Finding oil and gas reservoirs has just become a matter of following your nose – or rather a super-sensitive electronic nose developed by researchers in Scotland. The device, which measures tiny quantities of the gas ethane, can also be used as a breathalyser to sniff out lung cancer in its early stages.
Prospecting for oil and gas is usually an expensive and laborious process, involving bouncing sound waves through rock layers to see if they might be capable of trapping hydrocarbons. Results can take 6-12 months to interpret, and even then there is no guarantee that the rocks do contain oil – just that they have the potential to do so. Drilling new sites is therefore an expensive gamble for oil companies.
But oil and gas reservoirs naturally leak tiny traces of hydrocarbons such as ethane into the atmosphere. Dr. Bill Hirst and colleagues at Shell Global Solutions realised that detecting and tracking down the sources of these faint whiffs of underground gas could help improve the success rate of prospectors. To improve their first ‘Light Touch’ prototype sensor Shell contacted Professor Miles Padgett and his colleagues in the Optics Group at the University of Glasgow.
The Glasgow team developed a sensor system that fits into a Landcruiser and can sniff out ethane in the air at less than one part per billion. The ethane sensor continuously sucks air into a chamber where the gas is measured using an infrared laser. By measuring the amount of laser light absorbed at a certain wavelength, the instrument can measure how much ethane is in the chamber. To prospect for oil and gas, measurements of ethane and wind direction are combined to locate the likely sources of the gas detected using software also developed by the Glasgow group.
The new survey technique is much quicker and cheaper to use than traditional techniques and reveals whether oil and gas are actually present. The system can be used to screen an area before deciding whether to use other survey techniques, or to rank previously surveyed areas to predict which are most likely to contain oil and gas. Drilling is now underway in Oman at the first of several sites pinpointed by the technique and other locations will be drilled later this year.
But it is not only oil fields that breathe tiny quantities of ethane into the air – people can do so too as an indirect result of cancer. Part of the body’s response to cancerous cells produces elevated levels of free radicals – highly reactive chemicals that break down cell membranes into hydrocarbons including ethane.
Dr. Chris Longbottom of the University of Dundee recognised that the Glasgow technology was well placed to detect these gases in a patient’s breath where medical research has shown that they can provide clues as to what is going on inside the body. The ethane sensor is now being put to the test to detect early stages of disease including lung cancer in clinical trials at Ninewells Hospital in Dundee. Lung cancer often spreads before significant symptoms appear and there are no alternative techniques for early detection of the disease.