The present disclosure is directed to delivering nodes to an ocean bottom. A system can include a tether management system (TMS) towed by a vessel that moves on the surface of the ocean in a first direction. An underwater vehicle (UV) can be connected to the TMS and can move in a second direction that is different from the first direction. A thruster can be coupled to the TMS can cause the TMS to move in a third direction that is different from the first direction. A control unit can control the thruster to move the TMS in the third direction based on a cross-line location policy, and cause the UV to deploy nodes to target locations on the ocean bottom.

An autonomous seismic node is configured for free-fall from a water surface to the seabed and is capable of rising from the seabed on its own. The seismic node is positively buoyant in water and is substantially tubular in shape, with a length to a diameter ratio of 4:1 or greater. The node comprises a lower section and an upper section, each of which is inserted into an end of a tubular housing. The lower section has a lower end cap assembly with a release mechanism and the upper section has an upper end cap assembly with a plurality of electronic components and a detachable lifting cage. The seismic node may be coupled to a detachable anchor weight or seabed coupling device to assist in free fall to the seabed, and when detached after seismic recording is performed, allows the seismic node to rise to the water surface.

An acoustic vector sensor has an array of sensors to detect at least the bearing of a target. The acoustic vector sensor or hydrophone with sensor array avoids the need to deploy multiple hydrophones each with a single sensor. The array of sensor signals can be processed using any one of a number of methods.

A horizontal component of marine seismic survey data from an ocean bottom seismic survey can be migrated using a primary wave velocity model. The horizontal component can comprise a shear converted wave. An image of a subsurface location can based on the migration can be produced. Migrating the horizontal component can comprise wave-equation migrating the horizontal component, where the horizontal component is input as both a source wavefield and a receiver wavefield.

A method for processing seismic data may include receiving, via a processor, the seismic data acquired via a seismic survey. The seismic survey may include seismic sources that emit seismic wavefields at different locations. Each of the seismic sources may change a directivity pattern of a respective seismic wavefield based on a respective location of the respective seismic source. The seismic survey may also include seismic receivers that may receive the seismic data. The method may also include generating one or more basis functions that correspond to measurements of the seismic data, modelling a signal component of the seismic data as a sum of the one or more basis functions, and storing the signal component in a storage component. The signal component may be used to acquire an image of a subsurface region of the earth for identifying a feature in the subsurface region of the earth.

A method for seismic surveying comprises deploying a plurality of seismic receivers proximate an area of subsurface to be surveyed. At least one seismic energy source moves in a path that circumscribes a center, wherein positions of the plurality of seismic receivers remain fixed. At least one of a distance between the path and the center changes monotonically as seismic energy source traverses the path, or the center moves in a selected direction as the seismic energy source traverses the path. The source is actuated at selected times as the at least one seismic energy source traverses the path, such that a spacing between positions of the source along the source path and transverse to the source path varies between successive actuations of the source. Seismic energy is detected at the plurality of seismic receivers resulting from actuating the at least one seismic energy source.

A system and method of processing seismic data obtained using a plurality of towed single-component receivers in a marine environment is described, the towed single-component receivers configured to measure compressional P waves. The method comprises retrieving seismic data from a storage device, the seismic data comprising P-P data and shear mode data, wherein the P-P data and shear mode data were both received at the towed single-component receivers configured to measure compressional P waves to generate the seismic data. The method further comprises processing the seismic data to extract SV-P shear mode data and generating shear mode image data based on the extracted shear mode data.

Determination of an impulse response at a subsurface image level can include extrapolation of an up-going pressure wavefield to a subsurface image level, extrapolation of a down-going velocity wavefield to the subsurface image level, and determination of the impulse response at the subsurface image level from a hypothetical seismic source by spectral division of the extrapolated up-going pressure wavefield by the extrapolated down-going velocity wavefield.

It is proposed a seismic data acquisition device (400) intended to be placed on an ocean bottom floor, comprising a polymeric casing (412) defining a chamber that houses at least art of a data acquisition system (440, 444, 445); and a metallic device (414) in which the polymeric casing (412) is trapped, the metallic device (414) comprising two metallic beams (4141, 4142) that extend on opposite sides of the polymeric casing (412).

It is also proposed a method for assembling such a device and a corresponding method for seabed seismic data acquisition.

Estimating an earth response can include deconvolving a multi-dimensional source wavefield from near-continuously recorded seismic data recorded at a receiver position. The deconvolving can include spreading the near-continuously recorded seismic data across a plurality of possible source emission angles. The result of the deconvolution can be the earth response estimate.