A Hazard and Risk Management System for Large Rock Slope Hazards Affecting Pipelines in Mountainous Terrain

Pipelines and other linear facilities that traverse mountainous terrain may be subject to rock fall and rock slide hazards. A system is required to determine which sites pose the greatest hazard to the facility. Once sites are ranked according to hazard exposure, a risk management program involving inspection, monitoring, contingency planning and/or mitigation can be implemented in a systematic and defensible manner. A hazard rating methodology was developed to identify and characterize rock slope hazards above a South American Concentrate Pipeline, and to provide a relative ranking of hazard exposure for the pipeline, an access road and operational personnel. The rating methodology incorporates the geometry of the right-of-way, estimated pipe depth, staff and vehicle occupancy time, failure mechanism and magnitude, and the annual probability of hazard occurrence. This information is used in a risk-based framework to assign relative hazard ratings within rock slope sections of relatively uniform hazard exposure. This paper outlines a general framework for natural hazard and risk management along linear facilities, describes the rock slope hazard rating methodology, and illustrates how the system was applied along a South American Concentrate Pipeline.

Blockage Remediation in Deep Water Pipelines

Flow assurance is an important issue in the design and operation of production systems in deep waters. The implementation of prevention and remediation methods is necessary mainly due to the low temperatures, high production pressures, long tie-ins and oils prone to organic deposit formation. Despite the development and improvement of these prevention and remediation techniques, failures or exceptional operational conditions can lead to the complete blockage of the submarine flowlines, risers or equipment. Although the complete blockage is not frequent, the related production losses generally are high; furthermore, the technical difficulties and the costs involved in the removal of blockages can be high. The steps to the remediation of subsea blockages are the localization, identification and removal methods. Due to the variety of problems, the different subsea layouts and surface facilities, it is not possible to have a general recipe for all problems. This paper presents some blockage remediation cases, including the localization and blockage remediation methods. The blockage localization methods used for the blockage removal cases described in this paper are the following: a) the echo of pressure pulses reflected at the blockage and b) a tool that detects the pipeline diameter variation with the pipeline pressure variations. The field results for these methods and the pros and cons of the methods are discussed. The remediation methods described are the following: external heating, internal intervention and exothermal chemical reaction using gravity.

Reclamation of National Energy Board Regulated Pipeline Rights of Way: A Life Cycle Approach

As part of its mandate, the National Energy Board (NEB) regulates the construction, operation, and abandonment of interprovincial and international pipelines. The primary legislation which directly and indirectly addresses reclamation of NEB lines are the National Energy Board Act and the associated Onshore Pipeline Regulations, 1999, and the Canadian Environmental Assessment Act. The NEB uses a life cycle approach to pursue appropriate reclamation of disturbed rights of way. Initially, reclamation related issues are addressed at the application stage. Subsequent to the application process, the actual implementation of reclamation measures occurs during construction of the line. Success of reclamation is monitored during the operational life of a line through inspection and auditing procedures, with additional measures being implemented as necessary.

Pipeline Dent Management Program

Enbridge Pipelines Inc. operates the world’s longest and most complex liquids pipeline network. As part of Enbridge’s Integrity Management Program In-Line Inspections have been and will continue to be conducted on more than 15,000 km of pipeline. The Inspection Programs have included using the most technologically advanced geometry tools in the world to detect geometrical discontinuities such as ovality, dents, and buckles. During the past number of years, Enbridge Pipelines Inc. has been involved in developing a method of evaluating the suitability of dents in pipelines for continued service. The majority of the work involved the development of a method of modeling the stresses within a dent using Finite Element Analysis (FEA). The development and validation of this model was completed by Fleet Technology Limited (FTL) through several projects sponsored by Enbridge, which included field trials and comparisons to previously published data. This model combined with proven fracture mechanics theory provides a method of determining a predicted life of a dent based on either the past or future operating conditions of the pipeline. CSA Standard Z662 – Oil and Gas Pipeline Systems provides criteria for the acceptability of dents for continued service. There have been occurrences, however, where dents that meet the CSA acceptability criteria have experienced failure. The dent model is being used to help define shape characteristics in addition to dent depth, the only shape factor considered by CSA, which contribute to dent failure. The dent model has also been utilized to validate the accuracy of current In-Line Inspection techniques. Typically a dent will lose some of its shape as the overburden is lifted from the pipeline and after the indentor is removed. Often there can be a dramatic “re-rounding” that will occur. The work included comparing the re-rounded dent shapes from a Finite Element model simulating the removal of the constraint on the pipe to the measured dent profile from a mold of the dent taken in the field after it has been excavated. This provided a measure of the accuracy of the tool. This paper will provide an overview of Enbridge’s dent management program, a description of the dent selection process for the excavation program, and a detailed review of the ILI validation work.

The Role of a Geographic Information System (GIS) in the Sustainability of Export Pipeline Projects

Sustainable development in the energy industry is rapidly expanding beyond the conceptual stage. Policies addressing the three principles of Sustainable Development (economic growth, environmental protection, and social progress) are being established and strategies to execute these policies are being developed and implemented in the field. Export pipeline projects provide a wide variety of applications for the three elements of sustainable development. Properly designed, installed and operated pipeline systems enable the energy industry to deliver hydrocarbon products to the market place in a way that delivers economic rewards while preserving the integrity of the environment and surrounding communities and their ways of life. Conoco is developing a strong corporate culture around sustainable development; and, pipeline systems play a vital role in delivering the triple bottom line results for our stakeholders. This paper will present some of the key focal points used by Conoco Inc. in pipeline project development. It proposes GIS technology to make pipeline projects a contributor to sustainable growth success.

Pipeline Visualization, Simulation and Monitoring in Unstable Areas Affected by Soil Movements at Serra do Mar – Brazil

In this work we discuss the importance of visualization, simulation and monitoring pipelines constructed in areas geologically unstable. In particular it is of great concern pipelines crossing Serra do Mar, in Brazil, where there are colluvium deposits subject to slow movements not traceable by a simple visual inspection most of the times. In order to guarantee the structural integrity of the pipeline it is necessary to measure the tensions transmitted by the ground to the pipeline. Knowing that the soil-pipeline interaction is extremely complex the implementation of an extensive program involving visualization, simulation and monitoring that includes not only the slope but also the pipeline becomes mandatory. This program seeks the collection of information that allows the establishment of a reliable interaction model. This model must be capable of providing operational control parameters and subsidize the decision of an intervention in the pipeline. Therefore the safety of pipeline operations can be maximized through instruction of operators and establishment of monitoring and inspection routines. Right now, in a joint effort of CENPES and TRANSPETRO, a complete set of visualization and numerical simulation software platform is available and it is being used to build a 3D model of all the geotechnical risky areas in Serra do Mar. Also the installation and operation of a pilot monitoring system, including piezometers and inclinometers on the slope and strain gauges on the pipeline, at three different pipelines crossing Serra do Mar, with data acquisition in real time is being undertaken.

An Innovative Approach for Pipeline Repairs

A strategic combination of integrity software, relational databases, GIS, and GPS technologies reduced costs and increased quality of a comprehensive pipeline integrity assessment and repair program that Greenpipe Industries Ltd. completed recently on three crude oil pipelines—two 6-inch and one 8-inch—for Enbridge Pipelines (Saskatchewan) Inc. Greenpipe analyzed metal loss data from recent in-line inspection logs, calculated real-world coordinates of defects and reference welds, prioritized anomalies for repair taking environmental risks into account, and prepared detailed dig sheets and site maps using PipeCraft™, Greenpipe’s advanced GIS-based pipeline integrity-maintenance software package. GPS technology was used to navigate to dig sites and the accuracy of the GPS approach was compared with traditional chainage methods. Pipelines were purged and all defects were cut out and replaced by new pipe during a two-day shutdown on each pipeline. A comprehensive set of data, including high-accuracy GPS location of anomalies, reference welds, and replacement pipe welds, was collected at each dig site and entered into the PipeCraft relational database. After all repairs were completed, the client was provided with a GIS-based electronic final report, allowing point-and-click access to all data collected in the field, including in-line inspection logs, dig information sheets and as-built drawings. The new methodologies employed on this project resulted in a high quality, comprehensive and cost-effective integrity maintenance program.

The Design and Installation of the LEOS Leak Detection and Location System for the Northstar Project

The Northstar project is the first crude oil production facility constructed offshore in the Beaufort Sea. Produced crude oil is transferred via a buried subsea pipeline to shore and overland to the Trans Alaska Pipeline Pump Station PS1 facility. During the permitting process, concern was expressed that a very small chronic leak in the subsea oil line would remain undetected during the winter months of continuous ice cover. Therefore, the US Army Corps of Engineers stipulated that a prototype leak detection system be installed that would capable of detecting a threshold leak less than 32 BOPD. This paper addresses the efforts to develop and install the LEOS leak detection system for arctic operations. The system is based on the well-established LEOS leak detection technology (manufactured by Framatome ANP, formerly by Siemens AG). The system comprises a perforated plastic tube with a thin water impermeable acetate outer sheath that allows hydrocarbon molecules to diffuse into the air filled tube. The air inside the tube is replaced periodically (every 24 hours) and is passed through a hydrocarbon-sensing module. The module contains resistors sensitive to the presence of very small concentrations of hydrocarbon molecules. The presence and location of a leak is determined by measuring the time taken for the localized concentration of hydrocarbon molecules associated with a leak to reach the end of the tube. LEOS components and materials were engineered to survive installation during arctic winter conditions. It was also necessary to protect the plastic LEOS sensor tube as it was lowered through the ice, attached to the pipeline, into a pre-excavated trench and then backfilled. The 10km long LEOS tube was delivered to site in 31-coiled 300m (1000-ft) bundles that were transported from Germany to Alaska. The LEOS sensing tube was preinstalled in a protective outer polyethylene tube which was unreeled through a reverse bending jig. Crude oil production started at the Northstar production facility in October 2001 and the LEOS system has been operational since then and is providing the highest degree of assurance that no oil is escaping from the pipeline.

Feedback and Mapping Control of Natural Gas Engines

Automatic controls have been used on all types of machinery since the first complicated machines became popular in the 19th century. Controls are used to maintain pressures, temperatures, operating speeds, flows and many other operating parameters. Natural gas engines have used a variety of controls for various purposes since the first natural gas engines were produced. This paper will discuss the history of mechanical controls used on natural gas engines and the introduction and application of electronic controls. The paper will discuss open loop (mapping) and closed loop (feedback) type controls and common applications of each. Mechanical control systems such as governors, fuel regulators, fuel mixing valves, thermostats, and turbocharger wastegates will be discussed and classified as open or closed loop controls. Electronic control systems such as governors, air/fuel ratio controls, detonation controls, and turbocharger controls will also be discussed and classified. This paper will also discuss state of the art controls which perform numerous functions to get desired performance, and can be communicated with remotely.

Basis of the New Criteria in ASME B31.8 for Prioritization and Repair of Mechanical Damage

Mechanical damage in the form of dents has emerged as a key safety concern for pipelines. In response, ASME B31.8, with assistance from GTI, undertook a detailed review of industry research and operating experience with respect to various forms of mechanical damage. Revised criteria for prioritizing and effectively repairing damage in natural gas pipelines were developed based on the findings. The criteria address plain dents, third-party type damage, dents that affect weldments, dents affected by corrosion, and strain levels associated with deformation of the pipe section. This paper discusses the generalities of the scientific findings and basis for the changes to the Code.