Methods for controlling towed marine sensor array geometry

• US 8,976,622 B2
• Filed: 03/24/2009
• Issued: 03/10/2015
• Est. Priority Date: 04/21/2008
• Status: Active Grant

• Current Assignee: PGS Geophysical As (PGS ASA)
• Original Assignee: PGS Geophysical As (PGS ASA)
• Inventors: Hillesund, yvind, Lunde, Nils
• Primary Examiner(s): Hellner, Mark
• Application Number:
  US12/409,694
• Publication Number:
  US 20090262601A1
• Time in Patent Office: 2,177 Days
• Field of Search: 367/16
• US Class Current: 367/16
• CPC Class Codes: G01V 1/3817 Positioning of seismic devices
• CPC Class Codes: G01V 1/3826 dynamic steering, e.g. by paravanes or birds
• CPC Class Codes: G01V 1/3835 measuring position, e.g. by GPS or acoustically

Abstract

A method for towing a streamer array includes moving a vessel along a body of water. Streamers are towed by vessel. A relative position is determined at selected points along each streamer with respect to the vessel. At least one of the streamers is deflected at least one longitudinal position along the streamer in response to the determined positions to maintain the streamers in a selected geometry. The selected geometry is related to one of survey vessel heading, energy source trajectory, previously plotted sensor trajectory and a lateral separation related to distance from the towing vessel.

Claims

1. A method for towing a sensor streamer array in a body of water, comprising:

towing a plurality of sensor streamers behind a survey vessel in the body of water;

determining relative positions at selected points along each sensor streamer with respect to the survey vessel;

determining a trajectory of a geophysical energy source towed by the survey vessel; and

laterally deflecting at least one sensor streamer at a plurality of longitudinal positions therealong in response to the determined relative positions such that the at least one sensor streamer is maintained in a selected configuration in the water relative to the trajectory of the geophysical energy source.

2. The method of claim 1 wherein the determining relative positions comprises measuring acoustic travel time to a selected position along another sensor streamer.

3. The method of claim 1 wherein the determining relative positions comprises measuring geomagnetic direction.

4. The method of claim 1 wherein the sensor streamers comprise seismic sensors.

5. The method of claim 1 wherein the sensor streamers comprise electromagnetic sensors.

6. A method for towing a sensor streamer array in a body of water, comprising:

towing a plurality of sensor streamers behind a survey vessel in the water;

determining relative positions at selected points along each sensor streamer with respect to the survey vessel;

determining a preplot survey path, wherein the preplot survey path includes a geodetic heading that differs from a trajectory of the survey vessel; and

laterally deflecting at least one sensor streamer at a plurality of longitudinal positions therealong in response to the determined relative positions such that the at least one sensor streamer is maintained in a selected configuration in the water relative to the preplot survey path.

7. The method of claim 6 wherein the determining relative positions comprises measuring acoustic travel time to a selected position along another sensor streamer.

8. The method of claim 6 wherein the determining relative positions comprises measuring geomagnetic direction.

9. The method of claim 6 wherein the sensor streamers comprise seismic sensors.

10. The method of claim 6 wherein the sensor streamers comprise electromagnetic sensors.

11. A method for manufacturing a geophysical data product, comprising:

towing a plurality of sensor streamers behind a survey vessel in a body of water;

determining relative positions at selected points along each sensor streamer with respect to the survey vessel;

determining a preplot survey path, wherein the preplot survey path includes a geodetic heading that differs from a trajectory of the survey vessel;

laterally deflecting at least one sensor streamer at a plurality of longitudinal positions therealong in response to the determined relative positions such that the at least one sensor streamer is maintained in a selected configuration in the water relative to the preplot survey path;

activating at least one energy source to produce energy;

detecting the energy via sensors coupled to the plurality of sensor streamers, wherein at least a portion of the detected energy has been modified by interactions with geophysical formations below the body of water; and

recording, on a tangible computer-readable medium, data corresponding to the detected energy.

12. The method of claim 11, wherein the energy is seismic energy.

13. The method of claim 11, wherein the energy is electromagnetic energy.

14. The method of claim 11, wherein the determining relative positions comprises measuring acoustic travel time to a selected position along another sensor streamer.

15. The method of claim 11, wherein the determining relative positions comprises measuring geomagnetic direction.