By Kathryn Lougheed
Technology used to measure gravity in space is being used to develop oil-hunting devices that work at the bottom of the ocean, according to a scientist presenting at the British Science Festival in Aberdeen.
With oil and gas supplies rapidly diminishing, tapping into hidden reserves is a profitable business. But finding undiscovered oil fields in the 140 million square miles of the world's oceans is not a simple task. A sensor that can measure changes in gravity, even underwater, could be the answer.
Dr Charles Wang of the University of Aberdeen says, "The usual gravity we experience and understand is Earth's gravity, but in reality every object is a source of gravity." This means that, by detecting tiny changes in local gravity, the scientists can visualise hidden structures beneath the seafloor.
The technique relies on cold atom trapping. Atoms can behave as both waves and particles but when laser-cooled to extremely low temperatures their wave behaviour dominates. Gravitational waves interfere with the cold atom waves with differing degrees depending on the density and proximity of nearby objects. Because different geological formations differ in density, it is possible to create a 3D image of the structures under the ocean bed. By combining this with other technologies, oil prospectors will be able to identify the layers of rock between which oil may be trapped.
A similar method has been used in airborne surveys for oil reserves but has never been tried beneath the waves as the existing technology is extremely large and power-hungry. The key benefit of Dr Wang's sensor is that it will be just centimetres in size, meaning that it can be used onboard submersibles which can get closer to hidden oil fields, making them easier to spot. He is currently collaborating with an oil company and hopes that the sensor will be deployed in a few years' time.