Pipeline Research Council International

This report describes the various methods for calculating lost and unaccounted for gas and liquid in measurement accounting systems used in transportation via pipelines. A recommendation is made for a standardized approach. The approach is suitable for entire pipeline systems as well as subsections thereof. A corresponding spreadsheet is provided to provide an independent validation method for existing measurement accounting systems.

This document describes methods to calculate estimated gas compressibility without having the full gas composition. The purpose of these methods is for use cases where reasonable accuracy is required but not critical and the methods must be computationally efficient such that they can be used in programmable logic controllers, remote terminal units, and supervisory control and data acquisition systems; akin to the functionality of the NX-19 or AGA-8 Gross methods but with higher accuracy. Multiple simplified calculation methods were evaluated with one method performing significantly better than the other methods. The best performing method was then tuned to better fit the reference data. The equations and associated source code for that method are contained as appendices in this report. The methods discussed here were analyzed only with respect to the application to gas phase (including some supercritical conditions) natural gas with minimal helium, hydrogen, or hydrogen sulfide. This version includes source code on the calculation method.

This compendium is a selection of past PRCI research related to aboveground tank corrosion. Metadata is provided for each resource (when available) including the length of the report, its abstract, author(s), and company that performed the research. The process of identifying reports for this compendium involved keyword searches of all PRCI research documents (and in some cases, research by others). The list of documents identified in that keyword match was then manually reviewed for relevance. Documents that had content that was not directly relevant to the topic of this compendium, had minimal information, or duplicated information were excluded. Specifically, this study reviewed 73 documents and only selected 18 documents that were deemed relevant. Key excerpts and/or notes were taken from those documents and are included here. In many cases, the excerpt/notes are adequate such that the source document does not need to be read separately. However, there are some documents that contain much more content than can be adequately summarized herein. In those cases, the note recommends reviewing that document in its entirety. Links to each of the reports are provided to help facilitate quick access to the related reports. A valid PRCI account is needed to access these links on the PRCI website.

This compendium is a selection of past PRCI research and technical resources related to cathodic protection shielding. Reports were selected based on their final report abstracts and does not include further analysis or an additional technical review of the final report. Metadata is provided for each resource (when available) including the length of the report, its abstract, author(s), and company that performed the research. This list of documents includes PRCI funded research as well as research that PRCI has rights to access including cofunded work and information in the public domain. The reports are grouped by the related research category assigned to each document.

A compendium of the papers presented at the 7th IPC in 2008. The related papers are available for purchase from the ASME website.

The PRCI Technical Committees have carried many research projects related to the subject of Damage Prevention. This report; therefore, presents a summary of past PRCI-funded studies in the area of Damage Prevention. Since studies sponsored by other industry groups (e.g., INGAA, EPRG, APIA, CEPA, etc.) or by individual pipeline companies are not included, this report does not represent a review of the topic in the broader industry-wide sense. Instead, it is designed to provide a guide to past work so that current TC members can identify and locate project reports that might be of use in addressing their current day-to-day damage prevention issues.

Abstract This study collected and analyzed field data to validate the probabilistic model developed previously for predicting internal corrosion threats resulting from condensed water from nominally dry natural gas. Model-predicted wall loss was compared to actual measurement to validate the model. One past failure case from the National Transportation Safety Board(1) due to internal corrosion and in-line inspection (ILI) data from five pipeline operators were collected and used to validate the Model. Two of the data sets indicate wall loss that is either evenly distributed at all locations around the circumference of the pipe or predominantly at the top of the pipe, which is in agreement with the negligible wall loss predicted by the Model. Another two sets of data show significant wall loss occurring at the bottom of the pipe, which is in agreement with non-negligible risk of internal corrosion predicted by the Model. The 5th data set confirmed the analysis of ILI data uncertainty and corroborated the validation results. For the failure case, the prediction is in good agreement with the post-failure examination. Although uncertainties exist in both Model predictions and ILI measurements, the wall loss predictions from the Model are in good agreement with trends seen in the ILI measurements.

Onshore pipeline industry has deployed in the last decade comprehensive integrity management programs in a constrained environment. These programs address all types of threats and resulting defects, yet the most complex defects are those due to mechanical damage, as they can combine local pipe deformations (dents) with metal removal (gouges) or even cracks. These programs are first placed in the broader risk management perspective that justify the whole approach and provide a view of the context. Then, operational threat management programs for mechanical damage as implemented by operators are briefly described here, and serve as a basis to identify the main gaps in terms of technology and knowledge. Finally, both incremental and more game-changing innovations as produced by R&D performed by PRCI and consultants, are described in subsequent sections as possible options to fill the identified gaps. Examples of roadmaps are provided that explain the coverage in terms of existing and evolving knowledge and technology, as provided by these R&D programs, to fill these gaps. These various levels of representations are complementary tools to communicate about links between operations, R&D, and their contributions to public safety.

The option of internally coating a new pipeline, or a section of an existing pipeline has emerged in recent years as competition in the energy marketplace grows more intense and coating technologies have advanced from 100% solvent-base to 100% dry-based. Internally coated pipes would mean additional capital cost, but will result in lower pressure losses, hence lower compression power, lower fuel consumption and lower emission. Therefore, there is a trade-off that needs to be assessed, which is the subject of the present paper. The present paper first provides a proposed standardized method to report the internal wall roughness parameters that could be used to compare bare vs. different coating technologies in a consistent manner. The second part of the paper focuses on evaluating the impact and performance of internal coatings on flow efficiency in energy transmission pipeline systems. A tool and methods were developed to evaluate all of the various options specific to internal pipe coating (including bare pipe option) using a Life Cycle Cost (LCC) economic tool developed for this purpose. The incremental Cumulative Present Value Cost of Service (iCPVCOS) associated with the application of the various coating technologies, as well as quantification of the relative benefits of each compared to a bare pipe, are the main outcome of the tool. This provides an impetus to sound design and selection of the most cost effective technology for internally coating the pipes, whether for new or existing pipeline systems. Examples of various scenarios involving a 2900 km pipeline coated using different internal coating technologies are discussed.