Hydrodynamic Foils for Marine Sensor Streamer Depth Control

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Solution Overview

Problem

Current marine geophysical surveying technologies lack effective control over the depth of sensor streamers, which affects the quality of seismic data acquisition by allowing seismic signal reflections from the water-air interface to go unmanaged.

Innovation Solution

A hydrodynamic foil system is employed, where paravanes with tow ropes and spreader cables maintain lateral separation, and foils on the spreader cables provide vertical hydrodynamic lift to control the depth of sensor streamers in the water, allowing precise submersion of the streamer array.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If no depth control device is used on streamers, then the system is simple and easy to deploy, but the depth of sensor streamers cannot be controlled precisely, affecting seismic data quality

Engineering Contradiction:
Improvedepth control precisionVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The hydrodynamic foil system utilizes the natural motion of the vessel towing the streamers through water to generate lift forces. The foils automatically orient themselves to produce the required vertical lift component based on the towing speed and foil angle, eliminating the need for active control systems or power sources on the streamers themselves.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The hydrodynamic foils generate upward lift forces that counterbalance the downward gravitational force on the streamers. By adjusting the foil angle of attack, the vertical component of lift can be controlled to precisely balance weight, achieving depth control without mechanical depth control devices.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

2Measurement precision

If hydrodynamic foils are added to spreader cables, then depth control of streamers is achieved, but the device structure becomes more complex

Engineering Contradiction:
Improvedepth control precisionVSAvoidstructure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The depth control function is segmented into independent hydrodynamic foils that can be attached to existing spreader cables. Each foil operates independently and can be added or removed without affecting the core streamer system, allowing incremental complexity addition only where depth control is needed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The hydrodynamic foils serve multiple functions: they provide vertical lift for depth control, maintain lateral separation when attached to spreader cables, and can be configured to work with various streamer arrangements. This multi-functionality reduces the need for separate dedicated depth control devices.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Stability of the object's composition

If paravanes with tow ropes and spreader cables are used, then lateral separation of streamers is maintained, but the system requires additional components increasing complexity

Engineering Contradiction:
Improvelateral separation stabilityVSAvoidsystem complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The lateral separation function and depth control function are merged into a single integrated system. The spreader cables that maintain lateral separation between streamers also carry the hydrodynamic foils that provide depth control, eliminating the need for separate lateral control and depth control systems.

Inventive Principle:
Principle #5Merging (Combining)

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 solution enables precise control over the depth of sensor streamers, enhancing the quality of seismic data acquisition by managing seismic signal reflections and improving the accuracy of subsurface imaging.

Implementation Method 1

foils on the spreader cables provide vertical hydrodynamic lift to control the depth of sensor streamers in the water

Methodology Applied
Scientific EffectHydrodynamic lift: Aerofoil

Implementation Method 2

paravanes configured to provide lateral outward force as the vessel and paravanes are moved through a body of water

Methodology Applied
Scientific EffectHydrodynamic force: Drag

Data Source

PatentEP2317341B1Hydrodynamic depressor for marine sensor streamer arrays
Publication Date: 2020.04.22 PGS GEOPHYSICAL AS
  • EP2317341B1 patent drawingFigure 1
  • EP2317341B1 patent drawingFigure 2~3

AI summary

A hydrodynamic foil system for a sensor streamer array includes at least two tow ropes (8) each coupled at one end to a survey vessel (10) and at the other end to a paravane (14), the paravanes configured to provide lateral outward force as the vessel and paravanes are moved through a body of water. A spreader cable (24) is coupled to each of the paravanes. A plurality of laterally spaced apart sensor streamers (20) coupled at forward ends thereof to the spreader cable (24). A plurality of foils (25) is disposed on the spreader cables. The foils (25) configured to provide hydrodynamic lift in a vertical direction as the spreader cables are moved through the water.