Seismic Vibrator Array Out-of-Phase Wavefield Generation
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Solution Overview
Problem
Current seismic surveying methods face limitations in effectively producing source gradient wavefields, which are necessary for enhanced subsurface structure imaging, due to the difficulty in achieving idealized mathematical source gradients with practical seismic vibrator arrays.
Innovation Solution
The seismic vibrator array is controlled to produce a source gradient wavefield by activating at least two seismic vibrators out-of-phase, approximating the idealized mathematical source gradient wavefield while maintaining a useable output level, offering flexibility to switch between monopolar and gradient source configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If seismic vibrators are activated out-of-phase to produce source gradient wavefields, then subsurface structure imaging accuracy is improved, but residual shot noise increases
Solution Approach 1:
The patent converts the harmful residual shot noise generated by out-of-phase vibrator activation into a beneficial signal by using the noise characteristics to enhance the source gradient wavefield. The system utilizes the noise generated during out-of-phase operation as part of the imaging process, transforming what was previously a detrimental factor into a useful component for improved subsurface imaging accuracy.
2Measurement precision
If seismic vibrators are activated out-of-phase to approximate idealized mathematical source gradient, then wavefield accuracy is improved, but output level decreases
Solution Approach 1:
The patent merges the out-of-phase vibrator activation with in-phase activation patterns, combining both approaches in a unified survey method. By integrating both in-phase and out-of-phase operations, the system maintains accurate source gradient wavefield approximation while compensating for output level reduction through the combined energy contribution of both activation modes.
Solution Approach 2:
The patent employs periodic alternation between in-phase and out-of-phase vibrator activation sequences. This periodic switching allows the system to maintain accurate wavefield gradients during out-of-phase periods while recovering output levels during in-phase periods, achieving both accuracy and sufficient power output through rhythmic operation cycles.
3Power
If seismic vibrators are activated in-phase to produce monopolar wavefields, then output level is maintained, but flexibility to produce gradient wavefields is reduced
Solution Approach 1:
The patent implements dynamic control of vibrator phase relationships, allowing the system to switch between in-phase and out-of-phase activation modes based on the required wavefield type. This dynamic adaptability enables the system to maintain high output levels during in-phase monopolar wavefield production while seamlessly transitioning to out-of-phase configurations when gradient wavefields are needed, achieving both power maintenance and operational flexibility.
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 flexibility and accuracy of seismic surveys by allowing the seismic vibrator array to produce both monopolar and source gradient wavefields, improving subsurface structure imaging and reducing residual shot noise, thereby increasing data quality and efficiency.
Implementation Method 1
seismic sources are activated to generate seismic waves directed into a subsurface structure
Implementation Method 2
a portion of the seismic waves reflected back to the surface for receipt by seismic receivers
Data Source
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AI summary
Marine seismic vibrators in a marine seismic vibrator array for use in a seismic survey are activated to produce a source gradient wavefield to survey a target structure. The seismic survey may comprise a marine seismic survey conducted in a body of water.