Apparatus and techniques are disclosed relating to sensor housing and spacer carrier assemblies. In various embodiments, a spacer carrier provides a cavity through a body of the spacer carrier and a first alignment element positioned at a first end of the cavity. In some embodiments, a sensor housing is configured to be deployed within the cavity through the body of the spacer carrier. The sensor housing may include a housing body configured to receive a sensor and a second alignment element configured to interface with the first alignment element. In various embodiments, the first and second alignment elements are configured to maintain an orientation of the sensor housing within the cavity when the sensor housing is inserted into the spacer carrier.

Methods are provided to package and deploy a marine vibrator for use in connection with marine seismic surveys. Marine vibrators are provided with a number of buoyancy configurations with corresponding techniques for controlling the submergence depth of the marine vibrators. An exemplary marine vibrator comprises a positively buoyant hydrodynamic tow body, comprising: a low frequency electro-acoustic projector; a power electronics system; a control-monitoring electronics system; and a pressure compensation system, wherein the hydrodynamic tow body comprises one or more active control surfaces to adjust a submergence depth and a roll attitude of the hydrodynamic tow body. Additional embodiments employ a free-flooding, load-bearing frame with positive or negative buoyancy.

The disclosure discloses a trajectory optimization method and device for accurately deploying marine sensors under water. The method includes the following steps. 1. Randomly select N sets of initial control variables within a range. 2. Input all of N sets of x.sub.i to the sensor's underwater glide kinematics and dynamics models, and calculate the smallest distance between N actual deployment positions and target deployment positions. 3. Determine whether the number of iterative operations is less than the preset value, if yes, perform global random walk and local random walk on N sets of x.sub.i, obtain N sets of x.sub.i again, and return to step 2; otherwise, go to step 4. 4. Output the control variable x.sub.i corresponding to Δs(x).sub.nminmin and the corresponding trajectory as the optimal control variable and optimal trajectory. The disclosure can improve the accuracy of prediction on the underwater three-dimensional trajectory of the marine sensor.

Calibration based on twist and orientation for towed object can include determining an amount of twist as a function of length of a portion of a towed object based on output of tilt sensors in the portion of the towed object and a model that describes the twist along the portion of the towed object. An orientation of a seismic sensor can be determined based on the determined amount of twist and a position of the seismic sensor along a length of the portion of the towed object. The seismic sensor can be calibrated based on the orientation.

The present disclosure is directed to systems and methods of facilitating a seismic survey and locating seismic data acquisition units in a marine environment. The system can include a first seismic data acquisition unit. The first seismic data can include a cleat ring to couple the first seismic data acquisition with a second seismic data acquisition unit. The system can include a rope having a first end coupled to a first portion of the first seismic data acquisition unit and a second end coupled to a second portion of the first seismic data acquisition unit. The system can include a cavity formed by the cleat ring. The system can include a telltale component coupled to a portion of the rope. The rope and the telltale component can be stored in the cavity of the first seismic data acquisition unit.

A marine seismic data acquisition system includes a streamer spread including plural streamers; a first set of front sources configured to generate seismic waves; a streamer vessel towing the streamer spread and the first set of the front sources, in front of the streamer spread along an inline direction X; a second set of top sources configured to generate additional seismic waves; and first and second source vessels towing the second set of top sources directly above or below the streamer spread. A number NT of the top sources is larger than a number NF of the front sources.

A sub-bottom geophysical imaging apparatus includes a carriage assembly having at least one acoustic transmitter, and at least one acoustic receiver proximate the transmitter. A position determining transponder is mounted on the carriage. A plurality of position transponders is disposed at spaced apart positions to communicate with the transponder mounted on the carriage. A pair of tracks is provided for moving the carriage to selected positions above the bottom. Electrodes are provided for a resistivity sensor and a shear acoustic transmitter and receiver disposed in at least one of the pair of tracks. A signal processing unit is configured to coherently stack and beam steer signals detected by the line array, the electrodes and the shear transmitter and receiver. The signal processing unit is configured to record signals detected by the line array of acoustic receivers, the electrodes and the shear acoustic transmitter and receiver.

In the field of marine geophysical surveying, systems and methods for controlling the spatial distribution or orientation of a geophysical sensor streamer or an array of geophysical sensor streamers towed behind a survey vessel are provided. Various techniques for changing the spatial distribution or orientation of such geophysical sensor streamers in response to changing conditions are provided. For example, crosscurrent conditions may be determined based on configuration data received from positioning devices along the length of a streamer, and a new desired orientation for the streamer may be determined based on the crosscurrent conditions. The new desired orientation may include a new desired feather angle for the streamer.

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.

A seabed object detection system is provided. The system can include a receiver array. The receiver array can include a plurality of receivers disposed on a plurality of streamers. The plurality of streamers can include a central port side streamer, a central starboard side streamer, an auxiliary port side streamer and an auxiliary starboard side streamer. The system can include a source array. The source array can include a plurality of sources. The plurality of sources can include a central port side source, a central starboard side source, an auxiliary port side source, and an auxiliary port side streamer. The source array towed during a first pass can define a first path. The source array towed during a second pass can define a second path. The first path can be interleaved with the second path such that the first path overlaps the second path.