bluuebunny/crossref_metadata_2025_split huggingface dataset:
Under Pressure Operations on Dense Phase CO2 Pipelines: Issues for the Operator
Authors: Barnett Julian , Wilkinson Richard , Kirkham Alan , Armstrong Keith 
Published: December 2014

National Grid, in the United Kingdom (UK), has extensive experience in the management and execution of under pressure operations on its natural gas pipelines. These under pressure operations include welding, ‘hot tap’ and ‘stopple’ operations, and the installation of sleeve repairs.
National Grid Carbon is pursuing plans to develop a pipeline network in the Humber and North Yorkshire areas of the UK to transport dense phase Carbon Dioxide (CO2) from major industrial emitters in the area to saline aquifers off the Yorkshire coast. One of the issues that needed to be resolved is the requirement to modify and/or repair dense phase CO2 pipeline system.
Existing under pressure experience and procedures for natural gas systems have been proven to be applicable for gaseous phase CO2 pipelines; however, dense phase CO2 pipeline systems require further consideration due to their higher pressures and different phase behaviour. Consequently, there is a need to develop procedures and define requirements for dense phase CO2 pipelines. This development required an experimental programme of under pressure welding trials using a flow loop to simulate real dense phase CO2 pipeline operating conditions.
This paper describes the experiments which involved:
• Heat decay trials which demonstrated that the practical limitation for under pressure welding on dense phase CO2 systems will be maintaining a sufficient level of heat to achieve the cooling time from 250 °C to 150 °C (T250–150) above the generally accepted 40 second limit.
• A successful welding qualification trial with a welded full encirclement split sleeve arrangement.
The work found that for the same pipe wall thickness, flow velocity and pressure, dense phase CO2 has the fastest cooling time when compared with gaseous phase CO2 and natural gas.
The major practical conclusion of the study is that for dense phase CO2 pipelines with a wall thickness of 19.0 mm or above, safe and practical under pressure welding is possible in accordance with the existing National Grid specification (i.e. T/SP/P/9) up to a flow velocity of around 0.9 m/s.
The paper also outlines the work conducted into the use of the Manual Phased Array (MPA) inspection technique on under pressure welding applications.
Finally, the paper identifies and considers the additional development work needed to ensure that a comprehensive suite of under pressure operations and procedures are available for the pipeline operator.
Development of Distributed Fiber Optic Sensors for Offshore Pipeline Leak Detection
Authors: Kulkarni Mohan G. , Shafrova Svetlana , Rinehart Adam J. 
Published: December 2014

Distributed fiber optic (FO) sensors have been used for onshore pipeline monitoring and leak detection applications. The use of FO sensors for offshore pipeline leak detection is still very new and requires developments to adapt the technology to such applications. This includes progressing the understanding of FO sensor performance for offshore leak detection, the need to develop requirements and procedures for offshore installation of pipeline and FO cable, and the need to design and develop sensor technology to cover long underwater pipelines.
ExxonMobil Upstream Research Company (EMURC) has undertaken an extensive offshore pipeline leak detection research and development program. One of the key goals of the program is to develop FO sensor technology for offshore use. This paper summarizes the key findings from several technology development studies.
Internal Corrosion Management of Crude Pipelines
Authors: Prakash S. Surya , Al-Shamari Abdul Razzaq , Safri Shabbir , Jaragh Amer Abdullah 
Published: December 2014

Kuwait currently produces about 3 million barrels of crude oil per day and has a large pipeline network system for handling its oil and associated products (condensate, low pressure and high pressure gas, as well as produced and effluent waters). The total length of the pipeline network is about 4790 Km consisting of API 5L Grade-B carbon steel ranging in diameter from 100 mm to 1830 mm. The Kuwait Oil Company (KOC) is responsible for the corrosion and integrity management of the pipeline network system which involves: Internal Corrosion Monitoring to assess the internal corrosion status of the pipelines including the occurrence of microbial influenced corrosion; external corrosion protection with the help of coatings and cathodic protection, and periodic intelligent and cleaning pigging operations for internal corrosion assessment and cleaning.
The present paper focuses on the internal corrosion management of the export crude segment of the pipeline network system which is very important for a healthy economy. The internal corrosion monitoring protocol includes, online corrosion monitoring, cleaning pigging and intelligent pigging. Bacteria counts’ trending is also included as part of protocol. Some anomalies between the results obtained from corrosion trends, cleaning pigging results and intelligent pigging are highlighted and a sound engineering explanation is attempted to explain these apparent anomalies.
Development of Pipeline Regulations in the Norwegian Petroleum Industry and Examples of Follow Up
Authors: Sundby Trond , Anfinsen Kjell Arild 
Published: December 2014

The Petroleum Safety Authority Norway (PSA) is an independent government regulator responsible for safety, emergency preparedness and the working environment in the Norwegian petroleum industry. Norway’s regulations for petroleum operations offshore and on land are risk-based, and give great emphasis to principles for reducing health, safety and environmental (HSE) risk. They have been developed over more than 40 years, changing from detailed prescriptive regulations in the early days to the present requirements, which are largely formulated in performance-based (functional) terms. They specify requirements for the various aspects, characteristics or qualities which a product, process or service must possess. These requirements express the performance or result which the product, process or service is to yield — in other words, what the government wishes to achieve through them. The Norwegian petroleum industry embraces 15 500 km of pipelines, about half of which are large trunk lines for gas transport.
This paper will summarise the development of the regulations and give examples from the pipeline regulations and the way the PSA follows up the industry today. We will also present statistical data for incidents involving pipelines and risers over the past decade, and highlight areas where we think the industry has a potential for improvement.
Computational Model Based Method for Defining an Improved Criterion for Dent Fatigue Assessment
Authors: Lecchi Maxime , Hertz Clemens Stéphane , Notarianni Philippe , Polo Magali 
Published: December 2014

In the field of defects assessment, mechanical damage severity analysis is an issue of interest for many pipelines operators [1]. Indeed, common literature fatigue criteria [2] [3] [4] [5] often give underestimated dent lifetimes compared with experimental results. This causes repairs which could be avoided, therefore more predictive criteria would generate a significant maintenance costs saving.
This paper presents an improved method developed at CRIGEN (GDF SUEZ research center dedicated to gas and new energies) to assess dent defects subject to fatigue loadings. A realistic computational model based on the finite elements method has thus been developed. An analytic formulation of the stress concentration factor (SCF) giving more realistic results has then been set, allowing a classical fatigue analysis with S-N curves to be performed.
A specific software plug-in has been developed to automate the creation of the finite elements models. In these models dents are created at a realistic pressure with regard to the pipe characteristics. Then damaged pipe is exposed to a pressure variation to determine the maximal SCF.
After validation based on tests results, a simulated experimental design which covers diameters from 8 inches to 36 inches and steels from A37 to X70 has been set. Different indentation tools and different strokes have also been defined, resulting in 1080 simulations.
As a conclusion, this paper shows the method leading to the analytic formulation of the SCF allowing the fatigue assessment.
Comparison Between Standard and Modified Back-Slotted DWTT Specimens
Authors: Shim Do-Jun , Uddin Mohammed , Wilkowski Gery , Duan Da-Ming , Ferguson James 
Published: December 2014

The effect of fracture speed on the ductile fracture resistance of line-pipe steels can have an important effect in the basic understanding of the toughness requirements for crack arrest. Recently, the authors have extended the drop-weight tear test (DWTT) work and developed a modified back-slot (MBS) DWTT specimen to obtain higher fracture speeds. The initial experimental observations demonstrated that this type of specimen can be used to obtain higher fracture speeds. Furthermore, the experimental results clearly showed the effect of fracture speed on the ductile fracture resistance.
In this paper, an in-depth study was carried out to further investigate why higher fracture speeds are obtained in the MBS-DWTT specimens. For this purpose, quasi-static and dynamic/impact DWTT experiments were conducted for both standard DWTT and MBS-DWTT specimens. In addition, finite element analyses using cohesive zone model were carried out to investigate the fracture behavior in these tests. In summary, the higher fracture speeds in the MBS-DWTT come from two major factors. First, as demonstrated by the quasi-static test results, the natural unloading characteristics of the MBS-DWTT specimen (even under pure displacement-controlled loading) leads to higher fracture speeds. Second, the steep unloading curve of the MBS-DWTT specimen produces a higher possibility of an unstable ductile fracture even during the impact event, which will result in higher fracture speeds.
Systematic Approach to Measuring ILI Tool Performance
Authors: Keane Sean , Cheng Karmun , Korol Kaitlyn 
Published: December 2014

In-line inspection (ILI) tools play an important role within integrity management and substantial investment is made to continuously advance performance of the existing technologies and, where necessary, to develop new technologies. Performance measurement is typically focused for the purpose of understanding the measured performance in relation to the ILI vendor specification and for the determination of residual uncertainty regarding pipeline integrity. These performance measures may not provide the necessary insight into what type of investment into a technology is necessary to further reduce residual uncertainty regarding pipeline integrity, and beyond that, what investment, as an operator, results in an effective and efficient reduction in uncertainty.
The paper proposes a reliability based approach for investigating uncertainty associated with ultrasonic crack ILI technology for the purpose of identifying efficient investment into the technology that results in an effective and measurable improvement. Typical performance measures and novel performance measurement methods are presented and reviewed with respect to what information they can provide to assist in investment decisions. Finally, general observations are made regarding Enbridge’s experience using ultrasonic crack ILI technology and areas currently being investigated.
Development of X80M Line Pipe Steel for Spiral Welded Pipes With Low Temperature Toughness and Excellent Weldability
Authors: Sanchez Nuria , Güngör Özlem E. , Liebeherr Martin , Ilić Nenad 
Published: December 2014

The unique combination of high strength and low temperature toughness on heavy wall thickness coils allows higher operating pressures in large diameter spiral welded pipes and could represent a 10% reduction in life cycle cost on long distance gas pipe lines. One of the current processing routes for these high thickness grades is the thermo-mechanical controlled processing (TMCP) route, which critically depends on the austenite conditioning during hot forming at specific temperature in relation to the aimed metallurgical mechanisms (recrystallization, strain accumulation, phase transformation). Detailed mechanical and microstructural characterization on selected coils and pipes corresponding to the X80M grade in 24 mm thickness reveals that effective grain size and distribution together with the through thickness gradient are key parameters to control in order to ensure the adequate toughness of the material. Studies on the softening behavior revealed that the grain coarsening in the mid-thickness is related to a decrease of strain accumulation during hot rolling. It was also observed a toughness detrimental effect with the increment of the volume fraction of M/A (martensite/retained austenite) in the middle thickness of the coils, related to the cooling practice. Finally, submerged arc weldability for spiral welded pipe manufacturing was evaluated on coil skelp in 24 mm thickness. The investigations revealed the suitability of the material for spiral welded pipe production, preserving the tensile properties and maintaining acceptable toughness values in the heat-affected zone.
The present study revealed that the adequate chemical alloying selection and processing control provide enhanced low temperature toughness on pipes with excellent weldability formed from hot rolled coils X80 grade in 24 mm thickness produced at ArcelorMittal Bremen.
Measurement of Mechanical Properties on Line Pipe: Comparison of Different Methodologies
Authors: Cooreman Steven , Van Hoecke Dennis , Liebeherr Martin , Thibaux Philippe , Enderlin Mary Yamaguti 
Published: December 2014

Line pipe manufacturers always have to verify the mechanical properties on pipe to make sure that the pipe meets the requirements specified by the standard and/or customer. This involves measurement of mechanical properties along the hoop direction. The most accurate way to do so is by performing a ring expansion test, which, however, requires dedicated tools. The two other methodologies consist of standard tensile tests on either non-flattened round bar samples or so called ‘flattened tensile samples’. Round bar samples have the disadvantage that only part of the pipe’s wall thickness is considered. Furthermore they can only be used in case of larger OD/t ratios. Tests on flattened samples, on the other hand, require a flattening operation, which induces additional plastic deformation. However, this flattening operation is not standardized. Moreover, it was observed that the mechanical properties — especially the yield strength — resulting from tensile tests on flattened samples largely depend on test parameters such as residual deflection, extensometer position, flattening procedure, etc. Most manufacturers prefer to test flattened samples, because sample preparation is straightforward and cheap. Moreover it only requires a standard tensile bench.
An extensive FEA (Finite Element Analysis) study was launched to investigate the influence of those parameters on the measured yield strength. The applied FEA methodology consists of three steps. First the complete pipe forming process is modeled (in a simplified way). Next a pipe sample is flattened. Finally a tensile sample is cut from the flattened pipe sample and loaded in tension. The mechanical material behaviour is described by a combined kinematic-isotropic hardening model, which allows taking into account the Bauschinger effect. The results are also compared to simulations of ring expansion tests and tests on round bar samples.
Next a dedicated experimental test campaign was performed to verify the results of FEA. Results of ring expansion tests are compared to results obtained on round bar samples and flattened tensile samples.
The results of this study have shown that the applied methodology significantly affects the measured yield strength. Moreover tests on insufficiently flattened samples could considerably underestimate the actual yield strength on pipe. Finally some guidelines are provided to improve the reproducibility of the measured yield strength when using flattened samples.
Performance Monitoring and Modeling of Small Diameter MDPE Natural Gas Pipelines Subject to Ground Movement
Authors: Dinovitzer Aaron , Fredj Abdelfettah , Weerasekara Lalinda , Rahman Mujib , Wijewickreme Dharma 
Published: December 2014

Considering the need to undertake pipeline replacement in a cost-effective manner while ensuring the public safety interest, evaluating the performance of pipelines subject to soil loading from landslides is a key concern in some of the natural gas distribution systems operated by FortisBC Inc. As it is typically uneconomical and impractical to relieve stresses in distribution pipe systems by excavating or instrumenting the pipelines to measure the highly localized strains, undertaking numerical and/or analytical modeling combined with experimentation is a key aspect in attempting to relate the measured ground movement to performance of pipe. For this purpose, capturing the fundamental soil-pipe interaction in small-diameter extensible plastic pipes and undertaking field monitoring to validate the numerical model are critically important. With this background, this paper presents field measurement and numerical modeling undertaken to model the performance of 115 mm diameter medium density polyethylene (MDPE) pipes buried in West Quesnel, BC, Canada. Using field survey data, the active landslides occurring perpendicular to the pipe axis at these two sites have been periodically characterized since 2000/2001.
Materials removed from the pipe system were tested to characterize the pipeline material behavior and limit strains. The data derived from these tests along with a range of soil behaviors are used to support pipe-soil interaction numerical simulation and thus characterize the strains accumulated in the pipeline in service. This paper discusses the limitations, challenges and recommendations for numerical modeling of soil-pipe interaction in small-diameter plastic pipes.
Qualification of a Combined Ultrasonic Inspection Tool for Detection and Sizing of Circumferential Weld Cracks in Offshore Pipelines
Authors: Willems Herbert , Bjørgen Hans Petter , Kristiansen Thor-Ståle , Wieme Guus 
Published: December 2014

The target of inline crack inspection is normally related to the detection of axial cracks (weld cracks, SCC etc.) as axial cracks are usually expected under typical loading conditions in pressurized pipe. Ultrasonic crack inspection tools for this type of cracks have been available for over 20 years and have become a standard application in the ILI business. However, under certain conditions circumferential cracking may occur and the inspection technique needs to be modified accordingly. Especially under offshore conditions with limited pipeline accessibility not only the early detection of crack-like defects is required but also a precise depth sizing is important in order to minimize the risk of crack-related pipeline failure. In order to ensure a high probability of detection together with state-of-the-art depth sizing, a 10″ inline inspection tool was developed for the detection of circumferentially orientated weld cracks. The tool combines the advantages of the pulse-echo technique on the detection side with the excellent capabilities of the TOFD (time-of-flight-diffraction) technique for accurate sizing. Both techniques are implemented into a tethered tool where the pulse-echo unit serves for fast screening while the relatively slow TOFD-unit is used for sizing of any detected crack-like features.
In order to qualify the new tool for a special offshore application (inspection of circumferential cracking at welded anode pads) extensive testing was performed using a 10″ test pipeline prepared by Statoil. The test line contained 64 artificial weld defects for reference purposes as well as an unknown number of fatigue cracks in the weld area which were generated by fatigue testing of the corresponding pipes. The tests were full blind tests with no advance knowledge on locations and sizes of the cracks. The sizes of the fatigue cracks (length, depth) were determined by destructive examinations carried out after inline testing. The subsequent comparison of the destructive results with the non-destructive results showed that the specification of the tool with regard to detection and sizing was fully met. In the paper, the inspection concept and the setup of the new tool are described, and the results of the qualification tests are presented.
Considerations on the Use of the Pneumatic Hammer for HDD Pullback Assistance
Authors: Zhou Honggang , Liu Ming , Wang Yong-Yi , D’Eletto Daniel 
Published: December 2014

Horizontal directional drilling (HDD) is a trenchless technique which has been frequently used to install underground pipelines due to its minimal impact on surrounding areas. In some circumstances, pneumatic hammers (or pipe rammers) are needed to assist HDD pull-back. The repeated impacts from the hammer can free a stuck pipeline during HDD pull back and facilitate the HDD installation. However, the operation of the hammer may plastically deform the pipe and/or induce fatigue flaw growth in girth welds which can negatively affect the integrity of the installed pipeline.
Compared with the relatively large number of studies and guidelines on HDD, there are few studies on the application of the pneumatic hammer for the pull-back assistance. This paper describes the key considerations for using the pneumatic hammer in the HDD pull-back. The topic covered in the paper includes: (1) identification of key issues for integrity assessment; (2) realistic estimation of impact loads; (3) assessment of potential integrity threats; and (4) operation monitoring and documentation.
Development of Selective Seam Weld Corrosion Test Method
Authors: Beavers J. A. , Brossia C. S. , Denzine R. A. 
Published: December 2014

Selective seam weld corrosion (SSWC) of electric resistance welded (ERW) pipelines has been identified as a potential risk to pipeline safety. Due to recent pipeline failures, where seam weld defects may have played a significant role, the National Transportation Safety Board called upon the Pipeline and Hazardous Materials Safety Administration (PHMSA) to conduct a comprehensive study to identify actions that can be used by operators to eliminate catastrophic longitudinal seam failures in pipelines. Battelle contracted Kiefner and Associates, Inc. and Det Norse Veritas (U.S.A.) Inc. (DNV GL) with the objective to assist PHMSA in addressing this issue.
The objective of one of the tasks performed by DNV GL was to develop a reliable, rapid, non-destructive, field-deployable test method that can quantify SSWC susceptibility on operating pipelines containing ERW seams. For this effort, two different, field deployable, non-destructive methods were evaluated in laboratory testing. The methods were validated using a standard destructive test for assessing SSWC susceptibility. One method was based on measurement of the local potential difference between the seam weld and the adjacent base metal while the second was based on differences in the corrosion kinetics between the seam weld and the base metal. The method that is based on corrosion kinetics was found to be most effective in identifying SSWC susceptible pipe steels. It utilizes a barnacle cell to conduct linear polarization resistance measurements on small, selected areas of the pipe (e.g., the weldment or base metal). Additional laboratory as well as field-testing is planned to further validate the test method.