Seismic Image Artifact Attenuation via Coherency Weighting
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Solution Overview
Problem
Seismic processing, particularly migration, often generates migration artifacts that blur, distort, and occlude seismic events in vertical seismic profile (VSP) data, making it difficult to accurately locate geological features in subterranean regions.
Innovation Solution
The method involves obtaining VSP data and a seismic velocity model for a subterranean region of interest, using reverse time migration to create a pre-stacked migrated seismic image, and then generating coherency and weighting maps to correct each seismic slice, ultimately producing a post-stacked corrected migrated seismic image that attenuates migration artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If migration is performed to relocate seismic events to true locations, then positioning accuracy is improved, but migration artifacts are generated that blur and distort seismic events
Solution Approach 1:
The patent extracts and removes migration artifacts from the seismic image by identifying them as spurious events and eliminating them through filtering operations, thereby retaining only the genuine seismic events while preserving positioning accuracy achieved through migration
Solution Approach 2:
The patent converts the harmful migration artifacts into beneficial information by using their characteristics (such as coherence patterns) to identify and locate genuine seismic events, thereby improving the overall quality of the seismic image while maintaining the positioning benefits of migration
2Productivity
If migration artifacts are generated during processing, then seismic events are relocated, but the artifacts blur and distort the seismic events making feature location difficult
Solution Approach 1:
The patent implements feedback mechanisms through coherence analysis that continuously monitors the seismic image quality and adjusts processing parameters to minimize artifact generation while maintaining processing productivity, thereby reducing feature location difficulty
Solution Approach 2:
The patent introduces coherence maps as intermediary structures that separate genuine seismic events from migration artifacts, enabling clear differentiation and accurate feature location while maintaining the productivity benefits of migration processing
Data Source
AI summary
Methods and systems are disclosed. The methods may include obtaining vertical seismic profile (VSP) data and a seismic velocity model for a subterranean region of interest and determining, using the seismic velocity model and reverse time migration, a pre-stacked migrated seismic image based on the VSP data. The pre-stacked migrated seismic image includes seismic slices. The methods may further include, for each of the seismic slices in turn, determining a coherency map, determining a weighting map based on the coherency map, and determining a corrected seismic slice by applying the weighting map to each of the seismic slices. The methods may still further include determining a post-stacked corrected migrated seismic image based on the corrected seismic slices and determining a location of a geological feature within the subterranean region of interest based, at least in part, on the post-stacked corrected migrated seismic image.