Leak detection in Pipelines

[duh]

Hello,
How does the Oil Industry detect leaks in underground pipelines? Is it strictly with the use of pressure gauges? If so, how is the exact location of the leak surmised in a long underground pipeline?
Thanks!

 

[MortenA]

There are quite a number of systems out the:

-Odour detection
-Sounds made by liquid when ecsaping through leak
-Online capacity calculation during operational checked against actual operational data
-?

Best regards

Morten

 

[riwilliams]

API 1130 and API 1155 govern pipeline leak detection systems of which there are many: hardware-based - acoustic, fiber optic, chemical, and software-based: - transient modelling, mass balance, statistical analysis, pressure point analysis, etc.

Leak size is a function of the pipeline physical characteristics, length, diameter, etc.; instrumentation specifications and locations and gas properties, density, viscosity, vapour pressure, etc.

API defines the following:

Reliability Refers to the ability of a leak detection system to indicate the existence of a leak within the pipeline. This is to be defined as the number of false alarms within a set period of time under various flow conditions.
Robustness Refers to the leak detection system capability to continue to function even under changing operational conditions or loss of measurement data due to equipment failure. This is defined as no loss of function for pressure, temperature, flow, valve or compressor outage.
Sensitivity This is defined as the size of a leak that the leak detection system is capable of detecting and the time required for leak alarms to be generated. Minimum detectable leak rate and volume are parameters to be specified based on leak detection performance criteria studies.

Accuracy Leak detection accuracy is defined as the percentage error or uncertainty of the resultant calculations for leak flow rate, leak location and leak volume. The leak location error will be expressed as + number of meters of a specific pipeline milepost.