Virtual Streamer Control for Seismic Survey Positioning
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Solution Overview
Problem
Conventional systems for controlling the spread of towed seismic streamers in offshore marine seismic prospecting are inefficient, particularly due to manual operation of the reference streamer, which is time-consuming and prone to errors during turns and in the presence of cross currents, leading to undesirable feathering and reduced data quality.
Innovation Solution
A system and method that utilize an imaginary or virtual streamer to automate the positioning of actual streamers, with a controller calculating the shape and position of the virtual streamer and sending steering commands to lateral steering devices to maintain target separations, thereby reducing manual intervention and improving precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual positioning of the reference streamer is used, then the system can maintain basic streamer separation, but the positioning precision deteriorates during turns and in cross currents leading to undesirable feathering
Solution Approach 1:
The reference streamer positioning system automatically adjusts its own position using a fin actuator controlled by a PID controller. The system monitors its own separation from the imaginary streamer and self-corrects positioning errors without manual intervention, improving reliability during turns and in cross currents.
Solution Approach 2:
The system implements closed-loop feedback control where the actual separation between the reference streamer and imaginary streamer is continuously measured and fed back to the PID controller. The controller adjusts the fin actuator based on the error signal to maintain target separation, significantly improving positioning precision during dynamic operations.
2Ease of operation
If manual positioning of the reference streamer is used, then the operator can control streamer feather, but the operation time increases and efficiency decreases
Solution Approach 1:
The reference streamer positioning system automatically adjusts its own position using a fin actuator controlled by a PID controller. The system monitors its own separation from the imaginary streamer and self-corrects positioning errors without manual intervention, improving reliability during turns and in cross currents.
Solution Approach 2:
The system replaces manual mechanical positioning operations with an automated electronic control system. The PID controller and fin actuator substitute for manual steering operations, eliminating the need for continuous operator intervention while maintaining or improving positioning accuracy, thus significantly improving survey efficiency.
3Device complexity
If conventional reference streamer control is used, then the system structure remains simple, but the automation level remains low requiring continuous manual intervention
Solution Approach 1:
The reference streamer positioning system automatically adjusts its own position using a fin actuator controlled by a PID controller. The system monitors its own separation from the imaginary streamer and self-corrects positioning errors without manual intervention, improving reliability during turns and in cross currents.
Solution Approach 2:
The system replaces manual mechanical positioning operations with an automated electronic control system. The PID controller and fin actuator substitute for manual steering operations, eliminating the need for continuous operator intervention while maintaining or improving positioning accuracy, thus significantly improving survey efficiency.
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 enhances the precision and efficiency of streamer positioning, reducing the time required for turns and minimizing data gaps, leading to higher-quality seismic surveys by maintaining accurate streamer separations and reducing the need for manual operation.
Implementation Method 1
acoustic ranging devices 12, located along the lengths of the streamers are used to determine the shapes of the streamers and their relative separations. The acoustic ranging devices are typically acoustic transceivers operating on a range of channels over which they transmit and receive acoustic ranging signals to and from one another to produce accurate ranges 14 between their locations on the streamers.
Implementation Method 2
The steering commands are transmitted to the steering devices to adjust their control planes, or fins, to drive the streamers laterally, as indicated by arrows 20, to maintain the target separations.
Data Source
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AI summary
A method and system for controlling the shape and separation of an arrangement of streamers towed behind a survey vessel (10). Each streamer is steered laterally by lateral steering devices (16) positioned along its length at specific nodes. Each streamer is driven by its lateral steering devices to achieve a specified separation from a neighboring streamer. One of these actual streamers, used as a reference by the other actual streamers, is steered to achieve a specified separation from an imaginary, or ghost, streamer virtually towed with the actual streamers.