Pipeline Integrity Management Research Articles

Fitness-for-purpose evaluation of corroded pipelines using finite element analysis and fractural reliability estimation

The occurrence of internal and external pipeline corrosion has been attributed to the operational parameters of the pipeline, and other environmental and manufacturing constraints. In this study, a finite element analysis (FEA) approach was used for predicting the burst pressure of internal circumferentially corroded pipelines. The FEA determined burst pressures were tested with both experimental results and industry standard models, and a good agreement was observed. A burst pressure prediction model that depended on the ratio of the corrosion defect depth to the pipe-wall thickness (d/t) and the corrosion defect length to the pipe diameter (L/D) was developed. A structural reliability model of corroded pipe that is prone to burst failure was also predicted and the variability of the failure probabilities and reliability indexes with the internal operating pipeline pressure at different d/t were determined. Considering the reasonable results obtained from the prediction model, when compared with the experimental and industry-based models, it can be affirmed that the burst pressure prediction model developed in this study will to be a vital tool for pipeline integrity management.

Pipeline Leak Detection by Using Time-Domain Statistical Features

Leak detection is critical for the integrity management of oil and gas pipelines. The pipeline leak can cause a major accident, especially when transporting dangerous substances. The impact to the environment and human life is paramount and thus it is essential to detect the pipeline leak in time. Usually, a leak signal from the acoustic online monitoring sensor is characterized and identified by its waveforms, absolute amplitudes, and the frequency-domain energy distribution. However, these features are not steadily available due to the propagation attenuation under varied pipeline transportation conditions. In addition, sample leak signals are needed for most existing feature extraction and modeling methods, but the actual leak signals are seldom available. Although artificially simulated leaks can be adopted alternatively, it is not possible to fully duplicate the actual leak signals with complete features. To solve these problems, this paper proposes a pipeline leak detection approach by using time-domain statistical features from acoustic sensors. These features are extracted and vectorized from normal (no leak) sample signals, which are selected by an automated method. The size of the extracted feature vector is further reduced with principal component analysis method. A support vector data description model is built with the processed vectors as the input. The proposed method has been implemented in a field leak detection system. The experimental results from the field tests demonstrate the effectiveness of the proposed method.

Technologies and application of pipeline centerline and bending strain of In-line inspection based on inertial navigation

Inertial mapping unit (IMU) in-line inspection (ILI) has become routine practice for long-distance buried transport pipelines of oil and gas. It is capable of measuring the pipeline centerline position coordinates and locating the pipeline anomalies, features and fittings to help the oil company manage it. The IMU inspection data also can be used to compute the pipeline bending strain and assess the potential deviation from the original position where endures the extra stress. This paper introduces the main principle, measurement and data processing for IMU ILI. As a key point of calculation for centerline and bending strain, the identification and optimization of the signal are also discussed. At the end of this paper, the developments of IMU ILI are presented. The IMU ILI becomes an important and effective method for pipeline integrity management and safe operation of buried oil and gas pipelines.

Maintaining pipeline integrity through holistic asset management

A review of the concept of engineering asset management (EAM) and its role in integrity management within the context of energy pipelines has been conducted. The EAM system is shown to be concerned with pipeline integrity assurance at any point of the asset life. The effectiveness of a holistic EAM approach to assuring pipeline integrity is explored through case studies for pipelines that transport high pressure natural gas or liquid petroleum. The research examines the EAM system activities, data available and information flow and decision mechanisms utilised in industry and their effectiveness in incorporating the management or control of coating degradation and external corrosion into pipeline integrity management. The objective is to provide a holistic approach to defining the status of the EAM system that is in current use in energy pipeline organisations and to examine the role of EAM in integrity management of these pipelines. [Received 30 September 2014; Revised 15 June 2015; Accepted 21 March 2016]

Modeling and Calculation of Dent Based on Pipeline Bending Strain

The bending strain of long-distance oil and gas pipelines can be calculated by the in-line inspection tool which used inertial measurement unit (IMU). The bending strain is used to evaluate the strain and displacement of the pipeline. During the bending strain inspection, the dent existing in the pipeline can affect the bending strain data as well. This paper presents a novel method to model and calculate the pipeline dent based on the bending strain. The technique takes inertial mapping data from in-line inspection and calculates depth of dent in the pipeline using Bayesian statistical theory and neural network. To verify accuracy of the proposed method, an in-line inspection tool is used to inspect pipeline to gather data. The calculation of dent shows the method is accurate for the dent, and the mean relative error is 2.44%. The new method provides not only strain of the pipeline dent but also the depth of dent. It is more benefit for integrity management of pipeline for the safety of the pipeline.

Subsea Pipeline Integrity and Risk Management

Subsea Pipeline Integrity and Risk Management

A Study on Oil Pipeline Risk Assessment Technique Based on Fuzzy Analytic Hierarchy Process

Risk assessment of oil pipeline is the core content in the pipeline integrity management. Through risk assess- ment of oil pipelines, we could know the comprehensive operating condition of the pipelines, identify the dangerous fac- tors of the pipeline and find out the risk section of the pipeline, so as to work out the risk mitigation measures and provide a theoretical basis for integrity assessment of the pipeline. However, the commonly used Kent risk assessment method does not have a very reasonable distribution of the failure indicator values. Therefore, this paper establishes a failure indi- cator value adjustment model for oil pipeline risk assessment based on the fuzzy analytic hierarchy process. Risk assess- ment of Qingha Oil Pipeline has been carried out based on the foundation data and real condition of the pipeline, and the established model was used for weighed adjustment of the various failure risk factors of the pipeline. Thus, a risk assess- ment model which is more suitable for Qingha Oil Pipeline was obtained. This laid a very solid foundation for proposal of suggestions on mitigation of risk of damage by the third party and the implementation of protective measures of the pipeline.

Model error assessment of burst capacity models for energy pipelines containing surface cracks

This paper develops the probabilistic characteristics of the model errors associated with five well-known burst capacity models/methodologies for pipelines containing longitudinally-oriented external surface cracks, namely the Battelle and CorLAS™ models as well as the failure assessment diagram (FAD) methodologies recommended in the BS 7910 (2005), API RP579 (2007) and R6 (Rev 4, Amendment 10). A total of 112 full-scale burst test data for cracked pipes subjected internal pressure only were collected from the literature. The model error for a given burst capacity model is evaluated based on the ratios of the test to predicted burst pressures for the collected data. Analysis results suggest that the CorLAS™ model is the most accurate model among the five models considered and the Battelle, BS 7910, API RP579 and R6 models are in general conservative; furthermore, the API RP579 and R6 models are markedly more accurate than the Battelle and BS 7910 models. The results will facilitate the development of reliability-based structural integrity management of pipelines.

Residual Strength Calculation & Residual Life Prediction of General Corrosion Pipeline

General corrosion is of the primary reason that causes the pipeline to failure. Researching the residual strength and residual life of general corrosion pipeline is the main measure to conduct the pipeline integrity management, and has great significance to ensure the safety of pipeline transportation. The calculation of the residual strength of even corrosion pipeline under the combined effects of internal pressure and axial force was discussed according to the Tresca yield criterion in elasto-plastic fault mechanics, when the defected size is given, the maximum permissible operating pressure under the defect and the calculation formula for the residual strength of corrosion pipeline are given. On this basis, reliability-based residual life prediction of the corrosion pipeline was developed.

Grasping at Straws: Comments on the Alberta Pipeline Safety Review

The release last month of the Alberta Pipeline Safety Review was meant to be a symbol of the province’s renewed commitment to environmental responsibility as it aims for new export markets. The report’s authors, Group 10 Engineering, submitted 17 recommendations covering public safety and pipeline incidents, pipeline integrity management and pipeline safety near bodies of water — and many of them run the gamut from the obvious to the unhelpful to the contradictory. That the energy regulator ought to be staffed to do its job should go without saying; in fact, staffing levels were never identified as an issue. The recommendation that record retention and transfer requirements be defined for mergers and acquisitions, sales and takeovers is moot. There is no reason a purchasing party would not want all relevant documents, and no real way to enforce transparency if the seller opts to withhold information. Harmonizing regulations between provinces could reduce companies’ cost of doing business, but could also prove challenging if different jurisdictions use performance-based regulations — which is what the Review recommended Alberta consider. This very brief paper pries apart the Review’s flaws and recommends that the province go back to the drawing board. Safety is a serious issue; a genuine statistical review linking pipeline characteristics to failures and risk-mitigation activities would be a better alternative by far.

Necessity and Reliability of Pre-monitoring a Network for Geological Hazard

Important characteristics of long-distance pipelines in China are that they generally cover large areas and are subjected to variety of geological hazards, such as fault movement, landslide, flood, and surface subsidence. In concern of the possibility and high risk of geological hazard and according to the pipeline integrity management requirements, the authors focus on an important technical means which on the basis of the monitoring data to the change of the stress and strain of pipe body to establish an earlier monitoring warning system of geological hazards. This system can find the precursor of disaster accurately with a small amount of monitoring costs and improve the relevance of disaster prevention and reduce the cost of comprehensive management of pipeline. Based on this method, a project was conducted to prove reliability and necessity of this premonitoring network.

Recent Developments in Speed Control System of Pipeline PIGs for Deepwater Pipeline Applications

Pipeline infrastructures normally represent high cost of investment and the pipeline must be free from risks that could cause environmental hazard and potential threats to personnel safety. Pipeline integrity such monitoring and management become very crucial to provide unimpeded transportation and avoiding unnecessary production deferment. Thus proper cleaning and inspection is the key to safe and reliable pipeline operation and plays an important role in pipeline integrity management program and has become a standard industry procedure. In view of this, understanding the motion (dynamic behavior), prediction and control of the PIG speed is important in executing pigging operation as it offers significant benefits, such as estimating PIG arrival time at receiving station, planning for suitable pigging operation, and improves efficiency of pigging tasks. The objective of this paper is to review recent developments in speed control system of pipeline PIGs. The review carried out would serve as an industrial application in a form of quick reference of recent developments in pipeline PIG speed control system, and further initiate others to add-in/update the list in the future leading to knowledge based data, and would attract active interest of others to share their view points. Keywords—Pipeline Inspection Gauge (PIG), In Line Inspection Tools (ILI), PIG motion, PIG speed control system

Oil/Gas Pipeline Leak Inspection and Repair in Underwater Poor Visibility Conditions: Challenges and Perspectives

Mechanical pressure clamps are examples of innovative tools commonly used in the oil and gas industry for arresting leaks from damaged oil and gas pipelines. However, if leaks result from pipeline rupture, clamps are not usually recommended. It is therefore obvious that inspection of the leaking pipeline is very crucial in deciding the strategy for repair. For subsea pipelines where underwater poor visibility is pronounced, this important aspect of the pipeline repair process becomes difficult to implement. The result is a repair-leak-repair cycle. This challenge is commonly found in repairs of old pipelines in unclear water conditions. Old pipelines and their vulnerability to fractures that often lead to ruptures are discussed. In this paper, the challenges and technologies available for visualisation and examination in such unclear water conditions are discussed. There appears to be a gap in the existing pipeline integrity management system with respect to inspection and repair of pipelines in unclear water conditions. This gap needs to be filled in order to minimise spills and pollution. For pipelines installed in unclear water condition, a perspective is suggested to extend the capability of existing remotely operated vehicles to employ the use of clear laminar water system or a related technique to provide integrity engineers and operators with close visual assess to inspect leaking pipelines and effect adequate repairs. This paper suggests that the use of optical eye as the main tool for examination remains valuable in managing the challenges in underwater pipeline repairs in unclear water condition.

New Technique for Studying Soil-Corrosion of Underground Pipeline

Pipeline integrity management programs address a wide range of threats to safe operations. Among these threats, external corrosion has been among the most dominant failure mechanism experienced by buried steel pipelines. External corrosion can be detected through a variety of assessment methods, including inline inspection (ILI) and External Corrosion Direct Assessment (ECDA). In the absence of data from inspection, the corrosion rate can be estimated based on the use of buried corrosion coupons, corrosion probes and corrosion rate modelling using data derived from soil analysis. The objective of the study was to design a methodology of the external growth modelling of corrosion on buried gas pipelines under various exposures to soil conditions. The technique can be used to generate field data so as to model empirically the corrosion dynamic in soil or for verification of corrosion data from laboratory testing. The potential model based on the proposed technique is highly potential to predict the likelihood of corrosion growth rate experienced by buried lines exposed to corrosive environment. Hence, can greatly assist operator to secure the integrity of their pipelines until the structure reaches its designed lifetime.

Framework of pipeline integrity management

Pipeline integrity is the cornerstone of many industrial and engineering systems. This paper provides a review and analysis of pipeline integrity that will support professionals from industry who are investigating technical challenges of pipeline integrity. In addition, it will provide an overview for academia to understand the complete picture of pipeline integrity threats and techniques to deal with these threats. Pipeline threats are explained and failures are classified. Design practices are discussed using pressure criteria. Inspection techniques are studied and used as a basis for describing the corresponding integrity assessment techniques, which are linked with integrity monitoring and maintenance criteria. Finally, pipeline integrity management system design is presented using activity models, process models, and knowledge structures. The paper will be useful for further development of automated tools to support pipeline integrity management.

The Role of the External and Internal Reinforcing on the Structural Integrity of Industrial and Transporting Steel Pipelines

The lifetime management of different engineering structures and structural elements is one of the important technical-economic problems nowadays. On the one hand, the aim of our research work is to develop an integrity management plan for pipelines and pipeline systems, and afterwards a Pipeline Integrity Management System. Material databases play important role both on the integrity management and on the engineering critical assessment of the pipeline systems. On the other hand, the aim of our research work is to establish the Pipeline Integrity Management System with different data, frequently with experimental data. The direct purpose of the paper is to present the role of the external and internal reinforcing on the structural integrity of industrial and transporting steel pipelines, based on own examinations. External and internal reinforcement was developed using carbon fibre and glass fibre polymer matrix composites, respectively. Fatigue and burst tests were performed on pipeline sections containing natural and artificial metal loss defects, and girth welds including weld defects. Both unreinforced and reinforced pipeline sections were examined. The burst pressures belonging to the unreinforced and the reinforced pipelines, and belonging to the passed and not passed girth welds were compared.

Potential Benefits of Data Integration for Pipeline Integrity Management Programs

Abstract Pipeline integrity management programs are a requirement under Annex N of CSA Z662.07. Annex N requires that data from many sources and details be collected, integrated and analyzed on a continuous basis. The stated goal is to provide guidance for developing, documenting and implementing pipeline integrity management programs, which provide safe, environmentally responsible and reliable service(1). If executed properly, there should be improved pipeline integrity with measurable improvements and benefits. An important step in reaching this goal is risk assessment, which requires continuous data input to maintain valid integrity assessments. This dynamic process of data collection and integration enables continuous analysis and potentially leads to a more proactive integrity management system. The biggest problem for most operating companies in creating a dynamic and proactive integrity management program (IMP), compliant with Annex N, is in handling the significant data issues. Indeed, the data collection, integration and analysis are the most daunting tasks of the program. A software solution that accepts data from the many activities involved in the lifecycle of a pipeline system would be potentially beneficial. Application of integrated software tools in the oil and gas industry will result in improved integrity management, greater confidence in our pipeline infrastructure and economic benefits. We will review some of the data requirements of Annex N of CSA Z662.07 and identify the components of the program that may differ from your existing management plan. The nature and detail of data to be managed will be presented. Finally, we will provide an example of the role that software tools can play to assist in meeting the requirements of this challenging regulatory initiative.

Risk analysis based LNG facility siting standard in NFPA 59A

In the United States, liquefied natural gas (LNG) has the unique distinction of being the only flammable or hazardous material whose storage terminal (siting), handling and terminal operations are regulated by the federal government. Regulations are promulgated by the Pipeline and Hazardous Materials Administration (PHMSA) of the U.S. Department of Transportation (DOT). Storage and handling of all other flammable and hazardous materials are regulated by state laws. Current DOT regulations on LNG ( 49 CFR, part 193) are based on NFPA 59A, “Standard for the Production, Storage, and Handling of Liquefied Natural Gas,” 2001 edition. These regulations are very prescriptive and inflexible in that they do not allow alternative safety mitigation considerations for LNG facility siting without applying for a special permit. The types and sizes of accidental releases to be evaluated are prescribed and no deviation is allowed. Without considering a spectrum of events, their likelihood of occurrence and the resultant consequences it is impossible to design proper mitigation actions or emergency response procedures. The benefit of knowing and preparing for a properly evaluated “most likely event” scenario is the resultant correct application of economics, and personnel resources of emergency responders. The 2009 edition of NFPA 59A includes, in a mandatory annex, an alternative, risk-based requirements to evaluate the safety of land-based LNG facilities. DOT, in its regulations on the transportation of natural gas in interstate pipelines, requires the conduct of a “Pipeline Integrity Management” procedure to ensure public safety from accidental gas releases from interstate pipelines. The regulations refer to this procedure as “risk-based” even though frequencies of accidents or equipment failures are not considered. The National Association of Regulatory Utility Commissioners (NARUC) and the National Association of States Fire Marshals (NASFM) have recently passed resolutions calling on DOT (PHMSA) to initiate steps towards the development of risk-based LNG facility siting regulations. This paper discusses the risk evaluation approach incorporated into a mandatory annex in the 2009 edition of NFPA 59A and possible other methods of performing a LNG facility risk assessment. Also discussed are the parameters that society has to agree to establish an ‘acceptable’ level of risk. The paper indicates the risk process used in other countries, particularly in Europe. The results from the application of a risk analysis procedure to a specific case are presented. A comparison of the risk-based results with those obtained from the application of the current prescriptive requirements in NFPA 59A (or 49 CFR, part 193) is indicated. Recommendations are provided for future actions.

Pipeline life extension and integrity management based on optimized use of above ground survey data and inline inspection results

We present a detailed description of probabilistic methodologies based on Bayesian updating and structural reliability analysis for optimizing survey and/or inspection frequencies in a way that provides cost-effective solutions for ongoing integrity management or indeed for life extension or pressure uprating. A full description of the method is provided and the application of the techniques is clearly illustrated through case studies.

Corrosion Management for Aging Pipelines—Experience From the Forties Field

Summary In 2003, Apache became the operator of the Forties Field. The field has now been in operation for 33 years and much of the infield pipeline system has exceeded its original design life of 20–25 years. Apache intends to continue production in the Forties Field for, potentially, in excess of a further 20 years. With that in mind, they have identified numerous issues with respect to corrosion management of the infield pipeline system. Since late 2006, the Forties Field infield pipeline corrosion and integrity management has been carried out by IONIK Consulting/JP Kenny Caledonia Ltd. Working closely with Apache, the infield pipeline system has been reviewed; a number of issues have been assessed and quantified; and practices with respect to corrosion management, corrosion monitoring, and inspection have been implemented. This document examines the issues identified, the corrosion management strategy put in place, and the inspection actions undertaken. Examples of issues identified with respect to corrosion management systems include a requirement for a dedicated pipeline corrosion management strategy, pipeline corrosion modeling, a corrosion risk assessment of the pipeline system, a review of corrosion inhibition and pigging, and a review of key performance indicators with emphasis on pipeline management. Specific corrosion issues identified include anode depletion, preferential weld corrosion, localized corrosion, and 6 o'clock corrosion. Examples of other factors identified have been potential risks from microbial and underdeposit corrosion caused by low flow rates. This publication provides an overview of these issues and the implementation of solutions, alongside changes to items such as documentation and modification of existing procedures, risk assessment, corrosion management, and the implementation of an intelligent pigging program.