Marine Seismic Data Correction for Sea Surface State Variations

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Solution Overview

Problem

Marine seismic surveying is hindered by sea surface state variations, such as waves and swells, which cause amplitude and phase perturbations in seismic data, leading to inaccurate interpretations of subterranean formations.

Innovation Solution

The method involves correcting for sea surface state variations by separating up-going and down-going wavefields, identifying source-side effects, and applying a surface-consistent static correction using cross-correlations between constant receiver and channel ensembles, thereby isolating primary reflections and reducing the impact of sea surface state on seismic data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If marine seismic surveying is conducted in normal sea conditions, then seismic data can be collected, but sea surface state variations cause amplitude and phase perturbations leading to inaccurate interpretations

Engineering Contradiction:

Improveseismic data accuracyVSAvoidsea surface state variations

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies wavefield separation to isolate and remove the harmful effects of sea surface state variations from the seismic data. By separating up-going and down-going wavefields, the method converts the problematic mixed signal into distinct components, allowing the harmful sea surface effects to be identified and eliminated while preserving the useful primary reflection data for accurate subterranean formation interpretation

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent segments the seismic wavefield into up-going and down-going components through wavefield separation. This segmentation allows independent analysis and correction of each wavefield component, specifically enabling the removal of sea surface state variations from the up-going wavefield while maintaining the integrity of primary reflections from subterranean formations

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If wavefield separation and static correction are applied to correct sea surface effects, then seismic data accuracy improves, but data processing complexity increases

Engineering Contradiction:

Improveseismic data accuracyVSAvoiddata processing complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies static correction as a preliminary processing step after wavefield separation to pre-correct the up-going wavefield for sea surface state variations before further seismic processing. This preliminary action removes amplitude and phase perturbations early in the processing workflow, simplifying subsequent interpretation steps by providing pre-corrected data that requires less complex post-processing

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary processing step that computes a static correction term based on the separated wavefields and applies it to correct the up-going wavefield. This intermediary correction acts as a mediator between the raw separated wavefields and the final corrected seismic data, systematically removing sea surface effects through a structured multi-step process rather than attempting a single complex correction

Inventive Principle:

Principle #24Intermediary (Mediator)

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 results in smoothed, accurate seismic data that is less affected by sea surface state variations, improving the quality and reliability of subterranean formation interpretations.

Implementation Method 1

Each acoustic signal is essentially a sound wave that travels down through the water and into the subterranean formation

Methodology Applied

Scientific EffectSound wave propagation: Sound

Implementation Method 2

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

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 3

another portion may be reflected back toward the body of water to propagate toward the surface

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 4

Each streamer includes a number of seismic receivers that detect pressure and/or particle motion changes in the water created by the sound waves reflected back into the water from the subterranean formation

Methodology Applied

Scientific EffectPressure detection:

Data Source

PatentUS10598807B2Correction of sea surface state

Publication Date: 2020.03.24 PGS GEOPHYSICAL AS

AI summary

A method for correction of a sea surface state can include receiving geophysical data from a seismic survey, wherein the seismic survey utilizes a plurality of receivers disposed in a body of water and at least one source in the body of water, actuated at a plurality of shot points. The method can include identifying, in the geophysical data, a wavefield based on the actuation of the at least one source, and determining, based on the identified wavefield, a sea surface state at the at least one source at one of the plurality of shot points.