Negative Offset Interleaved Seismic Streamer System
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Solution Overview
Problem
Current marine seismic surveys face inaccuracies due to offset distances between seismic sources and receivers, leading to unreliable near-zero offset data and redundant reflections, which complicates geophysical structure imaging and requires multiple vessels, increasing complexity and costs.
Innovation Solution
A high-resolution marine seismic system with a single vessel towing a first plurality of seismic streamers and a second plurality of high-resolution streamers positioned equidistantly, with seismic sources interleaved to achieve zero or negative inline offset, utilizing vibration isolation modules and deflectors to maintain precise alignment and reduce noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the array of sources is towed closer to the streamers to avoid cable entanglement, then the risk of cable entanglement is reduced, but the offset in the obtained data increases, hindering data analysis accuracy
Solution Approach 1:
The system divides the streamers into multiple groups (first plurality and second plurality) with different offset configurations. Some streamers are positioned at larger offsets to avoid cable entanglement, while others are positioned at zero or negative offsets to provide accurate reference data for correction algorithms.
Solution Approach 2:
The system varies the offset parameter across different streamers and uses processing algorithms that adjust for offset effects. By having streamers at different offsets (including zero and negative offsets), the system can process the data to eliminate offset-related inaccuracies while maintaining safe cable distances.
2Object-affected harmful factors
If a larger distance is maintained between the source array and streamers to reduce noise interference from the vessel, then the noise interference is reduced, but the offset increases, impairing the geophysical image accuracy
Solution Approach 1:
The streamer array is segmented into multiple groups with different positioning strategies. Some streamers are positioned at larger distances to minimize noise interference, while others are positioned at zero or negative offsets to provide accurate reference measurements for correcting the noisy data.
Solution Approach 2:
The system uses streamers at zero and negative offsets as intermediary reference points. These reference streamers provide clean, accurate data that serves as a basis for processing and correcting the data from streamers positioned at larger offsets, effectively mediating between noise reduction and accuracy requirements.
3Measurement precision
If near field data is used to estimate zero-offset data, then some accuracy improvement is achieved, but the data set is not ideally near zero offset, reducing reliability
Solution Approach 1:
The system pre-positions streamers at zero and negative offsets before data acquisition begins. This preliminary configuration ensures that true near-zero offset data is captured directly during the survey, eliminating the need for post-processing estimates and providing reliable reference data for correcting other measurements.
Solution Approach 2:
The streamers positioned at zero and negative offsets serve as self-generated reference standards within the same survey deployment. These streamers provide intrinsic reference data that the system uses to calibrate and correct the data from other streamers, eliminating the need for external reference measurements or approximate estimation methods.
4Measurement precision
If multiple vessels are employed to perform surveys, then near zero offset data can be obtained, but the system complexity and costs increase
Solution Approach 1:
The system combines multiple streamer groups with different offset configurations (including zero and negative offset streamers) onto a single vessel platform. This merging allows the system to achieve near-zero offset data quality previously requiring multiple vessels, while reducing operational complexity and costs associated with coordinating multiple vessels.
Solution Approach 2:
A single vessel is designed to tow a multi-functional streamer array that performs multiple roles: some streamers act as primary data collectors at safe offsets, while others serve as reference streamers at zero/negative offsets. This universal configuration allows one vessel to perform the functions previously requiring multiple specialized vessels.
Data Source
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AI summary
A system and method for arrangement of seismic streamers in relation to seismic sources in marine seismic surveys using towed streamers is disclosed. The arrangement aims to achieve negative offset or near zero offset data during seismic surveys to achieve higher resolution survey results and accurate geographical modelling.