Noise suppression by adaptive speed regulations of towed marine geophysical streamer

Patent metadata

Field	Value
Publication number	US-9663192-B2
Application number	US-201213354004-A
Country	US
Kind code	B2
Filing date	Jan 19, 2012
Priority date	Mar 30, 2010
Publication date	May 30, 2017
Grant date	May 30, 2017

Abstract

A method for towing marine geophysical sensor streamers in a body of water includes moving a towing vessel at a selected speed along the surface of the body of water. At least one geophysical sensor streamer is towed by the vessel at a selected depth in the water. A velocity of the streamer in the water is measured at at least one position along the streamer. The selected speed of the towing vessel is adjusted if the measured velocity is outside of a selected range.

First claim

What is claimed is:

1. A method for towing one or more geophysical sensor streamers in a body of water, comprising:
moving a towing vessel at a selected speed along the surface of the body of water;
towing at least one of the one or more streamers from the vessel at a selected depth in the water;
measuring a velocity of the streamer in the water at at least one position along the streamer, the velocity of the streamer in the water proportional to motion induced noise of electromagnetic sensors; and
adjusting the selected speed of the towing vessel if the motion induced noise is outside of a selected range.

2. The method of claim 1 further comprising adjusting an angle of attack of a depth control surface of a depressor at a forward end of the streamer to maintain a selected downward force on the streamer in response to the adjusted selected speed.

3. The method of claim 1 wherein the velocity is measured using an acoustic Doppler current profiler affixed to an exterior surface of the streamer.

4. The method of claim 1 wherein geophysical sensors on the streamer comprise at least one of magnetometers, wire loops, and spaced apart electrode pairs.

5. The method of claim 1 further comprising:
measuring a lateral position of the streamer in the water at at least one position along the streamer; and
adjusting the lateral position of the streamer with a lateral force and control device proximate the at least one position along the streamer.

6. The method of claim 5 further comprising adjusting an angle of attack of at least one of the lateral force and control device and a depth control surface of a depressor at a forward end of the streamer to maintain a selected downward force on the streamer in response to the adjusted selected speed.

7. The method of claim 1 wherein adjusting the selected speed further comprises increasing the selected speed if the motion induced noise is below the selected range.

8. A marine geophysical survey system comprising:
a towing vessel;
a geophysical sensor streamer connected to the towing vessel;
a plurality of electromagnetic sensors longitudinally spaced apart along the geophysical sensor streamer;
a depressor at a forward end of the streamer;
a velocity measuring device affixed to an exterior surface of the geophysical sensor streamer, the velocity measuring device configured to measure velocity of the geophysical sensor streamer; and
a recording unit disposed on the towing vessel and operationally coupled to the velocity measuring device, the recording unit configured to control the speed of the towing vessel to maintain acceptable levels of motion-induced noise.

9. The system of claim 8 wherein the velocity measuring device comprises an acoustic Doppler current profiler.

10. The system of claim 8 wherein the velocity measuring device is configured to transmit velocity measurement signals to the towing vessel.

11. The system of claim 8 wherein the depressor comprises at least one of a depth control surface and a rudder.

12. The system of claim 8 wherein the depressor is configured to receive control signals from the towing vessel.

13. The system of claim 8 further comprising a lateral force and control device on the streamer.

14. The system of claim 13 wherein the lateral force and control device is configured to receive control signals from the towing vessel.

15. The system of claim 8 further comprising a lateral position measuring device on the streamer.

16. The system of claim 15 wherein the lateral position measuring device is a component of an acoustic range finding system.

17. The system of claim 15 wherein the lateral position measuring device is conjured to transmit lateral position measurement signals to the towing vessel.

18. The system of claim 8 wherein adjusting the recoding unit is configured to increase the speed of the tow vessel if the motion induced noise is below the acceptable level.

19. A method of geophysical surveying comprising:
moving a towing vessel at a selected speed along a surface of a body of water;
towing a geophysical sensor streamer from the vessel at a selected depth in the water;
actuating an energy source in the water to impart energy into formations below the body of water;
detecting energy in response to the energy imparted into the formations with sensors disposed along the streamer;
measuring a velocity of the streamer in the water at at least one position along the streamer, the velocity of the streamer in the water proportional to motion induced noise of electromagnetic sensors; and
adjusting the selected speed of the towing vessel if the motion induced noise is outside of a selected range.

20. The method of claim 19 wherein the energy source is an electromagnetic energy source, and the detected energy comprises components of electromagnetic energy.

21. The method of claim 19 wherein adjusting the selected speed further comprises increasing the selected speed if the motion induced noise is below the selected range.

Assignees

• Südow Gustav Göran Mattias
• Lindqvist Ulf Peter
• Juhasz Andras Robert
• Mattsson Rune Johan Magnus
• Pgs Geophysical As

Inventors

• Südow Gustav Göran Mattias
• Lindqvist Ulf Peter
• Juhasz Andras Robert
• Mattsson Rune Johan Magnus

Classifications

• G01V1/3826

  dynamic steering, e.g. by paravanes or birds · CPC title

• B63B21/66 Primary

  Equipment specially adapted for towing underwater objects or vessels, e.g. fairings for tow-cables ({paravanes for dragging fishing nets A01K73/02; } salvaging underwater vessels or objects B63C7/00; towed underwater vessels B63G8/42) · CPC title

• G01V3/083

  Controlled source electromagnetic [CSEM] surveying · CPC title

• B63H21/21

  Control means for engine or transmission, specially adapted for use on marine vessels · CPC title