Abstract: A marine seismic survey comprises towing a first source and a first streamer spread having a length L behind a first vessel. Sensors in the streamer spread record signals from the first source over a range of offset distances X to X+L. A second source is towed behind a second vessel that does not tow a streamer spread. Sensors in the streamer spread record signals from the second source over a range of offset distances A+L to A+2L. Sensors in the streamer spread do not record signals over a range of offset distances X+L to A+L from any active seismic sources used in the marine seismic survey.

Abstract: Processes and systems described herein are directed to performing marine surveys with marine vibrators that emit orthogonal coded pseudo-random sweeps. In one aspect, coded pseudo-random signals are generated based on coded pseudo-random sequences. The coded pseudo-random sequences are used to activate the marine vibrators in a body of water above a subterranean formation. The activated marine vibrators generate orthogonal coded pseudo-random sweeps. A wavefield emitted from the subterranean formation in response to the orthogonal coded pseudo-random sweeps is detected at receivers located in a body of water. Seismic signals generated by the receivers may be cross-correlated with a signature of one of the orthogonal coded pseudo-random sweeps to obtain seismic data with incoherent residual noise.

Abstract: Techniques are disclosed relating to acquisition and imaging for marine surveys. In some embodiments, a transition survey that uses both one or more sources of a first type (e.g., impulsive sources) and one or more sources of a second type (e.g., vibratory sources) may facilitate calibration of prior surveys that use the first type of sources with subsequent surveys that use the second type of source. In some embodiments, the different types of sources may be operated simultaneously at approximately the same location. In some embodiments, signals generated by the sources are separated, e.g., using deconvolution. The signals may then be compared to generate difference information, which in turn may be used to adjust sensor measurements from a previous or subsequent survey. In various embodiments, the disclosed techniques may improve accuracy in images of geological formations and may facilitate transitions to new types of seismic sources while maintaining continuity in 4D surveys.

Abstract: A seismic pressure and acceleration sensor can include a hydrophone having a volume encapsulated by an enclosure. The enclosure can include, a pressure-sensitive surface and a pressure-insensitive support structure. The sensor can also include an accelerometer positioned within the encapsulated volume. The accelerometer is mechanically isolated from the pressure-sensitive surface and mechanically coupled to the pressure-insensitive support structure.

Abstract: Techniques and apparatus are disclosed for performing marine seismic surveys. In some embodiments, one or more vessels are used to tow a set of streamers and two or more sources such that a first set of sources consists of all those that are disposed within a first threshold distance from the streamers, and a second set of sources consists of all those that are disposed beyond a second, greater, threshold distance from the streamers. Sources in the first set are activated more frequently than sources in the second set are activated.

Abstract: A plurality of sensors and a controller are disposed in a marine seismic streamer. Each of the sensors comprises an enclosure having two opposing interior walls, first and second piezoelectric elements disposed on the opposing interior walls, a third piezoelectric element disposed on a flexible substrate within the enclosure between the opposing interior walls, a pressure signal output node and an acceleration signal output node disposed on the exterior surface of the enclosure. A combined pressure signal derived from the pressure signal output nodes of the plural sensors is coupled to a pressure signal input of the controller. A combined acceleration signal derived from the acceleration signal output nodes of the plural sensors is coupled to an acceleration signal input of the controller. The streamer may be towed, and the combined pressure and acceleration signals may be recorded in a computer-readable medium.

Abstract: A marine sensor system includes an enclosure that defines an interior volume. The enclosure is configured to be immersed in water. A sensor having a positive output node and a negative output node is disposed within the interior volume of the enclosure. A first parasitic capacitance between the positive output node and the enclosure is substantially equal to a second parasitic capacitance between the negative output node and the enclosure. A cross feed signal that is propagated through a path in water outside the enclosure is coupled to the output nodes in a balanced manner, which enables a differential amplifier to reject the cross feed noise.

Abstract: Techniques are disclosed relating to marine geophysical surveys. Various output characteristics of a vibratory source may be modified based on whether a source is targeting an identified portion of a survey area. The portion of the survey area may be detected during the survey or may be pre-identified. In some embodiments, a survey system drives a vibratory source using digital codes having different lengths based on whether the source is targeting an identified portion of a survey area. The disclosed techniques may improve imaging of geology under certain types of formations or may reduce environmental impact, in various embodiments.

Abstract: Included are methods and apparatus for marine geophysical surveying. One embodiment of the presently-disclosed solution relates to a method for instantaneous roll compensation of vectorised motion data originating from a fixed-mount geophysical sensor during a marine seismic survey. A streamer is towed behind a survey vessel in a body of water. The streamer includes a plurality of geophysical sensors and a plurality of orientation sensor packages. Vectorised geophysical data is acquired using the plurality of geophysical sensors, while orientation data is acquired by the plurality of orientation sensor packages. The orientation data is used to determine an instantaneous roll angle of the streamer at different positions on the streamer. The vectorised geophysical data is adjusted to compensate for the instantaneous roll angle of the streamer at different positions on the streamer. Other embodiments and features are also disclosed.

Abstract: 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.

Abstract: Methods for performing a marine survey of a subterranean formation using a hybrid combination of ocean bottom seismic (“OBS”) receivers, wide towed sources, and moving streamers are described herein. In one aspect, a sail line separation in a crossline direction is determined based on an average streamer separation and number of streamers. An array of OBS receivers are deposited on a surface of a subterranean formation with an OBS receiver separation that is based on the sail line separation. Wide towed sources and streamers are towed above the array of OBS receivers behind a survey vessel that travels sail lines separated by the sail line separation. The wide towed sources may be activated above the array of OBS receivers. Wavefields reflected from the subterranean formation are recorded at the OBS receivers and receivers located in the streamers as seismic data.

Abstract: Embodiments relate generally to marine geophysical surveying. More particularly, embodiments relate to an underwater application system for application of a streamer coating to a surface of a streamer. An embodiment may comprise a marine geophysical survey system. The marine geophysical survey system may comprise a streamer and an underwater application system operable to apply a streamer coating to the streamer as the underwater application system travels axially along the streamer.

Abstract: Methods and systems described herein are directed to determining properties of a subterranean formation using an acoustic wave-equation with a novel formulation in terms of a velocity model and a reflectivity model of the subterranean formation. The acoustic wave equation may be used with full-waveform inversion to simultaneously build velocity and reflectivity models of a subterranean formation. The velocity and reflectivity models may be employed for quantitative interpretation. The velocity and reflectivity models may be employed to determine impedance and density of the subterranean formation for prospectivity assessment. The acoustic wave equation may be also used with least-squares reverse time migration in the image or data domains, to build a reflectivity model of the subterranean formation with enhanced resolution and amplitude fidelity.

Abstract: A method and apparatus for data acquisition including: acquiring a first set of data for a survey area with streamer receivers on a streamer spread; and simultaneously acquiring a second set of data for the area with ocean bottom receivers, the first and second sets of data together forming a complete dataset for velocity modeling and imaging. A method including: navigating a first propulsion source along a first path in the area, wherein a streamer spread and a first seismic source are coupled to the first propulsion source; navigating a second propulsion source along a second path in the area, wherein a second seismic source is coupled to the second propulsion source; while navigating the first and second propulsion sources, activating at least one of the first and second seismic sources; and acquiring data with receivers on the streamer spread and with ocean bottom receivers distributed throughout the area.

Abstract: Processes and systems described herein are directed to imaging a subterranean formation from seismic data recorded in a marine survey with moving marine vibrators. The marine vibrators generate random sweeps with random sweep signatures. Processes and systems generate an up-going pressure wavefield from measured pressure and vertical velocity wavefield data recorded in the marine survey and obtain a downgoing vertical acceleration wavefield that records source wavefields, directivity, source ghosts, and random signatures of the random sweeps. The downgoing vertical acceleration wavefield data is deconvolved from the up-going pressure wavefield to obtain a subsurface reflectivity wavefield that is used to generate an image of the subterranean formation with reduced contamination from source wavefields, directivity, source ghosts, and random signatures of the random sweeps.

Abstract: Seismic data are obtained by recording simultaneously in seismic streamer, acquired by activating approximately simultaneously two or more seismic sources towed at two positions in the vicinity of seismic streamers. A residual is updated iteratively for an inversion solution for the activations of the two or more seismic sources. The iterative updating of the residuals utilizes a sequence of overlapping temporal windows containing reflection events and utilizes normal moveout corrections based on largest reflection events in each temporal window. A final updated residual is added to a final updated model result.

Abstract: Embodiments relate generally to marine geophysical surveying. More particularly, embodiments relate to a wax application system for application of a wax coating to a surface of a streamer. An embodiment may comprise a marine geophysical survey system. The marine geophysical survey system may comprise a streamer and a wax application system operable to receive the streamer on deployment and apply a wax coating to the streamer as the streamer is being deployed from a survey vessel into a body of water.

Abstract: A marine seismic data acquisition system may include first and second containers deployable in a body of water. The first container includes a first seismic data acquisition channel capable of transducing seismic energy in the body of water having a first maximum amplitude, and the second contain includes a second seismic data acquisition channel capable of transducing seismic energy in the body of water having a second maximum amplitude. The first seismic data acquisition channel is associated with at least a first seismic sensor, and the second seismic data acquisition channel is associated with at least a second seismic sensor. The second sensor corresponds to a same sensor type as the first seismic sensor, and the first maximum amplitude is higher than the second maximum amplitude.

Abstract: Marine survey source route configuration can include towing, via a first marine survey vessel, streamers at a first average speed and at an average velocity along a first survey route. A second marine survey vessel can tow a source at a second average speed that is greater than the first average speed along a second survey route that periodically passes over the first survey route and at the average velocity in a direction of the first survey route.

Abstract: Disclosed are apparatuses, systems, and methods for urging matching rotational orientations of geophysical sensors in a marine geophysical streamer. An embodiment discloses a marine geophysical streamer comprising a jacket; spacers disposed longitudinally within the jacket, the spacers containing geophysical sensors; and an alignment preserver disposed within the jacket, the alignment preserver encompassing at least a portion of each of the spacers and configured to urge matching rotational orientations for the geophysical sensors.