Detection and Localization of Pipeline Leaks Using 3-D Bistatic Subsurface Imaging Radars

Oil pipeline leak detection and localization is an important problem with regard to environmental issues as well as loss of resources in oil transport systems. This article shows that a 3-D subsurface multistatic imaging radar can better detect water or oil leak when more scattered signals from the leaked region are collected from multiple directions and added coherently. However, a primal drawback in achieving detection is the dominance of the signal from the pipeline itself compared to the leak signal making direct radar-based leak detection quite challenging. By utilizing the differences in the scattering mechanisms of the pipeline and the leak, this article proposes a technique that identifies and eliminates the pipeline signal from the overall radar response, which improves leak detectability. Permittivity of oil–sand mixture is determined experimentally and fit to a semiempirical mixing formula. A realistic physics-based model is used to determine the 3-D volumetric shape of oil leak. Then, the pipe with leak is simulated in a full-wave simulator with the permittivity of the leak assigned using the mixing formula. Comprehensive simulations are carried out for oil leaks in various soil mixtures and pipe materials to test the effectiveness of the proposed approach. In addition, the proposed approach is investigated experimentally using a portable vector network analyzer (VNA) where the response of a small water leak out of metallic as well as PVC pipes is measured in bistatic settings. Both simulation and measurement results demonstrate the effectiveness of the proposed approach in detecting and localizing pipeline leaks.