Low Frequency Marine Acoustic Vibrator

Abstract

Embodiments relate to marine acoustic vibrators that incorporate one or more piston plates that act on the surrounding water to produce acoustic energy. An example marine acoustic vibratory may comprise: a containment housing; a piston plate; a fixture coupled to the containment housing; a spring element coupled to the piston plate and the fixture; and a driver coupled to the piston plate and the fixture and configured to move the piston plate back and forth.

What is claimed is: 
     
         1 . A system comprising:
 a marine acoustic vibrator comprising a containment housing, one or more piston plates coupled to the containment housing, and a driver coupled to the one or more piston plates to move the one or more piston plates back and forth; and   a submersible vehicle that supports and positions the marine acoustic vibrator in a body of water.   
     
     
         2 . The system of  claim 1 , further comprising a lead line coupled to an attachment point on the submersible vehicle. 
     
     
         3 . The system of  claim 1 , further comprising a hydrodynamic depressor used in conjunction with the marine acoustic vibrator for creating thrust as the hydrodynamic depressor is moved through the body of water to force the marine acoustic vibrator downward. 
     
     
         4 . The system of  claim 1 , wherein the submersible vehicle comprises a fin. 
     
     
         5 . The system of  claim 1 , wherein the marine acoustic vibrator is disposed in a window of the submersible vehicle. 
     
     
         6 . The system of  claim 1 , further comprising a source cable coupling the marine acoustic vibrator to a survey vessel. 
     
     
         7 . The system of  claim 1 , wherein the one or more piston plates each cover a corresponding opening in the containment housing, the one or more piston plates being coupled to the containment housing using rubber seals. 
     
     
         8 . The system of  claim 1 , wherein the one or more piston plates comprise a pair of piston plates being disposed on opposing sides of the containment housing from one another. 
     
     
         9 . The system of  claim 1 , further comprising a fixture coupled to the containment housing and spring elements that extend between the fixture and the one or more piston plates. 
     
     
         10 . The system of  claim 9 , wherein the one or more piston plates comprise a first piston plate and a second piston plate on an opposing side of the containment housing from the first piston plate, wherein the spring elements comprise a first pair of spring elements coupled to the fixture and the first piston plate and a second pair of spring elements coupled to the fixture and the second piston plate. 
     
     
         11 . The system of  claim 10 , wherein the fixture provides a line of symmetry that divides the marine acoustic vibrator in symmetrical halves with respect to at least the one more piston plates, the spring elements, and the driver, wherein the fixture comprises a frame. 
     
     
         12 . The system of  claim 9 , wherein the fixture supports the driver in the containment housing, the extending along a major axis of the containment housing, wherein the fixture is coupled to either end of the containment housing. 
     
     
         13 . The system of  claim 1 , wherein the one or more piston plates are configured to not bend or flex during operation of the marine acoustic vibrator. 
     
     
         14 . The system of  claim 1 , wherein the marine acoustic vibrator is configured to have a resonance frequency within a frequency range of about 1 Hz and about 10 Hz when disposed in water at a depth of about 0 meters to about 300 meters. 
     
     
         15 . A method comprising:
 towing a submersible vehicle through a body of water, wherein a marine acoustic vibrator is disposed in the submersible vehicle; and   triggering the marine acoustic vibrator to cause one or more piston plates in the marine acoustic vibrator to move back and forth and generate acoustic energy, wherein one or more spring elements exert a biasing force against the one or more piston plates.   
     
     
         16 . The method of  claim 15 , wherein the marine acoustic vibrator generates at least one resonance frequency within a frequency range of about 1 Hz and about 10 Hz. 
     
     
         17 . The method of  claim 15 , further comprising towing an array of marine acoustic vibrators in the body of water, each of the marine acoustic vibrators being disposed in a corresponding submersible vehicle, the array of marine acoustic vibrators comprising the marine acoustic vibrator. 
     
     
         18 . The method of  claim 17 , further comprising generating downward thrust with a hydrodynamic depressor to force the array of marine acoustic vibrators downward in the body of water. 
     
     
         19 . The method of  claim 15 , further comprising towing one or more air guns in conjunction with the marine acoustic vibrator, and triggering the one or more air guns to generate acoustic energy. 
     
     
         20 . The method of  claim 17 , further comprising: obtaining geophysical data; processing the geophysical data to generate a geophysical data product, and recording the geophysical data product on a tangible, non-volatile computer-readable medium suitable for importing onshore, wherein the geophysical data is obtained by a process that includes detecting the acoustic energy originating from the marine acoustic vibrator.