Marine Non-Impulsive Source Sweep Signal Optimization

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Solution Overview

Problem

Marine seismic surveys face challenges in combining impulsive and non-impulsive source outputs, leading to destructive interferences and undesired notches in the amplitude spectrum, which complicate data processing and reservoir characterization.

Innovation Solution

Optimizing the sweep signal for marine non-impulsive sources to be used in conjunction with impulsive sources, by adjusting parameters such as stop frequency, taper, and initial phase, to enhance energy distribution and reduce phase differences, thereby improving the peak-to-bubble ratio and spectral smoothness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If impulsive and non-impulsive sources are combined for marine seismic surveys, then survey coverage and data quality improve, but destructive interferences and notches appear in the amplitude spectrum

Engineering Contradiction:

Improvesurvey coverageVSAvoiddestructive interferences

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by modifying the sweep signal characteristics (stop frequency, taper, initial phase) of the non-impulsive source to compensate for the impulsive source output. By adjusting these parameters, the amplitude spectrum notches caused by destructive interference are reduced, allowing beneficial combination of both source types while minimizing harmful effects.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The optimized sweep signal acts as an intermediary that mediates between the impulsive and non-impulsive source outputs. It adjusts the non-impulsive source characteristics to be compatible with the impulsive source, enabling constructive combination of their signals while reducing destructive interference effects.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If conventional sweep signals are used for non-impulsive sources, then equipment simplicity is maintained, but energy distribution is insufficient at low frequencies

Engineering Contradiction:

Improveequipment simplicityVSAvoidenergy distribution

Core Design Contradiction:

Ease of manufactureVSUse of energy by moving object

Solution Approach 1:

The patent modifies the sweep signal parameters (stop frequency, taper, initial phase) to optimize energy distribution. These parameter changes concentrate more energy at low frequencies while maintaining the basic sweep signal structure, thus improving energy distribution without significantly complicating the equipment.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If sweep signal parameters are not optimized, then data processing is simplified, but notches in the amplitude spectrum complicate processing

Engineering Contradiction:

Improvedata processingVSAvoidspectral smoothness

Core Design Contradiction:

Ease of operationVSLoss of information

Solution Approach 1:

By optimizing the sweep signal parameters (stop frequency, taper, initial phase), the patent reduces notches in the amplitude spectrum. This creates a smoother spectral profile that is easier to process and interpret, reducing the complexity of data processing while maintaining information integrity.

Inventive Principle:

Principle #35Parameter changes

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

The optimized sweep signal improves the amplitude spectrum of combined outputs, increasing energy at low frequencies and reducing notches, resulting in higher quality data acquisition and clearer signals for subsurface characterization.

Implementation Method 1

A marine seismic source is a device that generates controlled acoustic energy used to perform marine surveys based on reflection and/or refraction of the acoustic energy

Methodology Applied

Scientific EffectVibration: Vibration

Implementation Method 2

The marine vibrator source can be controlled with a time signal that controls motion of the at least one plate of the marine vibrator source

Methodology Applied

Scientific EffectAcoustic energy generation: Sound

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

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

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS10996356B2Sweep signal for combination of a marine non-impulsive source output with a marine impulsive source output

Publication Date: 2021.05.04 PGS GEOPHYSICAL AS

AI summary

Parameters of a sweep signal that controls operation of a marine non-impulsive source can be set. Setting the parameters can include selecting a stop frequency of the sweep signal, defining a taper of the sweep signal, and adjusting an initial phase of the sweep signal. The parameters can be set such that a magnitude of an amplitude spectrum of a combined output of a marine impulsive source and the marine non-impulsive source is greater than or equal to a magnitude of an amplitude spectrum of a marine impulsive source output at frequencies below the stop frequency. A controller of the marine non-impulsive source can be programmed with the sweep signal having the parameters set to control the marine non-impulsive source.