Distinctive Composite Pulse Sequences for Marine Seismic Acquisition
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Solution Overview
Problem
Acquiring seismic data in marine environments is costly, often requires time-sharing between survey crews due to contamination risks, and poses harm to marine life from intense seismic energy, with conventional methods resulting in coarse sampling spacing and potential harm to animals using echolocation.
Innovation Solution
Implementing a seismic acquisition system where airguns fire in a series of distinctive composite pulses rather than simultaneously, creating a continuous or near-continuous stream of energy that is uniquely recognizable, allowing multiple crews to operate concurrently and reducing peak energy input into the water.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional air gun arrays fire a single powerful pulse simultaneously, then sufficient seismic energy is obtained to penetrate deep seafloor structures, but peak energy input becomes excessively high causing harm to marine life
Solution Approach 1:
The single powerful pulse is segmented into multiple smaller pulses arranged in distinctive composite sequences. Each air gun in the array fires at different times according to coded sequences, dividing the total energy delivery into temporal segments that maintain cumulative penetration capability while reducing instantaneous peak energy levels that harm marine animals.
Solution Approach 2:
Air guns fire in periodic coded sequences rather than simultaneous discharge. The periodic firing patterns with distinct temporal spacing allow energy to be delivered in controlled intervals, maintaining effective seismic penetration while providing rest periods that reduce cumulative impact on marine life.
2Productivity
If air guns are fired simultaneously to maximize energy efficiency, then data acquisition speed is improved, but sampling spacing becomes coarse due to the 10-second record length requirement
Solution Approach 1:
The distinctive composite pulse sequences enable continuous or near-continuous data acquisition by allowing overlapping record lengths. Multiple air guns fire in succession with coded sequences that permit continuous recording without waiting for complete echo periods, maintaining high productivity while achieving finer sampling spacing through denser shot point intervals.
3Productivity
If multiple survey crews operate in the same area simultaneously, then productivity and cost efficiency are improved, but data contamination occurs between crews
Solution Approach 1:
Each survey crew uses air guns with distinctive local characteristics - unique coded firing sequences assigned to specific crews or vessels. These localized quality differences in the pulse sequences allow simultaneous operations in the same area while enabling identification and separation of data from different crews during processing, preventing contamination and maintaining data reliability.
Solution Approach 2:
The distinctive composite sequences act as unique identifiers or 'colors' for each survey crew's seismic signal. By assigning different coded sequences to different crews, their seismic signatures become distinguishable, allowing simultaneous operations without data contamination while maintaining high productivity.
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 approach enables simultaneous data collection by multiple crews without contamination, reduces energy impact on marine life, and achieves denser sampling without increasing costs, improving data density and resolution while minimizing harm to marine life.
Implementation Method 1
emitting seismic energy into a marine environment that is able to travel into the seafloor and reflect from and refract through geological structures and be received and recorded by hydrophones
Implementation Method 2
fire in a series of distinctive composite pulses rather than simultaneously, creating a continuous or near-continuous stream of energy that is uniquely recognizable, allowing multiple crews to operate concurrently and reducing peak energy input into the water
Data Source
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AI summary
The invention relates to continuously or near continuously acquiring seismic data where at least one pulse-type source is fired in a distinctive sequence to create a series of pulses and to create a continuous or near continuous rumble. In a preferred embodiment, a number of pulse type seismic sources are arranged in an array and are fired in a distinctive loop of composite pulses where the returning wavefield is source separable based on the distinctive composite pulses. Firing the pulse type sources creates an identifiable loop of identifiable composite pulses so that two or more marine seismic acquisition systems with pulse-type seismic sources can acquire seismic data concurrently, continuously or near continuously and the peak energy delivered into the water will be less, which will reduce the irritation of seismic data acquisition to marine life.