An underwater detection apparatus, which includes a transmission transducer, a reception transducer, and a motor, is provided. The transmission transducer is configured to transmit a transmission wave within a given transmission fan-shaped space, the transmission fan-shaped space having a first transmission width in a given first plane and a second transmission width in a second plane perpendicular to the first plane. The reception transducer is configured to receive a reflection wave of the transmission wave within a given reception fan-shaped space, the reception fan-shaped space having a first reception width in the first plane and a second reception width in the second plane, the second reception width being narrower than the second transmission width, and in the second plane, one of a pair of edges of the transmission fan-shaped space being within the reception fan-shaped space. The motor is configured to rotate the transmission and the reception fan-shaped spaces.

Techniques are disclosed relating to geophysical surveying. In some embodiments, a marine survey vessel tows multiple sensor streamers in addition to vibratory sources deployed relative to the sensor streamers. In some embodiments, the vessel tows vibratory sources emitting energy within different frequency bands in different deployment zones. In some embodiments, one or more sources are driven with different sweep functions, different activation patterns, and/or different sweep lengths. Various disclosed techniques for manufacturing a geophysical data product may potentially simplify equipment used for towing sources, reduce survey complexity without reducing resolution, increase resolution without increasing survey complexity, improve energy content recovered from deep reflections, and/or reduce the environmental impact of emitting seismic energy.

A method and apparatus for marine surveying. A system includes: a standard-volume source element; a large-volume source element comprising an airgun having a volume greater than 1200 cubic inches; and a long-offset survey streamer. A method includes: towing a standard-volume source element; and towing a large-volume source element; activating the large-volume source element at large shotpoint intervals; and activating the standard-volume source element at standard shotpoint intervals, wherein the large shotpoint intervals are at least twice as long as the standard shotpoint intervals. A method includes: obtaining geophysical data for a subterranean formation; and processing the geophysical data to produce an image of the subterranean formation. A method includes: obtaining a firing plan for a plurality of seismic sources, wherein: a first seismic source of the plurality comprises a large-volume source element, and a second seismic source of the plurality consists of standard-volume source elements.

The disclosure provides systems and methods to enhance pre-stack data for seismic data analysis by: sorting the reflection seismic data acquired from cross-spread gathers into sets of data sections; performing data enhancement on the sets of data sections to generate enhanced traces by: (i) applying forward normal-moveout (NMO) corrections such that arrival times of primary reflection events become more flat, (ii) estimating beamforming parameters including a nonlinear traveltime surface and a summation aperture, (iii) generating enhanced traces that combine contributions from original traces in the sets of data sections, and (iv) applying inverse NMO corrections to the enhanced traces such that temporal rearrangements due to the forward NMO corrections are undone.

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.

The present disclosure discloses a seismic vibrator, a vibration device and a driving apparatus for the same. The seismic vibrator comprises: a base; a mounting plate; a first spring configured to connect the base and the mounting plate, so that the mounting plate reciprocates relative to the base; a coil fixed with the base; a magnet having one end fixed with the mounting plate, and the other end stretched into the coil; a magnetic steel fixed with the magnet, wherein a gap for accommodating the coil is provided between the magnetic steel and the magnet; and a counterweight fixed with the mounting plate. The vibration device comprises the above seismic vibrator and an adjustable base. Compared with the traditional electromagnetic controllable seismic vibrator, the structure of the seismic vibrator provided by the present disclosure is simpler.

Processes and systems described herein are directed to performing marine surveys with a moving vibrational source that emits a continuous source wavefield into a body of water above a subterranean formation. The continuous source wavefield is formed from multiple sweeps in which each sweep is emitted from the moving vibrational source into the body of water with a randomized phase and/or with a randomized sweep duration. Reflections from the subterranean formation are continuously recorded in seismic data as the moving vibrational source travels above the subterranean formation. Processes and systems include iteratively deconvolving the source wavefield from the continuously recorded seismic data to obtain an earth response in the common receiver domain with little to no harmful effects from spatial aliasing and residual crosstalk noise. The earth response may be processed to generate an image of the subterranean formation.

An inline source can be used for a marine survey. For example, a marine survey vessel can tow source units in line. The source units can be actuated near-continuously to cause a respective signal emitted by each of the source units to be uncorrelated with signals emitted by other of the source units.

Downhole tools and method for a well. At least some of the example embodiments are methods of imaging a formation around a first borehole, including: focusing first outbound acoustic energy, launched from a tool with the first borehole, on a volume within the formation spaced away from the first borehole, the focusing creates a first virtual point source (VPS) that creates a first return acoustic energy; receiving the first return acoustic energy from the first VPS at a plurality of seismic sensors; and determining a parameter of the formation between the first VPS and a location of the seismic sensors using the first return acoustic energy.

A method for configuring a multi-source and a hexa-source for acquiring first and second seismic datasets of a subsurface. The method includes selecting a number n of source arrays to create the multi-source; selecting a number m of sub-arrays for each source array, each sub-array having a plurality of source elements; imposing a distance D between any two adjacent source arrays of the multi-source; calculating a distance d between any two adjacent sub-arrays of a same source array so that bins associated with the first and second seismic datasets are interleaved; selecting source elements from at least six different sub-arrays of the n source arrays to create the hexa-source; and firing the multi-source to acquire the first dataset, and firing the hexa-source to acquire the second dataset.