Acknowledging the serious and substantial health and business effects of COVID‑19, I sincerely hope that all JPT readers and your families, peers, and employers are safe and healthy as they read this Flow Assurance Technology Focus.
During my 20-plus years of project experience around the world—in both onshore unconventional and offshore conventional production facilities—I have seen how flow-assurance effects from slug-flow design and engineering, operations, and maintenance concerns have created challenging technical issues needing safe, economical solutions. The recurring long-term mitigation of slugging and various flow-assurance phenomena are challenging issues that demand attention and considerable technical effort. The three papers outlined here discuss slightly different issues and approaches to slug-flow phenomena and oil/gas fluid production flow assurance. All three have been defined by mathematical modeling and verified with actual field confirmation and use.
Paper IPTC 19769 addresses pseudoslug flow, characterized by short, frothy chaotic slugs with velocities less than the mixture velocity of the flowing fluids and frequently observed in pipeline and riser systems. Specifically, the paper discusses liquid and gas entrainment mechanisms within the pseudoslug body on the basis of experimental observation. Earlier experimental results show the proposed dimensionless groups, Stokes, slippage, and Poiseuille, are strongly correlated to pseudoslug-body liquid-holdup experimental data that describe the observed physical behavior. A linearized regression model was developed that combines the liquid holdup proportionally in both the pseudoslug body regions and correlates them to the experimentally measured total pseudoslug liquid holdup. A validation study of the proposed model with experimental data shows good agreement.
The work described in paper OTC 30864 presents a unique set of two- and three-phase slug-flow experiments conducted in a 766-m-long 8-in. pipe at 45 bara pressure. The first half of the pipe was horizontal, while the second half was inclined at 0.5°. The reported experiments are the first three-phase slug flow experiments ever conducted in a large-scale setup able to study the evolution of slug length distributions over a long distance. These experiments can be of considerable value for developing tools to predict slug lengths in multiphase transport systems, a critical matter for oilfield operators.
Paper OTC 29925 presents a data-driven root-cause analysis of slug flow from a field asset that experienced severe riser slugging that limited production throughput. These results were used in combination with simulation studies and engineering experience to create a better understanding of the underlying root cause for this slugging. A novel approach was implemented that uses machine-learning techniques to model and analyze historical production data to find causes behind slug flow events. Oil companies are becoming reliant on the application of statistical and machine-learning methods to extract valuable insights from production data. This paper presents a data-driven process to analyze production data and identify root causes of slugging.
The desire to better understand ways to describe and improve flow assurance and multiphase flow for both offshore and onshore facilities continues to drive new production technology research, applications, and approaches. The three papers identified for additional reading focus on developing further new analytical tools while providing safe, cost-effective, and reliable operations for flow assurance. I invite you to join the Flow Assurance Technical Section to learn more.
Finally, I wish the best of luck and future outcomes for yourself and your family during these challenging times.
This Month's Technical Papers
Modeling Liquid Holdup in Pseudoslugs
Large-Scale Experiments Examine Slug-Length Evolution in Long Pipes
Machine-Learning-Assisted Approach Analyzes Slug-Flow Root Cause
Recommended Additional Reading
OTC 30818 Experience With Active Flow Assurance by Øyvind Iversen, Nexans Norway, et al.
SPE 200668 Scale Prediction and Management for Unconventional Production by Wei Wang, Chevron, et al.
OTC 30817 Evaluation of a Robust, In-Situ Surface Treatment for Pipeline Solids Deposition Mitigation in Flowing Systems by Marshall A. Pickarts, Colorado School of Mines, et al.
| Galen Dino, SPE, is senior consultant and project manager with Dino Engineering. He has more than 37 years of experience in international and domestic project management, project engineering, process design, supervision, fabrication, and construction. Dino holds a BS degree in chemical engineering from Louisiana State University and is a registered professional engineer in Texas. He founded the Production Facilities Study Group with the SPE Gulf Coast Section and has held associate-editor and technical-editor positions for SPE Projects, Facilities, & Construction and SPE Production & Operations. Dino serves on the JPT Editorial Review Board and can be reached at gdino@consolidated.net. |
