NPS 8 Geopig: Inertial Measurement and Mechanical Caliper Technology

The Geopig inspection tool provides pipeline operators with three-dimensional geographic and geometric information of their pipeline system. This paper reviews two of the primary technologies onboard the NPS 8 Geopig that are used to provide such information: the inertial measurement unit (IMU), which provides structural and geographical characteristics of the pipeline, and the mechanical caliper arms, which capture the internal diameter of the pipeline. Recognizing the benefits of the tool and the data it can provide, Wascana Energy Inc. executed an inspection of a natural gas pipeline in Northern Alberta. The pipeline, which had buckled and sheared at a specific location, was inspected with the Geopig to further identify any other possible buckles, wrinkles or dents prior to re-commissioning. This paper reviews the inspection project undertaken, the data compiled by the Geopig, and the steps taken in the development of a predictive finite element model of the pipeline.