Hydraulic Marine Seismic Source for Low-Frequency Force Control
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Solution Overview
Problem
Traditional seismic vibrators face mechanical and hydraulic limitations in generating sufficient force at frequencies lower than 5 Hz, especially 1 to 3 Hz, leading to a lack of low-frequency seismic data necessary for accurate seismic inversion and geological exploration.
Innovation Solution
A low-frequency hydraulic marine controllable seismic source system comprising a signal excitation system, hydraulic servo system, and marine vibration excitation system, utilizing an electrohydraulic servo valve to generate continuous displacement and vibration, with sensors for real-time feedback control, enabling vibrations at 2 to 100 Hz and 20 kN force output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a traditional seismic vibrator is used, then the system structure is simple and easy to operate, but it cannot generate sufficient force at frequencies lower than 5 Hz due to mechanical and hydraulic limitations
Solution Approach 1:
The patent employs a hydraulic servo system with an electrohydraulic servo valve to control the vibration exciter. The hydraulic system can deliver high force at low frequencies (2-100 Hz range) by utilizing fluid pressure and flow control, overcoming the mechanical limitations of traditional vibrators that cannot generate sufficient force below 5 Hz.
Solution Approach 2:
The system changes the operating parameters by using a servo-controlled hydraulic system that can dynamically adjust force and frequency parameters. The electrohydraulic servo valve enables continuous adjustment of the vibration exciter's output across a wide frequency range (2-100 Hz), allowing operation at low frequencies where traditional mechanical systems fail.
2Measurement precision
If the vibration frequency is reduced to below 5 Hz to obtain low-frequency seismic data, then the seismic inversion accuracy is improved, but the mechanical and hydraulic system cannot provide sufficient force
Solution Approach 1:
The hydraulic servo system maintains sufficient output force at low frequencies (2-5 Hz) by utilizing hydraulic pressure multiplication and flow control. The electrohydraulic servo valve precisely controls the hydraulic actuator to deliver the required force even at the lowest operating frequency of 2 Hz, enabling accurate low-frequency seismic data collection for improved inversion accuracy.
Solution Approach 2:
The system dynamically adjusts operational parameters by using feedback from sensors (displacement, acceleration, attitude) to the electrohydraulic servo valve, which modifies the hydraulic control signals to maintain optimal force output across the entire frequency range including low frequencies necessary for accurate seismic inversion.
3Force
If a hydraulic servo system with electrohydraulic servo valve is used to achieve low-frequency vibration, then the force output is sufficient, but the system complexity increases
Solution Approach 1:
The patent integrates the electrohydraulic servo valve and hydraulic servo system as a unified control mechanism. While the hydraulic components add complexity, they consolidate multiple functions (force generation, frequency control, amplitude regulation) into a single integrated system that delivers sufficient force at low frequencies, which would require multiple separate mechanical systems otherwise.
Solution Approach 2:
The system incorporates feedback loops where displacement sensors, acceleration sensors, and attitude sensors continuously monitor the vibration exciter's performance and feed signals back to the electrohydraulic servo valve. This closed-loop control automates the complex adjustments needed for low-frequency operation, reducing the need for manual intervention and simplifying operation despite the increased system complexity.
4Measurement precision
If sensors are added for real-time feedback control, then the vibration frequency and amplitude can be precisely controlled, but the device complexity increases
Solution Approach 1:
The patent implements a closed-loop feedback control system using displacement sensors, acceleration sensors, and attitude sensors that continuously monitor the vibration exciter's state. These sensors feed real-time data to the electrohydraulic servo valve, which automatically adjusts the hydraulic control signals to maintain precise frequency and amplitude control. This feedback mechanism achieves high measurement precision while the automation reduces operational complexity.
Solution Approach 2:
The sensor system serves multiple functions: displacement sensing for position control, acceleration sensing for vibration characterization, and attitude sensing for orientation compensation. By combining these sensing functions into a unified feedback system controlled by the electrohydraulic servo valve, the patent achieves comprehensive vibration control without requiring separate independent control systems for each parameter.
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 achieves a 300 mm total stroke displacement and 190 dB sound pressure level, overcoming mechanical limitations and enabling accurate low-frequency seismic data collection for geological analysis.
Implementation Method 1
The hydraulic servo system includes an electrohydraulic servo valve. A signal end of the electrohydraulic servo valve is connected to the signal excitation system. The signal excitation system generates an excitation sweep signal, and transmits the excitation sweep signal to the electrohydraulic servo valve. After receiving the excitation sweep signal, the electrohydraulic servo valve controls an internal valve core of the electrohydraulic servo valve to generate a displacement to move continuously.
Implementation Method 2
the feedback rod of the electrohydraulic servo valve outputs and applies a force of equal magnitude indicated by the input/output signal of the feedback rod to the vibration exciter to enable the vibration exciter to perform a vibration in a horizontal direction, and the force radiates to the seawater to generate a low-frequency high-energy seismic wave.
Implementation Method 3
The displacement sensor, the acceleration sensor, and the attitude sensor mounted in the marine vibration excitation system monitor a vibration state in real time, and feed information back to the electrohydraulic servo valve to control a vibration frequency and an amplitude.
Data Source
AI summary
A low-frequency hydraulic marine controllable seismic source system includes a signal excitation system, a hydraulic servo system, and a marine vibration excitation system. An electrohydraulic servo valve is communicated with an oil way. A signal end is connected to each of the signal excitation system, a vibration exciter of the marine vibration excitation system, and a displacement sensor, an acceleration sensor, and an attitude sensor arranged on the vibration exciter of the marine vibration excitation system. After receiving an excitation sweep signal, the electrohydraulic servo valve controls an internal valve core of the electrohydraulic servo valve to generate a displacement to move continuously. A force of equal magnitude indicated by an input/output signal of a feedback rod is applied to the vibration exciter to perform a vibration in a horizontal direction and radiates to seawater to generate a low-frequency high-energy seismic wave.