bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of the Crack-Arrest Toughness of the Pipeline Steel X 70
Authors: Felber S.
Published: October 2016

The resistance of a material against fracture is influenced by its behaviour during the three possible steps of the fracture process, which are crack initiation, crack extension, and crack-arrest. It is the task of materials testing, especially of fracture mechanics, to find out the relevant parameters. To stop a crack in a pipeline in order to limit the crack length it is of great interest to know the crack-arrest toughness, KIa, of the material used.

There are two main possibilities to stop a crack in a pipeline: The first one is to apply special crack arrestors, and the second one is to use a material with a high crack-arrest toughness. The first possibility is rarely realized, and so it is of great interest to gain knowledge of the fracture toughness values of the pipeline steels employed. In the past, big specimens, like Robertson plates for example, were used for the determination of the crack-arrest toughness, KIa, but they are very expensive and so nowadays they are replaced by small specimens like:

1st, the three-point bend specimens (specimens used in a proposal published by TVFA, University of Technology, Vienna),

2nd, the compact-crack-arrest specimens (specimens of the standard test method ASTM E 1221) and

3rd, the full-thickness compact-crack-arrest specimens (specimens proposed in the test method of Ripling and Crosley).

This work deals with the determination of the crack-arrest toughness, KIa, of the base material, the weld metal and the heat affected zone of a weld of the pipeline steel X 70. For this purpose tests were performed with each of the three materials, employing each of the three mentioned test specimens. Finally, this work contains a discussion and a comparison of the measured crack-arrest toughness values.
Tar-Polyurethane Joint Coating for the Three-Layer Polyethylene Pipeline Coating
Authors: Rogers Robert H.
Published: October 2016

This article describes a new joint coating system implemented by Bechtel for a major international, 48 inch diameter gas pipeline. Despite the long history of use as a pipe and valve coating, the new implementation is the industry’s first significant use of a thermoset hot spray coating applied to field weld areas of pipe, mill coated with a three layer polyethylene system. In the laboratory and in field trials, the coating demonstrated integrity, was applied much quicker than the traditional heat shrink sleeve, and eliminated several application contingencies. Laboratory investigations undertaken in Houston, Texas and Lyon, France were key steps in selecting the 100% solids tar-polyurethane coating. Additionally, the testing assisted in developing the surface preparation technique, and demonstrating the coating’s ability to adhere to the polyethylene coating as well as the steel pipe. Serious localized corrosion, and cathodic protection shielding associated with other joint coatings are less probable with the new joint coating system. Actual field cathodic protection testing indicated very low current consumption for the completed pipeline. The efficient joint coating operation contributed to setting new construction records.
High Temperature Pipeline Coatings Using Polypropylene Over Fusion Bonded Epoxy
Authors: Norsworthy Richard
Published: October 2016

The following is a discussion of test results and application techniques for high temperature pipe line coatings of polypropylene over fusion bonded epoxy. Recent tests to internal temperatures of 150°C (300°F) indicate these coatings, when applied properly, will perform well at these temperatures. Test results from several different tests are included.

Repairs, field joints and bend coating with these type coatings are discussed. Problems during and after application are summarized. Use of well written specifications and experienced, dedicated inspectors add to the quality of the coating process. As industry moves to hotter and hotter production, these factors become even more critical in the pipeline coating process.
Effect of Asphaltene Deposition on the Internal Corrosion in Transmission Lines
Authors: Morales José L. , Vllorla Alfredo , Palacios T. Carlos A.
Published: October 2016

Crude oil from Norte de Monagas field, in Venezuela, contains large amounts of asphaltenes, some of them are very unstable with tendency to precipitate. Because of liquid is carried over from the separation process in the flow stations, asphaltenes are also present in the gas gathering and transmission lines, precipitating on inner wall of pipelines. The gas gathering and transmission lines contain gas with high partial pressures of CO2, some H2S and are water saturated; therefore inhibitors are used to control the internal corrosion. There is uncertainty on how inhibitors perform in the presence of asphaltene deposition. To protect the pipelines from external corrosion, cathodic protection is used. Since asphaltenes have polar properties, there exists an uncertainty on whether it enhances asphaltene precipitation and deposition. The purpose of this paper to describe the causes that enhance asphaltene deposition on gas and some of the preliminary result from an ongoing research project carried out by Intevep and Corpoven.
Pipeline Accident Statistics: Base to Pipeline Rehabilitation
Authors: Chis Timur
Published: October 2016

The climate in which pipeline companies operate continues to change. Industry failures, related to public safety and environmental concerns, are now front page news.

New and proposed regulations such as drug and alcohol testing of employees, instruments internal inspection and standardise oil spill response plans, are modifying the way pipeline companies operate. Paralleling this influences, the market place is also changing.

Declining domestic production refinery closures and new specification for refined products are altering the pipe line distribution system.

All of these changes are presenting new opportunities and many challenges.

In 1995, when CONPET S.A.PLOIESTI Formalised Pipeline Integrity Program, the reasons for the program were to:

- What is the location to pipeline rehabilitation?

- What is failure probability?

This paper reviews some aspects of the pipeline accident statistic to the CONSTANTA DIVISION parts of CONPET S.A.PLOIESTI.
Inspection Challenges: Pigs Versus Pipes
Authors: Holden E. M. , Grimes K.
Published: October 2016

As the size of the international pipeline network grows, and systems age (by the year 2000, over 50% of US gas transmission pipelines will be over 40 years old), and as environmental pressures increase, the demand for inspection is ever more apparent. Pipeline operations’ experience has revealed many “new” defects and “new” inspection problems, many of which have challenged in-line inspection technology and stimulated further developments. This paper describes what pipeline inspection needs to find, the available technology and some examples of the inspection challenges.
Colonial’s Experience With Finding Longitudinal Defects With Internal Inspection Devices
Authors: Johnston Dennis C. , Thomas Stephen S.
Published: October 2016

A number of failures have been attributed to longitudinal cracking on large diameter liquid pipelines. Cracks caused by third party damage and railroad fatigue are discussed. Third party damage cracks originate from gouged dents caused by construction equipment striking the pipeline. The railroad fatigue cracks originate at the toe of tire longitudinal weld as a result of improper loading during transportation. An inspection program was developed to detect each of these cracking types. These inspection programs will be explained and examples of pipe anomalies demonstrated.
Life After Inspection
Authors: Grimes Keith , Jones David G.
Published: October 2016

To gain a financial benefit, a “smart operator” views inspection as part of an overall strategy to maintain a safe pipeline. This paper shows how periodic internal inspections, followed by defect assessments using fitness-for-purpose criteria and selective repair, is the most cost beneficial way of maintaining the safety of a pipeline. It is highlighted that it is important to use (i) genuine high resolution pigs for the inspection and (ii) expert fitness-for-purpose assessment. The cost savings on the optimized future safe operating strategies for the pipeline offset the costs of the inspection and expert assessment.
Coating Integrity Survey Using DC Voltage Gradient Technique at Korea Gas Corporation
Authors: Cho Y. B. , Park K. W. , Jeon K. S. , Song H. S. , Won D. S. , Lee S. M. , Kho Y. T.
Published: October 2016

The reliablity and applicability of various coating defect detecting techniques are investigated utilizing mock pipe. It is shown that both close interval potential survey and dc voltage gradient methods are impertinent as field techniques: They require considerable cathodic polarization in order to effectively locate the coating defects. DC voltage gradient with current interruption technique is recommended as a viable field method in that it is able to precisely locate the defects irrespective of CP condition. Utilizing this method field survey was undertaken for the KGC’s pipeline of 120 km and 106 assumed defects were located.
Stress and Strain State of a Gas Pipeline in Conditions of Stress-Corrosion
Authors: Kharionovsky V. V. , Tcherni V. P.
Published: October 2016

It is shown that in the analysis of causes of stress corrosion cracking (SCC) of gas pipeline (GP) insufficient attention is paid to the role of mechanical stresses. In the paper it is underlined that by consideration of SCC causes it is necessary to take into account real distortions of the form of cross-sections of a pipeline. These are ovality of cross-sections and, the main, dents. Conditions of occurrence of these defects of the form of cross-sections of pipes are considered. The kinds of stress and strain state (SSS) in GP are analysed. The techniques are developed of assessment of the level of residual strains in the area of distortions of the form of cross-sections of pipelines as well as of determination of stresses and strains in them at action of internal pressure. The technique is based on the theory of elastic thin shells. It is shown that through-wall -thickness stresses which were ontained by the technique can considerably exceed the yield stress of steel even for shallow dents. Conclusions are given about necessity to account for stresses in GP in the analysis of SCC causes as well as about necessity of standardizing allowable levels of these stresses.
A Material Model for Pipeline Steels
Authors: Hart James D. , Powell Graham H. , Zulfiqar Nasir
Published: October 2016

Experience has shown that the pipe steel used in the Trans-Alaska Pipeline System has complex properties that must be taken into account in making safety assessments of the pipe. To obtain a better understanding of the steel behavior, a detailed test program has recently been undertaken. The test results have been used to develop a nonlinear model of the steel for use in stress and deformation analysis of the pipeline. This paper first outlines the model, and shows that it captures important aspects of the steel behavior, including progressive yielding and anisotropy. The paper then shows how the values of the model parameters can be calculated from experimental stress-strain data, and how the model can be used for the analysis of pressurized pipelines, accounting for interaction between hoop and longitudinal stress. The theory is based on von Mises yield and the Mroz plasticity model.
Main Principles on Analysis and Design of Buried Ballasted Pipelines on Marshes
Authors: Dimov Leonid A. , Vershinin Valeriy N.
Published: October 2016

State of stress and deformation of buried oil-gas pipelines under, operation must meet appointed requirements on strength, deformability, general stability, etc. Fulfilment of those requirements while designing main and field pipelines in conditions of marshes and marshy soils is very problematical. The cause lies both in weak knowledge of peat reaction to longitidual and lateral displacements of the pipe and in impossibility on account of that to analize the pipe state of stress and deformation taking into consideration the joint pipe-soil deformation.

Wide research into pipe-peat interaction has been carried out at the Institute of Construction (Republic of Komi, Russia). In the paper there are enumerated main principles on design, analysis and engineering of buried ballasted pipelines on marshes, which have been worked at the Institute. The practical value of the work results for improvement of pipelines reliability under operation is emphasized in the paper, too.
Techniques for Preventing Accidental Damage to Pipelines
Authors: Lothon Alain , Akel Samir
Published: October 2016

Following a survey of all of the techniques capable of preventing third-party damage to its gas transmission pipelines, Gaz de France has selected two of them, “Electromagnetic Detection” and “Positioning by Satellite”.

The first technique is based on detection of the magnetic field existing around transmission pipes excited by a driving current. A receiver is mounted on the excavation equipment to detect the magnetic field, thereby preventing any risk of hitting the pipe.

The second technique consists in locating excavators by satellite. Each excavator needs to be equipped with a GPS beacon to know its position. Using the map of the transmission network stored in data-base form — i.e. digitized, the system calculates the position of the excavator relative to the pipes buried in its vicinity so as to avoid any accidental contact.

The main features, advantages and drawbacks of the two techniques are presented in this paper.
Drag Reducing Agent: A Multi-Use Tool for Liquid Pipeline Companies
Authors: Rew David H. , Sandman Steven R.
Published: October 2016

The role of Drag Reducing Agents (DRA) at Lakehead Pipe Line (LPL) has expanded considerably in recent years. It is now a multi-purpose tool that helps manage electric power usage as well as having traditional capacity increase uses. Indeed, DRA is now an important part of operating the LPL system.

This paper examines the multiple uses of DRA as used by LPL. It also describes the structure of the DRA program within the company and provides a summary of “lessons learned” since the DRA program started at LPL in 1991. This information should be useful for anyone who is considering implementing a DRA program.
Pipeline Operation and Safety
Authors: Tadors Magdi Kamel
Published: October 2016

Safety is central to the prosperity of the pipeline industry and the need to maintain high standards of the saftey at all times is of paramount importance and therefore, it is a primary concern of pipeline operator, adquate supervision and controlling the operation of pipelines as will as clearly defined codes of pract-ice, standards and maintenance schedules are necessary if protection is to be afforded to the pipeline system, employees, the puplic at large and enviroment.
Aerial Surveillance for Gas and Liquid Hydrocarbon Pipelines Using a Flame Ionization Detector (FID)
Authors: Riquetti Patrick V. , Fletcher Jayne I. , Minty Colin D.
Published: October 2016

A novel application for the detection of airborne hydrocarbons has been successfully developed by means of a highly sensitive, fast responding Flame Ionization Detector (FID.) The traditional way to monitor pipeline leaks has been by ground crews using specific sensors or by airborne crews highly trained to observe anomalies associated with leaks during periodic surveys of the pipeline right-of-way. Our goal has been to detect leaks in a fast and cost effective way before the associated spill becomes a costly and hazardous problem. This paper describes a leak detection system combined with a global positioning system (GPS) and a computerized data output designed to pinpoint the presence of hydrocarbons in the air space of the pipeline’s right of way. Fixed wing aircraft as well as helicopters have been successfully used as airborne platforms. Natural gas, crude oil and finished products pipelines in Canada and the United States have been surveyed using this technology with excellent correlation between the aircraft detection and in situ ground detection. The information obtained is processed with a proprietary software and reduced to simple coordinates. Results are transferred to ground crews to effect the necessary repairs.
Monitoring of the Natural Gas Supply to the Greater Buenos Aires
Authors: Gil Salvador , Cavallo Gustavo , Fusario Edgardo
Published: October 2016

In this work we present the main characteristics of a model of the high pressure ring that supply natural gas to the Greater Buenos Aires. This model is intended to predict possible emergencies situations in the system within two to three days in advance. It is based on the dependence daily consumption of natural gas on the average daily temperature and the status of the pressure regulators at the end of the pipelines. The result of a test of the model using actual data for the winter of 1994 and 1995 suggests that the model does provide adequate warning two days in advance. Finally we present a brief analysis of the accuracy of the temperature forecast, that is used in our prediction of temperature, to gauge the robustness of our model.
High Pressure Hot Fluid Oil Field Fiberglass Pipelines
Authors: Lee G. L.
Published: October 2016

This paper describes the successful innovation in materials selection, testing, design, construction and operation of Fiberglass Reinforced Plastic (FRP) pipelines to handle the highly corrosive hot oil field production gathering fluids ( 80 C, 6.9 MPa) and high pressure produced water (70 C, 17.2 MPa). Materials selection includes technical comparison of all available options and life cycle economics. Materials qualification includes long term hydrostatic strength test at 93 C. Design meets API 15HR and CSA Z662. The pressure sealabilty of the threaded connection is ensured with an innovative make up procedure that measures make up position and a belt tong that grips FRP without damaging it Construction practices include protection of FRP during back fill. Evaluation of operational performance includes shut-in / start up, cool down / warm up and additional pressure tests.
Crossing Conflict: The In-Service Lowering of a 34” Crude Oil Pipeline for the Construction of the Owen Flood Diversion Channel
Authors: Mikkola Cari A. , Fridel Thomas W.
Published: October 2016

Lakehead Pipe Line Company, Inc. (LPL) was involved in a collaborative effort with State, local, and private agencies to solve a major crossing conflict in Owen, Wisconsin. This report describes the analysis and design of an in-service lowering of a 34” crude oil pipeline. An integrity assessment was performed using internal smart pig data and magnetic particle and ultrasonic inspections. The pipeline lowering design was based on maximum allowable pipe bending moments and included a coating replacement program and river weight installation. The paper describes design options, right-of-way agreement, contracts, pipe repair techniques and construction.
Pipeline Purging Principles and Practice
Authors: Johnson James E. , Svedeman Steven J. , Kuhl Christopher A. , Gregor John G. , Lambeth Alan K.
Published: October 2016

Gas purging, a process of displacing one gas by another gas, occurs on a routine basis in the natural gas industry when pipelines are purged into and out of service. In a project sponsored by the Gas Research Institute and in cooperation with the American Gas Association (A.G.A.) the purging practices as outlined in the A.G.A.’s Purging Principles and Practices manual are being reviewed because many of today’s pipeline purging operations occur under conditions not addressed directly in the manual. The program focus is on the purging procedures outlined in Chapter 8 of the manual entitled Gas Transmission and Distribution Pipes.

The technical objective of the project is to develop an understanding of the scientific principles upon which safe, practical purging practices can be based. Direct displacement and inert gas slug purging operations are explained in terms of dispersion and mixing parameters and their relationship to the gas velocity. Field data is compared to the results of an analytical mixing model. Computer software for planning safe and cost effective pipeline purges has been developed. Finally, recommendations for revising Chapter 8 of the A.G.A. manual are presented.
Design and Construction of the World’s Longest Liquid Sulphur Pipeline
Authors: Baron John J. , Lawrence J. E. (Ted) , King Graeme G.
Published: October 2016

Sulphur is extracted from sour gas at Shell’s Caroline Gas Plant in the foothills of the Rocky Mountains in Alberta, Canada. A buried pipeline carries the liquid sulphur 41 km cross-country to a railhead at Shantz. Sulphur is difficult to handle by pipeline because it remains solid at temperatures up to 118.9°C. Challenges posed by high operating temperatures necessitated many innovations during design and construction.

The liquid sulphur pipeline is built from two coaxial pipes. The inner pipe carries liquid sulphur while the annular space carries circulating hot water under pressure. The inner pipe has a diameter of 219.1 mm (NPS 8) and the outer pipe has a diameter of 323.9 mm (NPS 12) with 80 mm of high density urethane foam insulation. A hot water return line with a diameter of 168.3 mm (NPS 6) and 50 mm of insulation completes the loop for the continuous circulation of hot water. Two hot water heaters are installed, one at each end of the line. The system can carry between 0 and 5,100 tonnes of liquid sulphur per day on a continuous basis, and can be easily expanded to 8,000 tonnes per day by adding extra pumps.

Construction of this unique pipeline required skilled workers operating under sometimes difficult climatic conditions. The route winds through hilly terrain in the foothills of the Rocky Mountains and crosses under three major rivers. Careful planning led to the successful completion of the world’s longest liquid sulphur pipeline on time and under budget. The pipeline has now been operated successfully for more than three years.
Detonation Arrestors: Evaluating Explosions due to Self-Reignition
Authors: Williams Daniel N. , Bauwens Luc
Published: October 2016

Detonation arrestors are a key safety component in several gas handling facilities. The arrestor should be able to handle the largest explosion expected in the system. Using numerical simulations, we have studied detonations in conditions characteristic of near-limit mixtures where the wave will fail. When subjected to a one- or two-dimensional perturbation, the detonation initially fails, splitting up into a weak shock, surface discontinuity, and a rarefaction wave. Eventually, the detonation is reignited by a powerful explosion, much stronger than the steady C-J wave, that originates behind the leading shock. The explosions occur as a result of slow chemical heating in a pocket of fluid. In two-dimensions the explosions may occur earlier because the shock structure causes uneven distribution of temperature. The reignition process was analyzed with a one-dimensional model, and the results suggest a simple rule that may be used to evaluate the time and distances for an explosion to occur.
Black Point Gas Pipeline Storage Pressure Letdown Control Valves
Authors: Kowalski Richard A. , Ng K. C. , Mueller Thomas J. , Miller Herbert L.
Published: October 2016

A long 778 km high pressure, submarine pipeline supplying natural gas will serve multiple combined cycle gas turbine peaking units on the Pacific Rim. The gas supply flow into the pipeline is constant, but the power plant will primarily operate during daylight hours or in certain situations, operate in a two-shift mode. So the pipeline essentially serves as an increasing pressure, gas storage vessel during the night, and pressure falls off during the day as the gas is fired. Hence, the gas letdown receiving station presented many critical design challenges. Among these were the need for constant plant service pressure control, especially during individual power generator unit startup, shutdown, and upset conditions. In addition, there was a very severe noise attenuation requirement and high gas flow rangeability was required. This complex, integrated gas pressure, control valve letdown system and its operation is described in detail.
Effect of Impeller Cutdown on Developed Head
Authors: Yedidiah S.
Published: October 2016

This paper discusses the manner, in which a new approach towards calculating the head developed by a centrifugal impeller can be applied towards predicting the head developed by a pump with a cut-down impeller.

A comparison with actual test-data demonstrates, that this approach is capable to produce more reliable results, than any of the presently known methods.
Interrelationship Between the Efficiency Characteristics and the Pressure Head Gradients Among Axial Flow Pumps
Authors: Tanaka Takaharu
Published: October 2016

There is a correlation between the efficiency of the pump to the head produced. On the axial flow pump, whose efficiency characteristic is favorable, the pressure head gradient between the impeller inlet and the outlet sections, at an equivalent flow rate, may become larger than that for the less favorable axial flow pump. This fundamental interrelation may be held in the flow passage regardless to the flow rate whichever they are operated at design or off design flow rate.

There may be a direct correlation between the efficiency of an axial flow pump and the ratio of the discharge valve cross section divided by the pipeline cross section. The smaller this ratio is the better the pressure head gradient is for the same flow rates. This ratio may be useful to estimate relative grade of heads, pressure head gradients, internal flow conditions, and efficiency characteristics among axial flow pumps.
Application Concerns With Adjustable Frequency Drives
Authors: Lockley William E.
Published: October 2016

This paper outlines the technologies used in adjustable frequency electric drives from 500 HP up, and gives an overview of some of the present application concerns and solutions to potential problems that should be considered for reliable operation. The electronic devices and systems as well as the types of motors are briefly described. Application concerns with the external power system, the drive itself, thermal, mechanical and electric problems with motors as well as systems concerns are discussed.
Acoustical Pipe Laggings for Reducing Turbocompressor and Flow Generated Noise
Authors: Frank Leslie D. , Spillman Ronald R.
Published: October 2016

A significant source of noise at pipeline facilities is piping radiated noise. Although the noise generation is due to the internal geometries and flow conditions of the rotating equipment or due to the orifices or valves, the acoustical radiator is the piping. Piping and compressor casings on numerous gas turbine driven turbocompressor packages as well as piping at meter stations and regulator stations have been treated using acoustical laggings, as a retrofit as well as during design. However very little information exists in the industry regarding the acoustical performance of site installed acoustical lagging systems. With the advent of innovative testing techniques, installed lagging system Insertion Losses have been obtained, and significant experience has been gained regarding material selection and system performance. As opposed to the massive panels typically used for acoustical enclosures on turbocompressor packages, acoustical laggings utilize lightweight and often removable materials. This paper discusses material properties that enhance the performance of acoustical lagging systems, considerations regarding corrosion prevention and removability, the importance of proper installation techniques, and field testing procedures to determine installed performance of acoustical lagging systems.
Sensitivity of Torsional Analyses to Uncertainty in System Mass-Elastic Properties
Authors: Murray Brad D. , Howes Brian C. , Chui Jonathan , Zacharias Valerie
Published: October 2016

Shaft torque and corresponding stresses in a motor driven - direct coupled - reciprocating compressor system, are significantly influenced by the system’s mass-elastic properties. Uncertainty in the system’s mass-elastic properties will therefore translate into uncertainty in the calculated system stresses. Three case studies provide the reader with an appreciation for the importance of defining uncertainty bands in the mass-elastic properties of a torsional system.

The case studies are followed by a theoretical discussion section. The reader is introduced to the concept of torsional resonance, uncertainty in calculated system torsional natural frequencies is defined, and the relative influence that specific system mass-elastic properties have on the overall system is discussed. A full compliment of system mass-elastic uncertainties is presented.
Reducing the Life Cycle Cost of Swing Check Valves
Authors: Roorda O. , McNeill J. D. , Wright M.
Published: October 2016

Within the oil and gas industry there is an emerging trend to estimate expenses for pipelines and system components using a Life Cycle Cost (LCC) basis. This paper describes a new sizing model for swing check valves that can assist in significantly reducing the LCC of the valve. The incremental fuel cost of the compressor arising from pressure loss across the valve is the largest component of the valve’s LCC. The valve’s pressure loss can be minimized by correct valve sizing ensuring full valve opening under normal flow conditions.

This new sizing program, applied to an NPS 20 natural gas pipeline, can result in cost savings in the order of two times the capital cost of a swing check valve when compared to traditional sizing methods.

The pressure loss across the valve is primarily determined by the opening angle of the valve disc during steady state operation. A steady state valve model was developed and formed the basis for a sizing program for swing check valves. The sizing program assists in optimizing the valve for specified operating conditions. Within margins, the valve opening characteristic can be optimized by adjusting the valve sizing parameters such as valve size, disc weight, counter balance mass and position for a specified set of operating conditions.

The LCC of a swing check valve can be further reduced by up to 45% through optimization of the valve design. The sizing program was used in a parametric study to assess the areas relevant in the design optimization of the valve. To further reduce the LCC of swing check valves, research should focus on improving the internal flow profile of the valve, reducing disc weight and eliminating the need for counter balance weights through improving low friction seal design.
Pipeline Control System Applications Targeting Business Objectives
Authors: Feniak John E. , King Dan A. , Mensik Michal
Published: October 2016

Today’s increasingly competitive markets require new levels of reliability, flexibility and cost performance from gas transmission pipelines. One method that pipeline companies can use to address these business objectives is to target station and turbomachinery control system design specification, retrofits and integration.

State of the art control tools and technologies have placed turbomachinery control engineering within the grasp of the end users. NOVA Gas Transmission Ltd. (NGTL) has taken advantage of this to specify, design, and implement integrated control systems that best address their business needs.

This paper explores the end user perspective on applying control system technology to both new and existing compressor stations. The specification of new units and control retrofits are described. The resulting increase in system reliability and flexibility, and reduced maintenance costs is also presented.
Ultrasonic Transducers for Measuring Air Flow Near One Bar and High-Temperature Fluid Flows up to 100 Bar
Authors: Liu Yi , Lynnworth Lawrence C. , Nguyen Toan H. , Xiao Dean , Walters Jeffrey
Published: October 2016

For ultrasonically measuring the flow of air at ordinary conditions in common pipe sizes, a simple 100-kHz transducer design often suffices, as the generator and detector of the contrapropagating waves. To prevent crosstalk, acoustic isolation is needed. Isolation can be provided by supporting each transducer between soft O-rings. When the gas is hazardous, corrosive, and at high temperature or high pressure, more rugged transducers are required. One such rugged design consists of one buffer rod inside a permanent pressure boundary. The transducer is always outside the pressure boundary and can be removed without recourse to isolation valves and insertion mechanisms.
Development of a Simulator-Based Training Program
Authors: Salerno Charles R. , Radu Edith , Persic Nerino , Schmitz David B.
Published: October 2016

This paper presents the Con Edison Gas Control experience in developing a simulator-based training program.

The simulator-based training is now part of the Con Edison safety training as it allows the gas controllers to get familiar with abnormal and emergency conditions and learn to react promptly to contain the problem.

The process of developing a training course required a sustained and dedicated effort. A number of iterative steps were necessary as we learned that the development of models and scenarios for training is a specific activity which is different from other activities such as simulator-based studies.

The simulator-based training course we developed has two parts: basic concepts and Con-Edison specific lessons. Each part required a different lesson format and issues related to the development of the lessons are discussed.
Elements of Comprehensive Pipeline Optimization
Authors: Short Michael , Meller Steven H.
Published: October 2016

It is well known that algorithms exist for reducing pipeline operating costs. These algorithms are exact for ideal pipelines and need to be modified to provide solutions for the real world. The issues include pipeline configurations, utility cost structures, and quantification of hydraulic safety. Successful modification requires understanding of the pipeline operating environment (on-line operations) and must be linked to pipeline operating conditions.

Many of the optimization tools available to the pipeline industry today are based upon a dynamic programming algorithm attributed to Bellman. The costs of unit operations are balanced with the energy absorbed in heat due to frictional and other losses. This is carried out in such a way as to reduce the massive computational effort of an exhaustive solution search to a manageable level. For a pedagogical treatment of the problem, this is adequate. However, there are many significant factors which need to be added into and around this basic calculation. First, an algorithm with electrical cost factors only cannot evaluate penalties associated with poor hydraulics choices. Demand grouping, parallel pipelines, large amplitude pressure cycles, look ahead, and unit cycling also can and should be included in a full analysis.

A modification to Bellman’s algorithm for non-linear pipeline configurations and electrical contracts will be developed and discussed in the context of a real-world petroleum pipeline operation.
The Role of Geotechnical Investigation for Directionally Drilled River Crossings
Authors: Barlow J. Peter , Cavers Drummond S.
Published: October 2016

The use of directional drilling techniques for pipeline river crossings has increased sharply over the past few years in Canada and the United States. Improvements in drilling technology and increased experience among a growing number of specialty contractors has helped to reduce the cost of directionally drilled installations and to reduce the risks. The advantages associated with reducing disturbance of the water course by the use of directional drilling are often considered to outweigh the additional costs typically associated with the method.

While the advantages of using directional drilling methods are compelling, the technique is not universally suited to all river valleys due to considerations of valley topography and geological setting. Specifically, there are certain geological and geometrical conditions that make the method completely unsuitable. In other cases, the geology beneath the river channel and the valley geometry may present a challenge to a drilled installation that can be overcome with adjustments to the design and drilling technique if anticipated.

The implications of encountering unfavourable geological conditions during construction can be significant. The implications can range from substantial construction cost overruns up to several times the original bid price, to installations that cannot be safely put into service and must be abandoned. Under certain geological and geometrical conditions, the risk of blowout or fluid leakage to the water course during installation may be significant.

The role of geotechnical and subsurface investigations to identify geological conditions prior to commencing construction is more critical for a drilled installation than for conventional trench techniques, as the consequences of encountering unanticipated conditions can be much more severe with drilled crossings. In addition, a trenched crossing is inherently more flexible than a directional crossing in terms of the ability of the contractor to adapt to different conditions than those anticipated at the start of the work.
Technique of Estimation of Actual Strength of a Gas Pipeline Section at its Deformation in Landslide Action Zone
Authors: Tcherni V. P.
Published: October 2016

The technique is given which permit to determine stress and strain state (SSS) and to estimate actual strength of a section of a buried main gas pipeline (GP) in case of its deformation in landslide action zone. The technique is based on use of three-dimensional coordinates of axial points of the deformed GP section. These coordinates are received by full-scale survey. The deformed axis of the surveyed GP section is described by the polynomial. The unknown coefficients of the polinomial can be determined from the boundary conditions in points of connection with contiguous undeformed sections as well as by use one of minimization methods at mathematical processing of full-scale survey results. The received form of GP section’s axis allows to determine curvatures and, accordingly, bending moments along all the length of the considered section. The account for the influence of soil resistance to longitudinal displacements of a pipeline is used to determine longitudinal forces. Received by this technique values of bending moments and axial forces as well as known value of internal pressure are used to receive all necessary components of actual SSS of pipeline section and to estimate its strength by elastic analysis.
A Case Study of Pipeline Route Selection and Design Through Discontinuous Permafrost Terrain in Northwestern Alberta
Authors: Wiechnik Cory , Boivin Raymond , Henderson Jim , Bowman Mark
Published: October 2016

As the natural gas pipeline system in Western Canada expands northward, it traverses the discontinuous permafrost zone. As the ground temperature of the frozen soil in this zone is just below freezing, it can be expected that within the design life of a pipeline the permafrost adjacent to it will melt due to the disturbance of the insulating cover by construction activities. Differential settlement at the thawing frozen/unfrozen soil interfaces gives rise to pipeline strain. Based on the calculated settlement and resulting strain level, a cost effective mechanical or civil design solution can be selected to mitigate the differential settlement problem. Since these design solutions can be costly, it is desirable to combine them with a pipeline route that traverses the least amount of discontinuous permafrost terrain while minimizing the overall length of the pipeline.

This paper will detail the framework utilized to select the routing for a package of pipeline projects in northwestern Alberta. The process began with a review of the state of the art in permafrost engineering in order to benefit from past experiences. Airphoto interpretation and terrain mapping were performed for potential pipeline corridors. Preliminary routing options through the corridors were chosen from this mapping information that minimized both pipeline length and amount of permafrost terrain traversed. The next step was to collect field data for each route that would determine the extent and characteristics of the permafrost. Essentially two sets of field data were collected: geophysical mapping of representative sections of each terrain type and physical sampling of the permafrost. Boreholes were located following field interpretation of the geophysical data to ensure they were optimally located to help in calibration of the geophysical data. Permafrost samples were tested in the laboratory for thaw settlement. Anticipated thaw settlements were used to estimate pipe strain levels. This information was then extrapolated for the entire proposed pipeline route and used to finalize both the pipeline route and the differential settlement design options. Monitoring sites will be instrumented to obtain data on the longer term performance of the pipeline, as well as for assessing permafrost degradation effects on the right-of-way such as settlement and impact on drainage patterns.

It is believed that the increased front end effort will result in lower operating costs and an overall reduced life-cycle cost. This basic design methodology can be applied to any project that traverses discontinuous permafrost terrain.
Relative Risk Assessment: The Competitive Advantage
Authors: Beighle Bruce D. , Gloven Mike P.
Published: October 2016

Lacking complete and accurate data, many pipeline companies have adopted various forms of relative (index-based) risk assessment models(2) which help define their acceptable risk position based on available pipeline data, limited resources and corporate beliefs. Through this proven risk assessment process, company management establishes their unique risk algorithm by benchmarking variables which contribute to the likelihood of failure, and the associated consequences of failure, for all pipeline systems. This algorithm then acts as a pipeline data filter to identify pipeline areas at greater risk relative to others.

A progressive relative risk assessment process can change an operator’s safety and resource allocation culture, resulting in reduced pipeline failure rates, increased operating flexibility and improved financial performance.
Risk Assessment of Gas Transmission Pipelines in Mexico
Authors: Martinez Jose L. , Alcerreca Héctor G. , Rodríguez B. Enrique , Hernandez Jesus
Published: October 2016

In recent years significant changes have taken place in the Mexican gas industry. Activities related to gas transmission, distribution and storage are no longer the exclusive privilege of PEMEX Gas & Petroquimica Basica (PGPB), a traditionally state-owned company. The first priority of PGPB is to ensure a safe, efficient and reliable pipeline network. Several projects have been established to guarantee a smooth transition from a monopoly to open market competition.

Among these projects is a pipeline risk assessment and management programme (RAMP), to provide feedback on all safety related conditions of PGPB’s pipeline facilities. This project is planned to have a permanent application within PGPB, although a risk acceptance criteria based upon experience gained through the different project stages has yet to be established. This paper provides an approach adopted to assessing risk in more than 13,000 kilometres of pipeline, regardless of the transported fluid. Risk management is considered to be the step following the risk factors evaluation. However, PGPB is aware of the importance of calculating realistic indexes, so that management policies may be defined according to a well known risk magnitude.
Safe Separation Distances: Natural Gas Transmission Pipeline Incidents
Authors: Golub Eugene , Greenfeld Joshua , Dresnack Robert , Griffis F. H. , Pignataro Louis
Published: October 2016

The paper discusses a methodology to define safety implications of and damages that have resulted from gas transmission pipeline failures where fire and/or explosions have occurred. The records of the National Transportation Safety Board were examined to determine the area that was burned and/or impacted by a resulting explosion. The impacted area was then correlated with the physical parameters of the pipeline to see if a relationship existed. The parameters considered included the pipe diameter, the operating pressure at the point of release, the volume of material released, the maximum radius burned by the fire, the height of the flame and the maximum distance effected by the resulting explosion (if one occurred). Two strong correlations were found between the operating pressure in the pipe and the area burned in the incident for the two cases, with and without an explosion taking place. These results may be used to define a safe separation distance for a natural gas transmission pipeline.
Progress of the US Department of Transportation Risk Management as a Regulatory Alternative
Authors: Leewis Keith G. , Shires Terri
Published: October 2016

As of June 1997, many interstate transmission pipelines are deciding whether or not to submit letters of intent, formally indicating they wish to participate in DOT’s Risk Management Demonstration. A joint industry regulatory quality action team developed the five documents for the demonstration: the Program Framework, the Risk Management Demonstration Standard, the Guidance on Performance Measures, the Communications Plan, and the Review Protocols and Criteria. By the August 1st 1997, twelve companies had applied to be accepted into the Risk Management Demonstration program and partner with DOT to show Congress that risk management is a safer and more efficient means of regulating the transportation of natural gas and liquids. Each company has submitted a unique range of RM activities. This paper summarizes the projects, discusses the common Program Wide and unique Project Specific performance measures that evolved from the consultative processes, and attempts to assess the initial success of the program.
Geologic Hazards Reconnaissance and Mitigation, and Implications to Natural Gas Pipeline Operations and Risk Management
Authors: Braun Jill , Major Graeme , Bukovansky Michal , West Donald O.
Published: October 2016

Northwest Pipeline Corporation (Northwest), a Williams Company, operates its 3,900-mile-plus natural gas transmission pipeline system in the northwestern United States. The system consists of a mainline (extending from the San Juan Basin in northwestern New Mexico to the U.S./Canadian border at Sumas, Washington) and numerous laterals that provide natural gas service to customers in six states. The original mainline was constructed in the mid-1950s, when the concern for, and the ability to identify geologic hazards as part of the alignment selection process was much more limited that today. As a result, the pipeline traverses extensive areas with pronounced exposure to numerous potential geologic hazards. A few of these hazards (particularly landsliding) have resulted in significant damage to, or rupture of the pipeline, which has typically been addressed by detailed investigations to characterize and mitigate the specific hazard. Methods have been developed and implemented over more than 15 years to identify and characterize the location, nature and magnitude of the geologic hazards, evaluate their effect(s) on the pipeline, and develop approaches to pipeline operation and management that can be used to mitigate the impacts of the hazards on the pipeline.