bluuebunny/crossref_metadata_2025_split huggingface dataset:
Building a Risk Based Decision Support System for Midstream Shale Gas Assets
Authors: Murray Jake , Landry Matt 
Published: December 2014

In order to support its goals of zero incidents through risk-based asset management, Access Midstream (Access) requires a solution for providing decision support by modeling integrity threats that indicate potential safety and environmental incidents on all of its pipeline assets. The objective is to tailor existing pipeline risk methods to properly account for the unique conditions inherent to midstream gathering assets while still being flexible enough to account for traditional gas transmission and liquids transportation lines.
Access has created a unique risk-based spatial decision support system (RB-SDSS), customized to the needs of a gas gathering company that also owns and operates incidental gas transmission and hazardous liquids pipelines. Access’ business needs call for a comprehensive solution that includes a risk model that can handle a diverse asset base. Most of the company’s pipelines are unregulated, but risk-based management and decision-making are still desired for regulated and non-regulated pipelines alike. Access has designed a decision support system that automatically retrieves and integrates data, estimates risk with directly and indirectly related inputs in its algorithm, and disseminates the data to business users across the enterprise. The processing model is calibrated for risk assessment and is capable of distinguishing between high and low risk lines. It is able to generate results that can be understood and upon which appropriate action can be taken. These results are refreshed monthly as new assets are constructed or purchased and existing asset attributes are updated. Access’ decision support system is repeatable and scalable owing to maximum use of automated processes.
The focus of this paper is to outline Access’ approach to building a risk assessment solution for its pipeline assets. Each component of the RB-SDSS is reviewed: (1) Data Integration, (2) Risk Modeling, and (3) Organizational Utilization. This includes strategies for assessing traditional pipeline threats, geospatial techniques used to infer data, how to assess data quality and completeness, challenges, lesson’s learned, and future improvements.
Evaluation of Design Premises and Uncertainties on the Thermo-Mechanical Behavior of a Subsea Pipeline
Authors: Antunes Bruno Reis , Solano Rafael Familiar , Hansen Alexandre 
Published: December 2014

Buckle formation process is a key subject for the design of subsea pipelines laid on the seabed and operating under high pressure and high temperature (HP/HT) conditions. When the controlled lateral buckling methodology is adopted triggers are placed along pipeline route in order to increase the buckle formation probability in specific locations, sharing pipeline expansion between these sites and reducing the level of stress and strain in each buckle.
Despite of its importance, buckle formation process is influenced by several parameters such as the seabed bathymetry, engineered triggers, lateral out-of-straightness (OOS) and pipe-soil interaction. While the first two items above can be defined with reasonable accuracy at previous stages of design, lateral OOS will only be known with tolerable confidence after pipeline installation. The level of uncertainty related to pipe-soil interaction is also considerable since pipeline embedment and friction factors are estimated using equations that include empirical correlations and field collected data. In addition these parameters are influenced by the installation process. Due to these uncertainties, conservative premises are usually assumed in order to obtain a robust pipeline thermo-mechanical design.
After pipeline installation and/or start of operation an investigation can be performed in order to confirm the assumptions considered in the design. This paper presents a comparison of premises adopted during design stage of a pipeline based on the controlled lateral buckling methodology and the feedback obtained with the post-lay survey performed. After a brief introduction, pipeline embedment, global buckling at crossings, lateral OOS and sleepers’ height are some of the subjects addressed. Finally, conclusions and recommendations are presented in order to support future similar projects.
Development of a Probabilistic Pipeline Risk Assessment Software for Mexico’s Oil State Company
Authors: Solis Roberto Ramirez , Simon Arturo Godoy , Gonzalez Jose Luis Martinez , Muhlbauer W. Kent , Lugo Angel Alva 
Published: December 2014

Pipeline risk assessment has been a major concern for Mexico’s Oil Sate Company (PEMEX) for the last couple of decades. During this period of time, isolated efforts from the different subsidiary bodies (upstream, midstream, and downstream) have been made regarding this matter, including the implementation of powerful software tools. However, due to several factors, none of these has provided an optimum solution for the company until now as they do not serve specific needs from PEMEX according to the country’s social and geographical environments. Besides that, a different software tool has been used by each subsidiary body, generating variations in practice and dissimilar criteria when assessing risk.
A project sponsored by the Ministry of Energy in Mexico and the National Council of Science and Technology seeks to address these issues by developing a unique and customized software solution for pipeline risk assessment in PEMEX. This paper presents the progress made so far regarding the development of this tool.
An Updated Fracture Resistance Dataset of Pipeline Ductile Fracture Propagation Based on High Speed DWTT Tests
Authors: Duan Da-Ming , Ferguson James , Zhou Joe , Uddin Mohammed , Shim Do-Jun 
Published: December 2014

One of the major research topics in the area of gas pipeline fracture control is the suitability of using Charpy energy for ductile fracture control for modern and/or high strength line pipes. A common understanding is that, for pipe body crack self-arresting, the deviation of the actual required Charpy energy from those predicted using the traditional procedure of Battelle Two-Curve Method (TCM) is getting larger with higher strength pipes. DWTT is being paid more attention to because of its larger and full thickness specimen that can better capture the fracture process than a Charpy specimen does. Previous work at TransCanada indicated that various fracture speeds can be achieved in DWTT specimens and it is the steady-state fracture speed that is representative to the actual fracture propagation in a gas pipeline. It has also been found that the steady-state fracture toughness, in terms of either fracture energy or CTOA, is fracture speed dependent with lower fracture toughness for higher fracture speeds. Previous analysis also indicated by considering the speed dependent toughness, better predictions can be obtained for both self-arresting fracture toughness requirement and the fracture propagation speed. Previous DWTT fracture toughness data published by the authors exhibited a strong speed dependence and it was demonstrated that if the actual speed dependence is plugged into the modified TCM, both the fracture toughness and fracture speed would be over predicted. The assumption was that the original TCM was calibrated using pipe fracture data that also had speed dependent fracture toughness but the speed dependence was less strong than those for the modern pipes.
This paper presents an updated DWTT fracture dataset that expands the previously published data by adding high speed DWTT test results of modern line pipe steels with a range of grades X70-X100 and three old vintage pipe materials that is representative to the pipes that were used for the original TCM testing and calibration. The toughness data for the low grade pipes also shows speed dependence which purports the previous assumption.
A Stress Check Procedure for Pipe Lowering-In Process During Pipeline Construction
Authors: Duan Da-Ming , Jurca Thomas , Zhou Charles 
Published: December 2014

The quality of pipeline construction is determined by the effort of controlling the pipe stress level. Constraints may include various factors, such as pipe size, side boom lifting capacity, the number of side booms, side boom spacing and the lifting height profile. The use of girth weld flaw size limit established by Engineering Critical Assessment (ECA) for a given construction condition, makes the accuracy of pipe stress even more important. This is not only because stress level is one of the controlling parameters of the ECA results, but also because in some cases, such as low girth weld fracture toughness, stress level must be controlled with a very narrow window to keep a meaningful ECA that leads to a reasonable weld repair rate. An optimized pipe lifting height profile can be obtained from stress analysis using finite element method based on available construction equipment capabilities. From a practical perspective, an optimized pipe lowering-in plan may not be executable in the construction field. It is thus desired that a practical approach be provided that captures the key feature of construction practice and at the same time makes the key measures recordable.
This paper provides a set of stress check equations derived using beam deformation theory. The calculation results using these equations show that for normal pipe lowering-in practice, pipe stress level can be effectively controlled by checking and controlling the lifting height of just one or two points. The approach proposed is to be used in conjunction with case specific finite element analysis.
Establishing the Correlation Between Charpy Impact Energies for Different Sized Specimens of Modern Pipeline Steels
Authors: Nonn Aida , Brauer Holger 
Published: December 2014

The safety assessment of flawed pressurized pipes requires the knowledge of toughness properties which are usually provided in terms of impact energy from standard full-sized CVN notch specimens. For pipes with wall thickness less than 10mm different Charpy standards allow for the application of sub-sized specimens. However, it is still not fully clear how the impact energy from sub-sized specimens can be used to evaluate the fracture resistance of the pipes and how this energy correlates to the one from the full-sized specimen. Although different empirical correlations between sub-sized and full-sized specimens exist in the literature their validity is questionable since they are based on the results for older generation of steels. In the recent years the application of damage mechanics models has been promoted to assess the fracture behavior and deformation capacity of pipelines. The main advantage of these models can be found in their capability to link the damage evolution and the underlying stress/strain condition.
In this paper damage mechanics approach is applied to describe fracture behavior of X65 pipeline material. Within the damage mechanics approach, Gurson-Tvergaard-Needleman (GTN) model is considered to be adequate for the simulation of ductile fracture. For brittle fracture, GTN model is extended by a propagation criterion which examines if the cleavage fracture stress is reached by the maximal principal stresses. The model parameters are calibrated and verified by means of load-displacement curves obtained from instrumented impact tests on different sized CVN specimens. This damage model is subsequently employed to simulate ductile-brittle transition behavior.
Recent Development of HFW Linepipe With a High-Quality Weld Seam Suitable for Sour Service Environments
Authors: Toyoda Shunsuke , Goto Sota , Kato Yasushi , Yabumoto Satoru , Sato Akio 
Published: December 2014

Based on the appreciable progress being made in quality control and assurance technology for the electric resistance welding process, the number of applications for high-frequency electric resistance welded (HFW) linepipe in highly demanding, severe environments, such as offshore and sour environments, has gradually increased. Resistance to hydrogen-induced cracking (HIC) is the most important property for a linepipe to possess for use in sour environments. However, resistance to HIC, especially along the longitudinal weld seam, has not yet been fully related to metallurgical factors.
In this study, to clarify the effects of inclusions on the sour resistance properties of X60- to X70-grade steels, their resistances to HIC were numerically simulated. For the simulation, the steels were assumed to have a yield strength of 562 MPa and a tensile strength of 644 MPa. To estimate the effect of nonmetallic inclusions, a virtual inclusion was situated at the center of a 10-mm-thick HIC test specimen. Tests were performed using NACE test solution A.
The crack propagation rate was calculated as a function of the content of diffusible hydrogen, the diameter of the inclusion, and the fracture toughness of the matrix after hydrogen absorption. In the propagation calculation, the resistance to chemical reactions at the interface of the inclusion matrix was also considered to be a delaying factor. By assuming a resistance to chemical reactions at the interface, the crack propagation rate could be fitted to the actual HIC propagation rate.
Based on the numerical simulation results, HFW linepipe with a high-quality weld seam was developed. Controlling the morphologies and distributions of oxides generated during the welding process is the key factor for improving the resistance to HIC. Using a combination of optimized chemical composition, microstructure and oxide content, the weld seam of the developed X70-grade HFW steel pipe showed excellent resistance to HIC.
Combining Speed Control Function and Wye Passage in a Long Subsea Gas Line: A Case Study
Authors: Lindner Hubert , van Remmerden Hans , Shamgar Amit 
Published: December 2014

Challenging conditions for pipeline inspection can be caused by several different parameters and conditions (length, diameter changes, installations and operating conditions). Very often the real challenge is resulting from a combination of these influencing parameters. For example, a very long pipeline becomes particularly critical for battery lifetime if the flow rate is low. Each single individual parameter does not necessarily constitute such challenge. Some basic examples and a particular combination of pipeline parameters and operational conditions are presented in this article.
The crucial parameters of the regarded pipeline are: 36″, about 700 km length, high wall thickness, high pressure and flow rates and a subsea wye piece. Some of these requirements are already demanding for former inspection tools. But the complex interaction of the features increases the challenge for the tool design significantly. Particularly the combination of high flow, high wall thickness and the wye piece passage required special attention.
The article describes the pipeline properties and run conditions and the consequences for the entire cleaning and inspection program. Notably the interactions of the parameters regarding the MFL inspection are highlighted and the resulting tool concept is presented as well as the run results.
Pipeline Integrity Analyses for Construction in Mountainous Areas
Authors: Zhang Fan , Liu Ming , Wang Yong-Yi , Surface Ryan , Phillips Adam 
Published: December 2014

The construction of a pipeline in mountainous terrain often exposes great challenges compared to that on flat land. To accommodate the terrain and resultantly complex route, the pipeline design must incorporate a large quantity of cold bends and elbow fittings. A recently constructed project provides a prime example of a pipeline crossing such terrain. The challenging construction conditions and the bends and elbows make the assessment of stress impacting long-term pipeline integrity critical, yet difficult. This paper focuses on three specific aspects of long-term integrity for construction in mountain areas using advanced finite element analysis (FEA).
The first scenario is tie-in welding. Tie-in welding connects separate pipeline segments constructed independently. In general practice, considerable lengths of pipe are left unburied to reduce the potential resultant stress due to the misalignment between the pipes at the tie-in weld location. However, in mountainous terrain the length of unburied pipe may be constrained by field conditions of the tie-in location. The implications are amplified at a tie-in adjacent to bends or elbows.
The second scenario is hydrostatic testing. The gravitational weight of water generates additional internal pressure in the pipeline segments at low elevations. In areas of significant elevation change, hydrostatic test section design defines the segments based on the maximum allowable hoop stress level calculated for straight pipe. However the bends and elbows often encounter increased combined stresses at such locations that may not be adequately considered.
The last scenario is ratcheting. Exacerbated by complex routing and profile, pipelines constructed in mountainous areas are at risk to develop significant uplift in the soil at bend locations during hydrostatic testing and initial operating cycles. If such uplift displacement accumulates during subsequent operating cycles, a phenomenon known as ratcheting, the pipe may eventually fail by upheaval buckling.
This paper evaluates the above scenarios of a NPS 30 section of pipeline consisting of several segments with wall thicknesses varying from 12.0 mm through 19.6 mm, and contains frequent bends and elbows. The pipeline route is mountainous with slopes exceeding 70 degrees, and includes a tunnel immediately adjacent to water crossings and steep slopes. Tie-in welds are made in tight confines at either end. Analysis based on this project profile provides detailed information and insight into the design and construction of pipelines in mountainous terrain.
Reducing Human Error Using a Human Factors Life Cycle Approach
Authors: Harron Lorna , Attwood Dennis 
Published: December 2014

Reduction of human error can have a significant impact on the potential for spills and leaks and translate into better safety performance and financial gains for an organization. As important as the technical components of a design, construction, operation, and maintenance program is the human component of the activities being performed.
In the Pipeline Industry, human factors can create the potential for a human error at many points along the life cycle of a pipeline. Using a life cycle approach to manage human factors can provide an organization the capability to integrate human factors into programs, standards, procedures and processes using a disciplined approach. This paper reviews the life cycle of a pipeline and identifies areas where the potential for human error can have catastrophic results. Guidance is provided on the development of a human factors life cycle for the organization and illustrates available industry resources as well as opportunities for further research and development.
Venting of a 32 km NG Pipeline: Field Measurements and CFD Simulations
Authors: Godbole Ajit , Michal Guillaume , Lu Cheng , Liu Xiong , Venton Philip , Laidlaw Noel 
Published: December 2014

This paper describes two separate field experiments involving the venting of natural gas pipelines. The pipelines were 32 km and 60 km in length respectively. The studies were carried out as part of an investigation of the phenomenon of Low Temperature Excursions (LTE) under the aegis of the Energy Pipelines Cooperative Research Centre (EPCRC), Australia. When a highly compressed gas is allowed to escape from a pipeline, the large drop in pressure is accompanied by a significant drop in the temperature of the gas. The general impression is that the pipeline material is also cooled to a comparable extent. This has often led to over-specification of the properties of the pipeline material. Theoretical and CFD studies have shown that although the gas undergoing severe decompression can indeed attain very low temperatures, the adjacent pipe wall does not experience cooling to a comparable extent. This appears to be in part due to the short time scales involved, and due to frictional effects at the gas-pipe wall interface [1].
In the field experiments described, in-situ measurements of gas pressure and pipe wall temperature were carried out. One of the field experiments also involved thermal imaging of the vent pipe surface. The measurements showed that even the most susceptible parts of the vent pipe were not excessively cooled during the event, i.e. much less than the cooling experienced by the gas at the corresponding location. CFD simulations of the highly transient flow in one of the field studies suggest that this may be due to a combination of the time scales involved, and frictional dissipation in severe pipeline decompression, i.e. rapid decompression from an initially high pressure level.
Based on the above findings, work is in progress to improve the temperature calculations in computer applications.
Conditioning TRANSPETRO’s Gas Pipeline Network to the Baía de Guanabara LNG Terminal New Regasification Profile
Authors: Krause Philipe B. , Carnevale Marcos Bruno B. , dos Santos Denis F. , Jardim Rodrigo B. L. 
Published: December 2014

Petrobras Transporte S.A. – TRANSPETRO’s Gas Pipeline System, composed by 7.3 thousand kilometers, 135 delivery stations and 21 compressor stations, has a very seasonally dependent operation. Highly linked with the Brazilian energy grid, during the dry season of the year a large part of the 77.3 million cubic meters of natural gas daily transportation are used to generate around 6.4 gigawatts to power the country. Additionally, the ever increasing number of power plants and distribution companies around the country demand more and more gas to be offered to supply the system. Among the different sources of natural gas available, the LNG is the most flexible for such seasonal operation.
In order to support this current demand and to attend future demands, the regasification ability of Baía de Guanabara LNG Terminal was increased in December 2012, by changing the regasification vessel that supplies the southeast portion of the gas pipeline network, from 14 to 20 million cubic meters per day. To prepare to receive the new ship, some tests were performed to determine the operational limits on system survival time without LNG supply during vessel exchange. This assessment involved two different issues. The ship change operation occurred during a period of high consumption, when the LNG terminal was needed to sustain the network inventory. A long period without this supply, caused by the exchange of LNG vessel, would affect the deliveries. On the other hand, the new ship’s commissioning curve would introduce a large amount of natural gas into the system during a short period of time, demanding that the deliveries absorbed such volume. Four planning scenarios were assessed based on some expected pipeline supply and delivery conditions. The work was important as a reference for future changes on operating supply units of TRANSPETRO gas pipeline system, showing the importance of pipeline simulation both as a planning tool for pipeline logistic problems and as operational support.