Geophysical Noise Reduction via Wavelet Transform and Signal Equalization

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Solution Overview

Problem

Conventional methods for removing incoherent noise from geophysical data are time-consuming, expensive, and imprecise, often affecting the geophysical information by being too aggressive or leaving noise if too conservative.

Innovation Solution

The method involves using two or more sensors to measure the wavefield, transforming the data to equalize signal parts, and selecting the data set with the lowest energy content to form a noise-reduced data set, utilizing integral transforms and wavelet transforms to account for sensor displacements and different aspects of the wavefield.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional de-noising procedures are applied to remove incoherent noise, then noise reduction is achieved, but geophysical information may be affected or lost

Engineering Contradiction:
Improveincoherent noiseVSAvoidgeophysical information
Core Design Contradiction:
Object-affected harmful factorsVSLoss of information

Solution Approach 1:

The wavefield data is segmented into multiple independent data sets using different sensor combinations. Each data set is processed separately through transformation and noise modeling, allowing selective noise removal while preserving signal integrity in each segment before recombination.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different transformation parameters and noise model parameters to the data sets. By varying transformation parameters (such as different transform types or parameters) and selecting optimal noise model parameters, the system adapts to different noise conditions while preserving geophysical information.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If rigorous de-noising procedures are applied, then noise is reduced, but processing time and cost increase

Engineering Contradiction:
Improveincoherent noiseVSAvoidprocessing time
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The patent performs preliminary transformation of wavefield data into transformed data sets before noise removal. By pre-processing the data through transformation (such as Fourier or wavelet transforms) and creating multiple data sets in advance, the subsequent noise removal becomes more efficient and requires fewer iterative processing steps.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Multiple copies or representations of the wavefield data are created through different sensor combinations and transformations. These copied data sets are then processed in parallel or selected from, reducing the need for repeated processing of the same data and thereby reducing overall processing time.

Inventive Principle:
Principle #26Copying

3Object-affected harmful factors

If conventional de-noising procedures are applied, then noise is reduced, but precision and accuracy decrease

Engineering Contradiction:
Improveincoherent noiseVSAvoiddata accuracy
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The patent implements an iterative process where transformed data sets are processed, noise models are applied, and results are evaluated. Based on the evaluation of noise reduction effectiveness and signal preservation, the process can be iterated with adjusted parameters, providing feedback-driven optimization of processing precision.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system adjusts transformation parameters and noise model parameters based on the specific characteristics of the data and noise conditions. By changing parameters such as transform type, transformation parameters, and noise model parameters, the system optimizes the balance between noise removal and signal preservation for each specific case.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS9784869B2Noise models by selection of transform coefficients
Publication Date: 2017.10.10 PGS GEOPHYSICAL AS
  • US9784869B2 patent drawing
  • US9784869B2 patent drawing
  • US9784869B2 patent drawing

AI summary

A data set representing features of a geologic formation is formed from two or more signal acquisition data set representing independent aspects of the same wavefield. A wavelet transform is performed on the two or more signal acquisition data sets, and the data sets are further transformed to equalize signal portions of the data sets. Remaining differences in the data sets are interpreted as excess noise and are removed by different methods to improve the signal-to-noise ratio of any resulting data set.