In-Service Dent Management From an Operator’s Perspective

Author(s):  
Keith Adams ◽  
Joe Zhou

Pipeline dents are common occurrences that have a potential integrity threat to the system. Dents are typically found through in-line inspections, and historically, low-resolution in-line inspection geometry tools were used to find the locations of dents. These tools gave little information about shape, orientation or other dent features. Newer ‘high-resolution’ tools give a much clearer picture of the dent shape, location, orientation and location of welds. This information has been previously unavailable and has enabled dent integrity assessment with much greater accuracy and confidence. However this still leaves the question of how to best address the information from older, low-resolution inspection tools. In the past, CSA Z662 required that all dents with a deflection greater than 6% or that contained stress concentrators, including welds, had to be repaired. In the newly published 2003 edition of CSA Z662, dents can be assessed by an engineering assessment to determine their acceptability. Historical evidence has shown that dents less than 6% can also be subject to failure under certain conditions, and is indicated in the notes of CSA Z662-03 10.8.2.4.2. Dents that contain stress concentrators, including corrosion, welds and cracks must be given special consideration, however often little information is available for the dent from solely a geometry tool. TransCanada PipeLines Limited has been involved in the development of a dent assessment methodology for several years. Based on the 2003 revisions to CSA Z662, TransCanada has started to implement a dent integrity management program. This paper discusses the approach taken by TransCanada: to create a database of dent features, classification of dents, finite element analysis (FEA) to determine cyclic stress spectra, fatigue analysis, validation through dig programs, and the management of these features from a system integrity standpoint.

Author(s):  
Chris Alexander ◽  
Julian Bedoya

Establishing integrity for piping and pipelines requires an understanding of the specific threats, their relationship to the overall condition of the system, and the mitigating measures required to assure safe operation. In the past, industry has relied on years of research and experience to develop a set of tools to analyze these threats and apply conservative solutions to ensure integrity and fitness for service. An effective integrity management program as discussed in this paper, known as the Engineering Based Integrity Management Program (EB-IMP), provides operators with a resource for integrating inspection results, analysis, and testing to qualify the components within a pressurized system. This paper presents a detailed discussion on how experience, advances in analytical techniques, experimental methods, and engineering rigor are combined to develop a tool to characterize and ensure system integrity. Several case studies are included to demonstrate how the EB-IMP method was used to evaluate the integrity of a piping system, as well as rail gondola cars used to transport coal. The intent with the approach presented in this paper is to foster further developments for advanced integrity management efforts.


Author(s):  
Scott D. Ironside ◽  
L. Blair Carroll

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.


Author(s):  
Hao Song ◽  
Chenteh Alan Yu ◽  
Yongming Cheng ◽  
Jing Hou

Abstract The riser is a critical element in a subsea production system for transporting hydrocarbons from the seafloor to the surface. The track record of existing riser systems worldwide has shown that risers tend to be designed conservatively to accommodate dynamic loads, strength and fatigue requirements, and corrosion/erosion provision needs. Among all the riser types, the steel catenary riser (SCR) is the most installed riser configuration for deepwater oil and gas production worldwide in the last two decades. This is mainly because of their simple configuration and relatively low manufacturing and installation cost. As riser technology advances, SCRs are designed to tackle more challenging environments and longer service lives. For the riser life extension applications, regulatory bodies prefer riser operations to be managed through an integrity management program, demonstrating that a robust framework with detailed records on the conditions of the risers is in place. This paper studies an integrity management program for SCRs with a 30-year design life in a harsh environment. The planned riser integrity management program is based on successful industry practice and the newly published riser integrity management standard API RP 2RIM [4]. It starts with a review of the riser design basis and as-built data, continuing with key field data measurement and production fluid sampling. A digital model, continuously calibrated with the measured data, is established to assess the integrity of the riser system. Key physical quantities are selected to monitor the structural health of the SCRs, including vessel motion measurement, measurement of SCR top hang-off angles and tensions, and full water column current measurement. The relationship between the measurement data and the riser strength and fatigue performance is established. Details of the riser integrity assessment in a digital model utilizing the measurement data are presented. The implemented proposed riser integrity management program is expected to provide a more focused and efficient method with a higher level of confidence in operating the SCRs during the design life and potentially beyond.


Author(s):  
Miaad Safari ◽  
David Shaw

Abstract As integrity programs mature over the life of a pipeline, an increasing number of data points are collected from second, third, or further condition monitoring cycles. Types of data include Inline Inspection (ILI) or External Corrosion Direct Assessment (ECDA) inspection data, validation or remediation dig information, and records of various repairs that have been completed on the pipeline system. The diversity and massive quantity of this gathered data proposes a challenge to pipeline operators in managing and maintaining these data sets and records. The management of integrity data is a key element to a pipeline system Integrity Management Program (IMP) as per the CSA Z662[1]. One of the most critical integrity datasets is the repair information. Incorrect repair assignments on a pipeline can lead to duplicate unnecessary excavations in the best scenario and a pipeline failure in the worst scenario. Operators rely on various approaches to manage and assign repair data to ILIs such as historical records reviews, ILI-based repair assignments, or chainage-based repair assignments. However, these methods have significant gaps in efficiency and/or accuracy. Failure to adequately manage excavation and repair data can lead to increased costs due to repeated excavation of an anomaly, an increase in resources required to match historical information with new data, uncertainty in the effectiveness of previous repairs, and the possibility of incorrect assignment of repairs to unrepaired features. This paper describes the approach adopted by Enbridge Gas to track and maintain repairs, as a part of the Pipeline Risk and Integrity Management (PRIM) platform. This approach was designed to create a robust excavation and repair management framework, providing a robust system of data gathering and automation, while ensuring sufficient oversight by Integrity Engineers. Using this system, repairs are assigned to each feature in an excavation, not only to a certain chainage along the pipeline. Subsequently, when a new ILI results report is received, a process of “Repair Matching” is completed to assign preexisting repairs and assessments to the newly reported features at a feature level. This process is partially automated, whereby pre-determined box-to-box features matched between ILIs can auto-populate repairs for many of the repaired features. The proposed excavation management system would provide operators a superior approach to managing their repair history and projecting historical repairs and assessments onto new ILI reports, prior to assessing the ILI and issuing further digs on the pipeline. This optimized method has many advantages over the conventional repair management methods used in the industry. This method is best suited for operators that are embarking on their second or third condition monitoring cycle, with a moderate number of historical repairs.


Author(s):  
Honglong Zheng ◽  
Muyang Ai ◽  
Lijian Zhou ◽  
Mingfei Li ◽  
Ting Wang ◽  
...  

As a preventative management mode, integrity management which is significantly effective is now applicable in modern industry. Based on the successful application of integrity management for the pipeline, managers expect an extension of the integrity management program for the oil and gas stations such as pumping stations, so as to make the best arrangement of resources and guarantee the safety of station facilities. The differences between station integrity management system in China and abroad are analyzed. It is claimed that the oil and gas station integrity management is more difficult and complicated in China. An integrity management program is developed for the oil and gas stations in China. The authors summarily introduce the station integrity management framework, and determine the processes and elements of management. For the main parts of the stations are plenty of facilities, the authors attempt to carry out the management on each category of facilities in particular. According to the characteristics and working status, field facilities can be classified into three categories: static facilities, dynamic facilities, and electrical instruments. For all these facilities, integrity management approach consists of five steps: data collection, risk assessment, integrity assessment, repair & maintenance, and performance evaluation. Station integrity management system comprises five aspects: system documents, standards & specifications, supporting technologies, management platforms and applications. This paper should be considered as a reference for the oil and gas station integrity managers in the future.


Author(s):  
M. Robb Isaac ◽  
Saleh Al-Sulaiman ◽  
Monty R. Martin ◽  
Sandeep Sharma

In early 2005, Kuwait Oil Company (KOC) initiated a Total Pipeline Integrity Management System (TPIMS) implementation in order to carry out a major integrity assessment of its operating facilities, equipment, buried plant piping and pipeline network and to establish a continuing integrity management program. KOC Transit System is a complex infrastructure consisting of over three hundred pipelines, thousands of wellhead flow lines, and consumer and offshore lines for which there was a significant loss of data when the facilities were destroyed during a military invasion in 1990. An initial pipeline system assessment identified issues and actions regarding condition of the pipelines, corridors, requirements on in-line inspection (ILI), documentation, RISK assessment, status of international code compliance, and overall state of the system. Following recommendations from that initial assessment led to the development of a long term strategy; the execution of which required the implementation of a comprehensive integrity management program. This case study discusses the results obtained after five years of implementation of TPIMS at KOC. It will demonstrate some of the complex components involved in managing the integrity of the Transit System that have been made possible through the implementation of the system. The general concept and structure of TPIMS will be described, and how it deals with the complexity of the KOC pipeline system. The system made it possible to integrate and manage data from various sources, by conducting integrity assessment using ILI, Direct Assessment and hydrostatic testing, as well as structure a comprehensive RISK & Decision Support mechanism. This is one of the world’s first implementations of this magnitude which encompasses such a wide range of services and variables; all being managed in a single environment and utilized by a multitude of users in different areas at KOC. The biggest challenge in a project of this scope is data management. Examples will be shown of the integration structure to illustrate the benefits of using a single comprehensive and versatile platform to manage system requirements; ultimately providing system reliability and improving overall operational efficiency.


Author(s):  
Jeff Sutherland ◽  
Stephan Tappert ◽  
Richard Kania ◽  
Karlheinz Kashammer ◽  
Jim Marr ◽  
...  

Over the past three years there has been increasing industry interest and profile regarding the role and pipeline integrity management potential of EMAT crack inspection technology in the Oil & Gas pipeline industry. This paper outlines the stages and results of the effective collaboration of a major pipeline operator and a service company to advance the true predictive performance of the EMATScan Gen III crack inspection technology. The paper will also summarize and provide examples of lessons-learned from this collaboration across all stages of EMAT based SCC integrity management program. The paper will similarly outline ongoing work in progress regarding the assessment of the ILI data relative to hydro-testing equivalency, detection of injurious defects and the related analysis and reporting improvements made over the past three years.


Author(s):  
Ron Scrivner ◽  
Chris Alexander

Establishing pipeline integrity requires an understanding of the specific threats, their relationship to the overall condition of the pipeline, and the mitigating measures required to assure safe operation. In the past, the pipeline industry relied on years of research and experience to develop a set of tools to analyze these threats and apply conservative solutions to ensure pipeline integrity. With the implementation of the Integrity Management Program (IMP) in 2004 by the Pipeline and Hazardous Material Safety Administration (PHMSA), pipeline integrity must be addressed by operators where the analysis methods and results must be documented and defendable. This paper presents a detailed discussion of how existing knowledge, advances in analytical techniques, experimental methods, and engineering rigor are combined to develop field-friendly tools to characterize and ensure pipeline integrity. Two case studies are included, the first, to demonstrate how the proposed method was used to assess the integrity of a corroded elbow, the second, provides the reader with an example of how to develop a tool for evaluating the severity of dents in pipelines using available public-domain research. It is the hope of the authors that the approach presented in this paper will foster further developments and advanced pipeline integrity management.


Author(s):  
Abe Nezamian ◽  
Robert J. Nicolson

Floating facilities for production, storage and offtake (FPSO) and other offshore production facilities have been used safely and reliably throughout the oil industry for many years. Asset Integrity is increasingly important to optimising safety and operational life and asset performance efficiency. Operators need to comply with Corporate, Regulatory and Certification requirements but recognise that developing and managing an effective and compliant Asset Integrity Management System is both time consuming and costly. Review of operational history of existing large FPSOs around the world indicated low confidence in operational life expectancy and to achieve the design life without possible dry docking or major repair. FPSOs have certain loading characteristics and damage consequences that make them different to other offshore installations and conventional ships, and often more challenging to maintain and operate. Maintenance and inspection campaigns are important inputs in the Asset Integrity Management (AIM) system of FPSOs and other floating offshore facilities. Considering that the unit shall stay on site during the whole life of the field, where disconnection or the removal of the mooring system is not planned, a comprehensive methodology for the asset integrity management, survey, inspection, testing, maintenance and repair of the unit during this period needs to be developed and subject to review based on the results of the scheduled inspections and audits. So as well as class and statutory requirements, inspection and survey, maintenance and repair plans should reflect the required availability, functionality, survivability and durability of the unit, giving due regard to its field life, as part of the safety management of the facility. Risk Based Integrity management methodology has been adopted in several projects and is an important tool to establish a rational inspection campaign for structural components, mainly for those located in areas where access is critical and operational constraints are an important parameter. This paper gives an overview of the challenges and discusses various aspects of ageing related to FPSO facilities, represented risk to the integrity of a facility and the required procedures and reassessment criteria for maintaining the structural integrity. This paper also provides an overall view on the regulatory requirements, documentation and calibrations/validations of the original design values to maintain the safety level by means of a maintenance and inspection programs balancing the ageing mechanisms and improving the reliability of assessment results. A brief summary of an example project of an asset integrity assessment and management program for life preservation of a purpose built FPSO and associated subsea system facilities is presented.


Author(s):  
Dario Zapata ◽  
Ingrid Pederson ◽  
Sean Keane

Safety case is utilized within the Enbridge Pipeline Integrity Management Program as a means to provide evidence that the risks affecting the system have been effectively mitigated (LeBlanc, et al. 2016). The safety case is an independent, evidence-based assessment based on system integrity management processes applied across all pipelines. This paper describes the process in which safety case methodology was implemented to manage geohazard threats. The benefits of assessing geohazard and other integrity threats will also be discussed. The safety case report documents the opportunities to address the identified problems in addition to the relationship between hazards, implemented controls, and associated susceptibility. To demonstrate that adequate safety controls for geohazard threats have been incorporated into the operational and maintenance phase of the pipeline system, the geohazard management component of the safety case was assessed using a bowtie diagram. The results gave visibility to the geohazard program and its effectiveness. Predefined safety performance metrics with probabilistic and deterministic criteria are evaluated to confirm the geohazard program’s continued effectiveness. Results from the safety case assessment identify opportunities for improvement and provide a basis for revision to maintenance, assurance and verification programs. Ultimately the assessment demonstrates that geohazard threats in the pipeline system are being recognized and assessed. The assessment provides evidence that adequate resources and efforts are allocated to mitigate the risk and identifies continuous improvement activities where needed. The safety case report generated as the final portion of an integrity management framework demonstrates risk is as low as reasonably practicable (ALARP).


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