Disclosed are dipole sources and associated methods. An example system may include a dipole source a first marine seismic vibrator and a second marine seismic vibrator. The first marine seismic vibrator may include two or more sound radiating surfaces. The second marine seismic vibrator may also include two or more sound radiating surfaces. A relative position of the second marine seismic vibrator to the first marine seismic vibrator may be fixed. The first marine seismic vibrator may be positioned above the second marine seismic vibrator in a towing configuration. The system may further include a control system operable to control the dipole source such that the first marine seismic vibrator is operating substantially 180 out of phase with the second marine seismic vibrator.

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.

Systems and methods for deployment and retrieval of ocean bottom seismic receivers. In some embodiments, the system includes a carrier containing receivers. The carrier can include a frame having a mounted structure (e.g., a movable carousel, movable conveyor, fixed parallel rails, or a barrel) for seating and releasing the receivers (e.g., axially stacked). The structure can facilitate delivering receivers to a discharge port on the frame. The system can include a discharge mechanism for removing receivers from the carrier. In some embodiments, the method includes loading a carrier with receivers, transporting the carrier from a surface vessel to a position adjacent the seabed, and using an ROV to remove receivers from the carrier and place the receivers on the seabed. In some embodiments, an ROV adjacent the seabed engages a deployment line that guides receivers from the vessel down to the ROV for on-time delivery and placement on the seabed.

Source element of a source subarray can be individually actuated according to an actuation sequence. The actuation sequence can be at least partially based on a relative position of each of the source elements within a particular geometry of the source subarray with respect to a previously actuated source element and a towing velocity of the source subarray.

Disclosed are seismic sources that may utilize an external driver to energize the air in the seismic source for generation of acoustic energy. An apparatus may comprise a seismic source comprising an internal cavity configured to contain a volume of a fluid. The apparatus may further comprise an external driver, wherein the external driver and the seismic source are coupled to permit fluid communication between the external driver and the internal cavity of the seismic source, wherein the external driver is configured to create a pressure wave that drives the seismic source and a gas resonance. The apparatus may further comprise a fluid reservoir, wherein the fluid reservoir and the external driver are coupled to permit fluid communication between the fluid reservoir and the external driver.

A tow body arrangement for a towable device in a sonar system includes a bridle having a front for connecting to a first tow cable and back for connecting to a second tow cable. The tow body arrangement also includes a tow body rotatably connected to the bridle between the front and back of the bridle. The tow body is shaped to generate hydrodynamic forces tending to rotate the tow body perpendicular to a longitudinal axis of the bridle.

An example system includes a first seismic source configured to emit seismic energy by generation of a first air bubble into the seismic medium at a first time, and a second seismic source spaced a predefined distance from the first seismic source. The second seismic source is configured to emit seismic energy by generation of a second air bubble into the seismic medium at a second time after the first time. The seismic energy has a low frequency characteristic.

Systems and methods of near surface imaging and hazard detection with increased receiver spacing are provided. The system includes: a first string of one or more acoustic sources, a second string of one or more acoustic sources opposite the first string, a first one or more hydrophones mounted within a predetermined distance of the first string, and a second one or more hydrophones mounted within the predetermined distance of the second string. The first one or more hydrophones records an acoustic shot generated from the first string. The second one or more hydrophones records the acoustic shot and acoustic reflections corresponding to the acoustic shot. The system generates an image from the recorded acoustic shot and the acoustic reflections.

Disclosed are control systems for marine vibrators. An example method may comprise recording a signal at a seismic sensor; running an iterative learning control characterization for a marine vibrator on the signal from the seismic sensor; measuring movement of an outer shell of the marine vibrator using a motion sensor to obtain a motion sensor signal; and controlling the marine vibrator using the motion sensor signal as a reference signal.

A method for a marine seismic survey can include towing streamers that are spaced apart in a cross-line direction by a streamer separation (L) and towing seismic source elements that are spaced apart in the cross-line direction by a source separation based on an integer (k), an inverse of a quantity of the seismic source elements (1/S), and the streamer separation as represented by (k+1/S)L. The seismic source elements can be actuated and seismic signals can be detected at each of a plurality of receivers on the streamers.