Orthogonal Function Estimation for AVOA Seismic Data Resolution
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Solution Overview
Problem
Current seismic data processing methods are inadequate for precise Amplitude Variation with Offset (AVO) and Amplitude Variation with Offset and Azimuth (AVOA) characterization, as they require small azimuth sectors for resolution, leading to under-sampling and reduced processing efficiency, and fail to correlate AVO variations between sectors.
Innovation Solution
A method that organizes seismic traces according to acquisition parameters, defines a base of orthogonal elementary functions, and determines combination coefficients to estimate amplitude variations, allowing for precise AVOA characterization across all data without sector separation, preserving azimuth resolution and enabling multi-dimensional AVOA characterization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If seismic data is separated into multiple azimuth sectors for AVO characterization, then the resolution of AVOA characterization is improved, but the number of traces in each subset is reduced leading to under-sampling and reduced processing efficiency
Solution Approach 1:
The patent applies segmentation by dividing the azimuth range into multiple sectors (e.g., 0-45°, 45-90°, etc.), allowing AVOA characterization to be performed separately in each sector. This segmentation enables precise measurement of azimuthal variations while maintaining sufficient trace counts within each sector for reliable statistical analysis and processing efficiency.
2Measurement precision
If the aperture angle of azimuth sectors is reduced to maintain AVO characterization resolution, then the measurement precision is improved, but the number of traces in each subset is reduced causing under-sampling
Solution Approach 1:
The patent transitions from traditional 2D AVO analysis to 3D AVOA analysis by incorporating the azimuth dimension. This dimensional expansion allows the use of multiple azimuth sectors simultaneously, where each sector maintains sufficient trace coverage while collectively providing comprehensive azimuthal coverage. The method effectively utilizes the additional azimuth dimension to resolve the trade-off between sector aperture and trace density.
3Ease of operation
If traditional AVO methods are used that assume linear amplitude variation, then the processing simplicity is maintained, but the accuracy of AVOA characterization is degraded
Solution Approach 1:
The patent changes the functional form of amplitude variation from the traditional linear model to a quadratic model that includes azimuthal dependence. The new model incorporates additional parameters (azimuthal coefficients) that capture the complex amplitude variations more accurately. This parameter expansion maintains processing systematicity while significantly improving AVOA characterization accuracy by accounting for non-linear effects.
Data Source
AI summary
The invention relates to a method of processing seismic data comprising a gather of seismic traces organised according to one or several acquisition parameters, each trace comprising a seismic signal defined by an amplitude as a function of time or depth, the method comprising the steps of:a) defining a base of elementary functions of the acquisition parameter(s),b) orthogonalising said elementary functions so as to define a base of orthogonal elementary functionsc) for a given time or at a given depth, determining combination coefficients defining a combination of the orthogonal elementary functions, said combination being an estimator of a variation in the amplitude of the seismic signal as a function of the acquisition parameter(s).