Seismic Receiver Clock Drift Correction via Cross-Correlation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Seismic receivers in seismic exploration often face challenges with clock drift, especially in marine environments where real-time synchronization with radio timing signals is not possible, leading to inaccuracies that can be costly and complex to correct, especially with the increasing number of sensors used in surveys.
Innovation Solution
A method is developed to correct clock drift in seismic receivers by identifying proximate trace pairs, determining relative time shifts, and inverting these shifts to estimate clock drift, allowing for time correction of seismic traces without the need for accurate internal clocks, using techniques like cross-correlation and dynamic image warping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If accurate internal clocks are used in seismic receivers, then time measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent introduces a post-processing correction method that acts as an intermediary between the simple (but drifting) receiver clocks and the required accurate timing. By using cross-correlation of seismic traces from proximate receivers, the system calculates relative time shifts and applies corrections to synchronize arrival times, effectively mediating the timing accuracy requirement without requiring complex hardware clocks in each receiver
Solution Approach 2:
The system uses the seismic data itself to correct the timing errors. The seismic traces recorded by the receivers are cross-correlated to determine relative time shifts, and these corrections are applied back to the same data, allowing the system to self-correct its timing inaccuracies without external intervention or complex hardware
2Measurement precision
If accurate internal clocks are used in seismic receivers, then time measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive, long-lasting accurate clocks with inexpensive, drift-prone clocks that are corrected through post-processing. The receivers use simple, cheap timing hardware that drifts over time, but the systematic correction method applied to the seismic traces compensates for this drift, achieving accurate timing results without requiring expensive clock hardware
Solution Approach 2:
A post-processing correction algorithm serves as an intermediary that bridges the gap between cheap drifting clocks and accurate timing requirements, eliminating the need for expensive precision clock hardware while maintaining measurement accuracy
3Measurement precision
If real-time synchronization with radio timing signals is implemented, then clock drift is corrected, but device complexity and power requirements increase
Solution Approach 1:
The patent extracts the timing synchronization function from the receiver hardware itself and moves it to the post-processing stage. Instead of requiring receivers to actively synchronize with radio timing signals in real-time, the system extracts relative time shift information from the seismic traces themselves and applies corrections offline, removing the need for complex real-time synchronization hardware
Solution Approach 2:
The patent replaces the mechanical/electronic real-time synchronization system (radio timing signals and receiver clock synchronization hardware) with a computational method based on cross-correlation of seismic traces. This substitution eliminates the need for radio communication hardware and real-time clock synchronization mechanisms
4Measurement precision
If real-time synchronization with radio timing signals is implemented, then clock drift is corrected, but power consumption increases
Solution Approach 1:
The patent extracts the synchronization function from real-time operation and moves it to post-processing, eliminating the continuous power consumption associated with receiving and processing radio timing signals during the survey. The receivers can operate in a lower-power mode without active synchronization hardware
5Quantity of substance
If the number of sensors is increased in seismic surveys, then data quality and coverage are improved, but clock drift correction becomes more complex and costly
Solution Approach 1:
The patent segments the large set of receivers into groups based on spatial proximity, forming proximate receiver pairs or clusters. This segmentation allows the correction method to be applied locally to small groups rather than requiring global synchronization of all receivers, making the system scalable to large numbers of sensors while maintaining computational feasibility
Solution Approach 2:
The patent applies corrections locally to proximate receiver pairs rather than requiring global synchronization. Each local group is corrected independently based on their mutual seismic traces, allowing the system to handle large numbers of sensors through distributed, localized processing rather than centralized complex coordination
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables the collection of accurate seismic data using many independent receivers with potentially inaccurate clocks, reducing manufacturing costs and complexity, and allows for time-variable corrections, improving the quality of seismic imaging without the need for separate timing signals.
Implementation Method 1
determining a relative time shift between the first trace and the second trace
Implementation Method 2
using the clock drift estimates to time correct the first and second traces of each proximate trace pair
Data Source
Figure 1
Figure 2~4
Figure 5~6
AI summary
According to one embodiment, there is provided a method of correcting recorded seismic data where each receiver clock is potentially inaccurate. Since the seismic wave field is not random, and contains coherent events that are recorded by all receivers in a local area, it is possible to estimate the differences in the time reference by comparing the recordings of different receivers in a local area. With no external time reference, time signal, or pilot trace, an entire seismic data itself can be used to determine how each receiver's clock is drifting from true time.