Control System for Positioning Marine Seismic Streamers

Abstract

A method of controlling a streamer positioning device ( 18 ) configured to be attached to a marine seismic streamer ( 12 ) and towed by seismic survey vessel ( 10 ) and having a wing and a wing motor for changing the orientation of the wing. The method includes the steps of: obtaining an estimated velocity of the streamer positioning device, calculating a desired change in the orientation of the wing using the estimated velocity of the streamer positioning device, and actuating the wing motor to produce the desired change in the orientation of the wing. The invention also involves an apparatus for controlling a streamer positioning device including means for obtaining an estimated velocity of the streamer positioning device, means for calculating a desired change in the orientation of the wing using the estimated velocity of the streamer positioning device, wd means for actuating the wing motor to produce the desired change in the orientation of the wing.

1 . A method comprising:
 towing an array of streamers including two outermost streamers and a plurality of inner streamers positioned therebetween, each streamer having a plurality of streamer positioning devices there along; and   controlling the streamer positioning devices so that the inner streamers are regularly spaced between the outermost streamers.   
   
   
       2 - 10 . (canceled) 
   
   
       11 . An apparatus comprising:
 an array of streamers including two outermost streamers and a plurality of inner streamers positioned therebetween;   a plurality of streamer positioning devices distributed along streamers, the streamer positioning devices each comprising wings having a common wing angle;   a control system including:   a global control system for:
 calculating information from a desired force on the streamer positioning device by a deterministic calculation; and 
 transmitting the calculated information; and 
   a plurality of local control systems to which the calculated information is transmitted from the global control system over the streamers, each local control system controlling a respective one of the streamer positioning devices, and the streamer positioning devices collectively controlling the shape of the streamers so that the inner streamers are regularly spaced between the outermost streamers.   
   
   
       12 - 20 . (canceled) 
   
   
       21 . The method of  claim 1 , wherein the calculated information comprises steering information. 
   
   
       22 . The method of  claim 21 , wherein the transmitted information includes a demanded vertical force, a demanded horizontal force, a towing velocity, and a crosscurrent velocity. 
   
   
       23 . The method of  claim 21 , wherein the transmitted information includes horizontal velocity and water in-flow angle. 
   
   
       24 . The method of  claim 21 , wherein the transmitted information includes force and velocity values. 
   
   
       25 . The method of  claim 24 , wherein the force and velocity values include a demanded vertical force, a demanded horizontal force, a towing velocity, and a crosscurrent velocity. 
   
   
       26 . The method of  claim 21 , wherein the transmitted information includes a desired horizontal force and a desired vertical force. 
   
   
       27 . The method of  claim 21 , wherein the transmitted information includes the magnitude and direction of a desired total force. 
   
   
       28 . The method of  claim 1 , wherein the transmitted information includes location information. 
   
   
       29 . The method of  claim 28 , wherein the location information includes a desired vertical depth, the magnitude of a displacement between the actual horizontal position and a desired horizontal position. 
   
   
       30 . The method of  claim 21 , wherein the location information includes a desired vertical depth, the magnitude of a displacement between the actual horizontal position and a desired horizontal position. 
   
   
       31 . The apparatus of  claim 11 , wherein the calculated information comprises steering information. 
   
   
       32 . The apparatus of  claim 31 , wherein the calculated information includes a demanded vertical force, a demanded horizontal force, a towing velocity, and a crosscurrent velocity. 
   
   
       33 . The apparatus of  claim 31 , wherein the calculated information includes horizontal velocity and water in-flow angle. 
   
   
       34 . The apparatus of  claim 31 , wherein the calculated information includes force and velocity values. 
   
   
       35 . The apparatus of  claim 34 , wherein the force and velocity values include a demanded vertical force, a demanded horizontal force, a towing velocity, and a crosscurrent velocity. 
   
   
       36 . The apparatus of  claim 31 , wherein the calculated information includes a desired horizontal force and a desired vertical force. 
   
   
       37 . The apparatus of  claim 31 , wherein the calculated information includes the magnitude and direction of a desired total force. 
   
   
       38 . The apparatus of  claim 11 , wherein the calculated information includes location information. 
   
   
       39 . The apparatus of  claim 28 , wherein the location information includes a desired vertical depth, the magnitude of a displacement between the actual horizontal position and a desired horizontal position. 
   
   
       40 . The apparatus of  claim 31 , wherein the location information includes a desired vertical depth, the magnitude of a displacement between the actual horizontal position and a desired horizontal position.