Ground Based Interferometric Synthetic Aperture Radar Combined With a Critical Slope Monitoring Program Will Provide Early Detection of Slope Movement Along Pipeline Corridors

The transition of satellite InSAR technology to a ground-based system provides a proven risk reduction technology if combined with a critical slope monitoring (CSM) program. Together the technology with the active engagement of a defined program can detect the onset of slope displacement, acceleration, and provide a method to determine slope collapse. Recently, using the radar software, Guardian, and its ability to document surface velocity in intervals of 24-hours or less has allowed for the development of site-specific levels of rockfall risk. The ground-based InSAR (interferometric synthetic aperture radar) systems and their near real-time capabilities allow for proactive and early warning monitoring. The technical requirements include the ability to operate 24/7 in all weather conditions, acquire data in near real-time, and visually present data in an interpretable format that requires no end user processing. Since slope failure without acceleration is unlikely, the rapid visual presentation of processed data becomes a crucial component for a CSM technology. The definition of the CSM program not only requires short intervals for data acquisition, processing, and visual presentation but also requires a monitoring professional that can interpret and communicate changes in slope movement. A specific CSM technology requirement demands, acquiring data at a continuous interval of 2-minutes or less, 24 hours per day for the duration of the monitoring project. Also, the CSM technology must be able to transmit alarm messages at the moment thresholds are met, visually present data with various time series plots, including displacement, and velocity maps while acquired radar data is continuously updated and with no end-user processing. A site-specific document called a trigger action response plan (TARP) needs to be prepared at the start of any CSM project. Currently, only the IBIS-FM and ArcSAR radars developed by IDS (Ingegneria Dei Sistemi) GeoRadar can meet the technical requirements of the defined CSM technology. During a CSM program, the short interval between each data acquisition provides two specific advantages. First, the short acquisition interval decreases interpolation, which automatically increases data confidence. Second, the short intervals also decrease the effects of atmospheric changes that are a part of all data acquisitions. Although the IBIS-FM and ArcSAR radar systems can operate in nearly all-weather conditions, sudden changes in local atmospheric conditions can still exhibit data effects. Both radar systems include active proprietary algorithms that account for ongoing atmospheric changes during acquisitions. In comparison, some remote sensing data acquired from, LIDAR, and total station technologies can be critically affected by sudden changes in local atmospheric conditions. Combining the near real-time capabilities of an interferometric synthetic aperture radar system with a dedicated professional will decrease risk to people and property by allowing slope movement trends to be identified and observed in near real-time, 24-hours per/day. The paper will discuss the highlights of several successful CSM programs. We describe deployment versatility, the ability to identify the onset of displacement accurately, and the critical identification of the onset of acceleration.

A New Approach for the Geotechnical Zoning of the Rights of Way

Usually, the definition of geotechnically homogeneous zones is established through the analysis of information on a regional (and even national) scale of those characteristics that define the topographic, geological, climatic, and land use conditions by categorizing them and applying algorithms of interaction between these variables. However, in technical literature and in technical reports of state entities that manage natural hazards, new advances are being made in the determination of other aspects or variables that detail the condition of geotechnical susceptibility; at the same time, nowadays there are technological tools for the massive analysis of information and its spatialization. This article presents a new approach to the definition of geotechnically homogeneous zones using these technological tools. A comparison is made against the conventional definition.

Natech Risk Management on Pipelines of Cenit

In recent years, the Colombian government has strengthened its legislation moving towards a disaster risk management system (Law 1523 in 2012) and has established guidelines on the role of public and private entities (decree 2157 in 2017) when defining the structure of disaster risk management plans. This paper presents the advancements on Natech risk management implementation in Cenit (major Colombian pipeline operator of hydrocarbons transport), to identify areas of potential disaster based on the application of its geohazards assessment model that considers prevention specific elements and consequence analysis.

Finite Element Modelling of a Series of Ground Displacement Episodes and Stress Relief Procedures

The Wapiti River South Slope (the Slope) near Grand Prairie, Alberta, Canada, is 500 m long and consists of a steep lower slope and a shallower upper slope. Both the upper and the lower slopes are located within a landslide complex with ground movements of varying magnitudes and depths. The Alliance Pipeline (Alliance) NPS 42 Mainline (the pipeline) was installed in the winter of 2000 using conventional trenching techniques at an angle of approximately 8° to the slope fall line. Evidence of slope instability was observed in the slope since 2007. The surficial geology of the slope comprises a colluvium layer draped over bedrock formation in the lower slope, and glacial deposits in the upper slope. Available data indicated two different slide mechanisms. In the lower slope, there is a shallow translational slide within a colluvium layer, and in the upper slope there is a deep-seated translational slide within the glacial deposits. Both the upper and lower slope landslides have been confirmed to be active in the past decade. Gradual ground displacements in the order of several centimeters per year were observed in both the upper and lower slopes between 2007 and 2012. Large ground displacements in the order of several meters were observed between 2012 and 2014 in the lower slope that led to the first stress relief and subsequent slope mitigation measures in the spring and summer of 2014. Monitoring of the slope after mitigations indicated significant reduction in the rate of ground movement in the lower slope. Surveying of the pipeline before and after stress relief indicated an increase in lateral pipeline deformation in the direction of ground movement, following the stress relief. This observation raised questions regarding the effectiveness of partial stress relief to reduce stresses and strains associated with ground movements. Finite element analysis (FEA) was conducted in 2016 to aid in assessing the condition of the pipeline after being subject to ground displacements prior to 2014, stress relief in 2014, and subsequent ground displacement from July 2014 to December 2016. The results and findings of the FEA reasonably matched the observed pipeline behaviour before and after stress relief in the lower slope. The FEA results demonstrated that while the lateral displacement of the pipeline, originally caused by ground movement, increased following the removal of the soil loading during the stress relief, the maximum pipeline strain was reduced within the excavated portion. The FEA was also employed to assess the pipeline response to potential ground displacement scenarios following December 2016. For this assessment, three ground displacement scenarios that comprise different lengths of the pipeline were analyzed. An increased rate of ground displacement, with a pattern that matched one of the analyzed scenarios, was observed in the upper slope in the spring of 2017. The results of FEA were used to assess the pipeline response to the increased rate of displacement in the upper slope. Subsequently a decision was made to stress-relieve the pipeline. The second stress-relief was conducted in the summer of 2017. This stress relief was conducted locally at the toe and head of the active slide in the upper slope, where the FEA showed the greatest stress concentrations in the pipeline.

Assessing and Managing Geologic Hazards in the Appalachian Region of the United States

Geohazards have the potential to adversely affect the operation or integrity of an existing pipeline, or the routing, design, and construction of a proposed pipeline. Identifying, characterizing, evaluating, and if necessary, mitigating and monitoring geologic hazards have become critical steps to successfully and safely building and operating pipelines in the Appalachian Basin region of the United States. The recent, rapid expansion of pipeline construction and operation in the region, along with natural geologic and geographic conditions which are conducive to landsliding and ground subsidence, have resulted in a recent increase in geohazard-related incidences both during and post-construction of pipelines. As such, there is an increasing need to recognize, understand, and closely manage geohazards in this region, prior to, during, and post-construction of pipelines. This paper will provide an overview of essential tools that have proven most useful in this region, to identify, characterize, and ultimately mitigate and monitor potential geohazards. This paper will also provide insight on how to evaluate specific project needs and best-fit approaches and solutions for the project at hand, to reduce the operator’s risk. A case study will be presented from the Appalachian Basin region, including how a phased approach was used to assess and manage geohazards. The phased approach includes (1) Phase I Assessments, which consist of a regional-scale desktop assessment to identify, initially characterize, and qualitatively classify (e.g., low, moderate, high hazards) geohazards; (2) Phase II Assessments, which consist of a non-intrusive ground reconnaissance completed at targeted sites; and (3) Phase III Assessments, which consist of subsurface investigations such as drilling, test pitting, or geophysical surveys to further characterize specific hazards. The information obtained from the phased approach can be used for the design of mitigation and/or monitoring, if deemed necessary. Overall approaches to selecting and utilizing best-fit mitigation and monitoring options, both during and post-construction, fit for the regional conditions and to the individual project, will also be discussed.

Cost Optimisation in Risk Reduction Management Based on Gross Disproportionation Concept

Gross Disproportionation concept is used as indicator once risk reduction measures are required. This indicator shows that a measure must be implemented if its cost (i.e. Capital Expenditure), is not grossly disproportionate if compared to benefits — represented by casualties suppression — reached by the measure. Due to this, a risk reduction measure is reasonable feasible unless its cost is highly disproportionate in comparison to its benefits. In hydrocarbon transportation industry, benefits represent the avoided cost if threats take place; on the other hand, for risk mitigation cost estimation, the cost per casualty averted must be accounted. The latter, provides a global cost of the mitigation measure adopted in relation to the direct cost of construction, with the reduction of the level of risk (i.e. social risk) and with the expected design period for that measure. In this last concept, the higher the reduction in the level of risk or the longer the design period of the mitigation measure, the lower the cost per casualty averted, a fact that reflects an effective mitigation measure in terms of risk reduction and its durability. This document shows, from a case study, how the application of the concept of grow disproportionation allows to select the type of optimal intervention over Ocensa’s pipeline, with the most favorable relation between cost and benefit, and the effective risk reduction level.

River Crossings: Developing a Mobile GIS Approach to Monitoring Activities

TGN operates a system of 9,000 kilometers of natural gas pipelines with numerous river crossings. According to the mandatory monitoring program, river crossings are visited at least once a year with additional visits for major rivers during the rainy season. Basic data such as depth of cover for each line, photographs and descriptions are surveyed in the field. Later on, this information is manually entered in an electronic form for its use in risk analysis, to evaluate the need of remediation works. This task has two main problems: first, it is very time consuming for surveyors, and second, it is difficult to know the location within the river crossing where data was taken. At the end, monitoring forms came late in the year and its information is difficult to understand. To cope with this problem, a new approach was developed. A GIS mobile application was developed and installed in tablets used in the field, guiding the surveyor through the completion of an electronic form along each pipeline, having a satellite image in the background, as a global reference of where he is standing. All the information is geo-referenced using a built-in GPS. Once it is finished, by means of a simple WIFI/4G connection, information is sent to GIS servers, without the need to be typed at the office. Later on, it is captured and placed into the monitoring form format. Specialists can access and evaluate this information from the database visualizing it in the corporate GIS with minimum delay. This improvement has resulted in a significant decrease in time for the entire data flow process and a better quality of the information gathered, which results in a more realistic risk analysis.

Watercourse Crossing Program: 10 Years Performance

Plains Midstream Canada (PMC) completes a watercourse crossing program as part of its overall integrity management program. The approximately 9,900 kilometers of operating and discontinued pipelines are evaluated within the watercourse crossing program. The pipelines are located throughout the Canadian Provinces of Alberta, Saskatchewan, Manitoba and Ontario. The terrain traversed ranges from relatively steep near the Rocky Mountains to extremely flat in northern Alberta and Southern Ontario. Since 2008, PMC’s systematic watercourse crossing program has evolved and now consists of approximately 5,000 individual watercourse crossings. The bankfull width of the watercourses ranges from less than 1 m for intermittent streams to more than 700 m at major rivers. The watercourse crossing program is subjected to a continuous improvement process, with a focus on key learnings from pipeline failures, free spans and exposure. This paper describes the results from the program over the last 10 years and highlights program improvements. In addition, data from a failure and three free spans on the pipelines now owned by PMC, but where the exposure, free span or failure occurred prior to PMC purchasing the pipelines were added to expand the available data for the key learnings.

Retroerosion in a TBG Gas Pipeline Crossing and its Rehabilitation

This Paper presents a case study of the Jardim Novo Maracanã stream situated in Campinas, São Paulo, in which recent streambed modifications were characterized, aiming to define the rates and the potential erosions along the channel alignment of which have Bolivia-Brazil Gas Pipeline crossing. Its presents the erosion process analysis and mitigation concepts aimed at the pipeline and fiber optic cables facilities integrity, as well as to indicate the design issues, considering the streambed deepening in this watershed. For this, satellite images and aerial photographs were collected in different periods, soil and subsoil surveys were performed, information on rainfall and watershed characteristics was analyzed, as well as hydrological and hydrotechnical studies were developed. These studies included geotechnical channel and banks analyzes, the spatial and temporal trends of the fluvial geomorphology evolution and the infrastructures safety conditions analysis. It was concluded that a new channel erosion process occurred after the streambed was filled by recent sediments. This process is associated with an increase floods magnitude, the slopes occupation intensification with the county urbanization and the streambed conditions changes, from an alignment sinuous to rectilinear and from a shallow to deeper channel. Once initiated, the channel erosion process maintained its retroerosion, i.e. its “headcutting” trend, deepening its equilibrium profile to its stratigraphic base level, located about 5.0 m below the 2014 stream bottom, in the pipeline cross section. Alternative concepts for the infrastructure integrity rehabilitation in these new morphological-fluvial conditions were also developed and dimensioned. Among these, the rectangular culverts alternative was adopted. They support a landfill at the crossing with the buried pipe and have to 100-year return period peak flows capacity.

Enhancing Geohazard Management Practice for South American Pipelines

Pipeline geohazard management practices and technologies have evolved rapidly over the past 15 years in step with industry’s drive towards zero failures. This paper describes the evolution in geohazard management for pipelines since the early 2000’s and describes how technology and management practices are currently being adapted to accommodate South American site conditions and data sources. It ends by outlining a possible framework for industry, regulatory and academic collaboration within South America that offers the potential for another step-function improvement in pipeline safety.