Geophone with Tunable Resonance Frequency for Seismic-While-Drilling
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Solution Overview
Problem
Geophones with fixed resonance frequencies are unsuitable for seismic-while-drilling applications due to high-intensity shocks and vibrations, leading to rapid degradation or inadequate performance, as they either experience frequent collisions or excessive damping, which affects their ability to detect varying frequency seismic waves effectively in different well depths.
Innovation Solution
The geophone design incorporates multiple inductive assemblies with tunable resonance frequencies and controllable damping, where each assembly can be independently configured for sensing or damping modes, using a coupling element to adjust spring stiffness and resonance frequency, and a damping control unit to optimize signal-to-noise ratios and protect the sensor during transport.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a geophone is designed with a fixed resonance frequency optimized for specific frequency ranges, then it provides good sensing performance for seismic waves within that range, but it experiences frequent high-energy collisions and rapid degradation when used in seismic-while-drilling applications with high-intensity shocks and vibrations
Solution Approach 1:
The geophone employs a tunable resonance frequency mechanism that allows the resonance frequency to be dynamically adjusted based on operating conditions. The system includes a mass-spring system where the spring stiffness can be modified, enabling the resonance frequency to be tuned to match the dominant frequency of seismic waves at different well depths, thereby optimizing sensing performance while reducing harmful resonances during transport
Solution Approach 2:
The invention changes the physical parameters of the mass-spring system by providing multiple spring elements with different stiffness values. The system can switch between different spring configurations to alter the resonance frequency and damping characteristics, allowing optimization for both sensing mode (matching seismic wave frequencies) and transport mode (avoiding high-energy collisions)
2Adaptability or versatility
If a geophone is designed with a broad response curve to handle varying frequencies, then it may improve versatility for different well depths, but it requires heavy damping that degrades sensor performance or causes frequent collisions between the mass and housing
Solution Approach 1:
The system dynamically adjusts its resonance frequency to match the optimal frequency for the current operating condition (sensing or transport). During sensing operations, the resonance frequency is tuned to match the dominant seismic wave frequency at the current well depth, providing high sensitivity. During transport, the frequency is adjusted to avoid resonance with transport vibrations, preventing mass-housing collisions
Solution Approach 2:
The geophone is designed to perform multiple functions: it can operate as a high-sensitivity seismic sensor during drilling operations and as a durable transportable unit during movement. The tunable resonance frequency mechanism allows the same device to be optimized for different operational modes, eliminating the need for separate designs for sensing and transport
3Measurement precision
If the resonance frequency is tuned to improve response to selected frequencies, then sensing accuracy is improved, but the geophone becomes unsuitable for detecting seismic waves at different frequency ranges required for varying well depths
Solution Approach 1:
The system provides multiple discrete resonance frequency settings by incorporating several spring elements with different stiffness values. The controller can select the appropriate spring configuration based on the well depth and expected seismic wave frequency, thereby maintaining high measurement precision across different operating conditions
Solution Approach 2:
The system includes a controller that can adjust the resonance frequency based on feedback about the operating conditions, such as well depth and detected seismic wave characteristics. This allows the geophone to automatically tune its resonance frequency to optimize detection accuracy for the current operational context
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 design allows for adjustable resonance frequencies and damping levels, enhancing the geophone's ability to detect seismic waves with improved signal-to-noise ratios and protecting the sensor from damage during drilling operations, thereby extending its lifespan and performance in varying drilling environments.
Implementation Method 1
The motion of the magnetic mass relative to the inductive coil generates a voltage at the coil's terminals proportional to the relative velocity of the mass
Implementation Method 2
The resonance frequency or frequencies of the mass-spring system may be chosen to improve the transducer's response to a selected frequency
Implementation Method 3
a design that provides a very broad response curve... may be expected to be so heavily damped that it is unsuitable for use as a seismic sensor
Data Source
AI summary
An illustrative geophone with tunable resonance frequency includes a first inductive assembly including an inductive coil having a first magnet arranged therein, wherein the first magnet and the first inductive coil move relative to each other, and a second inductive assembly including a second inductive coil having a second magnet arranged therein, wherein the second magnet and the second inductive coil move relative to each other. A coupling element couples a movable element of the first inductive assembly with a moveable element of the second inductive assembly. The first inductive assembly employs tunable damping to modify a resonant frequency of the second inductive assembly.