bluuebunny/crossref_metadata_2025 huggingface dataset:
Pipesworld: Applying Planning Systems to Pipeline Transportation
Authors: Milidiu´ Ruy L. , dos Santos Liporace Frederico
Published: December 2008

Most transportation problems consist of moving carriers of stationary cargo. Pipelines are unique in the sense that they are stationary carriers of moving cargo. As a consequence, the planning problem of these systems has singularities that make it very challenging. In this paper we present the Pipesworld model, a transportation problem inspired by the transportation of petroleum derivatives in Petrobras’ pipelines. Pipesworld takes into account important features like product interface constraints, limited product storage capacities and due dates for product delivery. The relevance and unique characteristics of Pipesworld has been recognized by the Artificial Intelligence planning community. Pipesworld has been selected as one of the benchmark problems to be used in the Fourth International Planning Competition, a biannual event to benchmark the state-of-the-art general purpose artificial planning systems. We report the results obtained by general purpose artificial intelligence planning systems when applied to the Pipesworld instances. We also analyze how different modelling techniques may be used to significantly improve the planners’ performance. Although the basic algorithms of these planners do not incorporate any specific knowledge about the pipeline transportation problem, the results obtained so far are quite satisfactory. We also describe our current work in developing Plumber, a dedicated solver, aimed to tackle effective operational situations. Plumber uses general purpose planning techniques but also incorporates domain specific knowledge and may work together with a human expert during the planning process. By applying Plumber to the Pipesworld instances, we compare its performance against general purpose planning systems. Preliminary tests with a first version of Plumber shows that it already outperforms Fast-Forward (FF), one of the best available general purpose planning systems. This shows that improved versions of Plumber have the potential to effectively deal with pipeline transportation operational scenarios.
Optimization of Hot Rolling Process for API-X60 Grade Line Pipe Steel With Lower Yield/Tensile Ratio for ERW Pipe Application
Authors: Ro Kwang Seop , Nayak K. Nagaraj , Arikere Bharath , Al-Shammary Saad , Sarkar Bimal K. , Al-Butairi Adel A.
Published: December 2008

The real challenge of achieving yield to tensile ratio (YR) lower than 0.85 along with YS & TS as per specification especially for ERW pipes was performed because the major concern with higher yield ratio is the resultant lower uniform elongation, lower work hardening exponent and also possible deformation under load (safety) when pipelines are used underground. A study was performed by controlling the HSM process parameters. To ensure tensile properties as per X60 grade with lower yield ratio, and good impact toughness, Finish Rolling Temperature (FRT), Coiling Temperature (CT) and Cooling Rate (CR) were varied at Hot Strip Mill in production scale. Generally, micro-alloyed steels show good strength as desired for X60 grade, along with high yield ratio up to 0.90 especially for lower thickness like 6.4mm due to thermomechanical rolling technology. The HSM process parameters for reducing yield ratio was focused on finding the effect of grain size and uniform microstructure. The results of coil form material showed that higher deformation temperature with normal CT and consistent water-cooling pattern could give optimum YS, TS with lower. YR. Comparatively, there was relatively high amount of change in YS, TS & YR with different combination of FRT, CT and CR. At customer end, after pipe making, it was found that yield ratio was lower than 0.85 with minimized YS drop due to Bauschinger effect. Interestingly, the tensile properties & yield ratio values were differing with respect to ERW pipe manufacturing methods (Cage forming & Linear forming processes). These were attributed to the differences in straining during pipe forming. The study indicated that API-X60 grade steel can be supplied with optimization of HSM process parameter to get desired yield and tensile properties as per specification with yield ratio of 0.84∼0.88 and also achieve desired yield and tensile results after ERW pipe making with yield ratio of 0.85 max.
A Unique Pipeline Fault Crossing Design for a Highly Focused Fault
Authors: Hart James D. , Zulfiqar Nasir , Lee Chih-Hung , Dauby Frank , Kelson Keith I. , Hitchcock Christopher
Published: December 2008

This paper describes the development of a unique pipeline fault crossing design upgrade for a 22-inch (559 mm) diameter Pacific Gas & Electric Company (PG&E) gas transmission line where it crosses the Calaveras fault near Sunol, California. The new design is capable of withstanding significant levels of horizontal fault offset while minimizing the deformation demands experienced by the pipeline. This unique design concept is applicable to fault crossings with well defined fault locations and highly localized fault offset profiles (e.g., for this fault, 85% of the offset is expected to occur within ±5 feet (±1.5 m) from the center of the fault trace, which was precisely located by field trenching studies). Relative to the original fault crossing design, the new design provides a more favorable “local” fault crossing angle “β” (β = 73° for the original design vs. β = 95° for the new design). The angle change is accomplished by installing an offset section of the pipeline adjacent to the fault such that the fault crosses the pipeline in the middle of a tangent section in the nearest offsetting leg. The four bends used to fabricate the offset section are cold bends with an average radius of 76.4 feet (23.3 m). The entire mitigated section of the pipeline is buried in a select sand trench. For this design configuration, right lateral fault motion results in (a) a “closing” action within the two adjacent cold bends located on either side of the fault and (b) a net tension force in the pipe (due to the obtuse β value) centered on the tangent section of the offsetting leg containing the fault crossing. The net tension force in the offsetting leg results in an “opening” action within the two adjacent cold bends on either side of the fault. By adjusting the local fault crossing angle β, the “bend opening” action that results from pipe extension across the fault can be made to nearly offset the “bend closing” action induced by the transverse component of the fault offset. The use of a select sand backfill in the retrofit section allows the bends to engage the soil with relatively low transverse and longitudinal resistance thereby enhancing the overall flexibility/compliance of the fault crossing design. Implementation of this unique design concept at the Calaveras fault crossing increased the amount of fault offset required to damage the pipeline from about 7 inches (18 cm) for the “as-built” design to well over 90 inches (2.3 m) for the retrofit.
External Corrosion and Internal Corrosion Direct Assessment Validation Project
Authors: Mikkola Carl A. , Case Christina L. , Garrity Kevin C.
Published: December 2008

In January, 2003, Enbridge Midcoast Energy, L.P., a subsidiary of Enbridge Energy Partners, L.P., implemented a comprehensive direct assessment development and validation project for its Natural Gas Business segment; a project intended to demonstrate the validity of External Corrosion and Internal Corrosion Direct Assessment (ECDA and ICDA). The work began in January 2003 and was concluded in June 2003. The primary goal of the project was to demonstrate that External Corrosion Direct Assessment and Internal Corrosion Direct Assessment as performed in compliance with the NACE and INGAA methodologies could be used to effectively verify and manage the integrity of non-piggable and non-interruptible natural gas pipeline segments. The programs were validated by in-line inspection (ILI) using high-resolution magnetic flux leakage tools and field verification digs. The objective of the project was to receive approval from the Texas Railroad Commission to use direct assessment (“DA”), where demonstrated to be appropriate, for integrity verification and management of pipeline systems that are not verifiable through other approved means. The Enbridge DA Validation Project was successfully completed and is considered to be one of the leading DA validation projects undertaken to date in the U.S. A total of 12,000 manhours and over $1MM was expended in performing the pre-assessment to identify a candidate pipeline, develop detailed procedures for DA execution and implementation, perform indirect surveys, modify pipe and complete cleaning pig runs, gauge pig runs, dummy pig runs, intelligent pig runs, perform detailed direct examinations and perform detailed analysis of the results including the preparation of the final report. This paper is intended to describe the steps that Enbridge took in validating DA.
High Sensitivity External Leak Detection for Liquid Fuel Pipelines
Authors: Parman David G. , McCoy Ken
Published: December 2008

Pipeline risk mitigation in high consequence areas can be facilitated through the use of a high sensitivity external leak detection (HSELD) system. Such systems have been implemented for both off-site and on-site pipeline applications, including the Longhorn Pipeline (Texas) and the Madrid Barajas International Airport (Spain). We define high-sensitivity external leak detection as a leak detection system that will continuously and automatically detect very small amounts of liquid fuels and is physically independent of pipeline pumping operations. In addition, such systems monitor their own integrity on a continuous basis, without requiring periodic recalibration or operator interaction. The HSELD system we describe incorporates a distributed sensor cable, installed in a slotted PVC conduit which is run in close proximity to the pipeline. Many pipeline leaks start out as very small cracks or holes resulting from corrosion and wear. In their initial stages, such leaks go undetected by standard leak detection methods, but over time large volumes of liquid fuel may leak into the environment. In high consequence areas, such as above aquifers and other environmentally sensitive areas, the leak may go undetected until traces show up in water samples. The critical characteristic of an effective HSELD is its ability to detect and accurately locate very small volumes of liquid fuels, so that these small leaks can be identified, cleaned up and repaired before environmental damage is done.
Methodology for Analysis of Installation of a Steel Lazy Wave Riser
Authors: Mourelle Marcio M. , de Siqueira Marcos Queija , de Avila Gabriela Grisolia , Torres Ana Lucia F. Lima
Published: December 2008

The Petroleum Industry has been looking for a configuration for large diameter steel risers, which can be used either at FPSO’s or Semi Submersible Platforms. An interesting option with a low cost increase is the lazy-wave configuration, which is obtained by the addition of buoyancy modules along a limited length of the riser, close to its touch down area. The steel lazy-wave riser is usually checked for the standard failure modes in the operational phase. The present work shows that it is also necessary in the early stages of design, to define an installation procedure in order to assure configuration feasibility, as high stresses develop at riser hog and sag areas as a function of buoyancy modules installation. Riser configuration changes during the installation process demands managing top angle, launched length and distances between the platform and the installation vessel. The limitations of the installation’s equipment have to be taken into account as well. The methodology for the riser analysis in obtaining a feasible solution is outlined. The riser analysis is performed using the Petrobras in-house computer code, ANFLEX and considers a real application scenario for study.
Removal of Water or Solids in Oil/Water, Gas/Solid and Gas/Liquid/Solid Pipelines Using Compact Inline Separator
Authors: More Parimal P. , Kang Cheolho , Jepson William Paul
Published: December 2008

Traditionally separators that are used for separation purposes in oil and gas industries are often bulky in size and incur high operating costs. Latest research has led to the development of a novel and compact inline separator, which is even cost effective. This paper exhibits the efficiency of the inline separator determined for two-phase and three-phase separation in multiphase pipelines. Laboratory tests were carried out to remove sand and water using large diameter, industrial-scale test facilities. For the removal of water in oil/water pipeline, separation tests were carried out with liquid velocities ranging from 0.5 ∼ 2 m/s with 10, 50 and 90% water cuts. At first stage, effectiveness in excess of 90% was attained in each of the water cuts. In second stage separation, an effectiveness of 95% was achieved. For the removal of sand in sand/gas pipeline, gas velocities varying from 4 to 14 m/s were investigated. Here, the amount of sand collected after the separation was 99.9% of the total volume inserted into the system before separation. Separation tests for three phases, gas/liquid/sand were also carried out with string of superficial gas velocities of 4 to 10 m/s and superficial liquid velocities of 0.5 to 1.5 m/s. In this case, effectiveness of around 99% was obtained. Thus it can be concluded that the innovative, inline separation system can effectively remove sand and water and reduces or eliminates the risk of corrosion/erosion problems.
Early Experience With Integrity Management Inspections for US Hazardous Liquid Pipeline Operators
Authors: Hansen Bruce , Wiese Jeff , Brown Robert
Published: December 2008

In 2000 and 2002, the US Department of Transportation’s Office of Pipeline Safety (OPS) published new regulations requiring integrity management programs for hazardous liquid pipeline operators. OPS had four fundamental objectives: 1) to increase the level of integrity assessments (i.e., in-line inspection or pressure testing) for pipelines that can affect high consequence areas; 2) to improve operator integrity management systems; 3) to improve government oversight of operator integrity management programs; and 4) to improve public assurance in pipeline safety. At the core of this new rule is a set of management-based requirements (referred to as “Program Elements” in the rule) that are fundamentally different from the existing, largely prescriptive pipeline safety requirements. The evaluation of operator compliance with these requirements requires the examination of management and analytical processes-aspects of operator’s business that are not reviewed in standard OPS compliance inspections. OPS realized a fundamentally different approach to oversight was needed to assure operators are developing and implementing effective integrity management programs. This paper describes the comprehensive changes to the OPS inspection program that were developed to perform integrity management inspections. OPS completed the initial integrity management inspection of all large hazardous liquid pipeline operators in early 2004, and is making progress in reviewing the programs of smaller liquid operators. During this initial year OPS gained substantial knowledge about the state of hazardous liquid pipeline operator integrity management programs. At a high level, OPS learned that operators generally understand what portions of their pipeline systems can affect high consequence areas, and are making the appropriate plans and progress in conducting integrity assessments for these areas. However, the development of effective management and analytical processes, and quality data and information to support these processes takes time. While most operators appear to be headed in the right direction, fundamental changes to management systems require time. OPS recognizes this situation and has developed an inspection and enforcement approach that not only assures compliance with the rule requirements, but also fosters continuous improvement in operator integrity management programs. This paper describes the lessons learned from the initial inspections, and OPS expectations for future integrity management program development. Finally, the intial year of integrity management inspections provided some valuable insights about how to perform these new type of inspections and improve external communication. This paper also addresses what OPS learned about its inspection program, and how this program is being positioned to support on-going inspections of hazardous liquid operator integrity management programs.
Parameters Choice in Detection of Viscous Liquid-Filled Pipelines With Axial Power Flow Distributions of Ultrasonic Guided Waves
Authors: Ta Dean , Liu Zhenqing
Published: December 2008

The propagation characteristic of ultrasonic longitudinal guided waves in viscous liquid-filled elastic pipes is investigated. The complex dispersion curves were computed on the assumption that the frequency is real number and wave number is complex number. Then an analysis is carried out of the Axial Power Flow (APF) amplitude and attenuation distributions. Finally, the optimal location, optimal mode and its frequency-thickness products (fd) of testing for pipes filled with viscous liquid are chosen by the APF and attenuation distributions. The results showed that the APF amplitude distribution is an effective parameter to choose modes and parameters of testing for pipes. On the other hand, at the ranges of fd of larger group velocity of each mode, this mode has feeble dispersion, while the other modes have smaller group velocity and stronger dispersion. And in that range, the mode has a larger APF at the wall of pipes. Therefore, at the range of fd of larger group velocity of each mode, this mode is used to test elastic pipes filled with viscous liquid should be more effective, the results agree with each other.
Burst Tests on Pipeline Containing Long Real Corrosion Defects
Authors: de Souza Ricardo Dias , Benjamin Adilson Carvalho , Freire Jose Luiz F. , Vieira Ronaldo D. , Diniz Jorge L. C.
Published: December 2008

Long defects are one of the various corrosion-damage geometries that may occur in oil and gas pipelines. Long internal defects appear in general at the bottom of the pipe, around 6 o’clock position, due to the presence of water at this place. Long external defects are caused in general by faults in the protective coating. The words “long defect” are being used herein to mean a corrosion defect longer than 20Det. In this paper the burst tests of five end-capped tubular specimens containing a single internal real corrosion defect are presented. In these tests the tubular specimens were loaded with internal pressure only. The specimens were cut from five longitudinal welded tubes made of API 5L X46 steel with an outside diameter of 457.2 mm and a wall thickness of 6.35 mm. The tubes are corroded pipe segments that were removed from service as part of a rehabilitation campaign. Each one of the five tubes contains a long and complex shaped internal defect. Measurements were carried out in order to determine the actual dimensions of each tubular specimen and its respective defect. Tensile specimens were tested to determine material properties. The failure pressures measured in the laboratory tests are compared with those predicted by two Level-2 assessment methods: the RSTRENG Effective Area method and the DNV RP-F101 method for complex shaped defects. Comparisons between the measured failure pressures and the failure pressures predicted by three Level-1 assessment methods (the ASME B31G method, the RSTRENG 085dL method and the DNV RP-F101 method for single defects) are also presented.
Test Behavior of Low-Toughness Pipe Affected by Corrosion Defects
Authors: Zelenak Paul A. , Kiefner John F.
Published: December 2008

The general rule of thumb for a carbon steel material at a temperature more than 60°F below its fracture propagation transition temperature (FPTT) is that it may be susceptible to failing in a brittle manner. Such a material, if it contains a sharp flaw and if it is subjected to a tensile stress, even a stress level within the normal operating range, may exhibit a failure. This type of failure is often termed a “low-stress brittle fracture”. Historical occurrences of such failures in various structural applications have raised concerns regarding the application of traditional corrosion analysis methods to “old brittle pipe”, despite the fact that few such failures are known to have occurred in thousands of miles of older pipe in service. Testing of tubular products as described herein has demonstrated that pipe materials operating at much larger temperature shifts below their transition temperatures are capable of exhibiting ductile fracture initiation in the presence of metal loss flaws and in the absence of other embrittlement mechanisms.
Development of a Dual-Diameter 10”/12” High Resolution Ultrasonic (WM) Tool
Authors: Viltart Patrick , Jacquiot Franc¸ois
Published: December 2008

Trapil is Europe’s leading refined product pipeline operator, with approximately 4,700 kilometers of pipeline in three networks in France. The Le Havre-Paris network has a number of dual-diameter 10” and 123/4” seamless lines in the Paris region. Built in the 1950s and 1960s, they are now located in heavily-populated areas where excavation to assess defects or perform repairs is difficult. Best in-line inspection practice for this type of line recommends the use of ultrasonic tools because of their depth-sizing accuracy and detection capabilities. The need for a dual-diameter, high-resolution ultrasonic tool to survey six 10”–123/4” lines prompted Trapil to develop its own tool offering a variety of benefits, such as using the RSTRENG effective area method to perform fitness-for-purpose calculations prior to excavation and determining the shape of dents.
Prediction of Long-Term Frost Heave of Chilled Gas Pipelines by Centrifuge Modeling
Authors: Morgan Vincent , Clark Jack , Hawlader Bipul , Zhou Joe
Published: December 2008

The use of chilled gas transmission for northern pipelines has been considered an effective solution to reduce potential problems relating to permafrost preservation, as well as to provide other benefits such as increased throughput. However, the potential for frost heave as the pipe crosses areas of unfrozen ground may have implications on induced strains and therefore pipeline integrity. C-CORE, under the sponsorship of Pipeline Research Council International (PRCI), has been investigating the effects of frost heave for different soil types and varying pipe geometry and temperature. Previous studies of the effects of frost heave of chilled gas pipelines involved the construction of full-scale test sites, operated over a number of years and small scale laboratory tests. Recent advances in centrifuge testing techniques have allowed small-scale models to be constructed and tested under increased gravitational acceleration to replicate full-scale conditions. The major advantages are the reduced scale and time effects used in the modeling of the frost heave. This allows a number of sequential tests to be performed to study a range of soil types, pipe temperatures, groundwater and climatic conditions in a relatively short time period and at significantly reduced cost. Centrifuge modelling also incorporates other forms of soil deformations with development of ice lenses which includes the consolidation of unfrozen soil and deformation of both frozen and unfrozen soil. The tests performed to date have focused on the determination of frost heave behaviour for a number of soil types covering the range of frost susceptibility. This paper discusses the interpretation of the test results, and provides a comparison with common methods of analysis for prediction of frost heave. A design methodology is also proposed, which makes use of centrifuge test and analytical methods.
Trench Effects on Pipe-Soil Interaction
Authors: Phillips Ryan , Nobahar Arash , Zhou Joe
Published: December 2008

Trenched pipelines subjected to large lateral soil movements were studied to quantify mitigative effects of trench geometry, backfill soil material and strength on the force-displacement behaviour in cohesive soils. Experimental and numerical models show a good agreement in terms of undrained ultimate forces, which are also consistent with design guidelines and previous studies. Undrained lateral pipe resistance factors, are assessed in terms of soil strength and soil weight in uniform soil. A normalised pipe displacement rate characterizes a transition in the lateral resistance from undrained to drained conditions is presented. The presence of a trench backfilled with material weaker than the native soil softens the lateral load-deformation (p-y) response compared to that of the same pipe buried in native soil. An increase in the trench width increases the pipe displacement to peak load. The lateral interaction force is much lower in a pipe with a wider trench than a narrower trench prior to reaching the peak load. The peak load occurs after pipe touches the trench wall and is controlled by the native soil strength. It decreases slightly with increase in the trench width because of upward movement of pipe prior to reaching trench wall. The mitigative effects of trench wall inclination are also demonstrated. A simple approach to determine the p-y response for a trenched pipeline backfilled with material weaker than the native soil is proposed.
Combined Axial and Lateral Pipe-Soil Interaction Relationships
Authors: Phillips Ryan , Nobahar Arash , Zhou Joe
Published: December 2008

A recent study recommended design guideline improvements to assess ground movement hazards for buried pipeline response. A review identified a wide variation of normalised axial resistance factors. This paper presents a three-dimensional finite element parametric study of pipe-soil interaction under combined axial and lateral loading. The normalised axial resistance is found to be very sensitive to the direction of pipe displacement and controlled by the interface friction near pure axial motion. An interaction diagram is developed and a design equation is proposed for combined axial and lateral loading.
Fracture Analysis for Pipeline Girth Welds in High Strain Applications
Authors: Stevick Glen , Hart James D. , Lee Chih-Hung , Dauby Frank
Published: December 2008

Over the last several years, Pacific Gas & Electric Company (PG&E) has designed and installed seismic upgrades at several locations where their transmission pipelines cross active fault zones. As part of the process of evaluating the seismic upgrade designs, PG&E commissioned SSD, Inc. (SSD) and Berkeley Engineering And Research, Inc. (BEAR) to perform buried pipe deformation and fracture assessments of the pipeline fault crossings to develop capacity estimates for compressive wrinkling and girth weld tensile fracture. This paper describes the elastic-plastic fracture analysis used to determine girth weld tensile fracture capacity and the relatively simple equations derived that have wide application for high toughness pipe and weld material. The equations have the form: ε(%)=α·Sf·D2c0.5(1) where the Sf is flow stress, D is pipe diameter, 2c is flaw length and α is a function of a/t where the a is flaw depth and t is the pipe wall thickness. The tension strain capacity depends on girth weld material toughness, flow stress and the length and depth of flaws that may exist in or near a girth weld. The analysis method used is based on the interaction of ductile tearing and elastic plastic fracture. Crack tip opening displacement (CTOD) is used to characterize material toughness. The derived equations can be used to predict allowable tension strain for X-60 and X-65 pipe with diameters ranging from 10 to 36 inches (273 to 914 mm) and for weld flaw depths of up to 1/3rd of wall thickness. Adequately tough pipe girth welds containing flaws can be shown to have safe tension strain capacities above 4%.
CoilTAC® Coil Thrust and Carry
Authors: Stewart Rick , Crawford Jim , Harper Tom , Kirspel Larry
Published: December 2008

In producing offshore oil and gas fields there is a need for maintaining flow assurance in the associated pipelines. Restricted and plugged pipelines result in loss of production which is loss of revenue. It is common for these pipelines to exceed the length that can be reached by conventional coiled tubing when cleaning obstructions becomes necessary. Paraffin, asphaltine’s, hydrates and sand are a few of the contaminants that can obstruct flow and cause plugging. Historically, pipeline intervention has been limited to conventional coiled tubing with a reach of only +/−5,000’. A typical maintenance practice involved “pigging” the pipeline with a poly foam pig to remove any obstruction. Under severe conditions multiple pigs with graduated ODs were used. The problem with the poly foam pig is that the flexibility allows it to be forced through a smaller ID, leaving the restriction in place. CoilTAC® (Coil Thrust and Carry), developed by Superior Energy Services, was designed specifically to extend the reach of conventional coiled tubing for pipeline intervention while negotiating a minimum 5D bend. The Thruster was designed for line sizes with internal diameters from 2.900” up. This Thruster system eliminates the compression force on the coiled tubing and has been proven to 14,800’, and it has the ability to exceed 50,000’. The Thruster utilizes a “mechanical intelligence” which is present into the thruster with takes into consideration applied force parameters prior to the cleanout procedure. The key factors are: working pressure of the pipeline, length of the pipeline and the length and size of the coiled tubing to be carried by the thruster. The forward motion of the thruster is initiated by annular pressure applied between the coiled tubing and the inside diameter of the pipeline. The pressure energizes the cups and moves the thruster forward. At a preset pressure, a check value opens inside the thruster allowing fluid to pass to the front of the tool and exit through a series of ports. This causes a washing/jetting action in front of the thruster as it moves down the pipeline. The debris that is removed from the pipeline is returned through the center of the thruster. Retrieving the thruster is accomplished by pumping down the center of the coiled tubing which applies pressure to the front of the tool to reverse the Thruster out of the pipeline. The returns during reverse thrusting are then taken on the coiled tubing/pipeline annulus. Pump pressure moves the thruster in and out of the pipeline not the coiled tubing injector, thus eliminating the helical buckling forces and extending the reach of the coiled tubing. Historically, paraffin-laden pipelines had to be abandoned and new lines laid at great expense to the operator — it was difficult to abandon subsea pipelines without complete removal. Now there is an option with the CoilTAC® system.
The Effect of Surface Roughness on the Erosion of Mild Steel
Authors: Nelson Stacy A. , Baker Michael J. , Deans William F.
Published: December 2008

This paper investigates the relationship between the surface roughness parameter, Ra, and the erosion of the material surface. Jet impingement tests were carried out on the surface of mild steel plates at an impact angle of 30 degrees to the material surface. The erosion test rig utilised sand as the erodent at a concentration of 2%wt, with average particle size of 270 μm. The average surface roughness Ra, of the test specimens ranged from 0.07 μm to 1.14 μm. The erosion damage was assessed by a unique application of the surface profilometry technique. In addition, by using Fast Fourier Transforms to convert the surface profile scans into wave-number spectra, the changes in the material surface after erosion exposure were easily monitored. The investigation showed that the surface roughness parameter plays a significant role in the erosion process, particularly in the initial stages. The operating conditions of the impinging jet were associated with an equilibrium condition, both for the surface roughness and the eroded depth. As a result, materials having an initial surface roughness value greater than the equilibrium Rae value showed a decrease in surface roughness, whereas those having an initial value less than the equilibrium value showed an increase in surface roughness. This trend was confirmed by the changes in the amplitudes of the wave-number spectra for each plate, over the erosion period. The eroded depth was maximum for the plate having the smallest difference between the initial Ra value and the equilibrium value Rae. This subsequently decreased as the deviation from the equilibrium value was increased.
Estimating Fatigue Life for Pipeline Integrity Management
Authors: Kiefner John F. , Kolovich Carolyn E. , Zelenak Paul A. , Wahjudi Tom
Published: December 2008

Pipelines comprised of materials manufactured prior to about 1980 are more likely than those comprised of newer materials to contain manufacturing or transportation-induced defects. These defects may become enlarged and fail in service because of pressure-cycle-induced fatigue crack growth. While such defects do not account for a large number of service failures, they clearly are a potential threat to pipeline integrity. In fact, the current U.S. pipeline integrity management regulations require seam-integrity assessments for certain types of pipe materials that appear to be particularly susceptible to this risk. To manage the risk of failure from pressure-cycle-induced fatigue a pipeline operator may need to carry out periodic seam-integrity assessments via either hydrostatic testing or in-line inspection using a reliable crack-detection tool. The appropriate period for reassessment depends on the sizes and growth rates of potential defects that may still exist (just-surviving defects) after an initial hydrostatic test or in-line inspection. The pressure cycles applied to the pipeline may cause the just-surviving defects to grow at a rate inherent in the material and its environment. Long-established principles can be used to predict the times to failure if the effective crack growth rate is known. A pipeline operator can use these principles to plan timely re-assessments to prevent failures. This paper describes one approach to predicting reassessment intervals. This approach has evolved over a period of more than 10 years. The authors have discovered some pitfalls and blind alleys that can lead to inappropriate predictions. The purpose of the paper is to show that while the well-known and widely available basic principles are sound, their application to pipeline integrity management requires an in-depth understanding of the particular pipeline being subject to assessment.
Spatial Analysis in PGPB’s Risk Administration System for Pipelines
Authors: Sam Garci´a Luis R. Chiang , Mora Mendoza Jose´ Luis , Betancourt Enrique Rodri´guez , Polanco Rene´ Pe´rez
Published: December 2008

All facilities related with petrochemical and gas transmission systems have something to do with geography and therefore Geographic Information Systems (GIS). Maintenance of pipelines; design, construction and operation of pumping and compression stations; as well as emergencies attention, are some examples of the cases in which Pemex Gas y Petroqui´mica Ba´sica (PGPB), one of biggest companies owned by Mexican government, use a GIS called “Facilities and Assets Information System” (FAIS). For risk administration PGPB has been using Bass Trigon’s Integrity Assessment Program (IAP), software based on Kent Muhlbauer’s methodology. From this software, PGPB has built a Risk Administration System for Pipelines (RASP), which is able to identify and evaluate risks that could affect the transportation capacity of the company’s petrochemical, lpg and natural gas transmission systems. Both systems worked separately through 1997–2003, even though, both were aiming the same transmission systems. GIS was used to give immediate response to regulation authorities, satisfying internal requirements related to the surrounding environment of the company’s pipelines and the pipelines themselves. RASP was used to obtain and evaluate risk factors that would support decisions on the resources that would be utilized in the daily maintenance jobs. During 2003, the FAIS’s software was upgraded to the latest version of ArcGis (8.3), including a change in the programming language to Visual Basic for applications, a database migration to Unix and a modification in the system to new user requirements, which included the integration of RAST results. Nowadays, analyzing risk data in a spatial context has been a common use in the Pipeline Division of PGPB, which has become a powerful tool to support critical decisions from managers and chief executives. In this work are presented some specific applications using the integrated FAIS and RASP systems to show risk assessment data analysis and their consequences.
Pre-Assessment is Key to Success for Direct Assessment in Integrity Management Programs
Authors: Valdes Alberto , McNealy Richard
Published: December 2008

Direct Assessment is allowed under the new Gas Pipeline Integrity Management Rules published by the Office of Pipeline Safety as an assessment method subject to specific applicability restrictions, direct examination criteria and restrictions to re-inspection intervals. The final developed costs for implementing direct assessment is largely dependent upon the extent of direct examination that in turn is a function of the pipeline condition and actual threats discovered and validated. Effective utilization of Direct Assessment within an Integrity Management Program is dependent upon the recognition of the value inherent in the Pre-Assessment Stage of the Direct Assessment Process as defined by the Rule, in which, threats are predicted, applicability confirmed and as a result of data and risk analysis, it is possible to estimate the condition of the pipeline to determine if the use of Direct Assessment is a practical consideration as well as permitted under the Gas Pipeline Integrity Management Rule.
A Pipeline LDS Trial: Comparing Compensated Volume Balance Against SPRT Statistical Based LDS in a Brazilian Pipeline
Authors: Baptista Renan Martins , Guedes Maricato Andre´ Luiz , Masiero Paulo Anchieta , Lima da Silva Jose´
Published: December 2008

This paper describes field trials for two different technologies (built in two commercial products) for leak detection, location and quantification systems (LDS). Modified Compensated Volumetric Balance was tested against SPRT Statistical Analysis, and the obtained results were analyzed/commented. The tests were carried out in a 43 km long 20 in. pipeline (PREPSP), carrying different batches of crude oils, located in the state of Bahia, Brazil. Actual leaks under shut in, steady state, pump transient startup and shutdown operational conditions were introduced, and the performance of both technologies analysed. For each of those conditions and technologies, a sensitivity curve was plotted, leak location and its quantification was tabled, compared and commented. Finally, reliability data for both technologies (essentially, number of false alarms and non-expected misbehavior) were gathered for a two weeks testing period.
Distributed Automation Systems Provide Information and Support to Decision
Authors: Feldman Rafael Noac
Published: December 2008

Transpetro — the transportation division of Petrobras — operates approximately 10.000 kilometers of pipelines and 43 oil terminals. It is the main oil and gas logistic company in Brazil and one of the top companies in Latin America. This work presents a concise description of Transpetro’s project to integrate these distributed sites. Most of the pipelines are remotely operated by the Operational Control Center (OCC), located in Rio de Janeiro, but there are also a number of pipelines and specific operations that are under the responsibility of the terminals, and these operations are called “distributed operations”. These operations include pump and compressors control, valves alignment, products quality monitoring, and even some pipelines control not integrated to the OCC yet, such as the ones that are used to deliver final products to the distribution companies. Each of the Terminals has, or is receiving, an automation system including instrumentation, programmable logic controllers, communication and supervisory systems. Pressure, density, flow and level are some of the variables collected by the automation system and made available to the terminal operator. The system also allows the remote control of valves, bombs, compressors and other equipment. All this information gathered by the automation system becomes digitally available on the level of the terminals supervisory systems, which in Transpetro are mainly based on Intellution iFIX and Telvent OASyS. Therefore, other systems can access the supervisory systems and use its digital information for the benefit of the company. On the Operational side, there are some specialist systems that refine and sophisticate the level of information available in the supervisory system. One of these is the Leak Detection System, which interfaces with the supervisory system using data transfer protocols such as DDE and OPC, receiving the process data and applying a computational model that allows the operator to identify a potential leak. In a Logistic Company such as Transpetro, it is important to keep all the information concerned to storage (in tanks or pipelines), both current and scheduled operations, in a set of systems functioning in an integrated way. One of these systems is the homemade one called BDEMQ (Storage, Transportation and Quality Data Base). Transpetro is now implementing the interface between the automation systems and BDEMQ in all terminals. The technology used is a C and Java language-based interface through an Ethernet TCP/IP network. Hence, once Transpetro has all the data digitalized in its terminals’ automation systems, it is possible to improve the level of control and information, increasing the support to the operators’ and managers’ decision taking processes.
The Geophysical Toolbox: A Practical Approach to Pipeline Design and Construction
Authors: Henderson J. , Bowman M. , Morrissey J.
Published: December 2008

Geophysical surveys map variations in physical properties of subsurface materials, many of which can have a direct impact on pipeline design and construction. This paper provides an overview of complementary geophysical methods available in the geophysical toolbox and shows, through the use of case histories, examples of the applicability of the methods for specific pipeline design and construction scenarios. In the context of pipeline design and construction, the objectives of a geophysical survey typically include one or more of the following applications: • muskeg mapping (thickness, lateral extent); • permafrost delineation (variations in ice content, frozen/unfrozen boundaries); • depth to bedrock; • rippability of bedrock; • soil type delineation (corrosion protection, granular inventories); • subsurface conditions at water crossings for horizontal directional drill planning using detailed investigations (boulder horizons, abandoned workings, depth to bedrock). To successfully address these objectives, it is often necessary to utilize more than one geophysical technique. Geophysical methods commonly employed in pipeline investigations include the following: • seismic refraction (marine and land based); • seismic reflection (marine and land based); • electromagnetics; • electrical imaging; • ground penetrating radar (marine and land based); • sonar. The fullest utility of geophysical information is achieved when combined with complementary approaches to provide the end-user with a value-added, cost effective approach. These other method include: airphoto interpretation, satellite imagery, and drilling. The incorporation of auxiliary data sets results in geophysical sections that provide a means of interpolating subsurface conditions between drill holes and reducing the risk associated with encountering surprises. These sections can also be used to provide for more accurate cost estimates by their inclusion in bid documents while at the same time ensuring a better data base for pipeline design. In addition to the advantages of using a geophysical toolbox, the ramifications of the pitfalls of geophysical approaches will also be discussed through the use of case histories illustrating situations in which an inappropriate geophysical technique was applied.
Flow Behaviour and Ductile Fracture Toughness of a High Toughness Steel
Authors: Xu S. , Bouchard R. , Tyson W. R.
Published: December 2008

This paper reports results of tests on flow and ductile fracture of a very high toughness steel with Charpy V-notch absorbed energy (CVN energy) at room temperature of 471 J. The microstructure of the steel is bainite/ferrite and its strength is equivalent to X80 grade. The flow stress was determined using tensile tests at temperatures between 150°C and −147°C and strain rates of 0.00075, 0.02 and 1 s−1, and was fitted to a proposed constitutive equation. Charpy tests were carried out at an initial impact velocity of 5.1 ms−1 using drop-weight machines (maximum capacity of 842 J and 4029 J). The samples were not broken during the test, i.e. they passed through the anvils after significant bending deformation with only limited crack growth. Most of the absorbed energy was due to deformation. There was little effect of excess energy on absorbed energy up to 80% of machine capacity (i.e. the validity limit of ASTM E 23). As an alternative to the CVN energy, the crack tip opening angle (CTOA) measured using the drop-weight tear test (DWTT) has been proposed as a material parameter to characterize crack propagation resistance. Preliminary work on evaluating CTOA using the two-specimen CTOA test method is presented. The initiation energy is eliminated by using statically precracked test specimens. Account is taken of the geometry change of the specimens (e.g. thickening under the hammer) on the rotation factor and of the effect of strain rate on flow stress.
Suggestions for Improving Initiation of Pipeline Projects
Authors: Thomas Janice , Stripling Travis E.
Published: December 2008

Effective and successful project management of today’s pipeline projects is a challenging and complex task. For the most part, these complexities are not due to technical issues, but pertain to “soft management issues” (communications, team building/alignment, stakeholder management, etc.) that must be immediately and aggressively addressed during project initiation. That is, a key success factor for these projects is setting up for success, upfront at the very beginning, and ensuring the right resources and processes are in place to manage the “soft side” as the project progresses. This includes initiating continuing processes to check the status of the project team climate, interaction health, and development of a “risk sharing/monitoring” culture.
Meditation as a Management Tool for the Pipeline Industry
Authors: Terrell Mark , Stripling Travis E.
Published: December 2008

Implementation of today’s large pipeline projects is a real challenge and requires application of our most effective management tools. This is also the case for ongoing corporate and general management within the pipeline industry. The practical use of meditation is a “leading edge” technique that is being utilized more and more by various organizations in a number of different industries. The use of meditation techniques has merit and should be considered as a potential management tool by the pipeline industry. This paper will discuss how a practical and easy to understand and use meditation methodology can be implemented in the pipeline industry as an effective tool to address “soft management issues” such as project team stress reduction, enhanced teamwork, increased creativity and innovation, and improved decision making. Since this is a “leading edge, state-of-the-art” approach for use in project management, the authors will suggest how over the coming months or years meditation techniques might be realistically introduced into pipeline industry management.