Victoria research could aid oil search

MEDIA RELEASE

14 November 2006

Victoria research could aid oil search

Researchers at Victoria University have been able to track for the first time the speed with which liquids move between different pores in rocks that hold hydrocarbons.

While geologists have been using nuclear magnetic resonance (NMR) for more than a decade to probe the nuclei of atoms to learn about the porous structure of rocks that hold oil and other hydrocarbons, Professor Paul Callaghan and postgraduate student Kate Washburn have shown how the technique could be extended to track the movement of liquid between different pores.

Their research was published in the latest edition of the prestigious journal, Physical Review Letters.

Professor Callaghan, who is the Director of the MacDiarmid Institute for Advanced Materials & Nanotechnology, said the method had many potential uses.

“Not only could it could assist production companies in more efficiently extracting oil from the ground, but it could also allow researchers to monitor the motion of molecules between different microscopic regions in liquid crystals or biological cells.”

NMR techniques involve placing a sample into a magnetic field, causing the atoms in it to resonate at a particular frequency. By directing a radio wave into the atom, the wave that comes back can tell scientists a lot about the sample. NMR works particularly well with compounds that contain hydrogen atoms such as water.

To understand the structure of a rock using NMR, researchers expose a porous rock such as sandstone to a strong magnetic field, causing the nuclei of the hydrogen atoms in the water to line up like tiny magnets. When a different magnetic field is briefly added, the nuclei begin to ‘wobble’ in synch and monitoring how long it takes for the wobbling to start can tell researchers the size of the pores in the rock. When the molecules are in a small pore, they collide with the walls more quickly and start wobbling sooner than those in a large pore.

Professor Callaghan says knowing the range of pore sizes doesn’t tell the researchers how well connected the pores are.

“To find that out, we need to repeat this test over time and look for changes. Using complex computational techniques, we’ve been able to work out how quickly the liquid moves between pores. In the oil industry, this is crucial information as it indicates how easily trapped oil will be able move through the rock and out of the well.”

ENDS

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