A seismic vibrator is configured to operate close to resonance for range of actuating frequencies. The vibrator has a baseplate, a reaction mass coupled to the baseplate via an elastic coupling mechanism and an actuator configured to displace the reaction mass with an actuating frequency. The vibrator also has a frequency-adjusting system configured to adjust a natural frequency of the elastic coupling mechanism and the reaction mass, to track the actuating frequency so that to achieve resonance.

A method of seismic exploration above a region of the subsurface of the earth containing structural or stratigraphic features conducive to the presence, migration, or accumulation of hydrocarbons comprises setting a tow depth of a resonant seismic source, producing a resonant frequency at a first amplitude with the resonant seismic source at the tow depth, detecting a depth excursion from the tow depth, reducing an amplitude of the mass from the first amplitude to a second amplitude, preventing the mass from contacting at least one of the first end stop or the second end stop based on reducing the amplitude to the second amplitude, correcting the depth excursion to return the resonant seismic source to the tow depth, and increasing the amplitude from the second amplitude to produce the resonant frequency with the resonant seismic source at the tow depth.

A method of seismic exploration above a region of the subsurface of the earth containing structural or stratigraphic features conducive to the presence, migration, or accumulation of hydrocarbons comprises setting a tow depth of a resonant seismic source, producing a resonant frequency at a first amplitude with the resonant seismic source at the tow depth, detecting a depth excursion from the tow depth, reducing an amplitude of the mass from the first amplitude to a second amplitude, preventing the mass from contacting at least one of the first end stop or the second end stop based on reducing the amplitude to the second amplitude, correcting the depth excursion to return the resonant seismic source to the tow depth, and increasing the amplitude from the second amplitude to produce the resonant frequency with the resonant seismic source at the tow depth.

A method for correcting for distortions in a seismic acoustic wavefield produced by a seismic vibrator that is immersed in a fluid, the method comprising: applying a pilot signal to the vibrator such that an acoustic wavefield travels outwards from the interface between the vibrator outer surface and the fluid: using a sensor located within the fluid so as to be sensitive to a property of the wavefield in the fluid to monitor the property of the wavefield as a function of time: and using the measured property to determine a change in wet volume of a component of the vibrator as a function of time V(t) or derivatives of V(t), and using the determined wet volume V(t) or its derivatives to correct for distortions in the seismic data produced by the vibrator.

This disclosure is related generally to marine surveying. An apparatus for generation of seismic waves in a body of water may include a wave generator. The apparatus may further include a housing defining an internal chamber having an open end. The housing may include baffles positioned between the open end and the wave generator. The housing may further include a vent positioned on an opposite end of the housing from the baffles.

This disclosure is related generally to marine surveying. An apparatus for generation of seismic waves in a body of water may include a wave generator. The apparatus may further include a housing defining an internal chamber having an open end. The housing may include baffles positioned between the open end and the wave generator. The housing may further include a vent positioned on an opposite end of the housing from the baffles.

A method and source element for generating seismic waves in water. The source element includes a housing having an opening; an acoustic piston closing the opening; an actuating mechanism located inside the housing and configured to actuate the acoustic piston; and a decoupling mechanism interposed between the acoustic piston and the actuating mechanism. The decoupling mechanism allows the acoustic piston to move substantially independent of the actuating mechanism for a first frequency range.

Disclosed are devices and methods for marine geophysical surveying. An example device may comprise a shell, a base plate, wherein the base plate is coupled to the shell, a driver disposed within the shell, an inner spring element disposed within the shell, wherein the inner spring element is coupled to the driver, wherein outer ends of the inner spring element are coupled to outer ends of the inner spring element at spring element junctions, an outer spring element disposed within the shell, wherein outer ends of the outer spring element are coupled to the spring element junctions, and a back mass disposed on the outer spring element.

An acoustic sound source designed to impart vibratory energy into its surrounding environment by linearly displacing transducer face plate(s) that are coupled to a rotary motor via crankshaft/connecting rod(s) or camshaft(s). The frequency of the vibrational energy is proportional to the speed of the rotary motor and the amplitude of the vibrational energy is proportional to the linear displacement of the transducer faceplates. The motor can be manually or automatically controlled to operate at a fixed speed and/or a variety of time varying speeds such as frequency sweeps or ramps. The linear displacement or amplitude of the transducer faceplates can also be manually or automatically controlled to operate at a fixed displacement or to have the displacement vary with time and/or frequency.

Imperfect separation at the higher frequencies has been observed and was eventually was tracked down to the poor GFE signal that is normally used in the inversion. The invention thus uses a “derived GFE” for each source, obtained by comparing the shot records and remove the differences, instead of the prior estimated GFE signal put out by the controller, thus accurately maximizing the separation of the data.