Bridging the Gap Between Qualitative, Semi-Quantitative and Quantitative Risk Assessment of Pipeline Geohazards: The Role of Engineering Judgment

Geohazards are threats of a geological, geotechnical, hydrological or seismic/tectonic nature that can potentially damage pipelines and other infrastructure. Depending on the physiographic setting of a particular pipeline, a broad range of geohazards may be possible along the pipeline route. However, only a limited number of geohazards such as landslides, fault displacement, mining-induced subsidence, liquefaction-induced lateral spreading, and hydrological scour, which can result in permanent ground deformation or exposure of the pipeline to direct impact, typically represent credible threats to pipeline integrity. Identifying potential geohazard occurrences and estimating the likely severity of each occurrence in relation to pipeline integrity is an integral part of geohazard management, and overall risk management of pipelines. Methods for identifying and assessing the potential likelihood and severity of geohazards vary significantly, from purely expert judgment-based approaches relying largely on visual observations of geomorphology to analytically-intense methods incorporating phenomenological or mechanistic models and data from monitoring and field characterization. Each of these methods can be used to assess hazard and risk associated with specific geohazards in terms of qualitative, semi-quantitative, or quantitative expressions as long as uncertainty and assumptions are understood and communicated as part of the assessment. Engineering judgment is highlighted as an essential component to varying degrees of each geohazard assessment approach.

Management of Climate Threat and External Forces Based on Knowledge Management

Geotechnical conditions in Colombia make the Weather-related and Outside Force Threat one of the principal threats to take into account in managing hydrocarbon transmission lines. This, along with the rotation of the personnel who support the management of this threat nationwide, has led the office of the Vice-president for Transportation and Logistics (VIT) at Ecopetrol S.A. to implement a knowledge assurance strategy that will ensure the sustainability of efforts in geotechnical matters made in recent years. This paper presents the experience of how it has been possible for management of the Weather-related and Outside Force Threat, by the office of Vice-president for Transportation and Logistics of Ecopetrol S.A., to be strengthened by proposing a prospective scenario of sustainability and knowledge that for five years has been contributing to strengthening the acquisition of knowledge and the management of the threat itself.

Pipeline Vulnerability to Natural Hazards

The strength and stiffness of the pipelines allow them to tolerate the effects of natural hazards for some period of time. The amount of time depends on the strength and deformability, the stress state, the age, the conditions of installation and operation of the pipeline and their geometric arrangement with regard to the hazardous process. Accordingly, some of the hazards due to weather conditions and external forces would not be time independent. In consequence the designing of monitoring systems to predict the behavior of the pipelines against natural hazards is required in order to carry out the preventive actions which are necessary to avoid failure of the pipes due to the exposition to those hazards. In this paper a method for assessing the transport system vulnerability is developed, a function for risk analysis is proposed (which is determined by the probability of the natural hazard, the pipeline’s vulnerability to the hazard and the consequences of the pipe rupture). The elements that are part of that evaluation are presented and illustrated by means of examples.

The Challenge of Geohazards in the Replacement of Hydrocarbon Pipelines

The effects of changes in land use and the effects of climate change have led to an increase in the morphodynamic processes that affect rights-of-way in Colombia. However, in view of the fact that these rights-of-way are considered to be the best possible routes in some areas in which the geological and geotechnical components are fairly complex, specialists are facing the challenge of establishing different perspectives for coexisting with the geohazards in these areas. This paper describes the analytical methodology implemented within Ecopetrol’s Office of the Vice President for Transportation and Logistics (VIT-Ecopetrol), in order to take this reality into account within the framework of proper asset management.

Change Detection Within Pipeline ROWs: Environmental Change Analysis Using High Resolution Satellite Imagery

One of the major concerns for pipeline operators is to efficiently monitor the events happening over the pipeline corridor, or right-of-way (ROW). Monitoring of the ROW is an important part of ensuring the safe and efficient transportation of oil and gas. Events occurring within this zone require rapid assessment and, if necessary, mitigation. These events could be physical intrusions such as encroachment from growing settlements, impact of vegetation, pipeline leakage or geo-environmental hazards. Analysis of satellite imagery can provide an efficient and low cost solution to access and quantify change across the ROW. Examining these events over a periodic interval requires implementation of specific methods that can support the on-going monitoring and decision making practices. In this context, satellite remote sensing images can provide a low cost and efficient solution for monitoring the physical and environmental impacts over the ROW of pipeline system. This paper reports on the development of a methodological approach for environmental change analysis using high resolution satellite images that can help decision making in pipeline systems. Analysis results and maps produced during this work provide an insight into landcover change over the study area and expected to support in on-going pipeline management practices. Two methods, Vegetation index differencing and post classification comparison have been implemented to identify change areas in the Taranaki region of the North Island of New Zealand. Vegetation index differencing with NDVI shows increase or decrease of overall vegetation within the study area. Special focus was given on large area increase and decrease with area threshold value above 0.2 hectare. Detailed analysis of change was conducted with post classification comparison method that uses land cover classification results of year 2010 and 2013. An overall change of 10% has been observed throughout the study area with large area change of approximately 5%. Results obtained from post classification comparison method were further analyzed with 6 focus areas and compared with the existing soil data and rainfall data. The methods adopted during this study are expected to provide a base for environmental change analysis in similar pipeline corridors to support decision making.

Approach to Risk Management for the Hydrocarbon-Transport Infrastructure With Regard to Climate Change

Planet Earth has recently witnessed a change in the behavior of climate variables (including temperature, rainfall, etc.), primarily attributed to global warming. This climate change is a threat that is materializing and has affected elements of the infrastructure, ecosystems, and environmental conditions worldwide, as well as the National Development Plans [“Planes Nacionales de Desarrollo”]. The hydrocarbon-transport infrastructure in Colombia has not escaped the effects of climate variability. Therefore, a strategy must be devised to manage the risk and to adapt these systems in the light of potential harmful effects, and also to supplement or improve the mitigation measures for the effects generated by the oil industry through its operations. Climate disturbances lead to an increase in the likelihood of landslides, wildfires, floods, avalanches, and other natural hazards. The major climate changes that have been identified and that may affect hydrocarbon-transfer systems in Colombia are the following ones: • A gradual increase in temperature. • Changes in the patterns and amounts of rainfall. • A rise in sea level. • An increase in the severity and frequency of extreme weather events. The strategy for adapting the hydrocarbon-transport systems in light of climate change focuses primarily on the following points: 1. Acquiring more knowledge about the climatic changes that are expected to occur in Colombia, including the change in the major climatic variables and their georeferencing. 2. Diagnosing the transport systems and their spatial correlation with future climate scenarios. 3. Identifying the industries or elements of the infrastructure that are most vulnerable to the expected climatic changes. 4. Proposing measures that will add strength and/or resilience, so that the elements of the system can resist the effects of climate change, or overcome them within a short period of time, without affecting the Business. 5. Prioritizing the interventions to be performed at sites that are critical to the Business. 6. Monitoring and tracking the climatic variables in order to adjust the susceptibility models in light of the major impacts (e.g., landslides). The primary goal of this paper is to outline the initiative that has been proposed by the Technical Asset Management Bureau [“Gerencia Técnica de Activos”] (GTA) of Ecopetrol’s Office of the Vice President for Transportation and Logistics [“Vicepresidencia de Transporte y Logística”] (VIT Ecopetrol) in order to adapt the currently operating transport systems so that they can deal with climate change, while ensuring their healthful and safe operation, in compliance with the applicable technical legal requirements. Another goal of this paper is to highlight the advances that have been made by the GTA in the procurement, compilation, analysis, and use of climate information and geotechnical data as basic elements of risk management.

Monitoring Stress/Strain in Buried Pipelines Through the Use of Fiber Bragg Grating Sensors

ECOPETROL S.A. has been working since 2006 in Pipeline Integrity Management Process. In that process, the threat related to climate and external forces play an important role, because of the vulnerability of ECOPETROL pipelines to this threat, not only by the geomorphology of Colombia, but also because of the strong impact of climate phenomenon such as “La Niña”, that consists in an unusual quantity of rain precipitation, represented in the increasing of slopes instability that affects the rights of way. Due to these events and the evolution of optical strain sensors monitoring technology, ECOPETROL has introduced an instrumentation pipeline program for monitoring the strain and advanced in the understanding of the behavior of pipelines. This paper describes the technology selected, the criteria used to select the monitoring sites and the thresholds stress/strain. The results of monitoring are discussed for a particular case.

Panorama of the Strategy for Managing the Risk Created by the Weather-Related and Outside Force Threat in VIT-Ecopetrol

The realization of the weather-related and outside force threat has historically caused losses of containment with their subsequent social, environmental, economic and image consequences for Ecopetrol. The zones in which these phenomena occur are characterized by the interaction of transmission systems with an environment that is complex in its topographical, geological-geomorphological and climatic conditions, and because of the anthropic impact of changes in land use. In Ecopetrol’s office of the Vice-president for Transportation Logistics (VIT-Ecopetrol), a threat management strategy has been proposed that seeks to minimize the vulnerability of the pipelines to processes that can impact on operating efficiency or that, because of their degree of complexity, require comprehensive management in order to guarantee operation at tolerable levels of risk. This article presents a panorama of the work performed with regard to the validation of the threat and risk levels of the assets, the internal analyses performed by geotechnical professionals for formulating the plans for the management of assets and the accompaniment of such in order to achieve the continuous operation of the transmission systems.

Procedure for Identifying Deformations in Oil and Gas Pipelines Subject to External Forces, Based on Primary ILI Data

Oil and gas pipelines that pass through mountainous terrain are subject to an increase in the number of sections affected by the bending deformation’s resulting from external forces, which, when coupled with the construction and operational processes of the systems, cause mechanical damage to the pipelines that has led to containment losses, resulting in operational cost overruns and harmful effects on the environment and on nearby communities, while leaving at high risk the integrity of the petroleum infrastructure. By using primary data obtained through so-called “smart” in-line inspections or intelligent line inspections (ILIs), the occurrence and magnitude of these deformations and displacements of the pipelines can be determined. With the aid of geotechnical analytical techniques, this information can facilitate the interpretation of the processes that induce these thrusts. The starting point is the existing knowledge of the characteristics of the installation of the pipelines and of the clearances permitted by the rules and/or reference standards of the industry. The next step consists of comparing that data against the XYZ Data inertial mapping data (obtained through rotations of the XGP geometric tool) in one or more ILI runs, as part of the mechanical analysis procedure. As a recommended practice, an algorithm is developed for handling the ILI data, showing in parallel the geotechnical zoning data, illustrating it with a study algorithm.

Identification and Monitoring of Geotechnical Risk Areas Using Inertial Data Supplied by In-Line Inspection Tools

By their nature, Pipeline Transmission Systems are exposed to threats from various sources. These include the threat of Weather and Outside Forces (WOF), this threat has a destructive potential associated with landslides, creeping, soil erosion and scouring in rivers, etc. Their hazards increase when pipelines are installed in areas with a tropical climate, having rains of a magnitude that often tend to destabilize the soil surrounding the pipelines, affecting its integrity and therefore the safety of people and the environment. The identification and monitoring of geotechnical risk areas, using inertial data, is based on the reprocessing and analysis of the raw data provided by in line inspection tools. The result of this analysis, after the noise reduction process using a variety of filters at different intervals, reveals areas where there is possible deformation. These zones are transformed into indications that are studied by an analyst, correlating other data sources such as terrain topography, soil characteristics, hydrology, ground motion records, ILI records (caliper records, MFL records, etc.), as-built data, stress concentrators, etc. The analyst determines if they are pipeline deformations due to soil movement or if the indication is caused by another source such as the noise caused by the electronic components of the tool, the operating conditions during the inspection, the filtering process, etc. Areas with signs of strain are evaluated to determine the tensional state in critical conditions for each specific case. If the stresses are close to the limits, a field inspection and an action plan are needed for each case. In certain cases, according to the experts, field indications are evaluated to verify the data obtained by the ILI Tool and to simultaneously give feedback to the noise reduction process. The execution of the calculation process allows the monitoring and identification of geotechnical risk areas, providing better control over parameters such as limits for reporting indications, control of discrimination and selection criteria, detailed assessment of each indication, etc. Finally, this process provides the opportunity to obtain additional information from the ILI inspection such as unregistered bending, misaligned welds, areas with excess root welding, etc.