Abstract: Methods are provided to package and deploy a marine vibrator for use in connection with marine seismic surveys. Marine vibrators are provided with a number of buoyancy configurations with corresponding techniques for controlling the submergence depth of the marine vibrators. An exemplary marine vibrator comprises a positively buoyant hydrodynamic tow body, comprising: a low frequency electro-acoustic projector; a power electronics system; a control-monitoring electronics system; and a pressure compensation system, wherein the hydrodynamic tow body comprises one or more active control surfaces to adjust a submergence depth and a roll attitude of the hydrodynamic tow body. Additional embodiments employ a free-flooding, load-bearing frame with positive or negative buoyancy.

Abstract: Methods are provided to package and deploy a marine vibrator for use in connection with marine seismic surveys. Marine vibrators are provided with a number of buoyancy configurations with corresponding techniques for controlling the submergence depth of the marine vibrators. An exemplary marine vibrator comprises a positively buoyant hydrodynamic tow body, comprising: a low frequency electro-acoustic projector; a power electronics system; a control-monitoring electronics system; and a pressure compensation system, wherein the hydrodynamic tow body comprises one or more active control surfaces to adjust a submergence depth and a roll attitude of the hydrodynamic tow body. Additional embodiments employ a free-flooding, load-bearing frame with positive or negative buoyancy.

Abstract: A coherent sound source is provided for marine seismic surveys. An underwater sound projector for producing time-harmonic waveforms comprises two pistons positioned on either side of an electro-magnetic force generator substantially having mechanical and magnetic symmetry about its geometric center thereby creating a virtual node to substantially cancel reaction loads that occur when the pistons are actuated. The underwater sound projector optionally also includes control systems to improve the fidelity of the force generator, provide pressure compensation to the pistons, finely adjust the static position of the pistons, and change the depth and roll when it is configured as tow body. A plurality of underwater sound projectors can be configured in an array.

Abstract: A coherent sound source is provided for marine seismic surveys. An exemplary underwater sound projector comprises a plurality of pistons actuated by an electromagnetic force generator having components comprising a stator, armatures, electrical coils, and permanent magnets. The pistons and the components are arranged to create mechanical and magnetic symmetry about a geometric center of the projector to reduce reaction loads that occur when the pistons are actuated. The stator and the armatures have magnetic poles that employ a tapered geometry. The projector optionally includes control systems to improve the fidelity of the force generator, provide pressure compensation to the pistons, finely adjust the static position of the pistons, and/or change the depth and roll when the projector is configured as a tow body. A plurality of such projectors can be configured in an array.

Abstract: A coherent sound source is provided for marine seismic surveys. An underwater sound projector for producing time-harmonic waveforms comprises two pistons positioned on either side of an electro-magnetic force generator substantially having mechanical and magnetic symmetry about its geometric center thereby creating a virtual node to substantially cancel reaction loads that occur when the pistons are actuated. The underwater sound projector optionally also includes control systems to improve the fidelity of the force generator, provide pressure compensation to the pistons, finely adjust the static position of the pistons, and change the depth and roll when it is configured as tow body. A plurality of underwater sound projectors can be configured in an array.

Abstract: Low cost miniature vector sensors are provided. An acoustic vector sensor is provided that comprises at least one accelerometer to measure at least one component of acoustic particle acceleration, wherein the at least one accelerometer has a resonant frequency within a measurement band of the acoustic vector sensor. In addition, a method is disclosed for measuring an acoustic signal. The method comprises the steps of configuring an array of acoustic vector sensors comprised of at least one accelerometer to measure at least one component of acoustic particle acceleration; operating the at least one accelerometer at a resonant frequency within a measurement band of the acoustic vector sensor; and generating a voltage using one or more of the acoustic vector sensors representative of the acoustic signal as the acoustic signal propagates past the array. The voltage optionally indicates a bearing of the acoustic signal.

Abstract: Low cost miniature vector sensors are provided. An acoustic vector sensor is provided that comprises at least one accelerometer to measure at least one component of acoustic particle acceleration, wherein the at least one accelerometer has a resonant frequency within a measurement band of the acoustic vector sensor. In addition, a method is disclosed for measuring an acoustic signal. The method comprises the steps of configuring an array of acoustic vector sensors comprised of at least one accelerometer to measure at least one component of acoustic particle acceleration; operating the at least one accelerometer at a resonant frequency within a measurement band of the acoustic vector sensor; and generating a voltage using one or more of the acoustic vector sensors representative of the acoustic signal as the acoustic signal propagates past the array. The voltage optionally indicates a bearing of the acoustic signal.

Abstract: A system and method are disclosed for reducing flow-induced noise in an urwater towed system. The system includes at least one neutrally buoyant towed array, a tow platform for defining a towed direction of the at least one towed array, a neutrally buoyant tow cable connected to the at least one towed array and the tow platform, and a deploy and retrieve apparatus for deploying and retrieving the tow cable. The deploy and retrieve apparatus is connected to both the tow cable and the tow platform. Deployment of the tow cable from the deploy and retrieve apparatus correspondingly deploys the at least one towed array, and retrieval of the tow cable with the deploy and retrieve apparatus correspondingly retrieves the at least one towed array. The speed of deployment of the tow cable can be varied to decrease the velocity of the towed array relative to the surrounding water thus reducing flow-induced noise.