Marine Vibrator Sweep Function Optimization for Acoustic Power and Environmental Impact
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Marine seismic vibrators are not practically used in marine seismic surveys due to low acoustic power, especially at low frequencies, which degrades seismic images and environmental concerns, and the complexity of replicating the output energy spectrum of airguns.
Innovation Solution
Configuring marine seismic vibrators to produce a sweep function based on quality requirements such as signal-to-noise ratio (SNR) and environmental impact, rather than matching the output energy of airguns, to provide sufficient energy for seismic surveys while minimizing environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If marine seismic vibrators are used to match the output energy spectrum of airguns, then the acoustic power and image quality improve, but the device complexity and environmental impact increase
Solution Approach 1:
The patent applies parameter changes by modifying the sweep function parameters (frequency, amplitude, duration) to optimize the vibrator output for marine conditions rather than attempting to replicate airgun spectra. This involves changing the operational parameters to achieve acceptable image quality without the complexity of spectral matching
Solution Approach 2:
Instead of making the vibrator match the airgun spectrum (conventional approach), the patent inverts the approach by making the airgun spectrum match the vibrator's natural output characteristics. This reversal simplifies the device requirements while maintaining survey quality
2Power
If marine seismic vibrators increase acoustic power output, then seismic image quality improves, but environmental impact on marine fauna increases
Solution Approach 1:
The patent changes the temporal and spectral parameters of the seismic signal, using longer duration sweeps at lower peak powers instead of high-power impulsive signals. This achieves sufficient signal-to-noise ratio for imaging while reducing peak acoustic levels that harm marine fauna
Solution Approach 2:
The patent employs periodic sweep functions where the vibrator continuously cycles through frequency ranges in a controlled manner, distributing the acoustic energy over time rather than delivering concentrated impulsive energy. This periodic action maintains imaging quality while reducing instantaneous environmental impact
3Power
If marine seismic vibrators use traditional sweep functions to match airgun energy, then output energy spectrum improves, but survey efficiency and environmental friendliness deteriorate
Solution Approach 1:
The patent optimizes sweep function parameters including sweep duration, frequency range, and amplitude modulation to achieve efficient data acquisition. By adjusting these parameters, the system achieves acceptable spectral content without the time-consuming process of matching airgun spectra
Solution Approach 2:
The patent applies partial action by not attempting to fully replicate the airgun energy spectrum across all frequencies. Instead, it focuses on achieving sufficient energy in the critical frequency ranges for marine imaging, accepting some spectral differences to gain efficiency
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 allows marine seismic vibrators to produce seismic images with desired quality and reduced environmental impact, as they can focus on achieving specific image quality and energy distribution rather than replicating airgun spectra, enhancing survey efficiency and environmental friendliness.
Implementation Method 1
The sources generate seismic waves, which propagate into the geological formations, creating pressure changes and vibrations along the way
Implementation Method 2
Some seismic sensors are sensitive to pressure changes (hydrophones), and others are sensitive to particle motion (e.g., geophones)
Data Source
AI summary
Marine seismic survey using one or more marine seismic vibrators, where the vibrator sweep function is based on a quality requirement, which may be a final image quality requirement or an environmental requirement. The sweep function may be nonlinear and the energy spectrum may not match the energy spectrum of an airgun.