In pipeline systems, whether gas or liquid, achieving a perfect balance between inbound and outbound volume, mass, or energy is unattainable due to measurement uncertainties, operational noise, and accounting errors. This report introduces advanced analytic methods which aid in getting closer to the 'perfect balance' by identifying specific meters contributing to balance discrepancies and by improving the accuracy of estimating the inventory of the product in the pipeline. By reducing measurement uncertainty, operators can enhance leak detection sensitivity and pinpoint where efforts should be focused to address specific measurement problems. The methods developed in this effort have been validated using double-blind simulated data and tested against a real dataset. Enhancements to reduce measurement uncertainty allow lost and unaccounted methods to reliably identify leaks, theft, and other unexpected or unaccounted-for product loss. These methods also support the ability to find smaller leaks using online leak detection systems. The target audience for this document is Measurement technicians, Measurement specialists, Measurement accountants, and Leak detection experts. This document also makes a good primer for individuals that are new to product measurement in the pipeline industry.
Calculating an accurate inventory of a product inside a pipeline system is critical to accurately estimating pipeline leak/loss for computational pipeline monitoring and lost and unaccounted methods. This document describes methods to calculate pipeline inventory for systems transporting single phase liquid and gaseous products. Several pitfalls with the current methods and common practices are identified along with enhancements and recommendations. The enhanced methods identified include methods to better account for transient conditions on gaseous pipelines that are more accurate than steady state methods but are simpler to implement than full transient pipeline models and produce nearly the same level of accuracy for single phase products. The target audience for this document are measurement accounting specialists, supervisory control and data acquisition (SCADA) integrators, and software suppliers of measurement accounting systems, leak detection systems, and SCADA systems
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.
An outline of pipeline research currently underway as well as a prospectus of work to be initiated over the next three years.
In March 2019, the United States Pipeline and Hazardous Materials Safety Administration (PHMSA) issued a Research Announcement to improve the detection capability and sizing accuracy of In-Line Inspection (ILI) systems for various types of anomalies. The objective is to focus on those anomalies that represent the most significant risk threats to the safe operation of pipeline systems and also reduce the number of excavations required for integrity management. Pipeline Research Council International (PRCI) Project NDE-4-19 was created in December 2019 as part of this initiative. The multi-phased PHMSA-PRCI-Blade Energy project aimed to conduct a collaborative study involving pipeline operators, ILI Technology Providers (TPs), subject matter experts, and consultants to quantitatively measure and improve the detection and sizing capabilities of current ILI systems for challenging and problematic corrosion features. A data-driven approach was devised, which factually identified problematic corrosion shapes and profiles by reviewing recent Root-Cause-Analysis (RCA) reports of corrosion-related pipeline failures that had previously been inline inspected. This information was used to design and construct an ILI corrosion test string containing complex features with similar profiles. All such profiles were then documented using the best possible Non-Destructive Evaluation (NDE) techniques. Three participating ILI TPs proposed appropriate inspection tools based on their knowledge of the string containing complex corrosion features. A series of blind pull-through tests of the ILI systems were conducted, and the participating ILI TPs delivered standard ILI reports for performance evaluation. The ILI TPs received detailed feedback identifying the detection and sizing gaps. They were given a limited subset sample of detailed 3D corrosion profile data to identify potential sources of detection and sizing improvement. A second series of ILI tests were performed, and the changes in detection capability and sizing accuracy were analyzed and quantified for each problematic corrosion profile, identifying the improvements and the remaining gaps. The results and findings of this 3.5-year-long project are presented in this article.
