The theft control is crucial for pipeline operators in many parts of world. The paper discusses the properties typical for theft-related leaks from liquid pipelines. Those are usually small, short-term leaks, with controlled flow. The technology and measures supporting the effective detection of such leaks are suggested. The paper documents real cases of product theft which appeared on 10"-12" pipelines, its reflection in pressure and flow trends, and the response of the leak detection system. The paper analyses the requirements put on all involved elements of technology from instruments, to telemetry, SCADA and finally leak detection methods; and touches also the processes involved in effective protection. The generally known software-based leak detection methods are analyzed in view of requirements put above. The combination of methods, with the emphasis on pressure wave analysis, is suggested, although the method limitations are acknowledged. The integration with batch tracking is suggested for exact determination of product properties in a batched pipelines. As a conclusion, the paper suggests the standard requirements to be put on a ‘theft-aware’ leak detection system, including speed of response, accuracy of localization, integration with batch tracking system, positioning of leak in a geographic information system, evidence to be generated and archived for further investigation, etc. Testing methodology proven in practice is suggested. The author is member of the pipeline modeling team in ttc, a Slovakia-based company focused in pipeline management systems. His background is in numerical mathematics. The company ttc is member of CSE Global Group.
The product theft from pipelines, in most cases known to author, appears as a product spill from an illegal tap, ½" - 2", with a valve to control the flow. The tap points may be in a block valve housing, on a bridge crossing or other non-buried section, or in proximity of valve stations, where there is easier for intruders to trace the pipeline in ground. Typical flow rate of leak is 2-10 m3/hr, unless it goes out of control, as when their equipment does not stand high pressure. Total size of one ‘leak incident’ is given by capacity of prepared storage, usually couple of thousand of liters. If it is a sophisticated operation, the leak is repeatedly closed and re-opened.
Type 1: ‘Offensive’ theft The violators try to reach their goal with a fast action, not taking much care for disguise. They don't expect to use their tap point repeatedly. Typical case reported from a pipeline operator is the intrusion into section valve housing through a hole sawn in the door, to not open the door limit switch, which would attract the attention of SCADA operator. The typical tapping point in the section valve housing is the degassing or sediment dumping valve.