Real Time Estimation of Leaking in A Natural Gas Pipeline-A Fluid Flow Modelling Approach

ABSTRACT 

This thesis investigates into the real time modeling of leak estimation in natural gas pipeline using fluid flow approach. The best bet to leak management is to provide a robust system that will provide a quick information on tracking the leak location, the actual time this leak occurred and the volume of fluid loss. This thesis employed a mathematical model of analyzing the fluid flow in the pipeline to provide these solutions of leak estimation in a natural gas pipeline which is in a steady state, isothermal condition. The leak estimation model was developed from first principle by modifying the Weymouth‘s equation. The modified equation were used to establish the fluid flow rate equation for pipeline with no leak case and a pipeline with leak case. The pipeline with leak case were partitioned into three sections. The first section depicts the point before the leak occurred, the second section depicts the point of leak occurrence and the third section depicts the point after the leak has occurred. Resolving the fluid flow equations for these pipeline cases yielded two results (models); the first result determined the fluid pressure in the pipeline at the point of leak occurrence, while the second result determined the point of leak location. Further analyses were carried out with the aid of the two results obtained to determine the fluid loss pressure at the point of leak and also to determine the pressure gradient profile of the pipeline with leak case. The pressure gradient profile of pipeline with the leak case were then compared with that of no leak case. The results of the analyses led to the actual time of leak (which is quite different from the time the leak were detected by a pressure transducers). The actual time of leak were then used to develop a model that quantify the volume of fluid loss in the pipeline. All the results were validated experimentally using a field data. The maximum error percent recorded for the point of leak location is 0.437% and the minimum error percent recorded for the point of leak location is 0.113%. The study further reveals that the output pressure of a pipeline experiencing leak can be estimated.