Abstract: A method and apparatus are provided for managing the acoustic performances of a network of acoustic nodes arranged along towed acoustic linear antennas. The network of acoustic nodes is adapted to determine inter-node distances allowing to locate the acoustic linear antennas. The method includes: obtaining a determined layout of the network of acoustic nodes; obtaining at least one marine environment property relating to an area of performance of a survey with the network of acoustic nodes; and quantifying the acoustic performances of the network of acoustic nodes, using a sound propagation model, the at least one marine environment property and the determined layout.

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 sensor detects a characteristic of a medium during a seismic survey. The seismic sensor includes a casing; a magnet located inside the casing; a coil assembly located inside the casing, wherein the coil assembly moves relative to the magnet; and a temperature-sensitive device connected to terminals of the coil assembly and configured to improve the damping. The magnet and the coil assembly produce some intrinsic damping and the additional damping introduced by the temperature-sensitive device is selected to counterbalance the temperature-dependent intrinsic damping so that a phase of a recorded seismic signal is compensated for temperature induced magnetic field changes.

Abstract: A seismic cable including sensors, data transmission lines extending the length of the seismic cable for conveying data signals issued from the sensors. Controllers distributed along the seismic cable operate as an interface between the sensors and the data transmission lines. Power supplying lines supply power to the controllers and the sensors. X power supplying lines are alternately connected to one out of X successive controllers. Each controller is adapted for applying on a power supplying line detected as defective the electrical tension provided by another power supplying line. Y data transmission lines are alternately connected to one out of Y successive controllers. Each controller is adapted to redirect towards at least one adjacent controller the data associated with a data transmission line which is determined to be defective.

Abstract: A streamer for seismic prospection comprising directional sensors (20), such as geophones or accelerometers, distributed along the streamer, characterized in that said streamer comprises at least two tilt sensors (30, 40) located in remote positions and in locations distant from the directional sensors (20) and means which determined the effective orientation of each directional sensor (20) by interpolating along the streamer the tilt detected by the two tilt sensors (30, 40).

Abstract: A method and apparatus are provided for steering a first acoustic linear antenna belonging to a plurality of acoustic linear antennas towed by a vessel. A plurality of navigation control devices are arranged along the plurality of linear antennas in order to act at least laterally on the position of the linear antennas. At least one of the navigation control devices arranged along the first acoustic linear antenna performs steps of: obtaining a local measurement of a feather angle or of a parameter linked to the feather angle, the local measurement being associated with the at least one of the navigation control devices arranged along the first acoustic linear antenna; computing a lateral force, as a function of the obtained local measurement; and applying the computed lateral force.

Abstract: An underwater cable deployment system for deploying an ocean bottom cable on the seabed including a cage having a lower frame and an upper frame, which lower frame is adapted to receive the ocean bottom cable and the upper frame is connected to an umbilical cable mounted on a vessel, the upper frame being removably attached to the lower frame, guiding and tensioning means for deploying the ocean bottom cable on the seabed, the lower frame further including a recording unit which is connected to the ocean bottom cable and is adapted to record data detected by at least one sensor unit of the ocean bottom cable and an electrical power unit adapted to provide power to the recording unit and to the ocean bottom cable.

Abstract: Device, system and method for protecting towed marine survey equipment from line entanglement are provided. A cutter device has a mounting mechanism configured to fixedly attach at a predetermined position along a cable used for towing, and one or more cutting structures. The cutting structures are attached to and extend away from the mounting mechanism, being configured to cut lines that get caught by the cutting structures or slide along the cable to the predetermined position.

Abstract: A digital seismic sensor adapted to be connected, via a two-conductor line, to an acquisition device. The digital seismic sensor includes: a digital sensor; a local sampling clock providing a sampling frequency; a receiver for receiving command data coming from the acquisition device and synchronization information providing accurate timing information to enable seismic sensor synchronization; a compensator for compensating, as a function of the synchronization information, a drift of the local sampling clock; a transmitter for transmitting seismic data towards the acquisition device; a driver for driving the receiver and the transmitter, according to a half-duplex transmission protocol over the two-conductor line and using a transmission clock extracted from the received command data; a power receiver for receiving electrical power; and a coupler for coupling the command and synchronization information receiver, the transmitter and the power receiver to the two-conductor line.

Abstract: An acquisition device includes a pair of input terminals for connection to an analog seismic sensor generating a seismic signal. The device includes a detector for detecting a disconnection of the sensor, which includes a current source for injecting a low current in the sensor to generate an offset signal which depends on electrical resistance of the sensor and is added to the seismic signal. The offset signal encroaches on only a part of an operating range of the acquisition device. The voltage measured at the input terminals is applied to an analog-digital converter and a filter to obtain a measured value of the offset signal. A processing unit either analyzes a temporal variation of the measured value and triggers an alarm if a determined condition is satisfied, or transmits the measured value to a remote device adapted to analyze the temporal variation.

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 module is provided for processing geophysical data coming from at least one geophysical sensor. The module includes: an electronic board configured to enable the processing of geophysical data captured by the at least one geophysical sensor; and two cable sections each including, at one extremity, a connector designed to be connected to said electronic board. Each connector forms one half-shell and is arranged so as to cooperate with one other half-shell in such a way as to form a shell in which the electronic board is placed.

Abstract: A stress-relief device is provided, which is configured for being mounted on a geophysical equipment or node connected to at least two cables. The device includes a case configured for surrounding the geophysical equipment or node and for making at least an opening for enabling a connection between each of the at least two cables and the geophysical equipment or node. The device also includes a housing for housing a portion of each of the two cables, the housing being configured for substantially preventing any movement of said portions of the two cables.

Abstract: Method for managing shots in a multi-vessel seismic system, including for each slave shooter vessel: a) computing first theoretical shot times, based on a speed a scheduler shooter vessel and shot points associated to the scheduler shooter vessel, associated next shots of the scheduler shooter vessel; b) computing, based on a speed of the slave shooter vessel and the shot points, second theoretical shot times associated to the next shots; c) computing, based on the first theoretical shot times, interpolated virtual shot times; d) computing, based on the first theoretical shot times, the interpolated virtual shot times and a minimum shot time interval, shooting time windows; e) for each next shot: if the second theoretical shot time is in the shooting time window, selecting as a predicted shot time the second theoretical shot time; otherwise, selecting a border of the shooting time window closest to the second theoretical shot time.

Abstract: It is proposed a method for steering a seismic vessel associated with a sail line and a current preplot line. The seismic vessel tows at least one acoustic linear antenna including receivers, the receivers receiving signals generated by at least one source and reflected by subsurface's layers at a plurality of reflexion points. The method includes: a) computing distances di, i?{1 . . . n}, from n reflexion points, included in the plurality of reflexion points, to a boundary of an already obtained binning coverage zone associated with an already used previous preplot line; b) computing a distance D, from the n reflexion points to n target reflexion points, as a function of the distances di; and c) providing steering information comprising or based on the distance D to a navigation system or to an operator of a navigation system, to alter the course of the seismic vessel.

Abstract: An anti-stiction method is proposed in an inertial micro-electro-mechanical device. The device includes: a mobile mass, suspended to an armature via a spring, and having at least one mobile electrode; and at least one fixed electrode rigidly attached to the armature, each fixed electrode cooperating with one of the at least one mobile electrode to form a pair of electrodes. The anti-stiction method carries out a step of detecting, for at least one stuck pair of electrodes, a stiction associated to a stiction force and a step of applying, during a predetermined time period, a predetermined voltage between the electrodes of at least one of the pair or pairs of electrodes, so as to create an electrostatic force which generates a displacement of the mobile mass according to the direction of the stiction force.

Abstract: Described herein is a seismic streamer formed of sections including a main sheath covered with an external sheath, wherein said external sheath is formed using a thermoplastic material loaded with a biocide material.

Abstract: A switch for a marine seismic sensor. The switch includes a bellows having a closed end, a side portion and an open end, wherein the side portion connects the closed end to the open end, the closed end includes a conductive surface, and the side portion acts as a spring; a base plug that includes first input and first output contacts on a first side and second input and second output contacts on an opposite side; and a plug located in the open end of the bellows and configured to form a chamber, inside which the second input contact and the second output contact are provided. The conductive surface short-circuits the second input contact and the second output contact when a pressure larger than a predetermined pressure (P) acts on the conductive surface.

Abstract: An apparatus for indicating overstress in an electro-mechanical cable. The apparatus includes an overstress an overstress indicator cable including at least one non-twisted conductor disposed within a section of the electro-mechanical cable, where the non-twisted conductor is adapted to break when tension in the non-twisted conductor is greater than an allowable working load for the electro-mechanical cable.

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.