Distributed Fiber-Optic Telemetry for Downhole Sensor Data and Location
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Solution Overview
Problem
Existing technologies for data transmission and telemetry of downhole devices in a well face challenges in efficiently retrieving data and locating autonomous sensors without direct connection or complex multi-hop wireless communication systems.
Innovation Solution
The use of a Distributed Acoustic Sensor (DAS) system with fiber-optic cables installed in a borehole, connected to interrogators, allows for the encoding, transmission, and detection of acoustic signals from autonomous sensors, enabling real-time data transmission and sensor localization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If direct fiber connection is used for data transmission, then data transmission reliability is improved, but device complexity increases due to direct connection requirements
Solution Approach 1:
The patent introduces acoustic waves as an intermediary medium for data transmission. Instead of direct electrical connections, autonomous sensors encode measurements into acoustic signals that propagate through the borehole fluid and are detected by the fiber-optic cable, eliminating the need for direct physical connections between sensors and the surface system.
Solution Approach 2:
The patent replaces mechanical/electrical connection systems with an acoustic field-based transmission system. The fiber-optic cable detects acoustic waves through optical interference patterns, substituting traditional electrical connectors and wiring with a non-contact optical detection mechanism.
2Area of stationary object
If multi-hop wireless nodes are deployed for data transmission, then coverage area is improved, but device complexity increases due to multiple nodes and communication protocols
Solution Approach 1:
The fiber-optic cable serves multiple functions simultaneously: it acts as both the transmission medium for acoustic waves and the detection system for retrieving data. This single system replaces the need for multiple wireless nodes, eliminating complex inter-node communication protocols while maintaining full borehole coverage.
3Ease of operation
If autonomous sensors are deployed without direct connection, then ease of operation is improved, but measurement precision deteriorates due to indirect signal transmission
Solution Approach 1:
The patent replaces direct electrical connections with optical detection of acoustic waves. The fiber-optic interrogator system measures acoustic signals through precise optical interference pattern analysis, maintaining high measurement precision while enabling autonomous sensor deployment without physical connections.
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
This approach enables real-time or almost-real-time data transmission and accurate localization of autonomous sensors, simplifying the data retrieval process and eliminating the need for complex wireless communication systems.
Implementation Method 1
transmitting the at least one encoded acoustic signal from the at least one autonomous sensor to at least one fiber-optic cable of a DAS system
Implementation Method 2
detecting the at least one encoded acoustic signal with the DAS system
Data Source
AI summary
A system and method for using a Distributed Acoustic Sensor (DAS) system to receive signals transmitted from remote autonomous sensors and to locate the autonomous sensors are disclosed. The method includes installing a DAS system in a borehole consisting of at least one fiber-optic cable connected to at least one corresponding interrogator, deploying at least one autonomous sensor and conducting at least one measurement. The methods also include encoding the at least one measurement in at least one encoded acoustic signal, transmitting the at least one encoded acoustic signal to the at least one fiber-optic cable, and detecting the at least one encoded acoustic signal with the DAS system. Furthermore, the methods include recording the at least one encoded acoustic signal received by the DAS system at a surface location and processing the at least one encoded acoustic signal with a processing unit to decode and obtain the at least one measurement.