Marine Seismic Source Dithering Constraint for Speed
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Solution Overview
Problem
In marine seismic surveys, dithering actuations of sources to separate overlapping signals can disrupt the consistent bottom speed of survey vessels, leading to increased survey duration and costs, as maintaining minimum actuation time intervals requires adjusting bottom speed to accommodate varying dither times and distances.
Innovation Solution
Constraining the dither time difference to a threshold dither time difference less than the maximum dither time difference allows for a faster and consistent bottom speed throughout the survey by controlling the difference between consecutive dither times, ensuring a minimum actuation time interval is maintained without significant speed reductions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dithering actuations of sources are applied to separate overlapping signals, then signal separation is improved, but bottom speed consistency deteriorates and survey duration increases
Solution Approach 1:
The patent applies parameter changes by modifying the dither time values within constrained ranges. Specifically, it limits the difference between consecutive dither times to a threshold value, thereby controlling the variation in actuation intervals while maintaining signal separation. This constrained parameter adjustment allows the system to achieve adequate signal differentiation without excessive speed variations.
2Measurement precision
If dithering actuations are applied to separate overlapping signals, then signal separation is improved, but survey duration increases
Solution Approach 1:
The patent optimizes survey duration by constraining dither time differences to threshold values. This controlled parameter adjustment ensures that actuation intervals remain sufficiently differentiated for signal separation while avoiding excessive delays that would extend survey duration. The threshold-based constraint balances signal quality with operational efficiency.
3Reliability
If bottom speed is reduced to accommodate varying dither times, then minimum actuation time intervals are maintained, but productivity decreases
Solution Approach 1:
The patent improves productivity by implementing threshold constraints on dither time differences. This parameter control allows the system to maintain minimum actuation time intervals for reliability while minimizing speed reductions that would reduce productivity. The constrained dither approach achieves both objectives by optimizing the balance between timing precision and operational speed.
Data Source
AI summary
Systems and computer readable media are described that actuate at least one marine seismic source according to a constrained sequence. The sequence exhibits an actuation time or distance interval between each actuation. The actuation time or distance interval corresponds to the sum of a nominal time or distance and a respective dither time or dither distance for each actuation. The sequence is constrained such that differences between consecutive dither times or dither distances remain within a threshold dither difference. Constraining the sequence according to the threshold dither difference enables increased bottom speeds for the source (i.e., increased speeds of the source relative to the seafloor), while still maintaining at least a minimum actuation time or distance interval for the source, taking into account both the nominal time or distance and the respective dither times or dither differences.