The Use of Remote Real-Time GNSS to Monitor a Pipeline in an Active Landslide

Abstract

Abstract Pembina Pipeline Corporation (Pembina) monitored three active interacting [1] landslides utilizing arrays of remote real-time GNSS (Global Navigation Satellite System) sensors to assist in the confirmation of safe continued pipeline operation. Each case study utilized remote sending high-precision real-time GNSS sensors to monitor landslides of varying movement rates, from slow-moving landslides which could be condition-monitored for many years, to fast-moving landslides which required pipeline mitigation within months. The first case study was Henderson Creek near Grande Prairie AB, which utilized remote real-time GNSS sensors to monitor over one meter of rotational slope movement in 6 months; both a conventionally-buried pipeline, and a temporary above-ground pipeline bridge were monitored before a permanent HDD replacement mitigation was completed. Sensors were installed on the temporary pipeline, the bridge, as well as shallow ground installations. The second case study was Athabasca River north slope near Ft McMurray AB, which utilized remote real-time GNSS sensors to monitor an above-ground pipeline in a slow-moving valley-scale landslide over a period of several years. The third case study was Smoky River east slope near Grande Cache AB, which utilized remote real-time GNSS sensors to monitor a rapidly-moving landslide on a conventionally-buried pipeline, which has plans for an HDD replacement mitigation in the near future. To verify the results of the GNSS sensors, each of these three landslide sites were monitored utilizing multiple technologies which showed close correlation with the remote real-time GNSS sensors, including conventional ground surveys, monitoring pin surveys, SIs, and repeated ILI IMU caliper runs. The GNSS monitoring system was precise enough to detect operational changes of the above-ground pipelines, including filling of the pipeline with product, suspected changes in internal pipeline operating pressure, and pipeline expansion and contraction due to temperature changes from night to day and winter to summer. Pembina successfully utilized a remote real-time GNSS monitoring system to allow greater assurance of safe continued pipeline operation at three separate moving slopes, until either a slope movement threshold was reached, or mitigation was completed. This paper highlights that pipeline operators can remotely condition-monitor their confirmed or suspected interacting pipelines in landslides with accuracy using remote real-time GNSS, on a real-time continuous basis as part of their Geohazard Management Program.