Methods for controlling towed marine sensor array geometry
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.
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 water;
determining relative positions at selected points along each streamer with respect to the vessel;
determining a trajectory of a geophysical energy source towed by the survey vessel; and
laterally deflecting at least one streamer at a plurality of longitudinal positions therealong in response to the determined relative positions such that the at least one 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 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 streamer with respect to the 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 streamer at a plurality of longitudinal positions therealong in response to the determined relative positions such that the at least one 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 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.