Distributed multi-sensor streamer

Abstract

This disclosure is related to the field of streamers. In one embodiment, a streamer may include a group of particle motion sensors. In some embodiments, at least two of the particle motion sensors in the group are movable relative to one another within the streamer, and the two particle motion sensors are configured to measure motion along a particular axis. In some embodiments, the streamer may additionally include a plurality of pressure sensors.

What is claimed is: 
     
         1 . An apparatus, comprising:
 a streamer that includes a group of particle motion sensors, wherein each particle motion sensor in the group is configured to perform measurements along a same particular axis, wherein the group of particle motion sensors includes a first particle motion sensor and a second particle motion sensor, and wherein the streamer permits flexing that changes an orientation of at least one of the first and second particle motion sensors relative to the axis;   circuitry configured to combine outputs of the particle motion sensors in the group;   one or more orientation sensors configured to determine a difference in orientation of the at least one of the first and second particle motion sensors relative to the axis; and   a compensation unit configured to compensate for flexing of the streamer by processing outputs of at least one of the first and second particle motion sensors, based on the determined difference in orientation.   
     
     
         2 . The apparatus of  claim 1 , wherein the first and second particle motion sensors are housed in respective bodies within the streamer, wherein the respective bodies are coupled to a strength member of the streamer. 
     
     
         3 . The apparatus of  claim 1 , wherein the streamer further includes a second group of particle motion sensors configured to measure motion along a different axis, wherein the second group of particle motion sensors includes a third and a fourth particle motion sensor that are movable relative to one another within the streamer. 
     
     
         4 . The apparatus of  claim 1 , further comprising control circuitry configured to control a streamer positioning device to untwist at least a portion of the streamer such that the difference in orientation is reduced. 
     
     
         5 . The apparatus of  claim 1 , wherein the difference in orientation is caused by twisting of the streamer. 
     
     
         6 . The apparatus of  claim 1 , wherein the circuitry is configured to combine the outputs of the particle motion sensors in the group in an analog fashion prior to digitization. 
     
     
         7 . The apparatus of  claim 1 , wherein the one or more orientation sensors are two tilt sensors. 
     
     
         8 . The apparatus of  claim 1 , wherein the one or more orientation sensors include a magnetic sensor. 
     
     
         9 . A method, comprising:
 towing an array of streamers behind a vessel in a body of water, wherein at least one streamer includes a group of particle motion sensors, wherein each particle motion sensor in the group is configured to perform measurements along a same particular axis, wherein the group of particle motion sensors includes a first particle motion sensor and a second particle motion sensor, and wherein the streamer permits flexing that changes an orientation of at least one of the first and second particle motion sensors relative to the axis;   combining outputs of the particle motion sensors in the group;   determining, using one or more orientation sensors, a difference in orientation of the at least one of the first and second particle motion sensors relative to the axis; and   compensating for flexing of the streamer by processing outputs of at least one of the first and second particle motion sensors, based on the determined difference in orientation.   
     
     
         10 . The method of  claim 9 , further comprising:
 updating a model of an orientation of the first particle motion sensor.   
     
     
         11 . The method of  claim 9 , further comprising:
 controlling a streamer positioning device to untwist at least a portion of the streamer such that the difference in orientation is reduced.   
     
     
         12 . The method of  claim 9 , wherein the difference in orientation is caused by twisting of the streamer during the towing. 
     
     
         13 . The method of  claim 9 , wherein the combining outputs is performed prior to digitization of outputs of the particle motion sensors in the group. 
     
     
         14 . The method of  claim 9 , further comprising:
 producing a geophysical data product based on signals from the group of particle motion sensors.   
     
     
         15 . The method of  claim 14 , further comprising importing the geophysical data product onshore. 
     
     
         16 . The method of  claim 15 , further comprising performing geophysical analysis onshore on the geophysical data product. 
     
     
         17 . A non-transitory computer-readable medium having instructions stored thereon that are executable by a computing device to perform operations comprising:
 combining outputs of particle motion sensors in a group of particle motion sensors included in a streamer towed behind a vessel in a body of water, wherein each particle motion sensor in the group is configured to perform measurements along a same particular axis, wherein the group of particle motion sensors includes a first particle motion sensor and a second particle motion sensor, and wherein the streamer permits flexing that changes an orientation of at least one of the first and second particle motion sensors relative to the axis;   determining, using one or more orientation sensors, a difference in orientation of the at least one of the first and second particle motion sensors relative to the axis; and   compensating for flexing of the streamer by processing outputs of at least one of the first and second particle motion sensors, based on the determined difference in orientation.   
     
     
         18 . The non-transitory computer-readable medium of  claim 17 , wherein the operations further comprise:
 controlling a streamer positioning device to untwist at least a portion of the streamer such that the difference in orientation is reduced.   
     
     
         19 . The non-transitory computer-readable medium of  claim 17 , wherein the combining outputs is performed prior to digitization of outputs of the particle motion sensors in the group. 
     
     
         20 . The non-transitory computer-readable medium of  claim 17 , wherein the difference in orientation is caused by twisting of the streamer during towing.