Pipelines often cross challenging terrains where natural hazards are the main risk for their integrity. Environmental conditions can also worsen over the infrastructure lifetime. To reduce the risk of disasters, integrity programs are developed implementing tools for early detection of threats that can lead to a failure with dramatic social, environmental and economic consequences. Fiber optic (FO) monitoring solutions have been widely used and implemented as one of the most efficient prevention tools of these programs. These solutions include geotechnical monitoring, third party intrusion detection and eventually small or pinhole like leak detection.
FO based geotechnical monitoring has been successfully operated along the Sierra section of the Peru LNG pipeline since 2010, detecting minor landslides and erosion events. It has also been implemented along other hydrocarbon transport systems to allow the early detection of such events. However, these natural hazards are not the only ones threatening the pipeline. In fact, the coastal section experiences other phenomenon such as sand dune migration and eolian erosion that put the pipeline at risk. Recently, the FO monitoring was extended to the coastal region using the existing communication fiber optic cable to sense temperature changes. Very localized events are thermally detected, their spatial and temporal signature analyzed. The comparison of this data with thermal models identified sections that are close to be exposed or whose soil cover is less than 50cm over a spatial extension that does not exceed a couple of meters. Depth of cover of 10 to 30cm is estimated from such analysis. These results are confirmed by past and ongoing site inspections. Such positive results again illustrate the potential value of fiber optic sensing to mitigate geohazard risks. It not only enhances the efficiency of the integrity program detecting and localizing threats, it also improves and rationalizes the maintenance activities as focused surveys can be conducted.