A Robust Approach to Pipeline Integrity Management Using Direct Assessment Based on Structural Reliability Analysis

2004 ◽  
Author(s):  
Marcus McCallum ◽  
Andrew Francis ◽  
Tim Illson ◽  
Mark McQueen ◽  
Mike Scott ◽  
...  
Keyword(s):  
Reliability Analysis ◽  
Structural Reliability ◽  
Voltage Gradient ◽  
Pipeline System ◽  
Pipe Failure ◽  
Internal Corrosion ◽  
Direct Assessment ◽  
Structural Reliability Analysis ◽  
Integrity Management ◽  
External Corrosion

Approximately 1450 km (900 miles) of a 4020-km (2500 mile) natural gas pipeline system operated by Crosstex Energy Service L.P in Texas are subject to the Texas Railroad Commission’s (TRRC) integrity management rules. Consequently, in preparation for the construction of an extensive and robust integrity management program, Crosstex commissioned Advantica to assist in the development and application of a pilot study on a 13.4 km (8.3 mile) section of a 14” pipeline. The purpose of the study, which is based on Structural Reliability Analysis (SRA), was to compare the level of integrity that could be inferred from the use of Direct Assessment (DA) techniques with the level that could be inferred from ILI results. Based on a preliminary assessment of available data, the study identified both external and internal corrosion as potential threats to integrity. SRA was used in conjunction with ‘Bayesian Updating’ to determine the probability of pipe failure due to external corrosion, taking account of results from above-ground measurements and a number of bell-hole excavations. The above-ground survey techniques utilized included Close Interval Survey (CIS) and Direct Current Voltage Gradient (DCVG). A similar approach was adopted to address the threat due to internal corrosion, but hydraulic modelling was substituted for the above-ground measurements. A third study based on SRA was used to determine the combined probability of failure due to both internal and external corrosion taking account of ILI results. The outcome of the analyses demonstrated that the level of integrity that could be inferred from the use of Crosstex’ DA methodology was similar to that which could be inferred from the use of ILI. The results were presented to the TRRC for review and approval. This paper gives a detailed description of the SRA based methodology that was employed by Crosstex and presents the results that clearly demonstrate the comparability of ILI and DA for the purpose of integrity management.

Integrity Assessment of Non-Piggable Pipeline Through Direct Assessment

2013 ◽  
Author(s):  
Jai Prakash Sah ◽  
Mohammad Tanweer Akhter
Keyword(s):  
Hydrostatic Pressure ◽  
Natural Gas ◽  
Stress Corrosion ◽  
Health Assessment ◽  
Assessment Method ◽  
Pipeline System ◽  
Internal Corrosion ◽  
Integrity Assessment ◽  
Direct Assessment ◽  
External Corrosion

Managing the integrity of pipeline system is the primary goal of every pipeline operator. To ensure the integrity of pipeline system, its health assessment is very important and critical for ensuring safety of environment, human resources and its assets. In long term, managing pipeline integrity is an investment to asset protection which ultimately results in cost saving. Typically, the health assessment to managing the integrity of pipeline system is a function of operational experience and corporate philosophy. There is no single approach that can provide the best solution for all pipeline system. Only a comprehensive, systematic and integrated integrity management program provides the means to improve the safety of pipeline systems. Such programme provides the information for an operator to effectively allocate resources for appropriate prevention, detection and mitigation activities that will result in improved safety and a reduction in the number of incidents. Presently GAIL (INDIA) LTD. is operating & maintaining approximately 10,000Kms of natural gas/RLNG/LPG pipeline and HVJ Pipeline is the largest pipeline network of India which transports more than 50% of total gas being consumed in this country. HVJ pipeline system consists of more than 4500 Kms of pipeline having diameter range from 04” to 48”, which consist of piggable as well as non-piggable pipeline. Though, lengthwise non-piggable pipeline is very less but their importance cannot be ignored in to the totality because of their critical nature. Typically, pipeline with small length & connected to dispatch terminal are non-piggable and these pipelines are used to feed the gas to the consumer. Today pipeline industries are having three different types of inspection techniques available for inspection of the pipeline. 1. Inline inspection 2. Hydrostatic pressure testing 3. Direct assessment (DA) Inline inspection is possible only for piggable pipeline i.e. pipeline with facilities of pig launching & receiving and hydrostatic pressure testing is not possible for the pipeline under continuous operation. Thus we are left with direct assessment method to assess health of the non-piggable pipelines. Basically, direct assessment is a structured multi-step evaluation method to examine and identify the potential problem areas relating to internal corrosion, external corrosion, and stress corrosion cracking using ICDA (Internal Corrosion Direct Assessment), ECDA (External Corrosion Direct Assessment) and SCCDA (Stress Corrosion Direct Assessment). All the above DA is four steps iterative method & consist of following steps; a. Pre assessment b. Indirect assessment c. Direct assessment d. Post assessment Considering the importance of non-piggable pipeline, integrity assessment of following non piggable pipeline has done through direct assessment method. 1. 30 inch dia pipeline of length 0.6 km and handling 18.4 MMSCMD of natural gas 2. 18 inch dia pipeline of length 3.65 km and handling 4.0 MMSCMD of natural gas 3. 12 inch dia pipeline of length 2.08 km and handling 3.4 MMSCMD of natural gas In addition to ICDA, ECDA & SCCDA, Long Range Ultrasonic Thickness (LRUT-a guided wave technology) has also been carried out to detect the metal loss at excavated locations observed by ICDA & ECDA. Direct assessment survey for above pipelines has been conducted and based on the survey; high consequence areas have been identified. All the high consequence area has been excavated and inspected. No appreciable corrosion and thickness loss have observed at any area. However, pipeline segments have been identified which are most vulnerable and may have corrosion in future.

An External Corrosion Direct Assessment Module for a Pipeline Integrity Management System

2006 ◽  
Author(s):  
Menno T. van Os ◽  
Piet van Mastrigt ◽  
Andrew Francis
Keyword(s):  
Management System ◽  
Structural Reliability ◽  
Individual Performance ◽  
Corrosion Activity ◽  
Time Saving ◽  
Survey Techniques ◽  
Direct Assessment ◽  
Integrity Management ◽  
External Corrosion ◽  
The Individual

A significant part of the high pressure gas transport system of Gasunie cannot be examined by in-line inspection techniques. To ensure safe operation of these pipelines, an External Corrosion Direct Assessment (ECDA) module for PIMSLIDER (a pipeline integrity management system) is currently under development. The functional specifications of this module are based on NACE RP0502-2002, a recommended practice for ECDA. In addition to this, a new probabilistic methodology has been adopted, to take account for uncertainties associated with ECDA and to quantify the contributions from aboveground surveys and excavations to the integrity of a pipeline. This methodology, which is based on Structural Reliability Analysis (SRA) and Bayesian updating techniques, is presented in more detail in paper IPC2006-10092 of this conference. The DA module of PIMSLIDER enables computerized storage, retrieval and processing of all appropriate pipeline data and therefore guarantees highly accurate, reproducible and time saving integrity analyses of the Gasunie grid. Another important function of this system is the ability to use the complete database of all pipelines to pre-assess the integrity of a particular pipeline. This automated retrieval of data from pipelines with similar characteristics and/or environmental conditions results in a substantial increase of accessible data and enables Gasunie to improve the reliability of applied statistics throughout the process. As a consequence, the overall cost of inspections and excavations can be greatly reduced. In the Pre-Assessment phase, the DA module assists the integrity manager in gathering and analyzing data necessary to determine the current condition of a pipeline. After collection and visualization of the available data, the user can identify suitable ECDA regions. Furthermore, the gathered data are used to construct prior distributions of parameters relevant to the SRA model, such as the number and size of corrosion defects and pipeline-related parameters. In the Indirect Inspections step, the DA module allows the user to store and analyze the data from aboveground surveys, in order to identify and define the severity of coating faults and areas at which corrosion activity may occur. The probabilistic methodology accounts for the individual performance of each applied survey technique in terms of missed defects and false indications, in general a major source of uncertainty in ECDA. In the Direct Examinations phase, excavations are carried out to collect data to assess possible corrosion activity. Subsequently, the ECDA module uses this information to update, among other things, the parameters concerning the performance of survey techniques, the number of defects and the corrosion rate. As a result, updated failure frequencies are calculated for each ECDA-region (after each excavation if required), which are then used by the DA module to advise the integrity manager if additional mitigating activities are necessary, or by defining a reassessment interval.

Using Ultrasound to Gauge Pipeline Internal Corrosion With Coating for ICDA

2006 ◽  
Author(s):  
Qingshan Feng ◽  
Zupei Yang
Keyword(s):  
Test Time ◽  
Thickness Gauge ◽  
Internal Corrosion ◽  
Direct Assessment ◽  
Metal Thickness ◽  
Integrity Management ◽  
External Corrosion ◽  
Key Steps ◽  
Thickness Measurements ◽  
Non Destructive

Internal corrosion direct assessment (ICDA) for pipeline enhances the abilities to assess internal corrosion in pipeline and is based on the principle that corrosion is most likely where water first accumulates. ICDA employs the same four-step process as all other direct assessment methods. The important step is direct examinations: the pipeline is excavated and examined at locations prioritized to have the highest likelihood of corrosion. A variety of inservice non-destructive examination processes are available to pipeline operators to inspect for internal corrosion. Manual assessment of internal corrosion is considered more challenging than normal external corrosion assessments since the corrosion feature is not visible and must be interpreted by the ultrasonic response, but in the past ultrasonic test need always remove the coating and then measure on the surface of bare pipe, which brings the measurement point of the pipe body more risk because of weaker quality of patch coating. Recently, advances in the design of ultrasonic corrosion thickness gauges utilizing dual element transducers have made it possible to take accurate metal thickness measurements while coatings need not to be removed. This feature is often referred to as echo-to-echo thickness measurements. Using the ultrasound thickness gauge to measure pipeline internal corrosion while external coatings need not to be removed can keep the integrity of coating, make pipeline operating and monitoring more economical and improve inspection activities to estimate corrosion in pipelines for ICDA. Gauge equipment requirement, Measurement procedures and Accuracy were validated in laboratory. How to arrange the gauge locations, interval test time and data treatment and analysis also are the key steps of ICDA for integrity management.

KOC’s Integrity Management Program for Non-Piggable Pipelines: A Case Study

2010 ◽  
Author(s):  
Ashish Khera ◽  
Abdul Wahab Al-Mithin ◽  
James E. Marr ◽  
Shabbir T. Safri ◽  
Saleh Al-Sulaiman
Keyword(s):  
Risk Analysis ◽  
Systematic Evaluation ◽  
Pipeline System ◽  
Pipeline Network ◽  
Integrity Assessment ◽  
Direct Assessment ◽  
Integrity Management ◽  
Management Techniques ◽  
External Corrosion

More than half of the world’s oil and gas pipelines are classified as non-piggable. Pipeline operators are becoming aware there are increased business and legislative pressures to ensure that appropriate integrity management techniques are developed, implemented and monitored for the safe and reliable operation of their pipeline asset. The Kuwait Oil Company (KOC) has an ongoing “Total Pipeline Integrity Management System (TPIMS)” program encompassing their entire pipeline network. In the development of this program it became apparent that not all existing integrity management techniques could be utilized or applied to each pipeline within the system. KOC, upon the completion of a risk assessment analysis, simply separated the pipelines into two categories consisting of piggable and non-piggable lines. The risk analysis indicated KOC’s pipeline network contains more than 200 non-piggable pipelines, representing more than 60% of their entire pipeline system. These non-piggable pipelines were to be assessed by utilizing External Corrosion Direct Assessment (ECDA) for the threat of external corrosion. Following the risk analysis, a baseline external corrosion integrity assessment was completed for each pipeline. The four-step, iterative External Corrosion Direct Assessment (ECDA) process requires the integration of data from available line histories, multiple indirect field surveys, direct examination and the subsequent post assessment of the documented results. This case study will describe the available correlation results following the four steps of the DA process for specific non-piggable lines. The results of the DA program will assist KOC in the systematic evaluation of each individual non-piggable pipeline within their system.

Complete Integrity Assessment of a Non-Piggable Multi-Diameter Cross Country Pipeline in a Network Shared by Multiple Electrically Continuous Parallel Pipelines

2021 ◽  
Author(s):  
Amit Mishra ◽  
Saurabh Vats ◽  
Carlos A. Palacios T. ◽  
Himanshu Joshi ◽  
Ishan Khurana
Keyword(s):  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Accurate Data ◽  
Internal Corrosion ◽  
Integrity Assessment ◽  
Direct Assessment ◽  
Integrity Management ◽  
The Subject ◽  
Cross Country ◽  
External Corrosion

Abstract A complete Pipeline Integrity Management System is the need of the hour. Apart from keeping in mind the enormous environment concerns in this rapidly dwindling era of hydrocarbons, a successful pipeline owner always strives to profitably operate their precious assets. To operate a pipeline efficiently, a plan is required to maintain its health and increase the remaining life. Various types of pipelines pose various problems which the owner needs to resolve systematically and with a well-ordered approach. A similar challenge was faced by a refinery in India. The refinery has a design capacity to process 15 MMTPA of crude per annum. The imports and exports are carried out through the local Port Trust which is one of the deepest inner harbour on the west coast. Multiple pipelines run to and from the refinery and the port trust (approximate distance — 10 km). The subject pipeline in question currently transports Mixed Xylene (MX) from refinery to port. The pipeline has a diversified operating history with various other products being transferred in the past. However, the pipeline is used very scarcely. The problem posed by the subject pipeline was similar to what many other cross-country pipelines face — the pipeline was not piggable. Five (5) other parallel pipelines share the same right-of-way, all of which are piggable and have their integrity assessment performed via Intelligent Pigging on a planned basis. There was also a concern about collecting the most accurate data since the pipeline had not undergone an integrity assessment since its commissioning in 2001. However, it was yearly pressure tested to ensure integrity of the pipeline. Parallel pipelines pose a bigger challenge for obtaining accurate data for a particular pipeline amongst them. Keeping all this in mind, a complete integrity management was planned for the MX pipeline and thus concluded on performing a turnkey Direct Assessment (DA) program. The DA program included Internal Corrosion Direct Assessment (ICDA) to assess and manage the threats of internal corrosion, External Corrosion Direct Assessment (ECDA) for external corrosion threats and Stress Corrosion Cracking Direct Assessment (SCCDA) for determining susceptibility towards the threat of stress corrosion cracking on the pipeline. Utilization of latest technologies helped in adapting and overcoming the multiple problems faced by legacy technologies especially in difficult ROW conditions and complex pipeline networks, such as the MX pipeline. This paper provides an insight into how an operator can combine latest available technologies and deploy it in unison with the complete integrity management plan.

Insights in the Application of Structural Reliability Analysis (SRA) for Challenging Pipeline Lateral Buckling Design

2014 ◽  
Author(s):  
Elena Gerginov ◽  
Andrew Rathbone ◽  
Chris Sullivan ◽  
Terry Griffiths
Keyword(s):  
Reliability Analysis ◽  
Structural Reliability ◽  
Complex Analysis ◽  
Real Life ◽  
Pipeline System ◽  
Lateral Buckling ◽  
Considerable Uncertainty ◽  
Structural Reliability Analysis ◽  
Levels Of Detail ◽  
Pipeline Failure

Lateral buckling of pipelines is influenced by, and sensitive to, a complex combination of factors associated with considerable uncertainty. Key elements such as pipe to soil friction, vertical and horizontal imperfections can vary significantly not only along sections of the same pipeline, but at the same location over time. These factors carry a probabilistic likelihood of occurrence that results in a probabilistic distribution of buckle formation forces and locations, as well as post buckle loads, as described by Rathbone et. al. (2008). To effectively capture all possible combinations of inputs and results, and thus gain a full understanding of potential buckle behaviour and interaction, would require many individual finite element analyses to be undertaken, which is not viable. The paper describes new insights into challenging pipeline lateral buckling design gained through use of a highly adaptable Structural Reliability Analysis (SRA) method. It discusses the difficulties in defining pipeline and seabed complexities while still retaining adequate detail to fully describe the pipeline system. A range of realistic lateral buckling design scenarios will be discussed, illustrating how to reduce existing limitations in probabilistic design through the use of the SRA method. The method is flexible enough to enable varying levels of detail to be modelled, from simple idealised checks of buckling susceptibility, which are commonly performed during the early phases of design, to the more complex analysis of pipeline failure, performed during detailed design. The paper will demonstrate the ability for the method to capture complex real life scenarios such as the effect of a bi-modal distribution in observed pipeline embedment, as well as the influence of covariance between frictions, on the probability of buckling and resulting strains.

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