A study of acoustic wave propagation inside cemented production tubings

Abdallah K. Farraj, Scott L. Miller, Khalid A. Qaraqe

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

Well operators use advanced downhole telemetry systems to monitor the flow rate, temperature, and pressure inside the well. The wired telemetry tools are currently popular in the industry although these tools have cost, maintenance, and reliability issues. Acoustic waves that propagate by vibrating the pipe's body inside the well were recently considered as an alternative technology. However, the bottom segment of the production tubing is encased in concrete in many wells; a previous work showed that concrete segments attenuate the acoustic waves to impractical levels, which limits the applications of this mode of propagation. As an alternative to vibrating the tubing body when there is a concrete segment over the pipe, this work investigates the use of the production tubing's interior as a communication medium for the acoustic waves. A testbed was designed using five segments of 7-inch production tubing to form a pipe string, a speaker to generate the acoustic waves, and a directive microphone to receive the acoustic waves propagating inside the pipe string. To study the effect of cemented pipes on acoustical wave propagation, the third pipe segment was encased in concrete. Input frequencies from 100 Hz to 2000 Hz were investigated; wave measurements were taken along the pipe string, and measurements were analyzed to extract information about the behavior of the acoustic channel. This work shows that acoustic waves are not affected by the presence of the concrete segment. Low-frequency acoustic waves experience very little attenuation as they propagate through the interior of the pipe string, signal dispersion is not an issue for most frequencies, and delay spread measures increase as the acoustic waves propagate down the pipe. This work advises that acoustic-wave technology can be a promising cost-effective and reliable solution for wireless downhole communication systems. Technical contributions include: characterizing the channel response to different input frequencies along the pipe string, investigating the power spectral density and signal-to-noise ratio measures, and studying the time dispersion parameters of the channel.

Original languageEnglish
Title of host publicationSociety of Petroleum Engineers - International Petroleum Technology Conference 2014, IPTC 2014
Subtitle of host publicationUnlocking Energy Through Innovation, Technology and Capability
PublisherSociety of Petroleum Engineers
Pages2890-2898
Number of pages9
ISBN (Print)9781632660053
DOIs
Publication statusPublished - 2014
Externally publishedYes
EventInternational Petroleum Technology Conference 2014: Unlocking Energy Through Innovation, Technology and Capability, IPTC 2014 - Doha, Qatar
Duration: 19 Jan 201422 Jan 2014

Publication series

NameSociety of Petroleum Engineers - International Petroleum Technology Conference 2014, IPTC 2014: Unlocking Energy Through Innovation, Technology and Capability
Volume4

Conference

ConferenceInternational Petroleum Technology Conference 2014: Unlocking Energy Through Innovation, Technology and Capability, IPTC 2014
Country/TerritoryQatar
CityDoha
Period19/01/1422/01/14

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