Marine Seismic Cable Sensor Groups for Directional Wave Separation

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Solution Overview

Problem

Current seismic acquisition systems face challenges in accurately determining the direction of sound waves due to interference from direct and surface-reflected signals, and existing methods for vertical array configurations are costly and complex, with streamer cables twisting and turning, making it difficult to distinguish between sensors.

Innovation Solution

A marine seismic survey system with a cable featuring groups of piezo-ceramic pressure sensors arranged close together, with electromechanical transducers to determine their relative position, and an inclinometric system to account for cable rotation, allowing for accurate vertical pressure gradient measurement and separation of wave directions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If pressure sensors are arranged in vertical arrays to determine sound wave direction, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:

Improvedirection determination precisionVSAvoidarray configuration complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the cable into multiple sections, each containing a pair of pressure sensors arranged at different depths. This segmentation allows direction determination through local depth comparisons rather than requiring complex overall array configurations, reducing system complexity while maintaining measurement precision.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent transitions from horizontal sensor arrangements to vertical depth-based arrangements by placing sensor pairs at different depths within the cable. This dimensional change enables direction determination through depth differences, simplifying the overall system architecture while improving directional measurement capability.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Productivity

If cable length is increased to cover larger survey areas, then productivity is improved, but stability of sensor positioning deteriorates due to cable twisting and turning

Engineering Contradiction:

Improvesurvey coverage areaVSAvoidsensor vertical position stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The patent acknowledges the dynamic nature of the towing cable and incorporates inclinometric systems that can measure and compensate for cable orientation changes. This dynamic approach allows the system to maintain accurate vertical position measurements despite cable twisting and turning during operation, enabling longer cable deployments for increased productivity.

Inventive Principle:

Principle #15Dynamics

3Ease of operation

If individual streamers are used instead of combined dual-sensor streamers, then ease of operation is improved, but measurement precision deteriorates due to inability to separate upward and downward waves

Engineering Contradiction:

Improvestreamer deployment simplicityVSAvoidwave direction separation accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent uses separate single-sensor streamers rather than combined dual-sensor streamers, dividing the measurement function into simpler individual components. Each streamer carries pressure sensors that record acoustic signals, and the simplified deployment is complemented by computational methods to achieve wave separation, maintaining ease of operation while improving measurement precision.

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 enables precise measurement of vertical pressure gradients, reduces interference from ghost signals, and maintains accuracy across various streamer orientations, improving seismic data acquisition efficiency and reducing deployment costs.

Implementation Method 1

a cable with a plurality of piezo-ceramic pressure sensors

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

one or more electromechanical transducers for determining the relative position of said at least two pressure sensors

Methodology Applied

Scientific EffectElectromechanical transduction: Electromagnetic Induction

Implementation Method 3

an inclinometric system to account for cable rotation, allowing for accurate vertical pressure gradient measurement

Methodology Applied

Scientific EffectInclinometric measurement: Accelerometer

Implementation Method 4

enables precise measurement of vertical pressure gradients

Methodology Applied

Scientific EffectPressure gradient measurement: Pressure Gradient

Data Source

PatentUS8358560B2Marine seismic acquisition system

Publication Date: 2013.01.22 REFLECTION MARINE NORGE AS

AI summary

A marine cable for seismic surveys is described with a plurality of ceramic pressure sensors (901-904) arranged in groups of at least two pressure sensors with a group output being representative of the vertical pressure gradient at the group location, and an inclinometric system including one or more transducers for determining the orientation of the sensors of the group in order to determine their true vertical separation.