Integrity Assessment of Internally Corroded Pipelines Rehabilitated With a Kevlar-Reinforced Flexible Liner

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
M. Fahed ◽  
I. Barsoum ◽  
A. Alfantazi ◽  
M. D. Islam
Keyword(s):  
Closed Form Solution ◽  
Pressure Level ◽  
Burst Pressure ◽  
Internal Corrosion ◽  
Integrity Assessment ◽  
Corrosion Defect ◽  
Flexible Polymer ◽  
Internal Lining ◽  
Lining Technology ◽  
Corrosion Barrier

Abstract Contemporary approach of corrosion prevention is to use internal lining system to isolate the corrosive medium from the host pipe's inner surface. The liners serve to offer a longer lifecycle of pipelines, as well as a corrosion barrier against aggressive chemical agents. A recent lining technology based on a Kevlar-reinforced flexible polymer composite liner called the InField Liner (IFL) has been successfully installed in several pipelines. It has been theorized that the added inherent strength of the liner due to the Kevlar-reinforcement can give rise to an increase in burst pressure level of the corroded pipeline. The mechanical response of the IFL liner is established accurately and used to define the constitutive behavior of the IFL material in a nonlinear finite element model of liner installed in a host pipe with internal corrosion defect. The results reveal that an increase in burst pressure is achieved with the IFL liner, which is attributed to the interaction between the IFL and the internal corrosion defect. The increase in burst pressure is especially noted for rather deep and short length defects. The primary reason to the increase is the stretch of the Kevlar fabric into the defect cavity inducing a load transfer between the liner and pipe at the defect zone. A closed-form solution is developed, which can be used to assess the increase in burst of pipelines containing internal corrosion defects when rehabilitated with an IFL liner. The results of the study demonstrate that the IFL internal lining technology can be used as a corrosion barrier in steel pipelines for rehabilitation of old pipelines, as well as providing an increase in burst pressure level when the liner is installed due to its complex interaction with the internal corrosion defect.

Burst Pressure Prediction of Pipes With Internal Corrosion Defects

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
M. Fahed ◽  
I. Barsoum ◽  
A. Alfantazi ◽  
M. D. Islam
Keyword(s):  
Parametric Study ◽  
Mechanical Response ◽  
Element Model ◽  
Closed Form Expression ◽  
Burst Pressure ◽  
Form Expression ◽  
Internal Corrosion ◽  
Corrosion Defect ◽  
Internal Lining ◽  
Corrosion Defects

Abstract Corrosion in pipeline walls can lead to severe loss of material to a point which will cause complete loss of pipeline integrity. The contemporary approach of corrosion prevention is to use internal lining system to isolate the corrosive medium from the inner surface of the host pipe. The objective of this study is to assess the burst pressure of pipelines with internal corrosion defects. The mechanical response of carbon steel API X42, X52, and X70 pipe grades are empirically estimated and implemented in a finite element model. The geometry of an internal corrosion defect is defined through its depth, width, and length, and a parametric study is undertaken to investigate the influence of the corrosion defect parameters to the overall burst pressure of the pipe. Based on the results from the parametric study, the Buckingham π-theorem is used to derive an analytical closed-form expression to predict the burst pressure of internally corroded pipes, which is found to agree markedly well with the experimental results.

Finite Element Analysis of Complex Corrosion Defects

2002 ◽  
Author(s):  
Duane S. Cronin
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Burst Pressure ◽  
Uniaxial Tensile ◽  
Element Analysis ◽  
Internal Corrosion ◽  
Corrosion Defect ◽  
Elastic Plastic ◽  
Defect Assessment ◽  
Corrosion Defects

Aging gas and oil transmission pipeline infrastructure has led to the need for improved integrity assessment. Presently, external and internal corrosion defects are the leading cause of pipeline failure in Canada, and in many other countries around the world. The currently accepted defect assessment procedures have been shown to be conservative, with the degree of conservatism varying with the defect dimensions. To address this issue, a multi-level corrosion defect assessment procedure has been proposed. The assessment levels are organized in terms of increasing complexity; with three-dimensional elastic-plastic Finite Element Analysis (FEA) proposed as the highest level of assessment. This method requires the true stress-strain curve of the material, as determined from uniaxial tensile tests, and the corrosion defect geometry to assess the burst pressure of corrosion defects. The use of non-linear FEA to predict the failure pressure of real corrosion defects has been investigated using the results from 25 burst tests on pipe sections removed from service due to the presence of corrosion defects. It has been found that elastic-plastic FEA provides an accurate prediction of the burst pressure and failure location of complex-shaped corrosion defects. Although this approach requires detailed information regarding the corrosion geometry, it is appropriate for cases where an accurate burst pressure prediction is necessary.

On the effect of long corrosion defect and axial tension on the burst pressure of subsea pipelines

2021 ◽  
Vol 111 ◽  
pp. 102637
Author(s):  
Zhan-Feng Chen ◽  
Wen Wang ◽  
He Yang ◽  
Sun-Ting Yan ◽  
Zhi-Jiang Jin
Keyword(s):  
Burst Pressure ◽  
Corrosion Defect ◽  
Axial Tension ◽  
Subsea Pipelines

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.

Characterization of the Uncertainties in the Inspection Results of Ultrasonic Intelligent Pigs

2013 ◽  
Author(s):  
Mamdouh M. Salama ◽  
Bruce J. Nestleroth ◽  
Marc A. Maes ◽  
Chris Dash
Keyword(s):  
Probabilistic Models ◽  
Service Providers ◽  
Quantitative Risk Assessment ◽  
Life Extension ◽  
Internal Corrosion ◽  
Integrity Assessment ◽  
Diameter Pipe ◽  
Length Width ◽  
Pull Through

In-Line Inspections using magnetic flux leakage (MFL) and the Ultrasonic (UT) intelligent pigs are the most common tools used to assess the integrity of pipelines. But, both MFL and UT inspection results are subject to various sources of uncertainties which must be quantified and accounted for in the integrity assessment of the inspected pipeline. A series of pull-through tests (PTT) of seven MFL tools and two UT tools from five service providers was performed on a 12-inch diameter pipe containing pre-existing internal corrosion defects of various length, width, and depth, and located in a variety of circumferential and longitudinal positions. The results of these tests are used to quantify the detectability statistics and the sizing uncertainties of the different tools for future use in developing calibrated probabilistic models for reliability based inspection, quantitative risk assessment and life extension studies for pipelines. The results of the MFL tools were presented in 2012 OMAE conference and this paper presents the results of the two UT tools.

The Failure Window Method and Its Application in Pipeline Burst

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Zhanfeng Chen ◽  
Hao Ye ◽  
Sunting Yan ◽  
Xiaoli Shen ◽  
Zhijiang Jin
Keyword(s):  
Internal Pressure ◽  
Maximum Stress ◽  
Oil And Gas ◽  
Maximum Shear Stress ◽  
High Accuracy ◽  
Burst Pressure ◽  
Empirical Equations ◽  
Integrity Assessment ◽  
Wall Thinning ◽  
Window Method

Accurate prediction of the burst pressure is indispensible for the engineering design and integrity assessment of the oil and gas pipelines. A plenty of analytical and empirical equations have been proposed to predict the burst pressures of the pipelines; however, it is difficult to accurately predict the burst pressures and evaluate the accuracy of these equations. In this paper, a failure window method was presented to predict the burst pressure of the pipes. First, the security of the steel pipelines under the internal pressure can be assessed. And then the accuracy of the previous analytical and empirical equations can also be generally evaluated. Finally, the effect of the wall thinning of the pipes on the failure window was systemically investigated. The results indicate that it is extremely formidable to establish an equation to predict the burst pressure with a high accuracy and a broad application, while it is feasible to create a failure window to determine the range of the dangerous internal pressure. Calculations reveal that some predictions of the burst pressure equations like Faupel, Soderberg, Maximum stress, and Nadai (1) are overestimated to some extent; some like ASME, maximum shear stress, Turner, Klever and Zhu–Leis and Baily–Nadai (2) basically reliable; the rest like API and Nadai (3) slightly conservative. With the wall thinning of the steel pipelines, the failure window is gradually lowered and narrowed.

Electrochemical Corrosion Finite Element Analysis and Burst Pressure Prediction of Externally Corroded Underground Gas Transmission Pipelines

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Ibrahim M. Gadala ◽  
Magd Abdel Wahab ◽  
Akram Alfantazi
Keyword(s):  
Finite Element ◽  
Stress Analysis ◽  
Reaction Kinetics ◽  
Moving Boundary ◽  
Electrochemical Corrosion ◽  
Burst Pressure ◽  
Element Analysis ◽  
Corrosion Defect ◽  
Nonlinear Stress ◽  
Pipeline Wall

An integrative numerical simulation approach for pipeline integrity analysis is presented in this work, combining a corrosion model, which is the main focus of this paper, with a complementary structural nonlinear stress analysis, using the finite element method (FEM). Potential distributions in the trapped water existing beneath pipeline coating disbondments are modeled in conjunction with reaction kinetics on the corroding exposed steel surface using a moving boundary mesh. Temperature dependencies (25 °C and 50 °C) of reaction kinetics do not greatly affect final corrosion defect geometries after 3-yr simulation periods. Conversely, cathodic protection (CP) levels and pH dependencies within the near-neutral pH range (6.7–8.5) strongly govern depth profiles caused by corrosion, reaching a maximum of ∼3 mm into the pipeline wall. A 0.25 V amplification of CP potential combined with a 0.5 mm widening in disbondment opening size reduces defect penetration by almost 30%. Resulting corrosion defect geometries are used for stress examinations and burst pressure evaluations. Furthermore, nonlinear elastic–plastic stress analysis is carried out using shell elements in order to predict the burst pressure of corroded pipes. Corrosion is modeled by reducing the stiffness of a damaged element that has the dimensions of the defect. The predicted burst pressures are in good agreement with those obtained using an experimental-based formula.

Strength Criteria Versus Plastic Flow Criteria Used in Pressure Vessel Design and Analysis1

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Xian-Kui Zhu
Keyword(s):  
Plastic Flow ◽  
Pressure Vessel ◽  
Yield Criterion ◽  
Pressure Vessels ◽  
Burst Pressure ◽  
Thin Wall ◽  
Strength Criteria ◽  
Integrity Assessment ◽  
Ductile Materials ◽  
Strength Design Criteria

This paper presents a critical comparison of the traditional strength criteria and the modern plastic flow criteria used in the structural design and integrity assessment of pressure vessels. This includes (1) a brief review of the traditional strength criteria used in the ASME Boiler and Pressure Vessel (B&PV) Code, (2) a discussion of the shortcomings of the traditional strength criteria when used to predict the burst pressure of pressure vessels, (3) an analysis of challenges, technical gaps, and basic needs to improve the traditional strength criteria, (4) a comparison of strength theories and plasticity theories for ductile materials, (5) an evaluation of available plastic flow criteria and their drawbacks in prediction of burst pressure of pressure vessels, (6) a description of a newly developed multiaxial yield criterion and its application to pressure vessels, and (7) a demonstration of experimental validation of the new plastic flow criterion when used to predict the burst pressure of thin-wall pressure vessels. Finally, recommendations are made for further study to improve the traditional strength design criteria and to facilitate utilization of the modern plastic flow criteria for pressure vessel design and analysis.

Validating ILI Accuracy Using API 1163

2014 ◽  
Author(s):  
Lucinda Smart ◽  
Harvey Haines
Keyword(s):  
Burst Pressure ◽  
Metal Loss ◽  
Internal Corrosion ◽  
Know How ◽  
Pressure Calculation ◽  
Loss Data ◽  
Pipeline Segment ◽  
External Corrosion ◽  
Corrosion Pits

It is important to validate the accuracy of in-line inspection (ILI) tools to know how many excavations are needed to maintain the integrity of a pipeline segment. Performing sufficient excavations is important to ensure there are no defects left in the pipeline that have even a remote chance of failure. In some cases additional excavations may be necessary to ensure safety where in other cases no excavations may be necessary. This paper looks at using spatially recorded metal-loss data collected “in-the-ditch” to measure the accuracy of ILI tool results. Examples of spatial in-ditch data are laser scans for external corrosion and UT scans for internal corrosion. Spatially mapped metal loss, because all of the corrosion area is mapped, has the advantage of allowing more comparisons to be made for a given corrosion area and also allows the interaction among corrosion pits to be studied for examining burst pressure calculation accuracy. From our studies we find the depth error for shallow corrosion 10%–20% wt deep is often not representative of deeper corrosion in the same pipeline and the interaction criteria for ILI tools needs to be larger than the interaction criteria for in-ditch data. Examples are shown with these types of results, and by interpreting the results in conjunction with API 1163, certain ILI runs are shown that require no excavations where others may require additional excavations than suggested by normal +/−10% wt ILI data.

Evaluation of Strength Design Criteria and Plastic Flow Criteria for Pressure Vessels

2014 ◽  
Author(s):  
Xian-Kui Zhu
Keyword(s):  
Plastic Flow ◽  
Axial Flow ◽  
Pressure Vessels ◽  
Burst Pressure ◽  
Design Criteria ◽  
Strength Criteria ◽  
Integrity Assessment ◽  
Strength Design ◽  
Strength Design Criteria ◽  
Flow Criterion

The present paper evaluates the traditional strength design criteria and recently developed plastic flow criteria used in the structural design and integrity assessment for pressure vessels. This includes (1) a brief review of the traditional strength criteria used in ASME Boiler and Pressure Vessel (B&PV) Code, (2) a discussion of the shortcoming of existing strength criteria when used to predict the burst pressure of pressure vessels, (3) an analysis of challenges, technical gaps and basic needs to improve the traditional strength design criteria, (4) a comparison of strength theory and flow theory for ductile pressure vessels, (5) an evaluation of available flow criteria and their shortcoming in prediction of failure pressure of pressure vessels, (6) an introduction of newly developed multi-axial flow criterion and its application to pressure vessels, and (7) a demonstration of experimental validations of the new flow criterion when used to predict the burst pressure of pressure vessels. On this basis, several recommendations are made for further study to improve the existing strength design and integrity assessment methods of pressure vessels.

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