Abstract: A method and apparatus are provided for estimating an inter-node distance between a sender node and a receiver node belonging to a network comprising a plurality of nodes arranged along towed acoustic linear antennas. An acoustic signal is transmitted from the sender node to the receiver node through an underwater acoustic channel. The method includes estimating the inter-node distance as a function of an estimate of a sound speed profile of the underwater acoustic channel, the sound speed profile depending on depth.

Abstract: A method for assistance in the localization of streamers towed by a vessel including at least one onboard acoustic controller, each streamer having: geophysical data sensors; acoustic means for measuring distance from at least one adjacent linear antenna; and means for the absolute localization of said antennas. The method includes at least one phase for the generating an acoustic cycle determining sequences and at least one phase for defining at least two distinct acoustic cycles representing a theoretical geometry capable of representing the shape of said streamers; at least one step for determining the real geometry of said streamers; at least one step for detecting a change in real geometry followed by a step for generating a new acoustic cycle, selected from among those defined during said phase for defining and adapted to said change in real geometry.

Abstract: Method and land-based system for generating seismic signals. The system includes a vehicle configured to move to a desired location above ground, the vehicle having a first end and a second end, opposite to the first end; a vibratory source configured to generate seismic waves into the ground; a lifting system connecting the first end of the vehicle to the vibratory source and configured to lift or lower the vibratory source relative to the ground; and a balancing device connected to the second end of the vehicle and configured to lift the second end of the vehicle from the ground.

Abstract: The present invention relates to an underwater floating device (1) characterized in that it comprises: an insert (4) comprising a thermoplastic material and a hollow tube (7), a foam (5) of a thermoplastic material, at least partly covering the insert (4), an outer skin (6) comprising a thermoplastic material formed by injection molding over the foam and configured for being in contact with water during use.

Abstract: A seismic streamer includes a sensor comprises an axially oriented body including a plurality of axially oriented channels arranged in opposing pairs; a plurality of hydrophones arranged in opposing pairs in the channels; a pair of orthogonally oriented acoustic particle motion sensors; and a tilt sensor adjacent or associated with the particle motion sensors. The streamer has a plurality of hydrophones, as previously described, aligned with a plurality of accelerometers which detect movement of the streamer in the horizontal and vertical directions, all coupled with a tilt sensor, so that the marine seismic system can detect whether a detected seismic signal is a reflection from a geologic structure beneath the streamer or a downward traveling reflection from the air/seawater interface.

Abstract: A seismic survey is conducted by positioning an array of remote acquisition units (RAUs). Each of the RAUs records seismic data derived from one or more geophones in digital form in local memory. The data is collected by a harvester unit traversed across the survey territory as by an aircraft using point-multipoint communications, and subsequently transferred from the harvester unit to a central control unit.

Abstract: A method for obtaining a node-to-surface distance between a reference surface and a first node belonging to a network of a plurality of nodes arranged along towed acoustic linear antennas. A plurality of acoustic sequences are sent between the nodes. Each sequence is used to estimate an inter-node distance as a function of a propagation duration of the sequence between nodes. After emission by the first node of a given signal: the first node measures a first propagation duration of a first reflection by the reference surface of the given signal, and a first value of the node-to-surface distance is obtained as a function of that first propagation duration; and/or a second node measures a second propagation duration of a second reflection by the reference surface of the given signal, and a second value of the node-to-surface distance is obtained as a function of that second propagation duration.

Abstract: A method for estimating an underwater acoustic sound velocity in a network of acoustic nodes arranged along towed acoustic linear antennas and in which a plurality of acoustic signals are transmitted between the nodes. The method includes: obtaining two predetermined distances each separating a couple of nodes placed along a same first acoustic linear antenna (31); for each couple of first and second nodes, obtaining a first propagation duration of an acoustic signal transmitted between said first node and a third node placed along a second acoustic linear antenna and a second propagation duration of an acoustic signal transmitted between said second node and said third node; and estimating said underwater acoustic sound velocity, as a function of said two predetermined distances and said first and second propagation durations obtained for each couple of nodes.

Abstract: Described herein is a land seismic data acquisition system comprising a central processing unit; a cabled network connected to the central processing unit comprising a plurality of acquisition lines each comprising: electronic units assembled in series along a telemetry cable and each associated with at least one seismic sensor, the units processing signals transmitted by the sensor(s); intermediate modules assembled in series along the telemetry cable and each associated with at least one of the electronic units, each intermediate module providing power supply and synchronization of the electronic unit(s) wherewith it is associated; wherein each electronic unit is associated with at least two intermediate modules including at least one upstream and at least one downstream from the electronic unit along the telemetry cable, and comprises synchronization means independent from the cabled network, bidirectional and autonomous power supply means, bidirectional storage means of the signals processed by the electr

Abstract: A seismic streamer includes a sensor comprises an axially oriented body including a plurality of axially oriented channels arranged in opposing pairs; a plurality of hydrophones arranged in opposing pairs in the channels; a pair of orthogonally oriented acoustic particle motion sensors; and a tilt sensor adjacent or associated with the particle motion sensors. The streamer has a plurality of hydrophones, as previously described, aligned with a plurality of accelerometers which detect movement of the streamer in the horizontal and vertical directions, all coupled with a tilt sensor, so that the marine seismic system can detect whether a detected seismic signal is a reflection from a geologic structure beneath the streamer or a downward traveling reflection from the air/seawater interface.

Abstract: System and method for providing an anti-fouling function to a streamer to be towed under water for seismic survey data collection. The method includes mixing a thermoplastic material with a biocide material to form an external sheath material; and forming an external sheath over a main sheath of the streamer to provide the anti-fouling function. The external sheath is formed from the external sheath material such that the biocide material is distributed throughout the external sheath.

Abstract: Systems and methods for laser scribing provide extended depth affectation into a substrate or workpiece by focusing a laser beam such that the beam passes into the workpiece using a waveguide, self-focusing effect to cause internal crystal damage along a channel extending into the workpiece. Different optical effects may be used to facilitate the waveguide, self-focusing effect, such as multi-photon absorption in the material of the workpiece, transparency of the material of the workpiece, and aberrations of the focused laser. The laser beam may have a wavelength, pulse duration, and pulse energy, for example, to provide transmission through the material and multi-photon absorption in the material. An aberrated, focused laser beam may also be used to provide a longitudinal spherical aberration range sufficient to extend the effective depth of field (DOF) into the workpiece.

Abstract: The disclosure concerns a data acquisition apparatus and method. According to the disclosure, a first means providing a series of first digital sampled data (X) at an imperfect sampling frequency (FE) provided by a local clock (2) comprises sigma-delta modulation means (3) arranged to produce said series of first digital sigma-delta modulated data (X), a second gauging means (50) for measuring the frequency error of the local clock (2) in view of a reference clock (6), a third means for correcting the first data based at least on the measured frequency error, which comprises at least an interpolation means (4) to produce second digital data (Y) based on at least an interpolation of said first series (X) and compensating the measured frequency error (FD), and at least a decimation filter (7) for producing third digital data (A) based on said second digital data (Y), are provided.

Abstract: A marine device has a floating buoy containing electronics, a submerged payload containing electrical devices and electronics, a power source and a mooring line. At least a part of the power source is submerged and electrically connected to at least one of the submerged payload and the floating buoy, and the mooring line extends between the buoy and at least one of the power source submerged part, the submerged payload and a submerged anchor having a mass allowing it to stay under the water surface.

Abstract: An apparatus and a method for multiplexing and demultiplexing Fiber Optic Interferometric Sensors (FOISs), including means for forming an optical source, at least one sensing cable, at least one wavelength demultiplexing system, and a calibration system.

Abstract: A module for operation in a seismic data acquisition system is described. The seismic data acquisition system includes a cabled network with a plurality of acquisition lines having electronic units assembled in series along a telemetry cable. Each electronic unit is associated with at least one seismic sensor and processes signals transmitted by the sensor(s). The module is designed to be associated with at least one of the electronic units to provide power supply and synchronization to the electronic unit(s). The module includes: autonomous synchronization means; bidirectional and autonomous power supply means to power at least one electronic unit upstream and/or downstream from the module; and means for storing and processing the signals processed by the electronic units, the storage means being bidirectional to store the signals from at least one electronic unit upstream and/or downstream from the module.

Abstract: A system mechanically alters the geometry of the surface of the water by breaking the water surface with a mechanical device. The mechanical device may comprise a plurality of propellers, a plurality of aquafoils in the shape of plows, a wire whip, or other mechanical device to reduce the coefficient of reflectivity of the air-water interface.

Abstract: The invention proposes a data transmission process, from a first unit (1) situated at a predetermined depth of an oil well to a second unit (2) situated at the surface of this well, the process comprising a digital-analog conversion stage (8) of the data to obtain an analog signal forming support of the data, and an amplification stage (9) of this signal prior to its emission in a cable (11) connecting the two units, characterized in that at least two distinct scramblings (20, 21) of the data are completed, such that there is a first and a second set of scrambled data. After passage in a single complex inverse Fourier transform, that intended for emission is selected (26), whereof the dynamic in amplitude is the lowest. If the probability of saturating with a single set is 10?q, then due to this process the probability will be 10?2q.

Abstract: A device for selectively opening and closing a fuselage coupled to a towed submarine object. The device comprises first and second shells articulatable with respect each other by a hinge assembly. A releasable locking system locks the shells on each other. Hinge members of the hinge assembly are slidable with respect to each other along the articulation axis of the shells in order to actuate the locking or unlocking of these shells.

Abstract: A system mechanically alters the geometry of the surface of the water by breaking the water surface with a mechanical device. The mechanical device may comprise a plurality of propellers, a plurality of aquafoils in the shape of plows, a wire whip, or other mechanical device to reduce the coefficient of reflectivity of the air-water interface.