Golomb Ruler Seismic Pulse Sequences for Source Separation
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Solution Overview
Problem
Current seismic acquisition methods face challenges in distinguishing seismic reflections from multiple sources due to cross-talk issues, which are difficult to resolve with existing signal processing techniques, especially in marine environments where reducing seismic energy impact is crucial.
Innovation Solution
The method employs a set of Golomb rulers with at least two rulers having four marks to design seismic pulse sequences, forming a difference triangle set that ensures unique pair-wise time intervals between pulses, allowing for effective separation of seismic reflections and minimizing emitted seismic energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple seismic sources are used concurrently to reduce survey time and cost, then productivity increases, but cross-talk between sources makes signal separation difficult
Solution Approach 1:
The patent segments the seismic survey process by assigning each source a unique Golomb ruler code pattern. This segmentation allows the combined signal from multiple sources to be separated at the receiver end by correlating with the known unique patterns, effectively dividing the complex multi-source signal into individual source contributions.
Solution Approach 2:
The patent changes the temporal parameter of signal emission by using Golomb ruler-based time spacing for each source. Instead of uniform or random timing, the unique time intervals defined by Golomb rulers create distinguishable signal patterns that enable separation while maintaining high survey efficiency.
2Adaptability or versatility
If pulse-type sources are used in marine acquisition, then the frequency content is fixed, but tuning the sources to have distinct characteristics becomes difficult
Solution Approach 1:
The patent introduces dynamics into the previously static pulse-type source system by varying the emission timing according to Golomb ruler patterns. This dynamic temporal modulation allows fixed-frequency sources to produce distinguishable signals through unique time-based signatures without requiring physical modification of the sources.
Solution Approach 2:
The patent employs periodic action through the structured time spacing of pulses according to Golomb ruler sequences. Each source emits pulses at regular intervals defined by its unique ruler pattern, creating periodic signals that are easily distinguishable and separable through correlation processing.
3Object-affected harmful factors
If seismic energy is reduced to minimize environmental impact, then harmful factors decrease, but signal quality and separation become more difficult
Solution Approach 1:
The patent substitutes mechanical energy increase with mathematical signal processing. Instead of increasing seismic energy to improve signal quality, the system uses Golomb ruler-based timing patterns and correlation processing to enhance signal distinguishability and quality while maintaining lower energy levels and reduced environmental impact.
Data Source
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AI summary
Seismic pulses are emitted are emitted with consecutive time intervals that follow a pattern described by several Golomb rulers, wherein at least two of the Golomb rulers have at least four marks, such that pair-wise time intervals between seismic pulse emissions are different, to distinguish seismic reflections stemming from different seismic pulses and/or seismic sources from each other. This allows executing seismic surveys with several simultaneously operated seismic source arrays, thereby reducing the survey cost. In a marine environment the seismic sources may be air-gun arrays towed by one or more vessels, and the method can be also applied onshore.