Downhole Acoustic Transducer Assembly for Wider Telemetry Bandwidth
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Solution Overview
Problem
Existing downhole acoustic telemetry systems face limitations in communication distance, attenuation, and narrow bandwidth due to the use of single transducer modems and mass-loaded piezo-transducers, leading to high costs and unreliable signal transmission.
Innovation Solution
A wireless acoustic telemetry system with multiple transducer assemblies, each comprising independently mass-loaded transducers tuned to specific resonance frequencies, providing a wider frequency response band for improved energy transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single mass-loaded piezo-transducer is used, then the transducer can be simplified and easier to manufacture, but the communication distance is limited to a few thousand feet due to insufficient acoustic energy at the receiver side
Solution Approach 1:
The patent combines multiple mass-loaded piezo-transducers into a single integrated assembly where multiple transducers are coupled to a common body or bodies. This merging allows the system to achieve the acoustic energy output of multiple transducers while maintaining a unified structure that can be installed as a single unit in the wellhead assembly, thereby extending communication distance without proportionally increasing manufacturing complexity.
2Length of stationary object
If multiple transducers are used to extend communication distance, then acoustic energy at the receiver is improved, but the system complexity and cost increase due to needing a network of relaying modems
Solution Approach 1:
Multiple piezo-transducers are merged into a single integrated assembly that functions as one unified transducer unit. This approach provides the acoustic energy of multiple transducers without requiring a complex network of separate relaying modems, as the integrated assembly directly generates sufficient acoustic energy for long-distance transmission through the production pipe string.
Solution Approach 2:
The transducer assembly is segmented into multiple independent piezo-transducers that can be individually mass-loaded and tuned, allowing optimization of each transducer's performance while maintaining overall system simplicity. The segmented structure enables better frequency response and acoustic energy distribution without requiring complex system architecture.
3Device complexity
If a single transducer is used, then device complexity is reduced, but the bandwidth is narrow and cannot effectively cover the passbands and stopbands of the acoustic channel
Solution Approach 1:
The transducer assembly is divided into multiple piezo-transducers, each of which can be independently mass-loaded and tuned to different resonance frequencies. This segmentation allows the system to cover a broader frequency spectrum and adapt to the varying acoustic channel characteristics (passbands and stopbands) while maintaining relatively simple individual transducer designs.
Solution Approach 2:
Each piezo-transducer within the assembly can be locally optimized with specific mass-loading and resonance frequency tuning tailored to its position and function within the assembly. This local quality optimization allows different transducers to target different frequency bands, collectively providing wide bandwidth coverage without requiring each transducer to be overly complex.
4Reliability
If transducers operate outside their resonance frequency to ensure transmission in passband, then transmission reliability is improved, but the acoustic energy generated is insufficient for long-distance propagation
Solution Approach 1:
The system segments the frequency spectrum by using multiple piezo-transducers, each tuned to a different resonance frequency that corresponds to a passband. This allows each transducer to operate at its optimal resonance frequency where it generates maximum acoustic energy, while collectively covering the necessary frequency bands for reliable long-distance transmission through the acoustic channel.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances signal transmission range and reliability by utilizing multiple transducers with tuned resonance frequencies, overcoming attenuation and bandwidth limitations, thereby reducing costs associated with networked modem systems.
Implementation Method 1
At least two mass-loaded transducers in each mass-loaded assembly can be tuned to a specific resonance frequency, and each specific resonance frequency can be spaced in frequency such that the at least two mass-loaded transducers in each mass-loaded assembly together can be configured to provide a wider frequency response band for energy transmission
Implementation Method 2
a mass loaded piezo-transducer, such as the one commercialized by Cedrat (PPA40L for example) has been used
Data Source
AI summary
Telemetry systems that include a wireless acoustic telemetry system and processes for installing and using same. In some embodiments, a wireless acoustic telemetry system can include a plurality of transducer assemblies spatially distributed on or about a pipe string. Each transducer assembly can include a modem and a plurality of transducers each coupled to a corresponding different body such that each transducer assembly comprises a plurality of independently mass-loaded transducers. At least two mass-loaded transducers in each mass-loaded assembly can be tuned to a specific resonance frequency, and each specific resonance frequency can be spaced in frequency such that the at least two mass-loaded transducers in each mass-loaded assembly together can be configured to provide a wider frequency response band for energy transmission as compared to one of the at least two mass-loaded transducers alone.