In the recent decades, new leak detection technologies for hydrocarbon pipelines are emerging constantly, and conventional technologies are evolving to achieve better performance. It gives pipeline operators a good chance to detect leaks in the early phase and protect the environment from contamination by leaked hydrocarbons. However, this also makes the selection of leak detection methods more complicated.
Two major tasks are required during the selection of leak detection methods: appropriately defining the selection criteria, and evaluating the leak detection capability of candidate technologies. For internal leak detection technologies, API 1130 (API, 2012) provides guidance to industry on the selection criteria and API 1149 (API, 1993) attempts to define the evaluation technique. Applying an evaluation technique that considers all likely operating conditions in its risk assessment is advisable.
The process of combining of all the potential performance scores of a leak detection technology for various operating conditions into a single fitness factor can be complicated. This paper recommends the use of a decision tree to calculate the leak detection methods' fitness factor. In this analysis, many facets of leak detection are considered. They include the physical principles of the technologies as well as their performance under different operation conditions.
The paper describes a systematic approach of evaluating the various leak detection methodologies against specific design criteria. The appendix includes descriptions of the strengths and limitations that the various leak detection techniques may have given a particular set of leak characteristics, operating conditions, physical design considerations, commercial implications, construction costs and operational costs. The paper proposes that a qualitative or semi-quantitative analysis on individual pipelines over all expected operating conditions could determine the best technology(s) to apply in mitigating the risk of undetected leaks in pipelines.
There are multiple real time leak detection technologies, and they all have strengths and weaknesses. Leaks can present themselves in different ways, and every pipeline has different physical design and operational parameters. Determining the best leak detection technology(s) for a specific application can be complex. Every leak detection technology can cover different portions of the risk spectrum but no single technology will mitigate all of the risk as illustrated in Figure 1.