Frequency-Dependent Reflection Operator for Marine Seismic Ghost Data Removal

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Solution Overview

Problem

Marine seismic surveying is hindered by ghost data, which results from reflections at the air-water interface, leading to reduced accuracy in subsurface structure representation due to amplitude and phase distortions and frequency losses.

Innovation Solution

A method and system utilizing a frequency-dependent reflection operator to compute and remove the effects of wavefield reflections from interfaces, specifically designed to address ghost data in seismic survey data by generating deghosted data through a forward model that accounts for varying reflection coefficients at different frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If seismic survey data is collected in a marine environment, then subsurface structure information can be obtained, but ghost data from air-water interface reflections degrades data accuracy

Engineering Contradiction:
Improvesubsurface structure representation accuracyVSAvoidghost data from air-water interface reflections
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and removes the harmful ghost data component from the seismic survey data by computing the reflected wavefield using a frequency-dependent reflection operator and subtracting it from the measured data, thereby isolating the useful subsurface reflection signals

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a frequency-dependent reflection operator as an intermediary that models the air-water interface reflection effects, allowing the harmful ghost data to be characterized and removed through computational processing rather than physical modification

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-generated harmful factors

If traditional deghosting methods are used, then some ghost data can be removed, but frequency-dependent reflection characteristics are not accurately captured

Engineering Contradiction:
Improveghost data removalVSAvoidfrequency-dependent reflection accuracy
Core Design Contradiction:
Object-generated harmful factorsVSMeasurement precision

Solution Approach 1:

The patent employs a frequency-dependent reflection operator that varies the reflection coefficient parameter across different frequency ranges, accurately capturing the frequency-dependent characteristics of air-water interface reflections and enabling precise deghosting across the entire frequency spectrum

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 approach effectively mitigates ghost data artifacts, enhancing the accuracy of subsurface structure representation by accurately removing interference effects from the air-water interface, thereby improving the quality of seismic data.

Implementation Method 1

a reflected seismic wavefield (that is in response to the seismic wavefield propagated by the seismic source) propagates generally upwardly toward an arrangement of seismic receivers

Methodology Applied
Scientific EffectWavefield reflection: Reflection

Implementation Method 2

based at least in part on a frequency dependent reflection operator, a wavefield propagating in a survey environment is computed, where the reflection operator represents a wavefield reflection from an interface that causes ghost data

Methodology Applied
Scientific EffectFrequency-dependent reflection: Reflection

Data Source

PatentEP2909766B1Deghosting survey data
Publication Date: 2022.07.27 GEOQUEST SYSTEMS BV
  • EP2909766B1 patent drawingFigure 1
  • EP2909766B1 patent drawingFigure 2
  • EP2909766B1 patent drawingFigure 3

AI summary

Measured survey data is deghosted by removing an effect of a reflected wavefield reflected from an interface that causes ghost data in the measured survey data, the deghosting of the measured survey data using a frequency-dependent reflection operator that represents different wavefield reflections from the interface at corresponding different frequencies.