Phase Correction for Simultaneous Seismic Sources
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Solution Overview
Problem
Simultaneous-multiple-sourcing seismic systems face challenges in accurately separating seismic data due to phase errors, particularly frequency-dependent phase errors, which lead to cross-talk and contamination between source signals, reducing the effectiveness of data separation and inversion processes.
Innovation Solution
A method involving the measurement and compensation of bulk and frequency-dependent phase errors using load cells and other sensors to correct the phase encoding scheme, ensuring accurate phase rotation and offset encoding for each seismic source, thereby improving data separation and inversion accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If simultaneous-multiple-sourcing seismic systems are used to improve survey efficiency and reduce costs, then productivity increases, but phase errors cause cross-talk and contamination between source signals reducing data separation accuracy
Solution Approach 1:
The patent implements feedback by measuring the actual phase response of each vibrator using load cells and other sensors, then using these measurements to update and correct the phase encoding scheme for subsequent sweeps. This closed-loop approach continuously refines the phase information to minimize cross-talk and improve source separation accuracy while maintaining simultaneous-multiple-sourcing efficiency
Solution Approach 2:
The patent dynamically adjusts phase parameters (phase rotation and offset encoding) based on measured vibrator responses. By changing the phase encoding scheme in real-time according to actual vibrator behavior, the system maintains accurate source separation despite variations in vibrator performance, thereby preserving both productivity and measurement precision
2Loss of information
If phase encoding schemes are used to separate source signals, then data separation becomes possible, but frequency-dependent phase errors create cross-talk between sources
Solution Approach 1:
The system measures the frequency-dependent phase response of each vibrator using load cells and updates the phase encoding scheme accordingly. This feedback mechanism allows the system to compensate for frequency-dependent phase errors that would otherwise cause cross-talk, enabling clean source separation while maintaining the benefits of simultaneous-multiple-sourcing
Solution Approach 2:
The patent performs preliminary measurements of vibrator phase response using load cells before conducting the actual seismic survey. These preliminary measurements establish the baseline phase characteristics of each vibrator, which are then used to pre-correct the phase encoding scheme, preventing cross-talk from occurring in the first place
3Measurement precision
If vibrators operate at different phases to enhance distinctiveness, then source identification improves, but equipment drift and wear cause phase excursions that reduce separation accuracy
Solution Approach 1:
The patent implements continuous monitoring of vibrator phase using load cells and other sensors during the survey. When phase drift or excursions are detected, the system automatically updates the phase encoding scheme to compensate for the changes. This real-time feedback ensures that source identification accuracy is maintained despite equipment wear and environmental variations
Solution Approach 2:
The patent makes the phase encoding scheme dynamic rather than static. Instead of using fixed phase relationships between vibrators, the system continuously adapts the phase encoding based on measured vibrator responses. This dynamic approach allows the system to maintain reliable source separation even as vibrator characteristics change over time due to wear or environmental conditions
Data Source
AI summary
A method of more accurate phase encoding of phase offset vibrators used in simultaneous-multiple-sourcing 3D seismic mapping. The method measures the actual input energy and the proxy energy thereby determining a bulk error and a frequency-dependent error, both to be applied to correct the proxy energy. The corrected proxy energy is then used to perform actual seismic survey, and the inversion is then performed using the corrected proxy energy to source separate each vibe where the error is minimized.