Omnidirectional Vector Geophone for Seismic Wave Field Divergence and Curl Detection

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Solution Overview

Problem

Existing seismic wave detection technologies cannot accurately detect full information of seismic wave fields, including divergence and curl, leading to significant errors in wave field separation and data fidelity, especially in terrestrial environments.

Innovation Solution

An omnidirectional vector geophone with a spatial structure of eight wave detectors arranged on a regular tetrahedron, allowing for the detection of full information including frequency, amplitude, phase, vibration direction, divergence, and curl of seismic waves, using a combination of cylindrical electromagnetic and flat sheet capacitor type detectors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If a single electromagnetic detector, capacitance detector or fiber optic strain detector is used, then the device structure is simple, but it cannot distinguish wave field vibration direction and cannot detect wave field divergence or curl

Engineering Contradiction:
Improvewave field information completenessVSAvoiddetector structure complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent divides the detection system into multiple detectors (at least three) arranged in specific spatial configurations. Each detector measures vibration in a specific direction, and through segmentation of the measurement functions, the system can reconstruct complete wave field information including divergence and curl that a single detector cannot provide.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from single-direction detection to multi-dimensional detection by arranging detectors in three-dimensional space. The spatial arrangement of detectors along different axes enables measurement of vibration in multiple dimensions, allowing calculation of divergence (volume expansion/compression) and curl (rotational motion) that are invisible to single-direction detectors.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If a three component detector is used to work out wave field vibration direction and amplitude, then the measurement capability is improved, but it still only measures translational vibration vector of a point and cannot detect nature, curl and divergence of vibration

Engineering Contradiction:
Improvewave field parameter detection accuracyVSAvoidvibration nature information
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent extends measurement from translational vibration only to include rotational vibration by adding curl detection capability. Through specific spatial arrangements of detectors and signal processing, the system measures not only the translational vibration vector but also the curl (rotational component) and divergence (volume change component) of the vibration field, providing complete characterization of vibration nature.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Loss of information

If existing acquisition technology is used to detect information such as amplitude, frequency, phase, then the detection function is limited, but it cannot detect the spatial properties of wave motions

Engineering Contradiction:
Improvespatial motion informationVSAvoidspatial properties measurement difficulty
Core Design Contradiction:
Loss of informationVSDifficulty of detecting and measuring

Solution Approach 1:

The patent segments the complex task of measuring spatial wave properties into multiple measurable components using distributed detectors. Each detector measures local vibration characteristics, and through spatial correlation and signal processing of these segmented measurements, the system reconstructs complete spatial motion properties including wave field divergence and curl that would be difficult to measure directly with a single device.

Inventive Principle:
Principle #1Segmentation

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 solution enhances the separation purity of pressure and shear waves, improves signal-to-noise ratio, fidelity, and accuracy of seismic data, particularly in mountainous areas, and provides a comprehensive basis for elastic wave theory analysis.

Implementation Method 1

A method of converting mechanical motion into an electric signal applies nothing more than an electromagnetic detector

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

A method of converting mechanical motion into an electric signal applies nothing more than an electromagnetic detector, a capacitance detector

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 3

A method of converting mechanical motion into an electric signal applies nothing more than an electromagnetic detector, a capacitance detector, a piezoelectric detector

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3370090B1Omni-directional vector seismic wave detector
Publication Date: 2021.06.16 PETROCHINA CO LTD
  • EP3370090B1 patent drawingFigure 1~2
  • EP3370090B1 patent drawingFigure 3~4
  • EP3370090B1 patent drawingFigure 5~6

AI summary

The invention discloses an omnidirectional vector geophone, comprising: eight wave detectors and support structures thereof, the support structures are used for supporting the eight wave detectors such that bottom surfaces of each two wave detectors are on one of regular triangle surfaces of a regular tetrahedron, crossing points of working shafts of the two wave detectors that are on the same regular triangle surface that cross with the regular triangle surface are both on an angular bisector of an angle of the regular triangle surface and are symmetric with respect to the center of the regular triangle surface. In the invention, based on divergence and curl equations of field theory, a particular spatial motion full-vector detection structure is designed to realize detection of full information including frequency, amplitude, phase, vibration direction of the seismic wave field, especially divergence and curl of a wave force field, to form a completely new omnidirectional vector geophone structure.