Seismic Cable Depth Control via Autonomous Vessel Tension
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing seismic prospecting methods in aquatic mediums face challenges in accurately controlling the depth of seismic cables, particularly at depths greater than 5 to 15 meters, which limits data quality and flexibility in positioning.
Innovation Solution
A method and system that utilize ballasts for neutral buoyancy and surface autonomous vessels with lead-in cables of negative buoyancy to control the depth of seismic cables, allowing for precise adjustment of cable length and tension to maintain a target depth, enabling stationary or quasi-stationary positioning and improved data acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the entire set of cables is towed by a seismic vessel at shallow depths (5 to 15 meters), then the operation is simple and conventional, but the depth flexibility and data quality at greater depths are limited
Solution Approach 1:
The system divides the cable into multiple segments with ballasts spaced apart along its length, allowing independent depth control of different cable portions. Each ballast can be adjusted to achieve neutral buoyancy at specific depths, enabling flexible positioning of the entire cable at greater depths without requiring the entire system to be towed as a single unit.
Solution Approach 2:
Autonomous surface vessels act as intermediaries between the seismic cable and the environment. These vessels exert tension on the cable through lead-in cables, enabling depth control and stationary positioning without requiring a large seismic vessel to tow the entire cable. This intermediary approach provides depth flexibility while reducing the complexity of continuous towing operations.
2Measurement precision
If ballasts are used to achieve neutral buoyancy for deep water positioning, then depth control capability is improved, but the complexity of depth control mechanisms increases
Solution Approach 1:
The system controls depth by varying parameters such as the deployed length of lead-in cables and the tension exerted by autonomous surface vessels. By adjusting these parameters, precise depth control is achieved without complex mechanical depth control mechanisms. The ballasts provide neutral buoyancy as a baseline, and fine-tuning is accomplished through parameter adjustment of the lead-in cable system.
3Manufacturing precision
If autonomous surface vessels exert tension through variable length lead-in cables, then depth control accuracy is improved, but the complexity of tension control systems increases
Solution Approach 1:
The lead-in cables are designed with variable length capability, allowing the tension control system to adapt dynamically to different depth requirements. By changing the deployed length of the lead-in cable, the system can precisely control the tension exerted on the seismic cable, achieving accurate depth positioning. This dynamic adjustment simplifies the control mechanism compared to fixed-tension systems while maintaining high positioning accuracy.
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 allows for accurate and flexible control of seismic cable depth, enhancing data quality and enabling effective seismic prospecting at greater depths with reduced mechanical and energy constraints, while maintaining the cables in a stationary or pseudo-stationary position.
Implementation Method 1
seismic cable having ballasts spaced apart along its length and providing a neutral buoyancy to the seismic cable
Implementation Method 2
each end of the seismic cable being connected to a respective surface autonomous vessel exerting tension on the cable through a respective lead-in cable having a negative buoyancy
Data Source
AI summary
The invention notably relates to a method for controlling depth of a seismic cable having ballasts spaced apart along its length and providing a neutral buoyancy to the seismic cable, the seismic cable being adapted for midwater data acquisition, each end of the seismic cable being connected to a respective surface autonomous vessel exerting tension on the cable through a respective lead-in cable having a negative buoyancy, the method comprising, with respect to a target depth, varying the deployed length of each lead-in cable and/or the tension exerted on the cable by each respective surface autonomous vessel.This provides an improved solution for seismic prospecting in aquatic mediums.