Leak Detection for Shut-In Pipelines

In this paper, a new leak detection system based on a pattern recognition algorithm in a shut-in condition of a pipeline is presented. For a fully shut-in pipeline, the governing fluid dynamic equations are simplified to the thermodynamic state postulates. Hence, the shut-in section can be treated as a closed thermodynamic system with no mass flow in or out of the system boundaries. The system always contains the same amount of matter, but heat and work can be exchanged across the boundaries of the system. The pattern recognition algorithm presented in this paper automatically monitors the pressure drop patterns and generates an alarm when the pattern of pressure gradients matches the leak signatures. The algorithm takes into account the effect of thermal cooling and other operational complexities to enhance the reliability performance of the scheme. Results of the performance of the shut-in leak detection system are presented and discussed in this paper. Both simulated and historical leak scenarios during shut-in state are used to investigate the performance of the shut-in leak detection scheme.