Autonomous Seismic Node Base Plate Coaxial Sensor Mounting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional ocean seismic imaging systems, such as streamer and ocean bottom cable systems, typically record narrow azimuth data, which is insufficient for capturing the complexity of geological formations like salt bodies in the Gulf of Mexico, necessitating more sophisticated subsurface imaging techniques.
Innovation Solution
An autonomous ocean bottom seismic node recording device with an integrated modular design, featuring a base plate, symmetrically arranged battery and recording unit housings, and a vector sensor housing mounted coaxially with the base plate, optimized for improved azimuthal fidelity and stability on the seafloor, allowing for extended data recording and efficient data access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional streamer or ocean bottom cable systems are used, then the system structure is relatively simple and easy to deploy, but the azimuthal coverage is limited to narrow azimuth data which is insufficient for complex geological formations
Solution Approach 1:
The ocean bottom cable system is segmented into multiple independent recording units (nodes) that can be distributed across the survey area. Each node functions autonomously with its own sensors, clock, and power source, enabling broad azimuthal coverage while maintaining manageable system complexity through modular deployment and retrieval
2Duration of action of stationary object
If autonomous ocean bottom nodes are deployed for extended periods, then long-term data acquisition is achieved, but the coupling stability to the seafloor deteriorates due to lack of secure anchoring
Solution Approach 1:
The coupling mechanism is pre-configured with spring-loaded feet that automatically engage with the seafloor upon deployment. The feet are held in a retracted position during transport and automatically extend when the node contacts the seafloor, providing immediate mechanical anchoring that stabilizes the node for long-term deployment without requiring complex active anchoring systems
3Reliability
If the node housing is sealed to protect internal components, then component protection is improved, but acoustic signal transmission from hydrophones deteriorates due to isolation from water
Solution Approach 1:
A pressure-equalization hole is provided in the node housing that allows water pressure to equalize with the internal cavity during depth changes. This intermediary feature maintains the sealed protection of internal components while permitting acoustic signals to transmit through the housing walls without distortion, as the pressure equalization prevents bulk head formation that would block signal transmission
4Ease of operation
If the center of mass is positioned high in the node housing, then access to internal components is improved, but the azimuthal fidelity of seismic signal measurement deteriorates due to instability on the seafloor
Solution Approach 1:
The node housing incorporates a weighted base or ballast system positioned in the lower portion of the housing to counterbalance the high-positioned center of mass. This creates a stable metacenter configuration where the low-positioned weight provides rotational stability on the seafloor, preventing tipping that would compromise azimuthal measurement fidelity while allowing easy access to components housed in the upper portion
Data Source
AI summary
The present invention relates to an improved autonomous node seismic recording device having an integrated modular design and one or more features that assist coupling of the unit to the sea floor in order to improve the vector fidelity of seismic signal measurement.