Marine Acoustic Source Array Synchronization
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Solution Overview
Problem
Conventional seismic surveys in marine environments face challenges in synchronizing acoustic source elements accurately, leading to sub-optimal alignment of peak acoustic pressure and emission of significant noise outside the frequency range of interest, which interferes with measurements and affects marine life.
Innovation Solution
The method involves deploying an array of acoustic sources and hydrophones in a marine environment, using band-limited notional source signatures to directly synchronize the acoustic sources and deliberately desynchronizing their triggering to attenuate out-of-band frequencies, thereby optimizing acoustic source array performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If time-break sensors are used to synchronize acoustic sources, then triggering timing can be measured, but accurate synchronization of peak acoustic pressure cannot be achieved due to indirect measurement and constant time offset assumptions
Solution Approach 1:
The patent replaces the mechanical time-break sensor system with an acoustic signal processing system. Instead of using physical sensors to detect triggering events, the system uses hydrophones to detect acoustic signals and cross-correlate them to determine time delays. This substitution enables direct measurement of acoustic pressure alignment rather than indirect mechanical triggering measurement.
Solution Approach 2:
The patent implements a feedback loop where acoustic signals from nearfield hydrophones are measured, cross-correlated to determine time delays, and these time delays are used to adjust the triggering of acoustic sources. This closed-loop feedback system continuously optimizes the synchronization of peak acoustic pressure across all sources in the array.
2Manufacturing precision
If acoustic sources are synchronized to maximize peak pressure alignment, then seismic signal quality improves, but out-of-band noise emission increases which interferes with measurements and affects marine life
Solution Approach 1:
The patent changes the triggering time parameters of acoustic sources based on their position in the array and the desired focal point. By calculating optimal time delays for each source and applying them, the system achieves peak pressure alignment at the target location while the natural bandwidth limitation of each source filters out-of-band noise. This parameter optimization allows simultaneous achievement of signal quality and noise reduction.
3Manufacturing precision
If nearfield hydrophones are used for tuning and measurements, then acoustic source synchronization can be optimized, but adjacent air gun signals cannot be distinguished in unprocessed measurements
Solution Approach 1:
The patent segments the combined acoustic signal from multiple sources by using cross-correlation to identify and separate individual source contributions. Each hydrophone measurement is correlated with the expected signal from each specific air gun, allowing the system to extract and analyze individual source signals even when they are mixed together in the unprocessed nearfield measurements.
Data Source
AI summary
A technique facilitates obtaining seismic data in a marine environment. An array of acoustic sources is deployed in a marine environment. The array can be utilized for creating acoustic pulses that facilitate the collection of data on subsea structures. The methodology enables optimization of acoustic source array performance to improve the collection of useful data during a seismic survey.