for the specific reservoir conditions that are here in WA," he said.
"It's pretty exciting when you can make an impact on a real project. Carbon sequestration is one of the best opportunities we have to reduce the amount of CO2 emissions going into the atmosphere."
Australia is the first nation in the world where commercial companies are now able to lease off-shore blocks to explore for carbon storage.
"It's early days yet, but the seeds have been planted to establish a carbon capture and storage industry," Professor Lumley said.
The best place for CO2 sequestration is in deep porous permeable rock with a big containment capacity where, over thousands of years, the carbon dioxide dissolves into salty water and then converts to minerals. But it must be secure so that the CO2 does not leak out.
"Looking for areas like this is almost like the opposite of exploring for resources," he said. "We want to find the right storage volume that has nothing valuable in it."
Dr Shragge, who came to UWA last year after working with Stanford's famous exploration project (SEP), said that until recently, there were only a few geophysics research groups in the world who were working on carbon sequestration.
"What makes it really important to WA is that these giant gas fields will be coming on line in the next 10 to 15 years, producing huge amounts of CO2," he said.
As well as developing sequestration methods, the Centre's imaging expertise may be used in the future to determine how much carbon a company has buried.
"It's likely that companies could get carbon credits in the future for carbon sequestration so there has to be a way for the government to verify how much is sequestered," Dr Shragge said. "Time lapse imaging could be useful here."
The images that cost so much are captured both on land and on the ocean. Offshore, boats tow long cables with thousands of sensors and source arrays that discharge acoustic energy. The scattered energy is recorded and focused by supercomputers, giving a picture of what fluids are moving underground.
On land, trucks with big vibrating pads are used to vibrate the surface of the earth. These waves go down through the earth and reverberate back to the surface, carrying information that is captured by sensors.
While the technology is catching on, Professor Lumley is considered one of a small group of pioneers in the field. "Over the past 15 years, 4D seismic has become a valuable tool but it still hasn't permeated the whole industry and become mainstream," he said.
"The technique can be applied to other types of fluid flow in the earth. For example, it could be useful in the geothermal energy industry to find where the hot water's going."
After following Professor Lumley down the hot road of time lapse imaging and carbon sequestration, Dr Shragge recently won a prestigious international award for his early career work and publications. The Society of Exploration Geophysicists awarded him the annual J Clarence Karcher Award for his important contributions to the sciences and the profession. Dr Shragge was chosen for the award from among 32,000 members of the society worldwide.
Published in UWA News, 23 August 2010