External Driver Seismic Source for Low-Frequency Acoustic Energy
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Solution Overview
Problem
Current seismic sources in marine seismic surveying have limited acoustic energy output in the low frequency band and are unable to efficiently generate sound waves below 10 Hz, which are essential for longer distance transmission through water and geological structures.
Innovation Solution
A seismic source system utilizing an external driver to energize the air within a fluid reservoir and internal cavity, incorporating fluid resonance to increase vibration amplitude and acoustic output, allowing for the generation of low-frequency acoustic energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If impulsive-type sources (air guns, explosives) are used to generate acoustic energy, then high energy output is achieved during short time span, but the frequency content is controllable only to small degree and limited acoustic energy output in very low frequency band from 1-10 Hz
Solution Approach 1:
The patent employs a vibratory source with controllable vibration frequency and amplitude, allowing dynamic adjustment of operating parameters. The source can operate across a wide frequency range including very low frequencies (1-10 Hz), enabling adaptive selection of optimal frequency for different surveying conditions and targets, thereby resolving the limitation of fixed frequency content in impulsive sources.
Solution Approach 2:
The invention changes the fundamental operating parameters from impulsive (short-duration high-energy) to continuous vibratory motion with controllable frequency and amplitude. This parameter transformation enables precise control over frequency content while maintaining adequate acoustic energy output, particularly in the very low frequency band where impulsive sources fail.
2Measurement precision
If higher frequency sound waves are used, then better resolution is achieved, but they are attenuated more rapidly and cannot be transmitted over longer distances
Solution Approach 1:
The vibratory source enables dynamic selection of operating frequency based on surveying requirements. When long-distance transmission is needed, the source can operate at lower frequencies (1-10 Hz) that experience less attenuation. When higher resolution is required over shorter distances, higher frequencies can be selected, providing flexible optimization of the resolution-distance tradeoff.
Solution Approach 2:
The continuous periodic vibration allows sustained energy transmission at optimized frequencies. By maintaining steady-state vibratory motion at frequencies tailored to the specific surveying scenario, the system ensures adequate energy reaches distant targets while minimizing unnecessary high-frequency content that would attenuate rapidly.
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
The system enhances acoustic output by up to 14 decibels and operates effectively in the low-frequency range, enabling longer distance transmission of sound waves through water and geological structures.
Implementation Method 1
actuation of the external driver generates a pressure wave that energizes the air in the fluid reservoir and internal cavity of the seismic source to a resonant frequency, thereby causing vibration and generation of acoustic energy
Implementation Method 2
incorporating fluid resonance to increase vibration amplitude and acoustic output
Data Source
Figure 1~2A
Figure 2B
Figure 3~5
AI summary
Disclosed are seismic sources that may utilize an external driver to energize the air in the seismic source for generation of acoustic energy. An apparatus may comprise a seismic source comprising an internal cavity configured to contain a volume of a fluid. The apparatus may further comprise an external driver, wherein the external driver and the seismic source are coupled to permit fluid communication between the external driver and the internal cavity of the seismic source, wherein the external driver is configured to create a pressure wave that drives the seismic source and a gas resonance. The apparatus may further comprise a fluid reservoir, wherein the fluid reservoir and the external driver are coupled to permit fluid communication between the fluid reservoir and the external driver.