Enbridge’s goal is to prevent all spills, leaks and releases from our liquids pipelines system. Used together, these methods provide overlapping leak detection capabilities.
- Visual surveillance and reports - These are reports of oil or oil odors from third parties and from Enbridge’s aerial and ground line patrols. We handle third-party reports through our emergency telephone line, and communicate with affected publics and local emergency officials through our public awareness program. We typically conduct aerial line patrols every two weeks. We may also conduct focused additional aerial and ground patrols upon review of the status of a pipeline.
- Scheduled line balance calculations - Sometimes called “over/short reports” in the industry, these are calculations of oil inventory that we do at fixed intervals, typically every two and 24-hours. We also maintain a rolling 24 hour calculation based on the calculations we have done at a set time each day. The purpose of these calculations is to identify unexpected losses of pipeline inventory that may indicate a possible leak. Enbridge utilizes line balance calculations within our Commodity Movement Tracking system.
- Controller monitoring - Enbridge’s Pipeline Controller monitors pipeline conditions (such as pipeline pressure) through our Supervisory Control and Data Acquisition (SCADA) system, which is designed to identify unexpected operational changes, such as pressure drops, that may indicate a leak.
- Computational Pipeline Monitoring (CPM) - CPM is a computer-based system that utilizes measurements and pipeline data to detect anomalies that could indicate possible leaks. The CPM system that Enbridge uses provides a sophisticated computer model of our pipelines, and continuously monitors changes in the calculated volume of liquids. At Enbridge, we refer to the model as our Material Balance System (MBS).
If the MBS-calculated amount of liquids within our pipeline is less than expected, an alarm is triggered at our Control Center in Edmonton, Alberta, Canada. We immediately investigate the cause of the alarm, which could be instrumentation problems, model errors, hydraulic anomalies or a leak.
We use these approaches together, along with our public awareness program, to detect possible problems and examine possible leaks. If, for example, our MBS notifies us of a possible leak, we can then implement additional leak detection analysis – by examining our controller monitoring pressures, reviewing our “over/short reports" or conducting a ground or aerial line patrol.