Active Isolation for Electric Seismic Vibrator Chassis
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Solution Overview
Problem
Existing seismic sources, such as hydraulic reciprocating vibrators, face limitations in delivering sufficient power at high frequencies due to fluid limitations and cavitation effects, and struggle to generate low-frequency waves with adequate amplitude, making them inefficient for seismic prospecting.
Innovation Solution
A vibratory seismic source utilizing a grid of linear electric motors powered by an electric generator and accumulator, which allows for controlled vertical movement of rods to deliver acoustic energy into the ground, with an active isolation system to absorb excessive vibrations and prevent chassis damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If hydraulic reciprocating vibrators are used to deliver seismic energy, then the system can provide sufficient power at low frequencies, but the hydraulic system is limited in providing sufficient power at high frequencies due to fluid limitations and cavitation effects
Solution Approach 1:
The patent replaces the hydraulic mechanical system with an electric linear motor system. The linear motors use electromagnetic fields to directly drive the reaction mass, eliminating hydraulic fluid limitations and cavitation effects. This substitution enables the system to deliver sufficient power across both low and high frequency ranges, achieving broadband seismic energy delivery from 1 Hz to 80 Hz and higher.
Solution Approach 2:
The invention changes the fundamental operating parameters by using electric linear motors that can independently control the motion of reaction masses across the entire frequency spectrum. The electric drive system allows for precise control of velocity, acceleration, and position, enabling effective operation at very high frequencies where hydraulic systems fail due to fluid dynamics limitations.
2Power
If linear motors are used to deliver seismic energy across a broad frequency spectrum, then sufficient power at high frequencies can be achieved, but the acoustic energy created may convey excessive vibration to the chassis and other portions of the seismic source
Solution Approach 1:
The patent extracts and isolates the vibration-generating linear motors from the chassis using an active isolation system. The isolation system physically separates the reaction mass and linear motors from the chassis, allowing the high-frequency seismic energy to be delivered to the ground while preventing excessive vibrations from being transmitted to the chassis and sensitive electronic components.
Solution Approach 2:
The active isolation system acts as an intermediary between the linear motors and the chassis. This isolation system includes vibration-absorbing elements and damping mechanisms that selectively transmit necessary vibrations to the ground while filtering out harmful vibrations that would damage the chassis. The isolation system mediates the interaction between the high-power linear motors and the vulnerable chassis structure.
3Speed
If the reaction mass is designed to provide adequate travel for low frequency wave generation, then low frequency seismic energy can be delivered, but the system becomes too large and cumbersome for practical deployment
Solution Approach 1:
The patent employs dynamic control of multiple reaction masses with different travel distances. Rather than designing a single oversized reaction mass to accommodate the longest travel requirement, the system uses multiple independently controlled linear motors that can dynamically adjust their motion parameters. This allows the system to generate low-frequency waves through coordinated motion of multiple masses, each with optimized, compact travel distances.
Solution Approach 2:
The invention segments the single reaction mass into multiple smaller reaction masses, each driven by its own linear motor. This segmentation allows each individual mass to have a compact travel distance suitable for portability, while the collective coordinated motion of all masses generates the necessary low-frequency seismic energy. The segmented approach enables low-frequency operation without requiring any single component to be oversized.
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
Enables efficient delivery of a broad spectrum of seismic energy from 1 Hz to 80 Hz or higher, overcoming the limitations of hydraulic systems and providing high-resolution data while minimizing wear and tear on the seismic source.
Implementation Method 1
A plurality of linear motors are arranged in a grid and positioned to depend from the chassis wherein each linear motor includes a rod that is arranged to move generally vertically to contact the ground with a lower end of the rod
Implementation Method 2
an active isolation system arranged between the grid of linear motors and the chassis for absorbing at least a portion of the acoustic energy that is created by the linear motors and preventing the acoustic energy from conveying excessive vibration to the chassis
Data Source
AI summary
The invention is an electric sweep type seismic vibrator source of the type used in seismic prospecting for hydrocarbons. The source uses an engine and generator combination to create electric power for all systems on the source such as driving a frame of linear electric motors that direct a rod or piston to contact the ground in a recurring fashion along with driving the source from location to location through a survey area. The seismic source further includes an active isolation system that provides for significant weight on the ground through the rods of the linear electric motors, but protects the vehicle body and the remainder of the systems on the seismic source to be insulated from the harshest vibration related to the acoustic energy being applied to the ground. The active isolation system may include reactive elements such as pneumatic and hydraulic shock absorbers, but also includes active elements such as linear motors operated to counteract the impulsive forces from conveying through the frame of the seismic source.