Natech Risk Assessment and Control Through Innovative Risk Reduction Measures – Pipeline / Landslide Interaction Case

Abstract

At the end of 2018, a large-scale landslide was identified near the Right of Way of one of the pipelines operated by Cenit Transporte y Logística de Hidrocarburos. In this zone it was possible to identify a populated area and a river. At the beginning the depth of the Landslide did not represent a hazard to the pipeline due to the Horizontal Directional Drilling technique applied when the pipeline was built. A monitoring program was developed through inclinometers and piezometers and In-Line Inspections were carried out to identify any disturbance in the alignment of the pipeline. From the monitoring program and In-Line Inspection data it was possible to confirm interaction between the landslide and the pipeline. A perpendicular force to the pipeline alignment produces a bending strain at two points, and landslide interact with the pipeline along a length of 170 m. The depth of the landslide failure surface was in between 17 to 22 m, and the pipeline was about 15 m deep. Due to this interaction, it was necessary to develop a risk assessment to identify a safe limit displacement. For a while, this allowed us to design both a temporal innovative solution considering a flexible pipeline and a definitive solution to build the new segment of the pipeline which was deeper than the last one, through the Horizontal Directional Drilling technique.