Leaks occurring in underground pipelines constitute a substantial danger for both, human beings and the environment. Oil escaping from pipelines pollutes the earth and ground water.
Leaking gas creates the danger of fires and explosions. In addition, leaks bring about large economic losses. It is extremely important to locate leaks as soon as they occur and to be able to locate small leaks. Until now, monitoring systems have only reacted to large leaks and have not been able to pinpoint them accurately. Oil leaks cause temperature anomalies below the pipeline, whereas escaping gas induces a temperature decrease above the pipeline due to the easing of pressure.
Efficient leak location and the long-term monitoring of gas and oil pipelines can therefore be achieved by measuring the temperatures along a pipeline and observing how these temperatures vary over time. Optical-fibre, temperature-measuring technology presents new opportunities in this connection.
An optical-fibre, temperature-measuring cable is laid along a pipeline, enabling the temperatures in the ground to be measured simultaneously over long pipeline distances with a high degree of locational accuracy.
The sensor cable is completely passive electrically and can therefore by fitted to pipelines where a high risk of explosions exists.
The leakage-location principle by means of optical-fibre, temperature-measuring technology
Using optical-fibre, temperature measuring to monitor pipelines makes possible:
- The economical location of leakages and the long-term monitoring of pipelines
- The monitoring of pipeline sections up to 30 km long by means of a system
- The opportunity of linking individual systems to form an overall system to monitor longer sections if necessary
- The quantifying of leakage rates using model calculations
- It is not necessary to empty and clean the pipeline before inspecting it
- Shutting-down the pipeline is not necessary
- Small quantities of escaping oil can be exactly detected and located
- Damage can be identified in its early stages
The measuring system enables the temperature along a section of pipeline to be measured by using optical-fibre sensors. Temperature anomalies caused by leakages are identified via this system and the efficient location of leakages and long-term monitoring of gas and oil pipelines are thus made possible.