Marine Seismic Vibrator Control System Harmonic Suppression

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Solution Overview

Problem

Current marine seismic data acquisition technologies face limitations in generating powerful low-frequency seismic energy sources and controlling the spectral content of seismic energy, which hinders effective subsurface exploration.

Innovation Solution

A marine seismic vibrator system with a control system that utilizes a magnetostrictive driver and dual resonant springs to generate seismic energy within the desired frequency range, combined with an iterative learning control system to ensure well-characterized spectral content and suppress harmonics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If impulsive type acoustic sources (air guns, water guns) are used to generate seismic energy, then energy generation speed is improved, but frequency content control capability deteriorates

Engineering Contradiction:
Improveenergy generation speedVSAvoidfrequency content control capability
Core Design Contradiction:
SpeedVSAdaptability or versatility

Solution Approach 1:

The vibrator system dynamically adjusts its operating parameters including frequency, amplitude, and duty cycle through electronic control circuits. The system can vary the drive signal frequency to generate different frequency ranges of seismic energy, and modulate the amplitude and duty cycle to control the spectral content, thereby achieving both rapid energy generation and flexible frequency control.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes physical parameters of the vibrator operation such as drive frequency, amplitude, and pulse width modulation to control the spectral content of generated seismic energy. By adjusting these parameters, the system can generate different frequency ranges while maintaining efficient energy production.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If conventional vibrator sources are used to generate low frequency seismic energy, then frequency range is improved, but power generation capability deteriorates

Engineering Contradiction:
Improvefrequency rangeVSAvoidpower generation capability
Core Design Contradiction:
Adaptability or versatilityVSPower

Solution Approach 1:

The system employs a vibrator that generates mechanical vibrations through controlled mechanical oscillation. The vibrator assembly includes a vibrating element that can be driven at various frequencies, and through mechanical resonance and vibration amplification, achieves both low frequency operation and high power output capability simultaneously.

Inventive Principle:
Principle #18Mechanical vibration

Solution Approach 2:

The vibrator system dynamically adjusts its operating parameters including frequency, amplitude, and duty cycle through electronic control circuits. The system can vary the drive signal frequency to generate different frequency ranges of seismic energy, and modulate the amplitude and duty cycle to control the spectral content, thereby achieving both rapid energy generation and flexible frequency control.

Inventive Principle:
Principle #15Dynamics

3Power

If high-powered land-based vibrator control methods are used for marine vibrators, then power capability is improved, but spectral content characterization deteriorates

Engineering Contradiction:
Improvepower capabilityVSAvoidspectral content characterization
Core Design Contradiction:
PowerVSManufacturing precision

Solution Approach 1:

The system incorporates sensors that detect the actual vibration output and feed this information back to the control circuit. The feedback signal is processed to determine the actual spectral content, and the control circuit adjusts the drive signal accordingly to achieve the desired spectral characteristics. This closed-loop control ensures well-characterized spectral content while maintaining high power capability.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system replaces conventional mechanical control methods with electronic control circuits that precisely regulate the vibrator's operation. Electronic control allows for more precise manipulation of the drive signal characteristics, enabling better spectral content characterization while maintaining high power output.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Adaptability or versatility

If vibrator sources are used to generate frequency sweeps, then frequency content is improved, but power generation capability deteriorates

Engineering Contradiction:
Improvefrequency contentVSAvoidpower generation capability
Core Design Contradiction:
Adaptability or versatilityVSPower

Solution Approach 1:

The vibrator system dynamically adjusts its operating parameters including frequency, amplitude, and duty cycle through electronic control circuits. The system can vary the drive signal frequency to generate different frequency ranges of seismic energy, and modulate the amplitude and duty cycle to control the spectral content, thereby achieving both rapid energy generation and flexible frequency control.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs a vibrator that generates mechanical vibrations through controlled mechanical oscillation. The vibrator assembly includes a vibrating element that can be driven at various frequencies, and through mechanical resonance and vibration amplification, achieves both low frequency operation and high power output capability simultaneously.

Inventive Principle:
Principle #18Mechanical vibration

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 effectively generates seismic energy with a flat amplitude spectrum within the seismic frequency range, enhancing the transmission of low-frequency sound waves and improving the accuracy of subsurface exploration data.

Implementation Method 1

a magnetostrictive driver and dual resonant springs to generate seismic energy

Methodology Applied
Scientific EffectMagnetostriction: Magnetostriction

Implementation Method 2

dual resonant springs to generate seismic energy within the desired frequency range

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 3

marine seismic vibrator system with a control system that utilizes a magnetostrictive driver and dual resonant springs to generate seismic energy

Methodology Applied
Scientific EffectVibration: Vibration

Data Source

PatentEP2267486B1Control system for marine vibrators and seismic acquisition system using such control system
Publication Date: 2021.05.26 PGS GEOPHYSICAL AS
  • EP2267486B1 patent drawingFigure 1
  • EP2267486B1 patent drawingFigure 2
  • EP2267486B1 patent drawingFigure 3

AI summary

A method for controlling output of a marine seismic vibrator includes operating the vibrator using a predetermined driver signal. A vibrator output signal is measured at at least two different places on the vibrator. The at least two measured vibrator output signals are used to determine a corrected driver signal, wherein the corrected driver signal results in fewer harmonics of fundamental frequencies in the vibrator output. The vibrator is operated using the corrected driver signal.