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.

Techniques are described for utilizing far offset impulsive source activations in various contexts, including when performing marine seismic surveys, when manufacturing a geophysical data product in conjunction with such surveys, or when generating an image of geological features of a subsurface. According to some embodiments, near offset impulsive source activations are caused in a body of water at each of a plurality of near offset shot points, and composite far offset impulsive source activations are caused in the body of water at each of a plurality of far offset shot points. Each of the composite far offset impulsive source activations comprises a succession of component impulsive source activations occurring over a far offset shot length. The far offset shot length is short enough to satisfy a stationary source assumption for frequencies at or below a maximum frequency of interest for the far offset shot points.

Computational systems and methods for randomizing the order in which multiple sources are fired in simultaneous source acquisition are described. In one aspect, pseudo-randomly shifted time delays are generated for each shot interval of a marine-survey-time line. Each shifted time delay is assigned to one or the sources. The sources within each shot interval are fired based on the shifted time delays.

A method for estimating a far field seismic energy source signature includes using detected near field seismic signals corresponding to actuation of each one of a plurality of seismic energy sources in an array of seismic energy sources. The near field seismic signals are detected at two spaced apart locations in the near field of each seismic energy source, the at least two spaced apart locations being arranged such that a direction of propagation of the detected near field seismic signals is determinable from the detected near field signals. A notional source signature for each seismic energy source and a notional ghost for each seismic energy source using the detected near field seismic signals. A far field signature is determined for the plurality of seismic energy sources using the determined notional source signature and notional ghost signature from each seismic energy source.

A seabed object detection system is provided. The system can include a source array. The source array can include a first source and a second source. The system can include a data processing system including one or more processors. The data processing system can determine a position of the first source and can identify a first firing time of the second source. The data processing system can initiate a first source shot of the first source at a known position and the second source at a known time. The data processing system can determine a target position and estimated position for the first source. The data processing system can determine a second position of the first source based on a difference between the target position and the estimated position. The data processing system can initiate a second source shot of the first source at a known position.

Techniques are disclosed relating to geophysical surveying. In various embodiments, a computer system may access seismic data for a geological formation, where the seismic data is recorded, using one or more sensors, during a seismic survey in which a first vibratory source was driven using a first digital code for at least a first time interval. The first digital code, in some embodiments, may include a first plurality of subsections corresponding to portions of the first time interval. In some embodiments, the computer system may image a first location of the geological formation using a correlation of only a first sub-section of the first plurality of sub-sections with the seismic data. Further, in some embodiments, the computer system may image a second location of the geological formation using a correlation of two or more of the first plurality of sub-sections with the seismic data.

A method for reducing inline directivity of an air-gun source signature by optimizing spatial distribution of air-guns is provided according to the present application, which relates to a field of design and optimization of an air-gun source. An evaluation standard in the air-gun distribution in an air-gun array direction is proposed. By a combination optimization along both the inline and depth directions, a design scheme having evidently broader effective bandwidth and effective take-off angle width than a design scheme of a conventional source is obtained, with which the directivity of the air-gun source signature can be reduced.

A method for conducting a seismic survey for collecting seismic data off shore. It comprises a first seismic survey providing a first set of data for an area using individual seismic sub-source arrays (2). It further comprises a second seismic survey of the same area for providing a second set of data. The individual seismic sub-source arrays (2) are similar to the sub-source arrays used during the former survey and are arranged in more than two shot-unit sources (3). Each shot-unit source (3) comprises a pair of neighboring individual seismic sub-source arrays (2) arranged to be fired substantially at the same time.

Systems and methods for deployment of ocean bottom seismic receivers into a body of water having a surface and a seabed. The system can include a remote operated vehicle (ROV) comprising a first wireless communication device. The system can include a seismic data receiver deployed on the seabed comprising a second wireless communication device. The first wireless communication device can be configured to communicate with the second wireless communication device. The ROV can move to a position adjacent to the seismic data receiver. The ROV can establish a wireless link with the seismic data receiver via the first communication device and second wireless communication device.

A proposed geometrical distribution for a first non-impulsive source and a second non-impulsive source of a source array can be received. A near-field-to-notional computation can be performed for the proposed geometrical distribution to yield a respective computed notional output of the first and second non-impulsive sources. Whether the computed notional output of the first non-impulsive source has a first amount of residue greater than a threshold amount of residue can be determined. Whether the computed notional output of the second non-impulsive source has a second amount of residue greater than the threshold amount of residue can be determined. An indication whether either of the first or second amounts of residue is less than or equal to the threshold amount of residue can be provided.