bluuebunny/crossref_metadata_2025 huggingface dataset:
L52307 Remaining Strength of Corroded Pipe Under Secondary Biaxial Loading
Authors: Chauhan Vinod
Published: August 2023

Corrosion metal-loss is one of the major damage mechanisms to transmission pipelines worldwide. Several methods have been developed for assessment of corrosion defects, such as ASME B31G, RSTRENG and LPC. These methods were derived based on experimental tests and theoretical/numerical studies of the failure behavior of corroded pipelines subjected only to internal pressure loading. In the vast majority of cases, internal pressure loading will be the main loading mechanism on the pipeline. However, there may be instances when pipelines could also be subjected to significant loading from the environment. For onshore pipelines, these additional loads could be as a result of ground movement due to landslides, mining subsidence, or even seismic activity. In the case of offshore pipelines the formation of free spans may impose significant bending loads. For instance, seabed scour can lead to the development and growth of free spans of pipelines resting on the seabed, particularly if they are not trenched. Whilst, the guidance detailed in standard assessment methods will be sufficient in the majority of cases, it may be inappropriate or non-conservative to use it in cases when the pipeline may also be subjected to significant external loading.

As a result, this work focus on :

The remaining strength of corroded pipelines subject to internal pressure and external loading cannot be explicitly assessed using the ASME B31G, RSTRENG and LPC assessment methods. However, these assessment methods have been validated using pipe with real corrosion and simulated (machined) defects welded to dome ends to form a pressure vessel and subsequently failed under internal pressure loading. Consequently, existing methods include some inherent biaxial loading and the remaining strength of corroded pipelines can be assessed with a limited amount of external loading.
Ground movement due to landslides can impose significant external loading to transmission pipelines. Stresses in pipelines due to landslides can be greater than the stresses due to internal pressure loading.
Methods developed by the nuclear industry for assessing corroded pipework are given in ASME Code Case N-597-2 and based on ASME B31G when the axial extent of wall thinning is limited. For more extensive corrosion, the assessment methods are based on branch reinforcement and local membrane stress limits. Strictly the methods given in ASME Code Case N-597-2 are only applicable to the assessment of piping systems designed to the ASME Boiler and Pressure Vessel Code, Section III.
Failure loci of pipelines with isolated corrosion defects and subjected to combined loads have been derived for common pipeline geometries and materials. The failure loci have been validated using tests performed on 457.2mm (18-inch) and 1219.2mm (48-inch) diameter pipe under combined bending/pressure loading. These failure loci can be used to assess the limit of acceptability of existing assessment methods such as ASME B31G and RSTRENG under combined loading conditions.
L52315 Testing of Environmentally-Friendly Gas Sampling Methods
Authors: George Darin
Published: August 2023

Recent environmental concerns have led to calls for reduced hydrocarbon emissions to the atmosphere from a variety of sources. One source of emissions being examined in this regard is natural gas spot sampling methods that vent pipeline gases to the atmosphere. Some sampling techniques and equipment have been developed that do not emit greenhouse gases, but the need exists to test these methods for their ability to collect accurate, representative samples. Another related concern is the accuracy of samples drawn from streams near their hydrocarbon dew point (HDP). While the spot sampling methods recommended by current industry standards perform well on streams far above their HDP, little data are available on their performance near or at the HDP, where poor sampling methods can cause heavy hydrocarbons to condense from the sample and distort the analysis. This project evaluated the ability of four natural gas spot sampling methods, including two zero emissions sampling methods, to capture accurate, representative samples of gas streams at or near their hydrocarbon dew point (HDP). Two of the sampling methods tested were variations on the GPA fill-and-empty method, with additional steps intended to heat the sampling equipment above the HDP or clear condensed hydrocarbon liquids from the sample line. The other two sampling methods, which use the A+ Q2 sample cylinder and a constant-pressure floating-piston sample cylinder, were developed to prevent condensation of heavy hydrocarbons during the sampling process.
L51396 Microseismic of a Gas Storage Reservoir - Volume 1
Authors: Hardy  , Mowrey  , Kimble
Published: August 2023

The main objectives of the overall program have been the development of techniques for evaluating optimum pressures for underground storage reservoirs and for evaluating their mechanical stability under such operating conditions. Based on the encouraging results of the preliminary micro seismic studies, it was decided to undertake a detailed state-of-the-art evaluation of a selected gas storage reservoir in order to further perfect experimental procedures and to develop additional documentation.
L51448 Factors that Control Toughness in Mechanized Gas Metal Arc Pipeline Girth Welds
Authors: Glover
Published: August 2023

The objective of this present research program has been to investigate the factors that control the toughness of low heat input gas metal arc welds deposited using a mechanized process. This research program has studied the fracture behavior of a series of mechanized gas metal arc welds made by the CRC process. A total of five wires were used and a sixth experimental wire included for comparison purposes. The wires were chosen to represent the effect of increasing alloy content. From each weld wet chemical analyses were taken together with oxygen and nitrogen analyses.
PR-214-104505-R02 Improved Methods for Estimating Remaining Fatigue Life of ERW Pipelines
Authors: Semiga  , Tiku
Published: August 2023

While the general fracture mechanics methodology for calculating fatigue life is well documented and validated, its application in the definition of pipeline system fatigue lives have differed from field experience. The source and magnitude of the conservatism inherent in the calculated fatigue life estimates are a concern when establishing integrity management programs. Of particular interest are the fatigue life estimates used in the integrity management programs for ERW pipeline systems that are primarily concerned with pipe wall anomalies oriented along the pipe axis. This project was initiated to consider several elements of the fatigue life estimation process to identify if there were sources of conservatism that could be better managed to permit integrity management programs to produce life estimates with known levels of conservatism. The project considered:

- Ovality and misalignment stress concentration factors;

- Fatigue crack growth rate (da/dN) material performance; and

- Bulging correction factor.

Both experimental and numerical simulation techniques were used to consider the impact of these factors on rate of fatigue crack growth of pipeline axially oriented defects. The project results were compared to existing codified treatments to quantify the level of conservatism inherent in the current state of practice. Recommendations were provided to enhance the precision and manage conservatism in fatigue crack growth rate calculations used in integrity management.

This work has a related webinar.
L51604 Ductile Fracture Properties of Selected Line Pipe Steels
Authors: Leis  , Brust
Published: August 2023

The objective of this report is to present the ductile fracture properties needed to assess stable flaw growth. These properties are presented following a brief discussion of the analysis method being developed to provide the gas industry with an accurate and validated model for predicting growth of a flaw due to the effects of a hydrostatic test or hydrostatic retesting. The end product will be a validated model that predicts crack extension during the load and hold portion of a hydrotest, and subsequent operation.

Test methods to develop these properties are presented along with discussion of data analysis. Results are presented for three line-pipe steels for the LT (through-wall axial flaw) orientation, for three levels of prestrain.
L00340 Manual for Determination of Supercompressibility Factors
Authors: Zimmerman
Published: August 2023

This manual is based on the findings of PAR Research Project NX-19 initiated by the Pipeline Research Committee in 1956 upon the recommendation of the Gas Measurement Committee. The initial purpose was to extend the range of the A.G.A. Supercompressibility Factor Tables published in 1955, 1956. However, a significant out-come of the project was that in addition to providing the basic data for extending the range, a base equation for calculation of supercompressibility factors was developed. Benefit: The methods, tables, and equations presented in this manual provide extended ranges of coverage, simplification of use, and broadening of the applicability of the procedures published in A.G.A. Gas Measurement Committee Report No. 3. \Orifice Metering of Natural Gas.\" To determine a supercompressibility factor for natural gas
L51278 Mutual Design Considerations for Overhead AC Transmission Lines and Gas Transmission Pipelines
Authors: Stein  , Elsea
Published: August 2023

This project was a joint effort by the Pipeline Research Committee of the PRCI and EPRI to develop analytical techniques for determining the induced potential on pipelines that parallel electric transmission lines. This is an area of interest to both electrical system and pipeline operators. The purpose of this project was to develop analytical methods for the prediction and mitigation of voltages induced on natural gas pipelines by nearby AC transmission lines. Analyses of AC corrosion effects, personnel safety, and pipeline component reliability were performed.

The study consisted of the following steps: - Consolidate known data concerning mutual effects arising from power lines and pipelines sharing a common right-of-way; - Develop a unified and systematic method for predicting electromagnetically induced voltages and currents on pipelines; and - Investigate mitigation techniques to minimize interference effects upon pipeline and component reliability and personnel safety. New techniques for interference prediction and mitigation were developed. Volume 1 details the engineering analysis and Volume 2 presents prediction and mitigation procedures.
L51409 Fracture Toughness of Pipeline Girth Welds
Authors: Glover
Published: August 2023

Over the past few years, greater and greater emphasis has been placed on the reliability of transmission pipelines resulting in more frequent engineering critical assessments. One of the areas of high interest in such critical assessments is the behavior of the field girth weld. However, before any fracture assessment can be carried out on the weld, the fracture toughness of the girth weld must be known. The design requirements of a transmission pipeline usually means that an elastic-plastic analysis is appropriate, and hence a test is needed to assess the general yielding fracture behavior of the girth weld. One of the most appropriate is the British Crack Tip Opening Displacement (CTOD) method. The use of the CTOD approach to evaluate weld defect significance has been widely used throughout the world, and these applications have highlighted potential problems with the test.

The object of this present program was to study the effect of this test technique and specimen location on the CTOD toughness of pipeline girth welds. This report covers the testing of three manual and one automatic girth weld under a variety of conditions and considers the significance of the various techniques. The experimental program was divided into two distinct phases. The first phase was designed to study experimental techniques, including the effects of constraint, fatigue pre-cracking, specimen design and crack-tip location. The second phase was a systematic study of the weld, concentrating on the effects of specimen location on toughness around the circumference.
L52047 PRCI Pipeline Repair Manual 6th Edition
Authors: Jaske  , Hart
Published: August 2023

Note the PRCI Pipeline Repair Manual 2021 Edition is now available and supersedes this edition. The 2021 Edition is available here.

Technology advancements in materials, techniques, new products, procedures, etc. offer pipeline companies the opportunity to extend the safe life of assets in place. A comprehensive Pipeline Repair Manual is needed to address these new advances, provide engineering guidance to choose appropriate repair techniques for specific defects in pipelines. This new updated Pipeline Repair Manual provides guidance to pipeline operators as they: (1) choose appropriate repair techniques for specific defects in in-service pipelines; (2) develop or enhance their own procedures and/or manuals for pipeline repairs; (3) or train or qualify maintenance personnel. The manual presents a catalog of known pipeline repair techniques, and discusses the various types of pipeline defects that lend themselves to being repaired while in-service. A matrix is provided to match defects in need of repair with appropriate repair methods. In addition defect assessment methods are presented as are safety considerations related to making in-service repairs. The manual is divided into the following major sections: (1) Response to the discovery of an anomaly or defect - this section presents safety issues and defines critical information that is required to make an appropriate repair response. (2) Pipeline repair methods - this section describes the known methods of repairing in-service pipelines. (3) Appropriate repairs for various types of defects - this section matches the types of defects that are likely to be encountered in in-service pipelines with appropriate repair methods. (4) Repair methods in Europe - this section was added after a review of the draft by a committee of pipeline repair specialists from several European pipeline operators who are members of the Group Europeene de Recherches Gazieres (GERG). It contains suggestions made by the committee to enhance the substance of this manual and to inform readers concerning European practices. (5) Guidelines for repair procedures - this section presents a model procedure, which a pipeline operator may use to create, enhance, or evaluate repair procedures.

This document was formerly known as 'Updated Pipeline Repair Manual Revision 6'
L52059 Evaluation of Grouted Tee Connections for Thin-Walled Pipe
Authors: Bruce
Published: August 2023

There are a number of applications where the attachment of hot tap fittings to in-service pipelines by welding is difficult, if not impossible. These applications include very thin-wall pipelines, older carbon steel pipelines with very high carbon equivalent values, pipelines made of high-alloy materials, sub-sea pipelines, etc. There are two primary concerns with welding onto in-service pipelines and piping systems. The first concern is for welder safety during welding, since there is a risk of burnthrough, where the welding arc causes the pipe wall to be penetrated allowing the contents to escape. The second concern is for the integrity of the system following welding, since welds made in-service cool at an accelerated rate as the result of the flowing contents ability to remove heat from the pipe wall. These welds, therefore, are likely to have hard, crack-susceptible heat-affected zones (HAZs) and may be susceptible to hydrogen cracking. An alternative method of attaching hot tap fittings is therefore attractive.

This repot evaluated the use of Grouted Tee technology developed by Advantica for the installation of in-service branch connections in situations where in-service welding is difficult or impossible.
L41009 Material Balance Equation for Partly Depleted Oil Reservoirs Repressured with Gas
Authors: Hodgson
Published: August 2023

This project researched the use of a model oil reservoir and new concepts of reservoir engineering to develop a simple method of predicting oil recovery as a byproduct of gas storage operations. This paper is the fourth in a series reporting the progress of a study of reservoir performance during complete gas re-pressuring and gas cycling. It presents a new material balance equation (MBE) for calculating initial oil volume and relationship of average reservoir pressure to net gas in storage. The new MBE is particularly helpful in making field case history studies of oil reservoirs that have been completely re-pressured with gas. These studies must reveal the percentage of oil recovery, which requires, in turn, that the initial oil volume be determined accurately.

A material balance equation was derived for calculating (1) the initial oil volume and (2) the relationship of average reservoir pressure to net gas in storage in reservoirs used for natural gas storage operations. The equation is also applicable to secondary-recovery operations where reservoirs are completely re-pressured and gas cycled. Using this equation minimized two probable sources of appreciable error in conventional material balance calculations: inaccurate measuring of and accounting for produced gas, and differences between true reservoir pressure and average reservoir pressures as derived from bottom-hole pressure measurements. A new procedure is presented for calculating water encroachment. By solving the conventional material balance equation and the derived equation for gas storage simultaneously, the values for initial oil in place and net water encroachment can both be determined.
L51460 The Effect of Random Seas on Pipeline Stability Vol II Finite Element Modeling of Pipeline Response
Authors: Hudsepth R.T. , Leonard J.W. , Tedesco J.W. , Zimmerman M. , Borgman Leon
Published: August 2023

Traditional design practices for offshore pipelines attempt to ensure stability along the entire pipeline system. In shallow water, the standard practice requires the burial of pipeline systems resulting in increased construction costs from trenching operations. Present design methodologies for marine pipeline systems generally require only a static-equivalent stability analysis using hydro-dynamic pipe loadings computed from a design wave.

The purpose of this analysis is to develop a finite element method (FEM) formulation that can be utilized for a detailed study of the evolution of pipeline configurations under random wave attack from directional seas. The primary features of the FEM algorithm developed include: 1) the ability to predict the large deflection response of the pipeline; 2) the ability to model nonlinear hydroelastic fluid forces; 3) the ability to independently model cohesive and cohesion-less sediment loads; and 4) the ability to adopt irregular bottom contours. Additional features provided by the finite element method include: 1) flexibility in discretizing the pipeline system; and 2) the ability to model features such as a missing weight coating along any arbitrary portion of the pipeline.
L51509 Two-Phase Flow in Horizontal and Inclined Pipes at Large Pipe Size and High Gas Density
Authors: Kiefner  , Duffy
Published: August 2023

Knowledge of flow regime, holdup and pressure drop is needed in order to design gas and oil pipelines confidently and to minimize construction and operating costs. Previous public studies of two-phase flow in inclined pipes have used small diameter pipes two inches in diameter or less, and have primarily used air and water as the working fluids at low pressure (near one atmosphere). Present design methods are based upon the results of these experiments. In most advanced analyses available today, the flow regime transition is governed by a Froude number, the balance between inertial and buoyancy forces.

The primary objective of the work has been to obtain experimental data to challenge the present two-phase flow analysis methods for large pipe size, high gas density, and pipe inclination. Present analysis and design methods for two-phase flow in pipelines are based on correlations of data from small pipes of order 2-inches diameter or less, for air-water flows at pressures near one atmosphere. To achieve this objective, Creare performed experiments in an existing test facility with a special test section assembled for this project. Pipe diameter and gas density are closer to prototypical oil and gas pipeline conditions than previous experiments reported in the literature. The key experimental results include flow regime observations, pressure drops, and holdup measurements. The instrumentation in the test facility allows detailed characteristics of the flow such as slug velocity, slug frequency, liquid film velocity, and slug length to be measured in the slug flow regime.
L51557 Pressure Losses in Compressor Station Yard Pipework - Phase II
Authors: Beavers
Published: August 2023

The economic assessment of piping layout in compressor station yards relies on accurate prediction of pressure losses within the network. Methods currently used to predict pressure losses in station pipe work are unreliable. As a result inadequate and inaccurate information is being used when making economic assessments of piping layout and in the prediction of operating costs. By improving the design process substantial economic advantages may be gained in balancing pressure losses and compressor inlet flow conditions against investment in piping and components. Currently the existing data concentrate on isolated component losses and there is a lack of reliable data on interaction of adjacent components frequently present in compressor yard layouts. Thus, in order to produce a comprehensive guide to compressor yard losses, there was considerable incentive to quantify these interactions.

This report details the experimental work to provide reliable pressure loss data for an engineer's design handbook. The tee tests include the effect of branch to run radius and two area ratios. A total of 36 bend/tee combinations were tested. Results are presented as overall bend/tee pressure loss coefficients and interaction corrections. The latter are used in the design handbook. The factors affecting bend and tee performance are discussed. Bend/tee interactions are explained qualitatively in terms of interaction of the pressure and flow distributions within the components. The work covers pressure losses in bends, close coupled bend/bend combinations, tees (combining and dividing) and tee/bend combinations.
L51379 Impacts of the Natural Gas Industry on Drinking Water Quality and Human Health
Authors: Smith
Published: August 2023

The Environmental Protection Agency (EPA), under the authority of the Safe Drinking Water Act of 1974, has responsibility for setting standards for safe drinking water. This and other recently enacted or amended public laws gives EPA broad regulatory responsibility for insuring the quality of both surface and groundwater supplies. Under these various laws each major industry will be evaluated for their potential impact on water quality and for any resultant effects on human health or the environment.

The report summarizes the results of a research project conducted by Midwest Research Institute (MRI) for the Pipeline Research Committee of the Pipeline Research Council International (PRCI) in support of the Association's activity in the water quality area. This study involved the review of available information on the health effects of the natural constituents and odorant additives of natural gas. Effort was also directed toward the compilation of available information on the levels of natural gas in groundwater supplies.
L51679 Diver Assisted Pipeline Repair Manual
Authors: Mohr M. O.
Published: August 2023

Much of the industries offshore pipeline system, especially in water depths of 100 ft. or less, is approaching its design life. As this pipeline system ages, the likelihood of a failure due to erosion and/or corrosion in any part of the system is expected to increase. Other factors such as operational errors, vessel related impacts, and environmental phenomenon all contribute to offshore pipeline failures. The basic technology for repairing damaged or failed pipelines offshore has been known for several years. This technology continues to be refined and developed to meet more hostile environments and to improve reliability. At the same time, attempts are being made to minimize the time taken to affect a repair, thereby reducing the downtime of the line and the total cost of the repair. Three volumes intended to provide the field engineer a guide for the identification and selection of an appropriate diver-assisted repair method for the determination of the required service support, the location of the appropriate repair hardware, and an estimation of the time and cost associated with the repair.
L51554 Field Observations on the Two-Phase Hovenweep CO2 Gathering System During Summer Operation
Authors: Alexander  , Kiefner
Published: August 2023

While laboratory-scale studies of single-phase flow have resulted in good correlations for the design of large-diameter pipeline systems, similar approaches for two-phase flow have not been as useful. Although theoretical modeling and simulation of single-phase turbulent flow has not yet been accomplished, empirical observation of many small-scale examples has lead to effective correlations through dimensional analysis. These correlations for a single-phase often do scale-up adequately for design of pipelines. However, when an additional phase is present, this approach has not worked well. It is likely that a better understanding of the fundamental interaction of two-turbulent phases will be necessary if small-scale studies are to be used for the design of large, high-pressure pipeline systems.

A more immediate way of gaining some knowledge of two-phase flow in large diameter pipes of the complexity present in the field is to over-design a pipeline system and construct it, field tune it to specifications, then observe its behavior. This is obviously a risky and expensive approach. However, many such systems have been constructed. It is on these successful two-phase pipeline systems that our attention should be focused in the immediate future if we are to improve two-phase pipeline design now of new but similar systems. Such is the focus of this study of the Hovenweep CO2 Gathering System.

The Hovenweep CO2 Gathering System was selected for study as a pipeline system that could add to the knowledge of the nature of steady-state two-phase flow in large diameter high pressure pipeline systems with hilly terrain. Characterization includes measurement of the following variables: 1. gas and liquid flow rates; 2. typical gas and liquid compositions; 3. liquid volume fractions; 4. pressure drop across each test segment; 5. temperature.
L51603 Investigation of Amine Induced Stress Corrosion Cracking of Steels in Natural Gas Treatment Plants
Authors: Unknown Author
Published: August 2023

The possibility of extensive SCC in natural gas treatment plants is of obvious concern to the gas transmission industry. As a result, PRCI initiated a research project at Southwest Research Institute (SwRI) to investigate the SCC susceptibility of carbon steels in MEA and DEA solutions typical of amine solutions used in natural gas treatment plants. The primary objectives of the project were: to determine the parameters responsible for cracking; and to determine modifications to plant equipment an and or process chemistry that might be used to control SCC in natural gas treatment plants.

This report describes the factors responsible for stress corrosion cracking (SCC) of steels in natural gas treatment plants using ethanolamine solutions to remove acid gases from natural gases; and to determine modifications to plant equipment and/or process equipment that might be used to control SCC in natural gas treatment plants.
L51694 Investigation of Techniques for Bulk Stress Measurement on Exposed Pipelines-Phases I and II
Authors: Kwun H.
Published: August 2023

Differential movement of a buried pipeline resulting from terrain instabilities such as subsidence, fault slippage, frost heave, ice scouring, soil movement, and landslide can create localized areas of high stress in a pipeline. These areas may be susceptible to mechanical failure and therefore may compromise the structural integrity of the line. Nondestructive testing (NDT) methods that can detect high-stress regions and measure the magnitude of the stress in the pipeline are needed to determine if or when remedial action must be taken to prevent stress-related damage. The areas of high stress can compromise the integrity of the pipeline, despite the fact that the highly stressed areas may not be readily detectable.

�This report describes two phases of development for a nonintrusive technique to quantify the local, throughwall average axial stress in an exposed pipe. The technique selected for evaluation and development is a low-frequency, electromagnetic technique, called multiparameter magnetic measurement (MPMM). MPMM is a combination of existing magnetic techniques including magnetic hysteresis measurement, nonlinear harmonic analysis, and multiparameter correlation. The work included both a proof-of-principle demonstration of the technique using samples of grade X-42, X-46, and X-52 pipe (Phase I), and further determination of practical applicability of the MPMM technique (Phase II). Phase II focused on evaluating the variability of magnetic response to stress among five samples of grade X-42 pipe.
L51807 Characterization of Axial Flaws in Pipelines with a Focus of Stress Corrosion Cracks
Authors: Leis
Published: August 2023

This report presents the results of a series of projects that involved: (1) characterizing the behavior of crack colonies associated with stress-corrosion cracking (SCC); (2) developing failure criteria to provide safety without undue conservatism; and (3) developing criteria to characterize crack coalescence prior to SCC leaks. Analytical details are given for the various types of axial cracks, with a focus on short, deep cracks, patches of SCC cracks often found in field-digs, and deep, co-parallel cracks. All analyses were done in a fracture mechanics framework for use in developing criteria to ensure safety and assess the serviceability of natural gas transmission pipelines.
L51741 Development of a Model for Fatigue Rating Shallow Unrestrained Dents
Authors: Rosenfeld
Published: August 2023

The ability to fatigue-rate dents in line pipe is important for three reasons. First, field failures give evidence that fatigue crack growth occurs in dents under certain circumstances in spite of the fact that plain dents are generally thought to have little effect on the integrity of natural gas pipelines based on the results of single-cycle burst tests. Second, many operators are discovering large numbers of dents on the bottom quadrants of their pipe associated with rocks and backfill loads. Guidance is needed for discerning dents for which excavation and inspection is economically wasteful and counterproductive to pipeline safety from those dents for which further action would be beneficial. Third, fatigue life may be a more rational basis for rating the severity of a dent than present criteria which rely solely on dent depth with a maximum depth of 6 percent of the pipe diameter as a generally accepted limit. In some cases deeper dents might be permitted to remain in service, while in other cases, shallower dents should be repaired.

The goal of this project was to develop guidelines for pipeline operators to assess the severity of dents on the basis of their fatigue life in-service. The assessment uses pipeline operating pressures and simple geometric measurements of the dent.
L52246 Damage Management for Operating Pipelines Gap Analysis
Authors: Fuglem
Published: August 2023

Given the extensive and aging infrastructure of pipelines in developed countries, as well as increasingly stringent regulatory requirements, there is a large incentive to improve damage management processes in order to reduce failures and maintain the existing pipeline infrastructure for a longer period of time. Industry is responding by focusing research and development efforts on key damage management concerns.

The objectives of this report were: to review previous work relating to damage management of onshore gas and liquid transmission pipelines as conducted by PRCI and other organizations: to identify gaps that remain to be filled through research and technological development and to rank the gap elements based on the degree of impediment posed and the potential for elimination in the near term. To carry out the work, a comprehensive literature survey was conducted including a detailed review of relevant documents and reports published by PRCI, GRI and other industry consortia. From this information, current capabilities with respect to the detection and sizing of damage, the prediction of defect growth, the assessment of remaining resistance capacity, and the mitigation and/or repair of damage were characterized for each damage mechanism. Available methods, models and tools were evaluated and any elements that are missing or that could be improved were identified. Missing or deficient elements of the damage management process were then evaluated and ranked.
L51608 Method for Assessing Electrical Resistance of Pipeline Casings
Authors: Yunovich  , Tossey
Published: August 2023

This research project was conducted to develop a suitable method to evaluate cathodic protection on encased pipe sections. The objectives of the research were: (1) to develop techniques to determine whether the casing and the carrier pipe are effectively isolated from each other or if they are shorted together, and (2) to develop a measurement technique which will allow the degree of cathodic protection of the carrier pipe within an electrolyte-containing annulus region of the casing to be assessed if the casing is not shorted to the carrier pipe.
L51872 Effects of Pressure Fluctuations on SCC Propagation
Authors: Cialone  , Williams  , Groeneveld
Published: August 2023

The objective of the research summarized in this report was to define the relationship between the nature of pressure fluctuations on gas transmission pipelines and the crack growth behavior under conditions designed to simulate near-neutral pH SCC. The roles ofR ratio, frequency, waveform, (including realistic complicated waveforms) time, and pressure transients on crack-growth behavior were evaluated. The project was divided into three tasks: Task 1 - Test Matrix, Task 2 - Assessment of the Superposition Principle, and Task 3 - Effect of Pressure Transients.
L52189 Analysis and Guidelines for Deep Water Risers
Authors: Groeneveld
Published: August 2023

The major challenges for deepwater riser systems are the higher external pressures, increased weights and tensions, larger dynamic loads and responses, potential for fatigue of the girth welds, severe flow assurance requirements, and the need to provide an economical design and installation.

Result: This report provides PRCI with an updated version of the pipeline riser design and application guide. The focus of this report is on deepwater risers to both fixed and floating platforms, in sizes up to 24-in (610 mm) outside diameter, and in the range of water depths between 1,000 and 10,000 ft (305-3050 m). As with the previous report from 1987; Pipeline Riser System Design and Application Guide by Brown and Root U.S.A, this document is intended to serve as a starting point for the planning and design of deep-water risers, and is intended primarily for use by design engineers.

This report describes nine different riser systems, together with various options, and discusses the applications and limitations of each system. Included for each riser are design issues related to installation and operation in the deepwater offshore environment, applicable design analyses and computer software references, and riser system component design. In addition, the guide contains identification of areas of current riser system technology that require further development work to make them more applicable in water depths approaching 10,000 feet (3050 m); references, including published papers and patents, related to this area of deep-water pipeline risers and a set of spreadsheets listing most of the existing and near-future deepwater oil and gas developments, with information about the risers used on each development.
PR-000-14216-R02 An Alternative to PID Control for Critical Control Functions
Authors: Choquette Gary
Published: August 2023

Previous work identified cases where relatively minor changes in air manifold pressure led to engine detonation. This occurred under lean combustion conditions where detonation is believed to be unlikely. This indicates that it is as equally important to have stable engine control functions as it is to have the proper air/fuel setpoint. The objective of this work is to identify alternatives to conventional control techniques that can be employed on reciprocating engines used in the natural gas transpiration industry to enhance air/fuel control stability which in turn should improve combustion stability.

The report identifies an alternate control method that adds symmetric/asymmetric dynamic integral control to the standard PID control method. While the example here is applied to reciprocating engine air/fuel control specifically, the control method can apply to many other complicated control methods such as surge control, flow control, temperature control, and pressure control. The report includes an example implementation for Allen-Bradley controlers using IEC 61131-3 Function Blocks.
L51935 Limitations of Cellulosic-Coated Electrodes
Authors: Johnson
Published: August 2023

Cellulosic-coated electrodes (primarily AWS EXX10-type) are traditionally used for stovepipe welding of pipelines because they are well suited for deposition of one-sided welds and are capable of high deposition rates when welding downhill. Despite advances in mechanized welding technology and the development of low-hydrogen consumables suitable for pipeline girth welding, manual welding, using cellulosic-coated electrodes is still widely utilized for pipeline construction throughout the world. Several incidents involving significant hydrogen-assisted cracking in the weld metal of pipeline girth welds made using cellulosic-coated electrodes have been reported recently. Two of these cases required removal of many welds at an expense of over $4 million dollars, in spite of established procedures having been used.

The objectives of this project were to identify the primary mechanisms contributing to transverse cracking of field welds and to provide recommendations regarding safe preheat/interpass temperatures that should be utilized when welding heavy-wall pipe and fittings using cellulosic-coated electrodes. Two cases of severe weld metal hydrogen-assisted cracking were investigated. In each case, the composition of the weld metal was substantially richer that would typically be expected for E8010-G electrodes. Subsequent investigation into factors influencing the composition of weld metal from cellulosic-coated electrodes revealed that arc length has a pronounced effect on carbon, manganese, and silicon recovery. The increase in composition observed with variation in arc length could not explain the extremely rich compositions observed in the cracked girth welds, however. Subsequent investigation demonstrated that it was possible to effectively double the manganese concentration and triple the silicon concentration when using cellulosic coated electrodes that have low coating moisture content.
L51942 Refinement of Cooling Rate Prediction Methods for In-Service Welds
Authors: Bruce
Published: August 2023

Welds made onto in-service pipeline are particularly susceptible to hydrogen cracking because of the fast weld cooling rates that tend to result from the ability of the flowing contents to remove heat from the pipe wall. The most commonly used procedures for controlling the risk of hydrogen cracking rely on the use of a sufficiently high heat input level. Two methods currently exist for predicting required heat input levels for welds made onto in-service pipelines: thermal analysis computer modeling and the heat-sink capacity measurement method.

The objective of this project was to refine these two complementary methods, and to investigate alternative approaches. The project was divided into three distinct tasks: further refinement of the PRCI Thermal Analysis Model for Hot Tap Welding, standardization of heat-sink capacity measurement, and investigation of alternative approaches to cooling rate prediction. The primary link between the PRCI model and the heat-sink capacity measurement method is the ability of the model to predict the heat-sink capacity of an operating pipeline. Detailed descriptions of user interface modifications required to incorporate the ability to enter the individual heating parameters of interest and have the model calculate the heating rate were developed.
L52343 Background of All-Weld Metal Tensile Test Protocol Procedures for High Strength Pipelines
Authors: Quintana  , Gianetto
Published: August 2023

This work was undertaken for the purpose of improving the reliability of strength measurements for the specific case of narrow gap pipe girth welds. The investigation was part of a major consolidated program of research sponsored by DOT-PHMSA and PRCI to advance weld design, establish weld testing procedures and assessment methodologies, and develop optimized welding solutions for joining high strength steel pipe.

Development of an all-weld metal tensile test protocol for high strength steel pipe applications. The focus is on test method evolution as researchers sought improvements in measurement consistency. With these improvements came a broader understanding of the stress-strain behavior of high strength weld metal and some of the factors that influence tensile results. The results show that traditional methods of measurement can become inadequate as materials and methods of fabrication change. In this case, continuing to downsize tensile specimens for measurement of weld metal properties without establishing a context for those measurements can easily lead to errors in assessing the suitability of welding materials and welding procedures for the intended applications.
PR-015-093709-R01 Evaluation of External Leak Detection Systems - Laboratory Work
Authors: Siebenaler Shane
Published: August 2023

A previous PRCI project (PR-015-084510, 2009) identified distributed temperature sensing (DTS) and acoustic emissions as potentially viable technologies for the detection of small leaks in liquid pipelines. Much of the assessment that led to this conclusion was based upon manufacturer-generated literature. However, there is a lack of existing, publicly-available test data on these technologies as they relate to detecting small leaks in liquid pipelines. Such data are needed by pipeline operators in order to determine the value in supplementing their existing leak detection systems with one of these technologies. The long-term goal of the PRCI team providing oversight to this work is to conduct full-scale field testing of these technologies. However, it is first important to determine the parameters that affect performance in order to design the large-scale testing and to identify conditions for which the technologies are not suitable. A project encompassing analysis and laboratory testing of DTS systems and modeling of acoustic emissions systems was conducted.

Includes some analysis of different liquids including crude oil, propane, gasoline, and carbon dioxide.
L52364 Evaluating the Use of Composite Materials in Reinforcing Vintage Girth Welds
Authors: Bedoya  , Scrivner  , Alexander
Published: August 2023

Girth welds are an essential part of every transmission pipeline. With much of the pipeline system in the United States having been installed before 1970, concerns may exist with some pipeline companies regarding the integrity of vintage girth welds. While it is true that the failure rate in the United States attributed to vintage girth welds (based on information reported to the authorities) have not been widespread, ranging from 2.1% to 8% depending on how the data is interpreted (cf. PRCI Report PR-335-094502, 2010), operators recognize that they cannot be complacent as their infrastructure ages and they should continue to look for alternatives to conventional repair and replacement options that continue to ensure integrity.

Measurement and comparison of the performance of composite systems to repair pipeline girth welds with perceived imperfections is included within this report. Defective girth welds are considered an integrity concern to some pipeline operators. The concern may be simply a result of questions regarding the quality of a given girth weld or they may arise from the specific operating conditions of the pipeline and/or some combination of both. Generally, the study has shown that composite repair sleeve can restore the integrity of the pipeline.
L52336 Weld Design Testing and Assessment Procedures for High-strength Pipelines Curved Wide Plate Tests
Authors: Weeks  , Weeks Dash
Published: August 2023

A variety of mechanical property tests are performed in the design, construction and maintenance phase of a pipeline. Most of the tests are performed by use of small-scale specimens with size typically in the range of a few inches to tens of inches (1 in = 25.4 mm). There are numerous test labs capable of performing most small-scale tests. These tests can be performed effectively under a variety of conditions, e.g., test temperature, strain rate, and loading configuration. More importantly, most routine small-scale tests are performed in accordance with national and international standards, ensuring the consistency of testing procedures.

To confirm pipeline designs and validate material performance, it is desirable to test girth welds under realistic service conditions. Full-scale tests can incorporate certain realistic features that small-scale specimens cannot. However, these tests can be time-consuming and expensive to conduct. Very few labs can perform the tests, even with months of start-up and preparation time. There are no generally accepted, consistent test procedures among different test labs. The data acquisition and post-processing may differ from lab to lab, creating difficulties in data comparison. Full-scale tests can only be performed under selected conditions as a supplemental tool to the small-scale tests.

The work described in this report focuses on the development of test procedures and instrumentation requirements for curved-wide-plate (CWP) tests. The results of this work can be used for:

Developing a test methodology to measure the physical response of a finite-length surface-breaking flaw to axial loads applied to a girth welded line pipe section,
Determining the appropriate instrumentation to fully characterize the global stress/strain response of the CWP specimen during loading,
Evaluating the applicability of the test methodology for sub-ambient temperatures, and
Developing a standardized test procedure for CWP testing with a wide range of test parameters.