Marine Seismic Data Noise Reduction via Angle-Domain Migration
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Solution Overview
Problem
Marine seismic surveys face challenges in accurately identifying sub-surface structures due to noise in seismic data caused by changing physical conditions, which reduces image resolution and accuracy.
Innovation Solution
The method involves migrating seismic data to obtain angular information from primary and multiples wavefields, updating attributes associated with the data, and using cross-equalization operators to reduce differences between data sets, thereby improving image quality and accuracy by incorporating information from both primary and multiples wavefields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional seismic data processing methods are used, then processing simplicity is maintained, but image resolution and accuracy deteriorate due to noise from changing physical conditions
Solution Approach 1:
The patent segments the seismic data into different wavefield components (primary wavefields and multiples wavefields) and processes them separately using different migration techniques. Primary wavefields are migrated using conventional migration, while multiples wavefields are migrated using pre-stack depth migration to extract angle information. This segmentation allows targeted noise reduction while maintaining processing manageability.
Solution Approach 2:
The patent transforms the processing approach by moving from traditional time-domain processing to angle-domain processing through pre-stack depth migration. This dimensional change allows extraction of angle information that is then used to update subsurface models and iteratively reduce noise, improving image resolution without proportionally increasing complexity.
2Measurement precision
If noise reduction techniques are applied to improve image quality, then measurement precision improves, but processing time and computational resources increase
Solution Approach 1:
The patent performs pre-stack depth migration and angle information extraction before the main imaging process. By preparing the subsurface model updates and angle information in advance, the iterative noise reduction process can proceed more efficiently with pre-computed correction factors, reducing overall processing time while maintaining high accuracy.
Solution Approach 2:
The patent implements an iterative feedback mechanism where angle information from multiples wavefields is used to update subsurface models, which then feed back into the migration process to further reduce noise. This feedback loop progressively improves accuracy while the iteration count can be controlled to balance processing time requirements.
3Loss of information
If only primary wavefields are used for migration, then processing complexity is reduced, but information completeness deteriorates leading to lower image quality
Solution Approach 1:
The patent converts the traditionally harmful multiples wavefields (often considered noise) into a beneficial information source. By migrating multiples wavefields and extracting angle information, the patent transforms what was previously discarded data into valuable constraints for updating subsurface models and improving the overall image quality of primary wavefields.
Solution Approach 2:
The patent makes the migration process multi-functional by using it to accomplish two tasks simultaneously: imaging primary wavefields and extracting angle information from multiples wavefields. This universal approach allows a single processing framework to handle both imaging and noise reduction functions, improving information completeness without proportionally increasing complexity.
4Measurement precision
If cross-equalization operators are used to reduce differences between data sets, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent changes the parameters used for comparing data sets by working in the angle domain rather than the traditional time or offset domain. By transforming data to the angle domain through pre-stack depth migration, the cross-equalization process operates on more meaningful parameters that directly relate to subsurface geometry, improving precision while the algorithmic complexity is managed through the structured parameter transformation.
Data Source
AI summary
Techniques are disclosed relating to reducing noise in marine seismic survey data. A shot-by-shot depth migration of recorded marine seismic survey data that includes multiples wavefields indicative of surface reflections may be performed. Post-migration data generated by the migration may include angle information derived from the multiples wavefields. Attributes of the marine seismic survey data may be corrected using the angle information in order to identify a potential sub-surface structure.