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.

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.

A notional source signature of a bubble may be determined. For example, a method for determining a notional source signature of a bubble can include estimating a position of a bubble created by actuation of an impulsive source. A notional source signature of the bubble can be determined based on the estimate.

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.

Method for acquiring seismic data by generating a first straight line (2) drawn from a starting point (3) to an end point (4), then generating a number of offset straight lines (6), each being placed perpendicular to the first straight line (2) and ending in a second point (7) in a distance X from the first straight line (2). The second points (7) provide an array of cross track offset values providing a survey line (10). A vessel steering module is described adapted to send command information to a vessel steering system. The invention also concerns use of the module for performing the method.

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.

Methods are described for separating the unknown contributions of two or more sources from a commonly acquired set of wavefield signals representing a wavefield where the sources are laterally located relatively close to each other and fire relatively close in time, and where the contributions from different sources are separated using different source encoding techniques in different parts of a frequency band of interest.

The present invention relates to the field of marine towing operations for marine seismic survey systems and seismic data gathering. More specifically, the present invention relates to seismic sources and receiver sensor cables, streamers, floats etc., that have means for adjusting and keeping a desired position in an array during a tow behind a vessel. The apparatus comprises a pulley apparatus, being a kind of miming block (1), connected with and supporting marine equipment (3, 3). The miming block (1) is configured to attach to the deflected lead wire or tow wire (2, 9). It has means for traveling along the wire (2, 9).

A system for constraining a dither time can comprise a source and a controller coupled to the source. The controller can be configured to actuate the source in sequence, while the source is moving through a fluid volume at a bottom speed, with an actuation time interval between each actuation comprising a sum of a nominal time and a dither time for each actuation and constrain the dither time for each actuation such that a reduction of the actuation time interval relative to a directly precedent actuation time interval is at most a threshold dither time difference, wherein the threshold dither time difference corresponds to a maximum bottom speed.

System and method for generating discrete dithering sequences DS.sub.i for marine seismic sources S.sub.i in a marine acquisition system. The method includes determining a number N of the seismic sources S.sub.i to be fired; calculating a dithering sequence DS.sub.i for each source S.sub.i such that when any two consecutive source activation S.sub.k and S.sub.l, where l=k+1, are selected, a combination DS.sub.kl of their dithering sequences DS.sub.k and DS.sub.l is a uniform random low-discrepancy sequence; and driving each source S.sub.i with the corresponding dithering sequence DS.sub.i to generate blended seismic data.