Dynamic Gain Adjustment for Seismic Receiver Clipping Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Seismic receivers in marine surveys are often overdriven by directly propagating seismic wavefields, leading to data clipping and loss of valuable information, as conventional gain settings are not adequately adjusted for the varying amplitudes of downgoing and reflected wavefields.
Innovation Solution
The gain of seismic receivers is dynamically adjusted in real-time based on the position of the seismic source and receiver, specifically reducing gain during the arrival of downgoing seismic wavefields to prevent clipping and increasing it afterwards to detect lower-amplitude reflected wavefields, using GPS and vessel speed information to determine optimal adjustment times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the gain of seismic receivers is set relatively high to adequately sample the reflected seismic wavefields, then the measurement precision of reflected wavefields is improved, but the receivers become overdriven by the directly propagating seismic wavefield causing data clipping
Solution Approach 1:
The gain of the seismic receivers is dynamically adjusted in real-time based on the arrival time of downgoing wavefields. The system transitions from a static high gain setting to a dynamic gain control mechanism that adapts to varying signal conditions, reducing gain during downgoing wavefield arrival to prevent clipping and restoring it afterward to maintain sensitivity for reflected wavefields.
Solution Approach 2:
The system determines the arrival time of downgoing wavefields in advance and proactively adjusts the receiver gain before the overdrive problem occurs. By calculating the time of arrival based on source-receiver geometry and reducing gain beforehand, the system prevents clipping before it happens rather than reacting after clipping occurs.
2Object-affected harmful factors
If the gain of seismic receivers is reduced to prevent overdrive by downgoing wavefields, then the harmful effect of data clipping is reduced, but the ability to detect low-amplitude reflected wavefields deteriorates
Solution Approach 1:
The gain adjustment operates in periodic cycles: maintaining high gain during normal conditions to detect reflected wavefields, reducing gain when downgoing wavefields are detected to prevent clipping, and restoring gain afterward to resume detection capability. This periodic switching allows the system to optimize for different signal types at different times.
Solution Approach 2:
The system calculates the time of arrival of downgoing wavefields in advance and proactively reduces gain before the overdrive problem occurs. By determining arrival times based on source-receiver geometry and adjusting gain beforehand, the system prevents clipping before it happens while maintaining the ability to detect reflected wavefields at other times.
3Device complexity
If conventional static gain settings are used in marine seismic surveys, then the device complexity is kept low, but the adaptability to varying wavefield amplitudes and source-receiver positions is insufficient
Solution Approach 1:
The gain adjustment system operates autonomously without requiring manual intervention or complex external control. The system self-regulates by detecting the arrival of downgoing wavefields and automatically adjusting its own gain settings based on pre-calculated arrival times and signal characteristics, reducing the need for complex manual control systems.
Solution Approach 2:
The system transitions from a static gain setting to a dynamic gain control mechanism that adapts to varying signal conditions. The gain is continuously adjusted based on real-time detection of wavefield arrivals, enabling the system to handle different source-receiver positions and wavefield amplitudes without requiring multiple fixed gain settings or complex switching mechanisms.
Data Source
Figure 1A~1B
Figure 1C
Figure 1D
AI summary
Embodiments of dynamic gain adjustments in seismic surveys are described. One method of acquiring a seismic survey includes determining an arrival time at a seismic receiver of a downgoing seismic wavefield associated with a seismic source based at least in part on an estimated position of the seismic source, an estimated position of the seismic receiver, or combinations thereof. The method also includes adjusting a gain of the seismic receiver based at least in part on the determined arrival time of the downgoing seismic wavefield in order to, for example, help prevent overdriving or clipping of the seismic receiver when the downgoing seismic wavefield arrives at or passes by the seismic receiver.