Modular Downhole Logging Sync via Fourier Transform
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Solution Overview
Problem
Downhole logging systems face challenges in synchronization between separated electronics, particularly in low telemetry bandwidth environments, where continuous synchronization signals are not feasible, affecting the accuracy of formation property measurements.
Innovation Solution
The implementation of estimated synchronization techniques between modular downhole logging system modules, using sync estimation operations based on Fourier transform analysis of response signals to account for drift between transmitter and receiver local operating frequencies, allowing for accurate sampling and derivation of formation property values without continuous sync control signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If continuous synchronization signals are transmitted between separated logging tool electronics, then synchronization accuracy is improved, but telemetry bandwidth is excessively consumed
Solution Approach 1:
The patent extracts the synchronization information from continuous telemetry signals and embeds it within the existing measurement data transmission. The receiver module derives synchronization parameters from the received measurement signals themselves, rather than requiring separate dedicated synchronization channels, thereby utilizing existing bandwidth efficiently while maintaining synchronization accuracy.
Solution Approach 2:
The patent makes the measurement signals serve dual purposes: both conveying formation property information and carrying synchronization information. The same telemetry channel that transmits measurement data also conveys timing and frequency reference information, eliminating the need for separate synchronization bandwidth allocation.
2Device complexity
If separated electronics are used in modular logging modules, then device complexity and modularity are improved, but synchronization between modules deteriorates
Solution Approach 1:
The patent introduces an intermediary synchronization derivation process where the receiver module extracts timing and frequency reference information from the received measurement signals. This intermediary step bridges the separated transmitter and receiver electronics, enabling them to operate independently while maintaining precise synchronization through the shared measurement data channel.
Solution Approach 2:
The patent implements a feedback mechanism where the receiver module continuously monitors the received signals for frequency and timing information, derives synchronization parameters, and adjusts its local oscillator accordingly. This closed-loop feedback ensures that separated modular electronics remain synchronized despite environmental variations and component drift.
3Productivity
If synchronization control signals are reduced, then telemetry data rate is improved, but measurement accuracy deteriorates
Solution Approach 1:
The patent merges the synchronization control function with the measurement data transmission function. By encoding timing and frequency reference information within the measurement signals themselves, the system eliminates the need for separate synchronization control channels, thereby maximizing telemetry bandwidth availability for measurement data while maintaining the necessary synchronization for accurate formation property derivation.
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 enhances the accuracy of formation property measurements while reducing the need for continuous synchronization, increasing telemetry data rate and maintaining measurement accuracy across varying environmental conditions.
Implementation Method 1
transmitter module transmits interrogation signals into a formation surrounding a borehole based on a local frequency of the transmitter module
Implementation Method 2
receiver module receives response signals corresponding to the interrogation signals
Implementation Method 3
estimating the local frequency of the transmitter module based on analysis of response signal Fourier transform results corresponding to different frequencies
Data Source
AI summary
A modular downhole logging system includes a transmitter module having a local frequency, wherein the transmitter module transmits interrogation signals into a formation based on the local frequency. The downhole system also includes a receiver module axially-spaced from the transmitter module and that receives response signals corresponding to the interrogation signals, wherein the receiver module includes sampling logic and sync estimation logic. The sync estimation logic is configured to perform sync estimation operations including estimating the local frequency of the transmitter module based on analysis of response signal Fourier transform results corresponding to different frequencies. The sampling logic/clock is configured to sample the response signals based on the estimated local frequency of the transmitter module, wherein a processor derives formation property values using the sampled response signals.