The Contribution of In-Line IMU Inspection to Geohazard and Crack Management Strategies

Geohazards and external loads are a significant threat to the integrity of pipelines in hilly terrain, at river crossings and where ground subsidence is taking place. Well designed pipelines can tolerate strains that exceed the nominal strain of 0.5% that corresponds specified minimum yield strengths, however the presence of weld defects and stress corrosion cracking can reduce the load capacity dramatically. Welds that are to specification but are under-matched on actual strength to the adjacent parent pipe have also been recognised as potentially vulnerable to low strain failures in high strength pipes. Modern pipelines in terrain susceptible to geohazards normally include design studies to identify and avoid or mitigate the threats. Surveillance of the right-of-way is also routinely carried out for pipelines with good integrity management practices, and particularly for major strategic lines. In-line inspection using an inertial measurement unit (IMU) is a well-known method to detect ground movement loads and contributes to the integrity management of pipelines. In this paper we illustrate : 1. How IMU inspection is an important tool in the management of geohazards and how it compliments other methods of geohazard assessment. 2. How locations of elevated pipe strain are identified and evaluated for external loading threats, and can be aligned with other data sets that indicate the pipeline load capacity. 3. How the locations of bending strain can be prioritised for further action. 4. How the loading profile in the pipeline can be incorporated into crack management strategies in order prioritise locations for further investigation or assessment.

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

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.

Challenges Related to Pipeline Free Spans in Watercourse Crossings

Free span assessment in watercourse crossings for the on-shore pipeline industry has become a more and more important part of pipeline integrity practice. One reason is that it has become increasingly well known that the dominant cause of pipeline failures in watercourse crossings is fatigue failure due to vortex induced vibrations at pipeline free spans. Recognition of this is now being identified in industry recommended practices and owners are incorporating this type of assessment into their pipeline integrity management practice. On shore pipelines are not designed with an allowable free span as is the practice with off-shore pipelines, but are buried. Design codes specify minimum depths of cover when constructed and indicate that pipelines should be maintained so that no excessive loads occur. In the past the no excessive loads requirement has been interpreted that the pipeline must remained buried. As experience from the off-shore environment and increasingly from experience on-shore has shown that most exposed and/or free spans do not fail. Due to various river erosion mechanisms; scour, bank erosion or avulsion, previously buried pipelines do develop free spans. Some of the free spans fail and release products directly into the watercourse. Failures, particularly for liquid products, are very expensive due to the economic loss, repair costs and environment clean-up of the watercourse and its banks. Similarly, costs associated with pipeline replacement for free spanning pipelines or repair of pipelines that might develop free spans are relatively high. It is important to develop an understanding of the probability of the pipeline failing due to a free span, or put another way, determine which free span is a threat to integrity. This paper discusses some of the challenges with assessing free spans in watercourse crossings as part of integrity programs and highlights experiences in assessing this threat to integrity. The objective of this paper is to discuss some of the key uncertainties related to the management of the threat due to free spans. These uncertainties are due to the reliability of information about the free span, water velocity and condition of the pipelines.

Supervised Learning Algorithms Applied in the Zoning of Susceptibility by Hydroclimatological Geohazards

Cenit Transporte y Logística de Hidrocarburos (CENIT), operator of about 7000 km of hydrocarbon transport systems, which constitutes it the largest operator in Colombia, has developed a strategic alliance to structure an adaptive geotechnical susceptibility zoning using supervised learning algorithms. Through this exercise, has been implemented operational decision inferences with simple linguistic values. The difficulties proposed by the method considers the hydroclimatology of Colombia, which is conditioned by several phenomena of Climate Variability that affect the atmosphere at different scales such as the Oscillation of the Intertropical Convergence Zone - ITCZ (seasonal scale) and the occurrence of macroclimatic phenomena such as El Niño-La Niña Southern Oscillation (ENSO) (interannual scale). Likewise, it considers the geotechnical complexity derived from the different geological formation environments, the extension and geographical dispersion of the infrastructure, and its interaction with the climatic regimes, to differentiate areas of interest based on the geohazards of hydrometeorological origin, when grouped into five clusters. The results of this exercise stand out the importance of keep a robust record of the events that affect the infrastructure of hydrocarbon transportation systems and using data-guided intelligence techniques to improve the tools that support decision-making in asset management.

Towards a Structured Maintenance and Integrity Management Program of Hydrocarbon Transport Systems - Emphasis on Geohazards

The main objective of the integrity and maintenance professionals of hydrocarbon transportation companies is to ensure the integrity and availability of transportation systems by monitoring and controlling the risks to which they are exposed. This article presents a series of aspects that give scope to a structured maintenance and integrity management program, and that can be established in each company based on its organizational structure and culture. Some examples are presented to take into account in geohazard management and that focus on achieving a holistic and prospective view of the professionals who manage geotechnical risk.

Practical Cases: Geohazards on RoW Generated by Third Party Damage

Camisea Pipeline Transportation System (PTS) in Peru, owned by Transportadora de Gas del Perú (TGP) and operated by Compañía Operadora de Gas (COGA), begins in the Amazon rainforest, crosses the Andes Mountains (4850msnm) and finally descends towards the Pacific coast. The PTS has been operating for more than 10 years and it has Natural Gas (NG) and Natural Gas Liquids (NGL) transportation pipelines. The NG pipeline is 888km long which includes two Loops (105km and 18km in the coast and mountain sectors, respectively). NGL pipeline is 557km long. From the beginning (0 km) to 210 km, the Right of Way (RoW) is located in the geotechnical context of the Amazon rainforest. Then, between km 210 and km 420, the PTS crosses the mountain chain of the Andes. Finally, between km 420 and Km 730 the RoW is located on the Peruvian Pacific coast. TGP’s operation of the PTS identifies, analyzes and controls the different types of threats that can affect the integrity of the pipelines. The operation is developed according to international standards defined in the Pipeline Integrity Management (PIM) of the operation. Consequently, hazards such as Third Party Damage (TPD), geohazard, external and internal corrosion, among others, are analyzed. However, associated to the economic growth and development of Peru, there have been some cases where the intervention of a person, community or industrial activity in the surroundings of the RoW has resulted in the level of geohazards are spontaneously modified and activated. Consequently, the degree of stability of the RoW is necessary to analyze the integrity of the NG and NGL pipelines. This article describes the occurrence of some practical cases where there was a change in the stability of the RoW of the TGP’s PTS triggered by activities related to TPD. It is highlighted that the identification, analysis, definition and execution of mitigation actions are carried out in a transversal way which involves the participation of different operational areas such as: Integral Maintenance, Geotechnics, Integrity, Social Management, among others. All the activities are done with the approach of keeping the balance between community, environment and infrastructure. Some of the cases considered are: Flood and scour of the RoW triggered by the failure of a water tank in an industrial area, scour of channels due the obstructions and an unstable slope process generated by constructions near the RoW. Today, the operation develops activities in order to mitigate geohazards generated by TPD. Some of these activities are, among others: Social awareness, technical talks, agreements with industrial and local administration entities, geotechnical maintenance and monitoring. In addition, it is highlighted that all the mentioned mitigation actions are carried out in a transversal manner between different operational areas. Afterward, the collected information is properly saved in the Geographic Information System database.

IPG2021 Front Matter

The front matter for this proceedings is available by clicking on the PDF icon.

Pipeline Geohazard Target Susceptibility Threshold – A Reliability-Based Rationalization

Pipeline geohazard assessment involves the delineation and quantification of threat severity associated with a suite of geohazard mechanisms deemed credible for a specific setting or project. The context for a typical assessment is loss of containment from the pipeline — an ultimate limit state (ULS) — considering individual geohazard mechanisms (e.g., landslide, fault displacement, rockfall, subsidence, etc.). To estimate the probability of loss of containment associated with a particular geohazard mechanism at a given location, the evaluation process can be partitioned into an estimate of the probability of occurrence of the geohazard mechanism at that location, and the conditional probability of loss of pipe integrity should the event occur. The product of these two probabilities is termed “susceptibility” expressed as loss of containment events per year at a given location. A typical approach to manage geohazards assessed in this way is to set a target susceptibility threshold to determine mitigation requirements to reduce the estimated susceptibility value for individual geohazards. The rationale for selecting a target susceptibility threshold value has been a topic of interest in recent pipeline projects in Canada. This paper demonstrates a reliability-based approach in rationalizing the selected pipeline geohazard target susceptibility threshold and linking geohazard assessment results to Quantitative Risk Assessment (QRA) of all threat categories in ASME B31-8S.

Risk Areas Zoning Using a New 3D Seismic Refraction Technique in the Gas Pipeline Right-of Way of a Gas and Condensed Field in the Peruvian Jungle

The use of the new three-dimensional refraction technique was applied around the right-of-way (DDV) of the hydrocarbon gathering pipeline system (U-200), approximately 14.4 km long and 1.5 km wide. This technique included: a) processing of field seismic gathers data in conjunction with LIDAR-DTM topographic information, with which a 3D model of P-wave velocities was constructed; b) calibration of the P-velocity model with field data; and c) interpretation of the final P-velocity model. The application of the new technique allowed the three-dimensional study of the subsurface around the U-200 by including the geological characterization of the velocities and the elaboration of several predictive geological maps (lithology, structural, topography, etc.). Correlations of these maps allowed the building of risk factor maps, in which areas with higher or lower geodynamic risk can be directly identified. These areas represented the zones where the pipeline/flowline was most prone to collapse.

EPGEO-ARPEL Latin America Project: Technical Guides on Monitoring and Geohazard Control Works in Pipelines

Since 2004, the Geotechnical Professional Team (EPGEO) from the Regional Association of Oil and Gas Companies in Latin America and the Caribbean (Asociación Regional de Empresas de Petróleo y Gas Natural en Latinoamérica y el Caribe, ARPEL) has been working on a knowledge management-related project for the Oil & Gas industry, consisting in the creation of three technical guides on Pipeline Integrity Management given the occurrence of geohazards in Hydrocarbon Transportation Systems. This initiative comprises the creation of 3 guides related to: i) Guide 1: Monitoring Geohazards for Pipeline Integrity, ii) Guide 2: Geotechnical Mitigation Works in Pipelines, iii) Guide 3: Geotechnical Risk in Pipelines. The EPGEO published Guide 1 in 2016 and made a presentation at the 2017 IPG (IPG2017-2538), while Guide 2 will be completed by 2021. Guide 3 will be created in 2021–2023. This document shows the methodology and contents for preparing the first two guides, focusing on Guide 2, which comprises different alternatives, analyses and technical solutions to the occurrence of geohazards that might affect the integrity of a pipeline transportation system.