Marine Seismic Source Steering via Dynamic Cable Control
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Solution Overview
Problem
Current marine seismic data acquisition systems lack real-time control mechanisms to maintain inline position of seismic sources due to environmental factors like currents, leading to inline differences between base and monitor 4D surveys.
Innovation Solution
The implementation of a software-controlled seismic source deployment system using winches, capstans, and heave compensators to adjust the inline distance of seismic source arrays relative to target coordinates, allowing for real-time or near-real-time inline positioning and shape reforming of source arrays during data collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If fixed distances are maintained from the towing vessel to seismic source arrays, then deployment simplicity is improved, but positioning precision deteriorates due to current-induced feather angle and tension changes
Solution Approach 1:
The patent transitions from fixed, static source array deployment to dynamic, adjustable deployment. The system continuously monitors the positions of seismic sources and actively adjusts source cable lengths and vessel steering to maintain predetermined inline positions despite environmental disturbances. This dynamic control enables the system to adapt in real-time to current conditions, resolving the contradiction between deployment simplicity and positioning precision.
Solution Approach 2:
The patent implements a feedback control system that continuously measures the actual positions of seismic sources using GPS and other positioning systems, compares these measurements to predetermined target positions, and generates corrective commands to adjust source cable lengths and vessel steering. This closed-loop feedback mechanism ensures high positioning precision while maintaining operational simplicity through automated control.
2Device complexity
If manual adjustments are made during line change, then operational complexity is reduced, but control capability deteriorates as no real-time control mechanism exists during acquisition runs
Solution Approach 1:
The patent enables the seismic acquisition system to self-regulate its source array positions during acquisition runs. The automated control system continuously monitors positions and adjusts source cable lengths and vessel steering without requiring manual intervention. This self-service capability maintains low operational complexity while significantly improving real-time control capability, allowing the system to correct positioning deviations autonomously.
3Stability of the object's composition
If source arrays are towed at fixed distances behind the vessel, then system stability is improved, but adaptability deteriorates when environmental conditions vary
Solution Approach 1:
The patent dynamically changes key system parameters including source cable lengths, vessel steering angle, and vessel speed to adapt to varying environmental conditions. The control system calculates required parameter adjustments based on measured source positions, current conditions, and predetermined target positions. This ability to change parameters in real-time provides environmental adaptability while maintaining overall system stability through controlled adjustments.
Data Source
AI summary
Systems and methods for automatic steering of marine seismic sources are described. One system comprises a marine seismic spread comprising a towing vessel and a seismic source, the seismic source comprising one or more source arrays each having a center of source array, each source array having one or more source strings; a seismic source deployment sub-system on the towing vessel, the sub-system controlled by a controller including a software module, the software module and the deployment sub-system adapted to control an inline distance between one of the centers of source array and a target coordinate. It is emphasized that this abstract is provided to comply with the rules requiring an abstract, allowing a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.