Testing ground penetrating radar and ethane gas sensing to detect oil in and under ice

There is a worldwide need to develop practical remote sensing systems to detect and map oil in and under ice. Such systems would facilitate leak detection and greatly improve spill response capabilities in ice-covered waters. Results from November 2004 tests with oil spilled under an ice sheet grown from urea-doped water at the Cold Regions Research and Engineering Laboratory (CRREL) in Hanover, NH, were presented. Two independent technologies were evaluated: high-frequency pulsed Ground Penetrating Radar (GPR) incorporating measurements of changes in amplitude with increasing offset (AVO analysis), and a highly sensitive ethane gas sensor. Both systems tested at CRREL detected the presence of oil trapped in and under ice. The agreement of experimental results with initial modeling performed prior to the tank testing indicated the potential to accurately predict GPR response to a variety of arctic spill scenarios and radar parameters in the future. The overall results demonstrated the potential for detecting oil under sea ice with GPR. The LightTouch™ ethane gas sensor uses a Tuneable Diode Laser Spectrometer, that can measure real-time concentrations to an accuracy of ∼ 50 ppt. Results showed measurable, but very low, levels of ethane flux being transmitted through the ice sheet within the oiled areas. This is an abstract of a paper presented at the 28th Arctic and Marine Oil Spill Program Technical Seminar (Calgary, Alberta 6/7-9/2005).