Wave Equation Deconvolution for Internal Multiple Attenuation
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Solution Overview
Problem
Existing seismic data processing methods are ineffective in accurately identifying and removing internal multiples, which contaminate primary arrivals and hinder the accurate imaging of subsurface geophysical features, particularly in hydrocarbon exploration.
Innovation Solution
A method utilizing wavefield extrapolation and reflectivity calculations to differentiate between primary and internal multiples, allowing for their subtraction from seismic data, thereby generating a clearer image of the subsurface indicative of oil or gas resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional seismic data processing methods are used, then primary arrivals can be processed, but internal multiples contaminate the data and hinder accurate imaging
Solution Approach 1:
The patent segments the seismic wavefield into primary arrivals and internal multiples by calculating reflectivity at different depth levels. The wavefield is divided into upgoing and downgoing components, and reflectivity is calculated at a first depth level and a second depth level to distinguish between different wave types. This segmentation allows separate processing of primaries and multiples to improve imaging accuracy.
Solution Approach 2:
The patent extracts internal multiples from the seismic data by calculating their contribution using wavefield extrapolation and reflectivity at different depth levels. The extracted multiple contribution is then subtracted from the total seismic data, leaving only the primary arrivals for accurate imaging. This extraction process removes the harmful contamination while preserving the useful primary signal.
2Reliability
If wavefield extrapolation and reflectivity calculations are performed to identify internal multiples, then multiple attenuation is achieved, but computational complexity increases
Solution Approach 1:
The patent performs preliminary wavefield extrapolation and reflectivity calculations at different depth levels before final imaging. By calculating the multiple contribution in advance using extrapolated wavefields and reflectivity sequences, the method prepares the data for efficient multiple removal. This preliminary action separates the complex identification task from the final imaging step, improving reliability while managing complexity through staged processing.
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 effectively attenuates internal multiples, improving the accuracy of subsurface imaging and resource identification by isolating primary arrivals, enhancing the detection of geophysical features associated with oil, gas, and other resources.
Implementation Method 1
calculating a second reflectivity r2 associated with a second formation in the subsurface, based on wavefield extrapolation of the seismic data d and a reflection in the first reflectivity r1
Implementation Method 2
Energy generated by a seismic source propagates as seismic waves downward into a geological formation, and part of the energy is reflected and/or refracted back up to the surface
Data Source
AI summary
A method for internal multiple attenuation of seismic data associated with a subsurface. The method includes receiving seismic data d associated with the subsurface, wherein the seismic data d includes primaries and internal multiples, receiving a first reflectivity r1 associated with a first formation in the subsurface, calculating a second reflectivity r2 associated with a second formation in the subsurface, based on wavefield extrapolation of the seismic data d and a reflection in the first reflectivity r1, wherein the second formation is different from the first formation, calculating the internal multiples using (1) wavefield extrapolation of the seismic data d, (2) the reflection in the first reflectivity r1, and (3) a reflection in the second reflectivity r2, attenuating the internal multiplies from the seismic data d by subtraction, and generating an image of the subsurface indicative of geophysical features associated with oil or gas resources.