Pgs Geophysical As

Nils Gunnar Olof Kröling

Per Birger Gunnarsson

Bo Magnus Bernhardsson

Stig Rune Lennart Tenghamn

Nils Lunde

Jon Falkenberg

A marine vibrator may include a containment housing, a sound radiating surface, and a compliance chamber. The compliance chamber may include a compliance chamber housing, a non-linear linkage assembly, and a low pressure chamber. The compliance chamber housing may define at least a portion of a compliance chamber internal volume having a compliance chamber internal gas pressure. The low pressure chamber may comprise a low pressure piston and a low pressure chamber housing. The low pressure chamber housing may define at least a portion of a low pressure chamber internal volume having a low pressure chamber internal gas pressure. The low pressure piston may be configured to move in response to a pressure differential across the low pressure piston such that a resonance frequency of the marine vibrator may be changed.

Compliance chambers for marine vibrators

Techniques are disclosed relating to control of seismic sources such as marine vibrators. According to some embodiments, iterative learning control (ILC) systems may be used to control such seismic sources. According to some embodiments, local sensor(s) placed in, on, or near a seismic source and/or remote sensors placed in the far-field region may be used to determine a transfer function for the seismic source for such ILC control. A sensor is configured to measure the acoustic output of the marine vibrator along with signal pulses from at least one impulsive seismic signal source. The ILC is disabled when it is determined that the impulsive seismic is active based on the sensor measurements.

Control system for marine vibrators operating near impulsive seismic signal sources

The disclosure herein generally relates to a device for use in marine seismic surveying. A displacement apparatus has a base and an actuated head. The actuated head is coupled to an actuation means comprising a shaft, a cam, and a motor. The cam is coupled to the shaft at a radial position from the center of the cam. A vacuum piston is optionally coupled to the actuation means. A variable resonance spring, such as an air spring, is coupled to the actuated head in order to tune the apparatus to operate in resonance at a range of frequencies.

Continuous resonance marine vibrator

Techniques are disclosed relating to control of seismic sources such as marine vibrators. According to some embodiments, iterative learning control (ILC) systems may be used to control such seismic sources. According to some embodiments, local sensor(s) placed in, on, or near a seismic source and/or remote sensors placed in the far-field region may be used to determine a transfer function for the seismic source for such ILC control.

Method for calibrating the far-field acoustic output of a marine vibrator

Techniques are disclosed relating to control of seismic sources such as marine vibrators. According to some embodiments, iterative learning control (ILC) systems may be used to control such seismic sources. According to some embodiments, a control unit provides first input signals to the marine vibrator which include an excitation signal and a high-amplitude, low-frequency signal, the latter is operable to decrease friction effects in the marine vibrator. Furthermore local sensor(s) placed in, on, or near a seismic source and/or remote sensors placed in the far-field region to measure the acoustic output of the marine vibrator. The control unit is further configured to generate initial values for a transfer function of the marine vibrator based on the measured acoustic output.

Control system for marine vibrators to reduce friction effects

Marine vibrators and methods of use are disclosed. A marine vibrator may comprise a containment housing, where the containment housing comprises a marine vibrator internal volume, wherein the marine vibrator internal volume comprises a first gas at a first gas pressure. The marine vibrator may further comprise a sound radiating surface. The marine vibrator may additionally comprise a compliance chamber in contact with the first gas, wherein the compliance chamber comprises a chamber housing and a moveable structure, wherein at least the chamber housing and the moveable structure form a compliance chamber internal volume which holds a second gas at a second gas pressure, wherein the moveable structure is configured to move in response to a change in the first gas pressure, and wherein the compliance chamber is configured to condense the second gas in response to compression of the marine vibrator internal volume by the moveable structure.

A system comprises a plurality of acoustic transmitters, mounted inside the streamers, adapted to transmit broadband signals having low cross-correlation between the signals of different transmitters; a plurality of acoustic receivers, mounted inside the streamers, adapted to receive the signals from the transmitters; at least one processor adapted to cross-correlate the signals received at the receivers with copies of transmitter signals to determine identities of the transmitters of the received signals and to determine travel times of the received signals; and a main processor adapted to convert the travel times to distances between the identified transmitters and the receivers and to determine relative positions of the streamers from the distances.

Growing community of inventors

Bjarred, Sweden

Nils Gunnar Olof Kröling