A method of operating a pressure wave generator (1) with a pressure chamber (2), wherein the pressure wave generator (1) comprises a closure element (9) which, in a closed position, closes the pressure chamber (2) with respect to an outlet (15) and, in an open position, —allows a working medium to flow out of the pressure chamber (2) into the outlet (15); an actuator by means of which the closure element (9) can be brought from the closed position into the open position and, in particular, can also be brought from the open position into the closed position;
wherein the method comprises repeatedly performing the following steps: filling the pressure chamber (2) with a gaseous working medium at a pressure of over one hundred bar; moving the actuator and thereby moving the closure element (9) in an opening direction to open the pressure chamber (2) with respect to the outlet (15), and discharging the pressurized working medium from the pressure chamber (2) through the outlet (15) within a discharge time period of less than fifteen milliseconds.

A technique facilitates controlled creation of pressure waves in a downhole environment. The technique enables creation of, for example, dynamic underbalance (DUB) pressure waves or dynamic overbalance (DOB) pressure waves which can be used to perform desired activities downhole. According to an embodiment, a pump is coupled with a pressure chamber and conveyed downhole into a borehole to a desired location. The pump may be operated downhole to change a pressure level in the pressure chamber until a sufficient pressure differential exists between an interior and an exterior of the pressure chamber. A release mechanism in communication with the pressure chamber is then rapidly opened to establish the desired pressure wave as the differing pressures equalize.

A seismic source using tuned pulse sources to form an ultra-low frequency (ULF) cluster intended for use in generating seismic energy impulses for marine seismic exploration and more specifically to improved performance by increasing low frequency output to within a range of 1 Hz to 3 Hz to provide greater penetration of the seismic signal through complex overburden such as salt or basalt.

A seismic source using tuned pulse sources to form an ultra-low frequency (ULF) cluster intended for use in generating seismic energy impulses for marine seismic exploration and more specifically to improved performance by increasing low frequency output to within a range of 1 Hz to 3 Hz to provide greater penetration of the seismic signal through complex overburden such as salt or basalt.

A seismic source having two or more operating heads with a firing chamber pressure vessel of compressed air for generating seismic oscillations at low and ultra-low frequencies (ULF) for marine seismic exploration. The multi-headed sound source increases low frequency signal in ranges from below 1 Hz to around 7 Hz to provide greater penetration of the seismic signal through complex overburden such as salt or basalt, improve velocity model building with methods such as Full Wave Inversion, improve the ability to build blocky reservoir models, and improve resolution by reducing side lobes.

A seismic source having two or more operating heads with a firing chamber pressure vessel of compressed air for generating seismic oscillations at low and ultra-low frequencies (ULF) for marine seismic exploration. The multi-headed sound source increases low frequency signal in ranges from below 1 Hz to around 7 Hz to provide greater penetration of the seismic signal through complex overburden such as salt or basalt, improve velocity model building with methods such as Full Wave Inversion, improve the ability to build blocky reservoir models, and improve resolution by reducing side lobes.

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 for generating a high-resolution pseudo-reflectivity image of a subsurface region includes receiving seismic data associated with a subsurface region and captured by one or more seismic receivers, constructing a velocity model of the subsurface region based on the received seismic data, performing a seismic migration of the received seismic data based on the constructed velocity model to obtain migrated seismic data, computing polarized normal vectors associated with one or more subsurface reflectors of the subsurface region based on the migrated seismic data, and generating a pseudo-reflectivity image of the subsurface region based on both the computed polarized normal vectors.

A method for generating a high-resolution pseudo-reflectivity image of a subsurface region includes receiving seismic data associated with a subsurface region and captured by one or more seismic receivers, constructing a velocity model of the subsurface region based on the received seismic data, performing a seismic migration of the received seismic data based on the constructed velocity model to obtain migrated seismic data, computing polarized normal vectors associated with one or more subsurface reflectors of the subsurface region based on the migrated seismic data, and generating a pseudo-reflectivity image of the subsurface region based on both the computed polarized normal vectors.

Methods and systems for measuring cluster efficiency for stages of wellbores are provided herein. One method includes selecting a frequency band for generating broadband tube waves within the fluid column of the wellbore and generating the broadband tube waves within the fluid column of the wellbore using a pressure pulse generator that is hydraulically coupled to the wellbore. The method also includes recording data corresponding to the broadband tube waves and reflected broadband tube waves using pressure receivers that are hydraulically coupled to the wellbore. The pressure receivers are arranged into arrays with two or more pressure receivers in each array. The data recorded by the pressure receivers relate to characteristics of reflectors (including perforation cluster/fracture interfaces) within the wellbore. The method further includes processing the recorded data using interferometry and performing full waveform inversion(s) on the processed data to determine frequency-dependent, complex-valued reflection coefficients at each perforation cluster/fracture interface.