Marine Non-Impulsive Source Sweep Length Optimization

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Solution Overview

Problem

Marine seismic surveys using non-impulsive sources face inefficiencies due to long sweep lengths required for desired energy output and signal-to-noise ratio, leading to frequency drift and oversampling, which increases data acquisition time and costs, and environmental impact.

Innovation Solution

Implementing shorter sweep lengths over narrower frequency ranges for multiple non-impulsive sources, with additional sources operated within specific frequency ranges to achieve optimized energy output and reduce frequency drift, allowing for higher vessel speeds and reduced data acquisition duration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If long sweep lengths are used for non-impulsive sources, then desired energy output and signal-to-noise ratio are achieved, but data acquisition time increases and vessel speed decreases

Engineering Contradiction:

Improvesignal-to-noise ratioVSAvoiddata acquisition time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent divides the frequency spectrum into multiple narrower frequency ranges, with each non-impulsive source operating within a specific range. This segmentation allows each source to use shorter sweep lengths while collectively covering the full frequency spectrum, thereby reducing total data acquisition time while maintaining signal-to-noise ratio through optimized energy distribution across multiple sources.

Inventive Principle:

Principle #1Segmentation

2Power

If long sweep lengths are used for non-impulsive sources, then desired energy output is achieved, but frequency drift occurs and oversampling increases

Engineering Contradiction:

Improveenergy outputVSAvoidfrequency accuracy

Core Design Contradiction:

PowerVSManufacturing precision

Solution Approach 1:

Each non-impulsive source is assigned a specific frequency range tailored to its operational characteristics. This local optimization allows each source to operate at peak efficiency within its designated band, achieving desired energy output without excessive sweep lengths that would cause frequency drift. The narrowed frequency ranges prevent oversampling by matching source capabilities to specific spectral regions.

Inventive Principle:

Principle #3Local quality

3Productivity

If multiple non-impulsive sources operate over narrower frequency ranges, then data acquisition time is reduced, but system complexity increases

Engineering Contradiction:

Improvedata acquisition efficiencyVSAvoidnumber of sources

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent employs multiple non-impulsive sources that can operate independently within their assigned frequency ranges, but are coordinated through a unified survey design. This multi-functionality approach allows the system to achieve faster data acquisition by parallel operation, while the standardized configuration and coordinated control mitigate the complexity increase through systematic organization of multiple similar components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 reduces data acquisition time and costs, minimizes environmental impact, and improves the efficiency of marine seismic surveys by optimizing sweep lengths and energy output while maintaining a desired signal-to-noise ratio.

Implementation Method 1

A marine non-impulsive source can be controlled with a time signal that controls motion of the at least one plate of the marine vibrator source. The signal produced by the motion of the plate can be described as a sweep

Methodology Applied

Scientific EffectMechanical vibration: Vibration

Implementation Method 2

At each interface between different types of rock, a portion of the wavefield may be refracted, and another portion may be reflected

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 3

At each interface between different types of rock, a portion of the wavefield may be refracted, and another portion may be reflected

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 4

The marine survey receivers thereby measure a wavefield that was initiated by the actuation of the marine survey source

Methodology Applied

Scientific EffectAcoustic detection: Acoustics

Data Source

PatentUS11175425B2Survey design for data acquisition using marine non-impulsive sources

Publication Date: 2021.11.16 PGS GEOPHYSICAL AS

AI summary

Survey design for data acquisition using marine non-impulsive sources can include operating a first marine non-impulsive source at over a first frequency range for a first sweep length and operating a second marine non-impulsive source over a second frequency range for a second sweep length. The first sweep length can be based on available geological information of a subsurface location that is a target of a marine seismic survey, an intended speed of a marine survey vessel, and the first frequency range. The second sweep length can be based on the available geological information, the intended speed, and the second frequency range.