Westerngeco L.l.p.

Reflection Marine Norge As

Schlumberger Technology Corporation

Other

W'etsern Geco L.i.

Geco Technology B.v.

Robert Montgomery Laws

Jon-Fredrik Hopperstad

David Fraser Halliday

Dirk-Jan Van Manen

Johan O A Robertsson

Julian Edward Kragh

Emmanuel Coste

Kambiz Iranpour

Everhard Johan Muyzert

James Edward Martin

Claudio Bagaini

Philip Andrew Felton Christie

Nicolas Goujon

Ralf Ferber

Ali Ozbek

Massimiliano Vassallo

John Richard Tulett

Thomas Elboth

Julian Edward (Ed) Kragh

Aslaug Stroemmen Melboe

Aslaug Strømmen Melbø

Aslaug Strømmen Melboe

Stephen Patrick Morice

Håkon Aune

Arash Jafargandomi

Tore Andre Nilsen

David Halliday

Johan OA Robertsson

Jon-Fedrik Hopperstad

Johan Olof Anders Robertsson

Described herein is a method for acquiring data using a marine vibrator towed by a vessel, the method comprising: obtaining data comprising at least one nominal pre-plot position in a horizontal plane; monitoring a position of the marine vibrator in the and a speed of the vessel; determining an offset between the position of the marine vibrator and the nominal pre-plot position in the towing direction; based on the offset and the vessel speed, adjusting one or more survey parameters and driving the vibrator with a series of one or more sweeps so that a predetermined frequency in the sweep or a subsequent sweep is emitted when the position of the vibrator is within a maximum distance of the nominal pre-plot position.

System and method for acquiring marine seismic data using a vibrator

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.

System and method for characterizing a seismic acoustic signal

Marine seismic surveys, including ocean bottom surveys, utilizing marine vibrator arrays that are capable of being driven in anti-phase to produce a directional source gradient. Marine seismic surveys may include activating the vibrator array to emit a plurality of radiation patterns with at least a first radiation pattern that has a first notch at a take-off angle that is not dose to vertical. Some marine seismic surveys included emitting directive wavefields from two or more simultaneous seismic source arrays, where the two or more seismic source arrays have a phase that changes from shot-to-shot to allow simultaneous source separation of the directive wavefields.

Marine vibrator directive source survey

Marine seismic surveys, including ocean bottom surveys, utilizing marine vibrator arrays that are capable of being driven in anti-phase to produce a directional source gradient. Marine seismic surveys may include activating the vibrator array to emit a plurality of radiation patterns with at least a first radiation pattern that has a first notch at a take-off angle that is not close to vertical. Some marine seismic surveys includes emitting directive wavefields from two or more simultaneous seismic source arrays, where the two or more seismic source arrays have a phase that changes from shot-to-shot to allow simultaneous source separation of the directive wavefields.

A shot interval between activations of at least one frequency-controllable survey source is determined, where the shot interval is determined based on an expected frequency of an output of the at least one frequency-controllable survey source. The at least one frequency-controllable survey source is activated using the determined first shot interval.

Determining an interval between activations of at least one survey source

A technique for reconstructing a seismic wavefield includes receiving data over one or more channels of a plurality of channels from a plurality of stations. The data is recorded by a plurality of seismic receivers and represent measurements of properties of the seismic wavefield. Each station includes a region in space including one or more seismic receivers. Each channel either measures a property of the seismic wavefield or a property of the seismic wavefield after the seismic wavefield has undergone a known transformation. At least one channel is derived as a function of one or more other channels. The technique includes using a processor based machine to process the data to model the seismic wavefield as a sum of basis functions; apply to the basis functions at least one forward transformation that describes the measurements received over the channel(s); and determine optimum basis functions based at least in part on the measurements.

Wavefield reconstruction

A technique includes towing at least one seismic source in connection with a survey of a structure; and operating the seismic source(s) to fire shots, where each shot is associated with a frequency sweep. The technique includes varying phases of the frequency sweeps from shot to shot according to a predetermined phase sequence to allow noise in an energy sensed by seismic sensors to be attenuated.

Seismic data apparition from phase shifted sources

Marine seismic vibrators in a marine seismic vibrator array for use in a seismic survey are activated to produce a source gradient wavefield to survey a target structure. The seismic survey may comprise a marine seismic survey conducted in a body of water.

Wavefield generation using a seismic vibrator array

A marine survey acquisition system. The system may include a vessel for towing a marine survey spread. The marine survey spread may include streamers, marine vibrators and a cable. The cable may be coupled to a respective streamer from among the streamers and one of the marine vibrators. The cable may power the respective streamer and the one of the marine vibrators. The one of the marine vibrators may emit energy at a high frequency range.

Methods and systems for marine survey acquisition

Methods and apparatuses for acquiring marine seismic data to generate images or determine properties of an interior section of the Earth using simultaneous marine vibrator sweeps and methods for processing the acquired seismic data. Phase of sweeps produced by the marine vibrator(s) are controlled to provide for removal of crosstalk. The phases between marine vibrator sweeps may be random or controlled to have a predetermined/desired phase difference. The predetermined phases may be determined to minimize the crosstalk between sweeps based on known seismic velocity of the survey area.

Simultaneous marine vibrators

A method for selecting parameters of a seismic source array comprising a plurality of source elements each having a notional source spectrum is described, the method comprising calculating a ghost response function of the array; calculating directivity effects of the array; and adjusting the parameters of the array such that the directivity effects of the array are compensated by the ghost response to minimize angular variation of a far field response in a predetermined frequency range. A method for determining a phase center of a seismic source array is also related, the method comprising calculating a far field spectrum of the array at predetermined spherical angles, and minimizing the phase difference between the farfield spectra within a predetermined frequency range by adjusting a vertical reference position from which the spherical angles are defined.

Method and system for selecting parameters of a seismic source array

Seismic acquisition using phase-shifted sweeps

The technologies described herein include systems and methods for performing a first seismic survey and performing a second seismic survey after a predetermined amount of time has lapsed between the first seismic survey and the second seismic survey. The shot times and the shot positions of the second seismic survey may be substantially the same as the shot times and the shot positions of the first seismic survey. After performing the seismic surveys, seismic data generated by the first seismic survey may be processed to generate a first image, and seismic data generated by the second seismic survey may be processed to generate a second image. After generating the first and second images, a difference between the first image and the second image may be computed to generate a time lapse difference image.

Seismic data acquisition and source-side derivatives generation and application

Marine seismic survey using one or more marine seismic vibrators, where the vibrator sweep function is based on a quality requirement, which may be a final image quality requirement or an environmental requirement. The sweep function may be nonlinear and the energy spectrum may not match the energy spectrum of an airgun.

Marine vibrator sweeps

A technique facilitates obtaining seismic data in a marine environment. An array of acoustic sources is deployed in a marine environment. The array can be utilized for creating acoustic pulses that facilitate the collection of data on subsea structures. The methodology enables optimization of acoustic source array performance to improve the collection of useful data during a seismic survey.

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Cambridge, United Kingdom

Robert Montgomery Laws