Seismic Cable Horizontal Position Control via Adjustable Lead-in Forces
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Solution Overview
Problem
Conventional seismic prospecting in aquatic mediums faces challenges in precision control of seismic cables' horizontal position, particularly at greater depths, which affects data quality and accuracy in 3D imaging of geological layers.
Innovation Solution
A method involving autonomous surface vessels connected to seismic cables via negative buoyancy lead-in cables, allowing for precise control of the cables' horizontal position through adjustable forces with axial and lateral components, using feedback loops based on tension and direction measurements to maintain stationary or quasi-stationary positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the seismic cable is positioned midwater using autonomous surface vessels with negative buoyancy lead-in cables, then the flexibility in positioning and ability to operate at greater depths is improved, but the precision control of horizontal position deteriorates
Solution Approach 1:
The patent implements a feedback control system where the horizontal position of the seismic cable is continuously monitored and compared to a desired position. The position control unit receives position information and generates control signals to adjust the forces applied by lead-in cables, creating a closed-loop system that automatically corrects deviations and maintains precise horizontal positioning despite the flexibility of the autonomous vessel configuration
Solution Approach 2:
The patent controls the horizontal position by dynamically adjusting parameters such as the tension and angle of the lead-in cables. By changing these physical parameters in response to position feedback, the system achieves precise control over the seismic cable's horizontal location while maintaining the adaptive benefits of the autonomous vessel architecture
2Measurement precision
If forces are applied by lead-in cables to control cable position, then the horizontal position control is improved, but the mechanical constraints and energy consumption increase
Solution Approach 1:
The patent optimizes the force application by dynamically adjusting the tension and orientation parameters of the lead-in cables based on real-time position feedback. This parameter control approach applies only the necessary force to achieve positioning, avoiding excessive mechanical constraints and energy consumption that would result from fixed or over-dimensioned force application systems
3Measurement precision
If forces are applied by lead-in cables to control cable position, then the horizontal position control is improved, but the energy consumption increases
Solution Approach 1:
The feedback control system monitors the actual position and compares it to the desired position, applying corrective forces only when deviations occur. This prevents continuous energy-consuming force application and allows the system to maintain precision control while minimizing energy consumption by acting only when necessary to correct position errors
Solution Approach 2:
The patent applies partial action by using only the minimum necessary force through the lead-in cables to achieve and maintain the desired horizontal position. Rather than continuously applying maximum force or using excessive control authority, the system applies just enough force to correct position deviations, thereby reducing energy consumption while maintaining positioning precision
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 precision and stability of seismic data acquisition, enabling better control over cable positioning, reducing mechanical and energy constraints, and improving data quality for 3D imaging of subsoil structures.
Implementation Method 1
seismic cable being connected to the surface vessels via respective negative buoyancy lead-in cables
Implementation Method 2
each end of the seismic cable being connected to a respective autonomous surface vessel that exerts a force on said end, such that the seismic cable can be kept stationary or quasi-stationary during the data acquisition
Data Source
AI summary
The invention in particular relates to a method for controlling the horizontal position of a seismic cable adapted for acquiring seismic data midwater. The method comprises, based on a deviation observed between the position of the seismic cable and a setpoint horizontal position, a correction of the position of the seismic cable through an adjustment of the forces respectively exerted by lead-in cables on the ends of the seismic cable, the exerted forces simultaneously and each having an axial component and a lateral component relative to the seismic cable at at least one moment of the correction.This allows an easy to implement and relatively precise control of the horizontal position of a seismic cable adapted for acquiring seismic data midwater and kept stationary or quasi-stationary during the data acquisition.