Resonant Seismic Source With Adjustable Suspension For Low-Frequency Output
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Solution Overview
Problem
Existing seismic source elements are ineffective in generating low-frequency seismic waves in the range of 0.5 to 5 Hz, which is crucial for deep penetration and accurate imaging in complex geological settings, as they produce weak energy levels that fail to provide the necessary signal-to-noise ratio for successful seismic imaging.
Innovation Solution
A resonant seismic source system that includes a frame, a reaction mass oscillating relative to the frame, and a resonant suspension system with adjustable spring or pneumatic components to generate low-frequency seismic waves by oscillating at a specific resonant frequency, enhancing the low-frequency energy output without compromising moderate and high-frequency energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If existing vibratory source elements are used, then moderate and high frequency energy is generated, but low-frequency energy (0.5 to 5 Hz) is insufficient
Solution Approach 1:
The patent changes the operating parameters of the vibratory source by implementing low-dwell sweeps that extend into the low-frequency range (0.5 to 5 Hz). This involves modifying the frequency sweep characteristics and dwell times to accumulate low-frequency energy while managing the trade-off with stroke limitations.
Solution Approach 2:
The patent employs periodic low-dwell sweeps at multiple frequency points within the low-frequency band. By repeatedly exciting the ground at different low frequencies with adequate dwell times, the system accumulates sufficient low-frequency energy to improve the signal-to-noise ratio for deep penetration imaging.
2Use of energy by moving object
If low-dwell sweeps are used to boost low-frequency output, then low-frequency amplitude increases, but stroke limitations cause peak amplitude levels to remain weak and dwell times become very long
Solution Approach 1:
The patent applies partial action by using multiple low-dwell sweeps at different frequency points rather than attempting to achieve the full low-frequency spectrum in a single continuous sweep. This approach accumulates low-frequency energy incrementally, reducing the required dwell time at each frequency point while still achieving sufficient overall low-frequency amplitude.
Solution Approach 2:
The patent segments the low-frequency spectrum into multiple discrete frequency points or bands, each excited by separate low-dwell sweeps. This segmentation allows the system to target specific low-frequency ranges of interest without being constrained by the stroke limitations that would prevent achieving broad low-frequency coverage in a single operation.
3Measurement precision
If the seismic survey bandwidth is extended to lower frequencies, then depth penetration and imaging capability improve, but the cost of the survey increases
Solution Approach 1:
The patent implements partial action by extending the bandwidth only to the extent necessary for achieving the desired depth penetration and imaging accuracy. Rather than continuously lowering the frequency, the system identifies and targets specific low-frequency thresholds that provide sufficient imaging capability, avoiding unnecessary extensions that would increase survey time and cost.
Data Source
AI summary
Method and resonant source for generating low-frequency seismic waves. The resonant source includes a frame; a reaction mass configured to oscillate relative to the frame; a resonant suspension system connecting the reaction mass to the frame and including at least a spring; and a spring clamp system connected to the resonant suspension system and configured to modify a resonant frequency of the resonant suspension system. The resonant suspension system is configured to allow the reaction mass to oscillate relative to the frame with a corresponding resonant frequency.