Feasibility of a TDR-based technique for fluid hydrocarbon leak detection

Undetected leakage of fluid hydrocarbons from pipelines or underground storage tanks into the subsurface environment are environmental and public health hazards. It is evident that there is a need for efficient, effective and accurate technology to detect these leaks rapidly and non-destructively, so as to make the process safe, to make quantitative risk assessment, and to provide effective preventive measures. There are unsurmountable limitations in many existing leak detection techniques. Moreover, early detection of leakage would allow rapid remediation at source to significantly reduce the remediation costs, and more importantly the environmental impact. The results of an experimental investigation for the technical feasibility and practicality of a technique for detection and location of fluid hydrocarbon leaks in underground pipelines and storage tanks based on the principles of time-domain reflectometry (TDR) are presented in this paper. The measurement sensitivity of the technique was evaluated for 3 different types of cables, 2 cable configurations (parallel-wires or coaxial), 2 leaking fluids (tap water or petrol), a single leak or double leaks, and 2 backfill materials (fine sand or gravel) by a series of field-scale model tests. The testing parameters were varied systematically. The experimental results indicate that TDR is a technically feasible technique for the detection of fluid hydrocarbon leaks from pipelines and underground storage tanks when the setup configuration is appropriate.