Receiver Motion Correction in Marine Seismic Wavefield Separation
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Solution Overview
Problem
Conventional marine seismic surveys face challenges in accurately separating upgoing and downgoing wavefields due to receiver motion errors caused by changing water conditions, leading to inaccurate seismic images of subterranean formations, especially in rough water and long recording time intervals.
Innovation Solution
The implementation of processes and systems that correct receiver motion in seismic data by computing reverse-time receiver-motion-corrected downgoing and upgoing pressure wavefields, allowing for accurate wavefield separation and image generation by extrapolating these wavefields to a static observation level, thereby mitigating the effects of arbitrary depth and time displacement variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional receiver motion correction techniques are used, then small or negligible receiver displacements can be corrected, but large receiver displacements in rough water conditions or long recording intervals cannot be adequately corrected
Solution Approach 1:
The patent transforms the receiver position correction from a simple spatial shift to a complex transformation involving time-variant position functions. By modeling receiver positions as functions of both space and time, and applying reverse-time propagation, the system adapts to large displacements in rough water conditions while maintaining correction accuracy.
2Stability of the object's composition
If streamers maintain a static linear configuration, then receiver positions remain stable, but changing water conditions cause smooth undulations and time-variant positioning errors
Solution Approach 1:
The patent transitions from assuming static streamer configurations to dynamically modeling streamer positions as time-variant functions. By incorporating receiver position functions that vary with both space and time, and applying reverse-time propagation to a static observation level, the system compensates for dynamic undulations caused by changing water conditions.
3Device complexity
If wavefield separation is performed without receiver motion correction, then processing is simpler, but upgoing and downgoing wavefields are not adequately separated resulting in inaccurate images
Solution Approach 1:
The patent applies receiver motion correction as a preliminary step before wavefield separation. By first correcting receiver positions to a static observation level using time-variant position functions, and then performing wavefield separation on the corrected data, the system achieves accurate upgoing and downgoing wavefield separation without excessive complexity.
Data Source
AI summary
Processes and systems for generating images of a subterranean formation from recorded seismic data obtained in a marine survey are described. Processes and systems compute reverse-time receiver-motion-corrected upgoing and downgoing pressure wavefields at different locations of corresponding upgoing and downgoing observation levels based on the recorded seismic data. The reverse-time receiver-motion-corrected upgoing and downgoing pressure wavefields are time forwarded and extrapolated to obtain a corresponding receiver-motion-corrected upgoing and downgoing pressure wavefields at locations of a static observation level. An image of the subterranean formation is generated based at least in part on the receiver-motion-corrected upgoing pressure wavefield and the receiver-motion-corrected downgoing pressure wavefield.