Pipeline landslide risk management: API 1187 Recommendations

Introduction

Landslides are complex geological phenomena that can have devastating effects on pipeline infrastructure and pose a significant threat to pipelines crossing complex terrain, especially those located in areas prone to geotechnical movements; they can be caused by both natural events and human activities and represent a constant risk to operations, especially in pipelines crossing mountainous or unstable areas.

API RP 1187, issued in 2024 focuses on establishing a risk management framework to identify, monitor, and mitigate the threats posed by these landslides, ensuring pipeline integrity and reducing the possibility of catastrophic failures.

Proactive landslide management, supported by a structured plan and advanced pipeline monitoring technologies, is essential to minimize risks and avoid disruptions to operations. In this context, API RP 1187 provides specific guidelines that enable operators to implement a comprehensive safety approach.

Importance of landslide management in pipelines

Landslides can trigger dangerous incidents such as pipeline leaks or ruptures, putting both the safety of surrounding communities and the environment at risk. These events are especially dangerous in transmission pipelines, where any failure can result in serious consequences. API RP 1187 highlights the need for a proactive approach to managing these risks, advocating the implementation of proper design, careful route selection, and the adoption of effective mitigation measures.

The document stresses that landslide management is important to maintain pipeline integrity and to comply with safety and environmental regulations.

API RP 1187 regulatory framework

API RP 1187 is a reference document that establishes best practices for landslide management on overland transmission pipelines carrying natural gas, hazardous liquids, and carbon dioxide. Although its application is primarily focused on welded steel pipelines, its principles can also be adapted for other infrastructures. This standard was developed in response to the need for a regulatory framework that provides recommendations for geotechnical risk mitigation based on operator experience and sound engineering practices.

The document emphasizes that the unpredictable nature of landslides requires a flexible approach, where operators must apply their technical judgment and adjust measures according to local conditions and the specificities of each project. The standard also stresses the importance of considering active landslides, and also those that, although inactive, could pose a future risk, which is essential in the design and planning of pipeline routes.

API RP 1187 is an essential tool for any professional seeking to maintain high levels of safety and operability in pipelines exposed to geotechnical risks.

Key components of landslide management program

API RP 1187 is the Landslide Management Program, which is a long-term strategy that must be integrated into the Pipeline Integrity Program (IMP). The objective of this program is to minimize the likelihood that a landslide will cause undesirable consequences, such as a leak, rupture, or loss of pipeline capacity.

This program follows a Plan-Do-Check-Act (Plan-Do-Check-Act) approach, which ensures that activities related to landslide management are constantly reviewed and adjusted throughout the life of the pipeline, which can span decades. The program focuses on three main components:

Hazard identification: Through detailed terrain analysis and historical data collection, landslide risks in areas near the pipeline are assessed.

Data management: Proper data collection, storage, and analysis is important for assessing landslide evolution. This includes the use of GIS platforms to store spatial and non-spatial data, such as landslide boundaries, pipeline stress measurements, and monitoring records.

Spatial data, such as physical locations of landslides or monitoring instruments, allows clear and accurate visualization of information for analysis. Non-spatial data, such as reports or specific landslide characteristics, should be linked to spatial data or external files, ensuring easy and up-to-date access to all necessary information.

Implementation of mitigation measures: Depending on the risk assessment, preventive or corrective actions can be implemented to minimize potential impacts. These measures can range from continuous pipeline monitoring to physical terrain modification or structural reinforcement of the pipeline.

Landslide hazard assessment framework

API RP 1187 introduces a three-level structured assessment framework that allows operators to analyze landslide risks in a progressive manner appropriate to the specific needs of each site. These are outlined below.

• Level 1 assessment: This is the first step in the process and is carried out as a preliminary desktop study. The objective is to identify potential landslides along the pipeline and evaluate the available information on each hazard. It is based primarily on the analysis of aerial imagery, geological data, and historical records of the area.
• Level 2 assessment: In this phase, more detailed but non-intrusive field investigations are conducted at sites where a potential hazard has been identified. This level of assessment provides a better understanding of the geotechnical characteristics of the terrain, past landslide activity, and the proximity of the pipeline to the risk zone.
• Level 3 assessment: This is the most detailed level and is applied only in cases where the risks identified in the previous levels are significant. It includes intrusive studies such as geotechnical drilling or geophysical investigations, as well as comprehensive evaluations of the pipeline to determine its ability to resist the effects of landslides. At this stage, a Fitness for Service (FFS) analysis may also be performed to decide whether immediate corrective action is necessary.

This framework ensures that additional resources are only allocated when strictly necessary, thus optimizing mitigation and cost control efforts.

Monitoring and mitigation techniques

Once potential landslide risks have been identified, constant monitoring is key to detect changes in the terrain that may threaten the integrity of the pipeline. Monitoring techniques can range from visual observations to the use of advanced technologies such as LiDAR, InSAR (synthetic aperture radar), or tilt meters (inclinometers) installed directly in the ground.

LiDAR can create digital terrain models, identifying subtle changes in topography that could indicate the onset of a landslide. InSAR, on the other hand, by comparing satellite images over time, can detect ground deformations with pinpoint accuracy. These tools allow operators to anticipate dangerous movements before they affect the pipeline.

In terms of mitigation measures, API RP 1187 provides a series of recommendations based on the nature and severity of the landslides. Common strategies include:

• Excavation for stress relief: In areas where the pipeline has already been compromised, controlled excavation can be performed to reduce accumulated stresses in the pipeline.
• Pipeline Strengthening: In particularly vulnerable areas, pipelines can be strengthened against landslides, including the use of more robust materials or the design of additional support systems that can absorb and distribute the forces generated by a landslide.
• Subsoil drainage: Water accumulation is one of the main triggers for landslides. Implementing drainage systems can reduce ground saturation and improve soil stability.

These measures must be combined with continuous monitoring, as changes in climatic conditions or land use can reactivate previously stabilized landslides.

Periodic reassessment and change management

The document also highlights the importance of periodic reassessment of a pipeline’s right-of-way (ROW) conditions and the ability of the pipeline to handle landslides over time. Natural and human-influenced conditions can change, as can the availability of new data and information. Therefore, the level 1 reassessment should be updated regularly, with intervals that can reasonably be set at 10 years or less, depending on the specific circumstances of the segment or site.

Periodic reassessments and management of Change (MOC) are fundamental components of API RP 1187. Changes in the operation or environment of a pipeline can significantly alter the risk of slippage, therefore, they must be carefully evaluated. The standard requires operators to have a clear process for proactively identifying and managing these changes.

The most relevant changes that may affect landslide management include:

• New construction: During the construction of new pipelines, it is essential to conduct a thorough geotechnical study that considers the possibility of landslides. Construction data, such as trench depth and ground conditions, should be recorded and used for future evaluations.
• Acquisition of pipeline systems: When a company acquires an existing pipeline, it should conduct a full assessment of the history of slippage on that infrastructure, integrating the records into its own risk management system.
• Changes in land use: Modifications to the surrounding environment, such as road construction or deforestation, can alter the stability of the terrain and increase the likelihood of landslides. These changes must be monitored and managed to avoid unforeseen impacts.

Cases of pipeline failures due to landslides

Pipeline failures due to landslides have been one of the motivations that have led to the development of standards or practices such as API RP 1187 to avoid events of this type. Some of the most relevant cases are presented below:

• Pipeline rupture on the Yellowstone River, Montana, USA: In July 2011, a landslide caused by high river erosion and soil saturation eroded the bank of the Yellowstone River, causing an ExxonMobil pipeline near Laurel, Montana, to rupture. Releasing approximately 1,500 barrels of crude oil into the Yellowstone River, causing significant environmental damage. The cause of the landslide was due to heavy rains.
• North Saskatchewan River Pipeline Spill, Alberta, Canada: In July 2016, a landslide near the community of Maidstone in Saskatchewan caused the rupture of a pipeline operated by Husky Energy spilled approximately 1,570 barrels of crude oil into the North Saskatchewan River.

Conclusions

API RP 1187 provides a robust framework for managing the risks associated with pipeline landslides, enabling operators to maintain high levels of safety and operational efficiency. By following recommendations for hazard identification, data management, monitoring, and implementation of mitigation measures, the risk of structural failure can be significantly minimized.

The flexibility and adaptability of this standard allows it to be applied in a variety of geographic and operational contexts, making it an essential tool for any pipeline operator. In an environment where extreme weather events and human activity can exacerbate geotechnical risks, implementing a robust landslide management program is vital to safeguarding the energy infrastructure of the future.

References

1. https://www.nytimes.com/2011/07/03/us/03oilspill.html
2. https://www.cbc.ca/news/canada/saskatchewan/husky-energy-pipeline-oil-spill-court-hearing-1.5171779