Study Reviews Advances in Downhole Fiber-Optic Modeling and Analytics
Authors: Feder Judy 
Published: June 2021

This article, written by JPT Technology Editor Judy Feder, contains highlights of paper SPE 200826, “Recent Advances in Downhole Fiber-Optics Modeling and Analytics: Case Studies,” by Derek S. Bale, SPE, Rajani P. Satti, SPE, and Roberto Failla, SPE, Baker Hughes, et al., prepared for the 2020 SPE Western Regional Meeting, originally scheduled to be held in Bakersfield, California, 27 April–1 May. The paper has not been peer reviewed.
The upstream industry has witnessed significant breakthroughs in developing and deploying permanent, on-demand, and distributed temperature and acoustic fiber-optic monitoring systems to optimize well completions and enhance production. Beyond steady advances in hardware, challenges associated with the analysis of distributed optical data are being addressed to enable delivery of value-driven solutions and services. The complete paper discusses a methodology for integrating intelligent completion and production systems with a modeling and analytics framework for efficient development of fiber-optic-based data-interpretation services for complex downhole environments.

Introduction
During the last 30 years, the industry has found novel ways to apply fiber-optic technology to monitor in-well events, operations, and critical parameters. Recently, applications including the need to maximize hydrocarbon recovery, remotely manage assets for improved cost-efficiency and safety, and reduce carbon footprint have accelerated the adoption of fiber-optic-based systems. Specific to wellbore completions, the confluence of increased durability and reliability of downhole fiber-optic systems, computer processing speed, and the ability to couple fiber sensors to completion and production equipment has led to significant growth in several applications. Fiber-optic techniques such as distributed temperature sensing (DTS) and distributed acoustic sensing (DAS) have proved particularly successful for applications such as injection and production profiling, well-integrity monitoring, leak detection, perforation cluster efficiency, and fracture monitoring.
For all the benefits delivered by downhole fiber-optic technology, challenges specific to data transmission and storage remain, in particular with regard to data analysis and interpretation, that must be understood to fully enable delivery of value-generating solutions. These challenges are illustrated in Fig. 1 of the complete paper.

Philosophy and Description of Solutions
The solutions to the challenges described previously need to be downhole-tool-centric, cost-effective, and time-efficient. The complete paper is focused on presenting a methodology that follows a scientific and pragmatic work flow and demonstrating successful applications using a combination of intelligent downhole hardware and advanced modeling and analytics.
The methodology begins with designing and developing intelligent downhole tools capable of providing the necessary data to enhance or optimize production, mitigate risk, and improve operational efficiency. Intelligent downhole tools can include interval control valves, downhole pressure and temperature gauges, connectors, control units, and cables, and are deployed into a complex downhole environment. As these smart tools are run downhole, fiber-optic cables are deployed in tandem to acquire continuous, spatially distributed data (i.e., strain, temperature, or acoustic) along the completion.