An improved baseplate design is described that correct the flexure with a plurality of actuators mounted on top of the base plate. Sensors and a feedback circuit enables the detection of flexure and a corresponding compensating scheme to correct and/or prevent the flexure in order for the baseplate to complete couple with the ground for more accurate seismic survey.

An improved baseplate design is described that correct the flexure with a plurality of actuators mounted on top of the base plate. Sensors and a feedback circuit enables the detection of flexure and a corresponding compensating scheme to correct and/or prevent the flexure in order for the baseplate to complete couple with the ground for more accurate seismic survey.

Apparatus for the generation of pressure waves for seismic surveys in marine environment comprising a cylinder (3), defining an axis, in which a striker piston (1) and a pump piston (2) are situated, each having two respective opposite sides with respect to said axis, of which a side of the striker piston (1) situated in front of the pump piston (2) is defined first impact side, and a side of the pump piston (2) in front of the striker piston (1) is defined second impact side, the pump piston (2) and the striker piston (1) sliding in the cylinder (3) in a direction parallel to the axis, and the pump piston (2) and striker piston (1) being such as to strike against each other, by means of the first and the second impact sides, the striker piston (1) being driven by activation means pressing on the side opposite to its own impact side, wherein the cylinder (3) comprises, at one of its ends, a chamber (15) having a diameter larger, smaller or equal to that of the portion of cylinder (3) in which the striker piston (1) is housed, wherein in said chamber (15) a part of the pump piston (2) can slide, communication passages which connect the chamber (15) with the water of the marine environment (10), so as to transmit an impulse generated by said impact to the marine environment.

Apparatus for the generation of pressure waves for seismic surveys in marine environment comprising a cylinder (3), defining an axis, in which a striker piston (1) and a pump piston (2) are situated, each having two respective opposite sides with respect to said axis, of which a side of the striker piston (1) situated in front of the pump piston (2) is defined first impact side, and a side of the pump piston (2) in front of the striker piston (1) is defined second impact side, the pump piston (2) and the striker piston (1) sliding in the cylinder (3) in a direction parallel to the axis, and the pump piston (2) and striker piston (1) being such as to strike against each other, by means of the first and the second impact sides, the striker piston (1) being driven by activation means pressing on the side opposite to its own impact side, wherein the cylinder (3) comprises, at one of its ends, a chamber (15) having a diameter larger, smaller or equal to that of the portion of cylinder (3) in which the striker piston (1) is housed, wherein in said chamber (15) a part of the pump piston (2) can slide, communication passages which connect the chamber (15) with the water of the marine environment (10), so as to transmit an impulse generated by said impact to the marine environment.

It is proposed a positioning assistance system for a vibrator truck, that is configured to determine a vibration point distance between the vibrator truck and the vibration point location; determine a stopping distance for stopping the vibrator truck at a vibration point location, according to a determined current speed of the vibrator truck and according to a speed profile; determine a time for stopping the vibrator truck at the vibration point location according to the current speed of the vibrator truck, when the stopping distance corresponds to said vibration point distance; and trigger the lifting down of the baseplate of the vibratory system, when at least the following condition is met: said stopping time is inferior or equal to a time for lifting down the vibratory system to the ground. Corresponding vibrator truck and method are also proposed.

A seismic marine vibrator (100) may comprises first plates (102) and second plates (104) arranged along a longitudinal axis (101), longitudinal and peripheral first (106) and second (108) elements respectively secured to the first (102) and second (104) plates, and an actuator (112) operable to reciprocate the first elements (106) relative to the second elements (108) along the longitudinal axis (101) so as to reciprocate the first plates (102) relative to the second plates (104). The seismic marine vibrator further comprises peripherally closed air-filled chambers (109) and peripherally open chambers (111), the volume of said open chambers (111) being varied when the first plates (102) are reciprocated so as to take in and expel water radially to generate an acoustic wave. This forms an improved seismic marine vibrator.

A seismic marine vibrator (100) may comprises first plates (102) and second plates (104) arranged along a longitudinal axis (101), longitudinal and peripheral first (106) and second (108) elements respectively secured to the first (102) and second (104) plates, and an actuator (112) operable to reciprocate the first elements (106) relative to the second elements (108) along the longitudinal axis (101) so as to reciprocate the first plates (102) relative to the second plates (104). The seismic marine vibrator further comprises peripherally closed air-filled chambers (109) and peripherally open chambers (111), the volume of said open chambers (111) being varied when the first plates (102) are reciprocated so as to take in and expel water radially to generate an acoustic wave. This forms an improved seismic marine vibrator.

An acoustic dipole waveform generator has a hollow housing defining an elongate axis and having secured therein at least a force reaction member defining at least a force reaction surface and having hingingly secured thereto an actuator element. The piezoelectric actuator elements define mutually non-aligned length change axes and extend from the reaction member towards at least one moveable piston member hingingly secured to at least one of the actuator elements inside the housing. The piston member is constrained to move in a direction extending perpendicular to the axis, the piston member defining respectively at mutually spaced locations in the housing a pair of heads that, on movement of the piston member, each generate a respective pressure wave and the housing permitting transmission of the wave externally thereby permitting generation of a dipole pressure waveform externally of the housing on changing of the lengths of the actuator elements.

An acoustic dipole waveform generator has a hollow housing defining an elongate axis and having secured therein at least a force reaction member defining at least a force reaction surface and having hingingly secured thereto an actuator element. The piezoelectric actuator elements define mutually non-aligned length change axes and extend from the reaction member towards at least one moveable piston member hingingly secured to at least one of the actuator elements inside the housing. The piston member is constrained to move in a direction extending perpendicular to the axis, the piston member defining respectively at mutually spaced locations in the housing a pair of heads that, on movement of the piston member, each generate a respective pressure wave and the housing permitting transmission of the wave externally thereby permitting generation of a dipole pressure waveform externally of the housing on changing of the lengths of the actuator elements.

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.