A New Approach for Real Time Pipe Locating
David B. Cist
Event name: 18th EEGS Symposium on the Application of Geophysics to Engineering and Environmental Problems
Session: Advances in Sensor Design for Geotechnical Purposes
Publication date: 03 April 2005
Info: Extended abstract, PDF ( 1.55Mb )
A new method of detecting and following pipes has been developed that should facilitate efforts to track and locate natural gas leaks. This ground penetrating radar (GPR) tool is deployed like a metal detector; the user swings a 400 MHz antenna back and forth over the ground. The data are then reduced and processed in real-time to automatically display the location and depth of targets found along the arc. Swinging the device around the body guarantees that any pipe crossing the arc will produce a “hyperbolic” shape in the data. This shape is then recognized and displayed in real time according to recognition confidence, depth and X,Y GPS position. The advantages of mapping pipe (metal, PVC, clay) are clear. But perhaps the more intriguing application has to do with locating gas leaks. As one follows a gas pipe along its course, GPR has demonstrated the ability to detect gas leaks by sensing changes in the surrounding soils. This means GPR can detect the leak site rather than the surface exit point of the gas. Our goal is to map these subtle changes in soil properties in real-time, offering a new method for constraining, and hopefully pinpointing, natural gas leaks.