Seismic Vibrator Force Control for Low Frequency Sweep Limits
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Solution Overview
Problem
Seismic vibrators face limitations in generating seismic source signals with enhanced frequency sweeps due to physical constraints, such as reaction mass travel distance, leading to potential damage and distortion in seismic data acquisition.
Innovation Solution
The method involves determining user-defined forces at specific frequencies and comparing them to maximum forces calculated using sweep parameters, driving the seismic source at the maximum force to prevent exceeding physical limits and reduce distortion, using a processor-controlled system to manage the seismic source's amplitude and frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the seismic source is driven at high amplitudes to enhance seismic sweep performance, then the energy level and signal strength are improved, but the reaction mass may exceed its travel distance limits causing damage and distortion
Solution Approach 1:
The system performs preliminary calculations of maximum force at each frequency point before executing the sweep, using the reaction mass weight, gravity, and maximum reaction mass displacement to establish safe operating limits in advance
Solution Approach 2:
The system continuously monitors the relationship between user-defined force, maximum force, and reaction mass displacement during the sweep, adjusting the drive signal in real-time to prevent exceeding physical limits while maintaining optimal performance
2Reliability
If the reaction mass displacement is limited to prevent damage, then the reliability is improved, but the force and amplitude that can be generated are reduced
Solution Approach 1:
The system dynamically adjusts operating parameters including force, amplitude, and frequency based on the calculated maximum force envelope, optimizing the balance between reliability and performance by changing parameters in real-time rather than using fixed limits
Solution Approach 2:
The system transitions from static displacement limits to dynamic force control, where the maximum allowable force varies with frequency according to the reaction mass weight and maximum displacement constraints, allowing optimal performance at each frequency point
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 seismic sweep performance by preventing reaction mass over-travel, improving peak and average phase quality, and reducing distortion, thereby enhancing the accuracy and reliability of seismic data acquisition.
Implementation Method 1
A seismic vibrator in its simplest form is merely a heavy vehicle that has the ability to shake the ground at a predetermined range of frequencies of about 2 to 100 Hz
Implementation Method 2
determining a maximum force at the frequency using sweep parameters... determining a signal for driving the seismic source... driving the seismic source at the frequency in dependence upon the maximum force
Data Source
AI summary
A method of performing a seismic sweep determining a user-defined force at a frequency using user defined inputs; determining a maximum force at the frequency using sweep parameters; and using the maximum force to drive a seismic source if the user-defined force is greater than the maximum force.