Dual Sensor Seismic Streamer Array Geometry Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Marine seismic surveying systems face challenges in maintaining accurate depth and heading control of seismic streamers, which affects the quality of seismic data collected from Earth formations beneath water bodies.
Innovation Solution
A method involving dual sensor systems with pressure and motion responsive sensors, where ghost time delays are calculated and adjusted to cross-ghost seismic signals, allowing for precise depth and position control of seismic sensors using LFD control devices and acoustic position determination systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If streamers are towed through water for long distances, then seismic data can be collected from subsurface formations, but the streamers deviate from straight-line paths due to water interaction and currents, causing position uncertainty
Solution Approach 1:
The system continuously monitors streamer position using GPS and depth sensors, then feeds this information back to LFD control devices that actively adjust control surfaces to correct deviations from the desired straight-line path, maintaining position accuracy despite water currents and towing forces
Solution Approach 2:
The patent replaces passive mechanical streamer positioning with active electronic control systems that use GPS, depth sensors, and computer-controlled LFD devices to maintain streamer geometry, substituting mechanical stability with electronically controlled position correction
2Reliability
If LFD control devices with large diameter are used for streamer positioning, then depth and heading control is improved, but the device size creates issues during streamer deployment and retrieval from water
Solution Approach 1:
The LFD control device incorporates movable control surfaces that can extend and retract, allowing the device to compact to a smaller diameter for easy deployment and retrieval, then extend to provide full control authority during seismic survey operations
Solution Approach 2:
The control device is divided into modular components including the hollow spool, winged fuselage, and control surfaces that can be independently positioned, allowing the structure to compact for deployment while maintaining full functionality during operation
3Ease of operation
If streamer positioning devices are made compact for easy deployment, then deployment and retrieval is simplified, but the positioning control capability is reduced
Solution Approach 1:
The device transitions dynamically between compact and extended configurations, using movable control surfaces that can be positioned to provide full control authority when needed while allowing compact storage during deployment and retrieval operations
4Measurement precision
If dual sensor systems with both pressure and motion responsive sensors are used, then sensor position accuracy is improved through cross-ghosting, but system complexity increases
Solution Approach 1:
The patent combines pressure responsive sensors and motion responsive sensors into collocated dual sensor systems, merging their complementary measurement capabilities to achieve more accurate position and depth determination through cross-ghosting techniques
Solution Approach 2:
The system uses ghosting techniques where signals from one sensor type are mathematically transformed to replicate what the other sensor type would measure, creating virtual copies of sensor responses to verify and correct position measurements
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 enhances the accuracy of seismic data collection by maintaining precise sensor positions and array geometry, improving the quality of seismic surveys and reducing errors in subsurface imaging.
Implementation Method 1
determining at least an initial depth of a plurality of spaced apart seismic sensors in a body of water
Implementation Method 2
A plurality of acoustic transmitters, mounted inside the streamers, are adapted to transmit broadband signals
Implementation Method 3
a plurality of acoustic receivers, mounted inside the streamers, are adapted to receive the signals from the transmitters
Implementation Method 4
at least one processor adapted to cross-correlate the signals received at the receivers with copies of transmitter signals to determine identities of the transmitters of the received signals and to determine travel times of the received signals
Implementation Method 5
A ghost time delay is determined for each sensor based on the at least an initial depth. Seismic signals detected by each motion responsive sensor and each pressure responsive sensor are cross ghosted
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A method for marine seismic surveying includes determining at least an initial depth of a plurality of spaced apart seismic sensors in a body of water. The sensors each include a substantially collocated pressure responsive sensor and motion responsive sensor. A ghost time delay is determined for each sensor based on the at least an initial depth. Seismic signals detected by each motion responsive sensor and each pressure responsive sensor are cross ghosted. The at least initial depth is adjusted, and the determining ghost time delay and cross ghosted seismic signals are repeated until a difference between the cross ghosted motion responsive signal and the cross ghosted pressure responsive signal falls below a selected threshold.