Dual-wavefield multiple attenuation in seismic data processing
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Solution Overview
Problem
Current seismic data processing methods, such as SRME, face challenges in effectively attenuating surface multiple reflections due to ghost-induced effects and improper prediction of sea surface reflections, leading to residual multiples in marine seismic surveying.
Innovation Solution
The method involves performing wavefield separation on dual-wavefield seismic data to isolate ghost-free events, followed by multidimensional convolutions and adaptive subtraction to predict and remove multiples, while iteratively refining the process to account for sea surface reflection effects, using both source-side and receiver-side separations to enhance accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional SRME methods are used to attenuate surface multiples, then processing speed is maintained, but residual multiples remain due to ghost-induced effects and improper prediction of sea surface reflections
Solution Approach 1:
The patent segments the seismic data processing into distinct wavefield separations: source-side separation into upgoing and downgoing wavefields, and receiver-side separation into upcoming and downcoming wavefields. This segmentation allows targeted processing of primary reflections versus multiples, improving attenuation accuracy by treating different wavefield components separately rather than as a single mixed signal.
Solution Approach 2:
The patent performs preliminary wavefield separations before multiple attenuation processing. By separating source-side upgoing/downgoing and receiver-side upcoming/downcoming wavefields in advance, the method prepares purified data sets that enable more accurate multiple prediction and subtraction, addressing the ghost-induced effects problem before the main attenuation operation.
2Reliability
If wavefield separation and iterative SRME are applied to account for sea surface reflection effects, then multiple attenuation accuracy is improved, but processing time increases
Solution Approach 1:
The patent implements iterative SRME processing where the multiple attenuation operation is repeated multiple times with progressively refined inputs. Each iteration uses the results from the previous iteration to improve the prediction and subtraction of multiples, systematically accounting for sea surface reflection effects through periodic application of the attenuation algorithm.
Solution Approach 2:
The iterative SRME process incorporates feedback by using the output from each iteration as input for the next iteration. The method feeds back the partially attenuated data into subsequent processing cycles, allowing continuous refinement of multiple removal and progressively better accounting for complex sea surface reflection effects.
3Measurement precision
If dual-wavefield data with two sets of sources and receivers is used, then wavefield separation accuracy is improved, but data acquisition complexity increases
Solution Approach 1:
The patent utilizes dual-wavefield data acquisition that measures both pressure and particle velocity components of the seismic wavefield. This adds another dimension of measurement beyond conventional single-component recording, enabling mathematical separation of upgoing and downgoing wavefields through the relationship between pressure and velocity measurements.
Data Source
AI summary
Method for attenuating surface multiple reflections in dual-wavefield seismic data. In one implementation, the method may include: (a) performing wavefield separation on dual-wavefield seismic data to separate events in the seismic data into data sets according to ghost characteristics; (b) applying a multidimensional Surface-Related Multiple Elimination (SRME) to two or more of the data sets to yield an SRME result in a manner that retains surface reflection information affecting surface multiple reflections; and (c) repeating step (b) one or more times.