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: According to one or more aspects of the invention, a marine seismic survey method comprises towing at least two streamers below a sea surface forming a survey spread, each streamer comprising a survey sensor and a profiler; and at each profiler, emitting an acoustic signal; recording an echo of the emitted signal at the profiler; and determining a parameter from the recorded echo, the parameter comprising at least one selected from the group of a distance between the profiler and the sea surface, a water current vector and a sea surface slope.

Abstract: A seismic survey apparatus includes a plurality of serially connected electrical nodes; a power supply capable of supplying power to the electrical nodes and detecting a voltage leakage among the electrical nodes; and a software component capable of locating the leakage upon its detection. A method for use in seismic surveying includes powering a plurality of serially connected electrical nodes in a seismic surveying system; automatically detecting a voltage leakage among the electrical nodes on the power domain; and automatically locating the detected voltage leakage.

Abstract: Methods and apparatus for cable termination and sensor integration at a sensor station within an ocean bottom seismic (OBS) cable array are disclosed. The sensor stations include a housing for various sensor components. Additionally, the sensor stations can accommodate an excess length of any data transmission members which may not be cut at the sensor station while enabling connection of one or more cut data transmission members with the sensor components. The sensor stations further manage any strength elements of the cable array.

Abstract: An apparatus includes a streamer having one or more sensor holders for retaining seismic sensors therein. The sensor holders have a reduced cross-sectional area to increase gel continuity and coupling through the streamer.

Abstract: A skeg mounts from the stern of a towing vessel and extends below the waterline. A channel in the skeg protects cables for steamers and a source of a seismic system deployed from the vessel. Tow points on the skeg lie below the water's surface and connect to towlines to support the steamers and source. A floatation device supports the source and tows below the water's surface to avoid ice floes. The streamers can have vehicles deployed thereon for controlling a position on the streamer. To facilitate locating the streamers, these vehicles on the streamers can be brought to the surface when clear of ice floes so that GPS readings can be obtained and communicated to a control system. After obtaining readings, the vehicles can be floated back under the surface. Deploying, using, and retrieving the system accounts for ice at the surface in icy regions. In addition, handling the seismic record can account for noise generated by ice impact events.

Abstract: A disclosed geophysical survey cable includes a signal amplifier coupled between two electrodes spaced apart along the length of the geophysical survey cable (the electrodes being coupled to the signal amplifier by a first conductor pair), and a noise amplifier coupled to a second conductor pair positioned substantially parallel to the first conductor pair. The geophysical survey cable further includes a combiner that combines a noise signal provided by the noise amplifier with a sensor signal provided by the signal amplifier to provide a sensor signal with a reduced noise component.

Abstract: An apparatus includes a streamer having one or more sensor holders for retaining seismic sensors therein. A housing is disposed about a sensor with a gel-like material disposed between the housing and the sensor, thereby decoupling the sensor from its surroundings. The housing is disposed in the sensor holder and the streamer is filled with either liquid or another gel-like material.

Abstract: A seismic streamer system for acquiring seismic data includes a plurality of first cable sections each employing a first sensor configuration therein, and at least one second cable section operatively connected to one or more of the first cable sections and employing a second sensor configuration therein. In various embodiments of the streamer system, one or more of the second cable sections are sparsely integrated into a streamer, a streamer array and/or a seismic spread. The first sensor configuration may, e.g., include a conventional hydrophone distribution, and the second sensor configuration may, e.g., include multicomponent sensors such as at least one of a particle velocity sensor, a pressure gradient sensor, an accelerometer and a combination thereof. The present invention is useful for attenuating noise in the measured seismic data as well as deghosting the data.

Abstract: The present invention relates to streamer cables. One embodiment of the present invention relates to a method for preparing a streamer cable. The method may comprise retrofitting the streamer cable with a solid void-filler material, where the streamer cable was configured as a liquid-filled streamer cable. The retrofitting may comprise introducing a void-filler material into the streamer cable when the void-filler material is in a liquid state and curing or otherwise solidifying the void-filler material to a solid state. In another embodiment, the present invention relates to a streamer cable comprising an outer skin and-at least one sensor positioned within the outer skin. The streamer cable may also comprise a solid void-filler material positioned between the outer skin and the at least one sensor, wherein the solid void-filler material is coupled to the at least one sensor.

Abstract: To analyze content of a subterranean structure, electric field measurements at plural source-receiver azimuths in a predefined range are received. Total magnetic field measurements are also received at plural source-receiver azimuths in the predefined range. The electric field measurements and the total magnetic field measurements are provided to an analysis module to enable determination of electrical resistivity anisotropy of the subterranean structure.

Abstract: A technique for use in marine seismic surveying includes a method and an apparatus. In one aspect, the method includes towing a seismic spread including a source multiple streamers on a generally curved advancing path, the streamers being actively steered. The source is fired and data is acquired on the curve. In other aspects, the method is performed with only a single vessel or the generally curved advancing path is a sincurve advancing path. The method may include a dual circular shoot in another aspect. And, in yet another aspect, the invention includes an apparatus comprised of a computing apparatus on board a tow vessel receiving positioning data from the marine seismic streamers. It is also programmed to: sail the tow vessel in a generally curved advancing path and actively steer the marine seismic streamers through the generally curved advancing path.

Abstract: A cleaning device for cleaning a marine streamer towed underwater and related methods are provided. The cleaning device includes a housing configured to be attached to the streamer, a motor mounted inside the housing, a propeller configured be rotated by the motor and to drive the housing along and relative to the streamer in a towing direction, and a controller configured to control the motor and the propeller.

Abstract: A marine seismic streamer includes at least one particle motion sensor array. The array includes a plurality of particle motion sensors disposed at spaced apart locations along the streamer. Outputs of the particle motion sensors are functionally coupled to form an array. A number of the particle motion sensors and a spacing between adjacent particle motion sensors are selected to attenuate noise in a selected mode of propagation and within a selected wavenumber range. The streamer includes means for weighting a signal output of each particle motion sensor in the at least one array. A signal weight applied to each sensor by the means for weighting is selected to optimize attenuation of the noise.

Abstract: A method of acquiring marine seismic data using an acoustic source to generate an acoustic signal, a portion of which is reflected at one or more subsurface formation interfaces as a seismic signal is described. The method includes sailing a surface vessel along a sail line which lies over a survey area while towing a seismic streamer, the sail line having a sinusoidal configuration defined by an amplitude and a wavelength. The streamer includes a plurality of hydrophones for receiving the reflected portion of the acoustic signal. The method is characterised in that the streamer follows the sinusoidal configuration of the sail line while seismic data is acquired, the streamer having a length at least equal to the distance travelled by the surface vessel as it sails along one full wavelength of the configuration as measured along the sinusoidal sail line.

Abstract: A method and apparatus for evaluating submarine formations, such as geological formations located generally under a body of water. Multiple hydrofoils (130), responding to moving water, hydrodynamic, or Bernoulli forces, provide controllable orientation and separation for multiple receivers (135) as they are towed (125) through water (110) in the course of a geophysical survey such as a controlled source electromagnetic survey. The inventive method can be used to provide mutual orthogonality for three antennas in a multiple component electromagnetic receiver.

Abstract: A method for acquiring marine seismic data includes towing a seismic energy source in a body of water and towing a seismic sensor at a selected distance from the seismic energy source. The seismic energy source is actuated a plurality of positions, a distance between each of the plurality of actuations being randomly different than any other such distance. Seismic energy detected by the seismic sensor is substantially continuously recorded through a plurality of actuations of the at least one seismic energy source. The recording includes recording a geodetic position of the at least one seismic energy source and the at least one seismic sensor at each actuation.

Abstract: An apparatus is provided to directly measure the flow noise characteristics of both acoustic sensors and accelerometers mounted in a towed array hose. Sensors can be mounted in a full-scale diameter array module test apparatus and can be subjected to high Reynolds number flow fields that have the physical features of at-sea towing conditions. Additionally, rapid re-design of sensor mountings, hose materials, and actual sensors can be accomplished and evaluated. The parameters of internal tension and flow speed can vary independently in order to determine their importance.

Abstract: The present invention relates to a seismic cable (3) comprising at least two sensor nodes (4), the cable being adapted to lie permanently on a seabed (5). By covering each sensor node (4) and a length of the cable (3) connecting the sensor nodes (4) with a flexible protective socket (7), there is obtained a leak-tight connection, whereby penetration of water and/or moisture into the components of the sensor node (4) is not permitted.

Abstract: The invention concerns a method to acquire seismic waves by means of a streamer towed by a vessel and comprising a plurality of seismic receivers. The streamer comprises a head portion that is slanted relative to the water surface and a tail portion having at least one section with a different slant.

Abstract: The invention concerns a method for seabed seismic acquisition. According to the invention, a pair of geophones (3a, 3b) is placed on the seabed and mounted in opposite directions so that the axes of maximum sensitivity of the geophones lie substantially orthogonal to the surface of the seabed. The invention also concerns a device for seismic acquisition and a seabed seismic node.

Abstract: An electromagnetic sensor streamer may include a jacket, at least one electromagnetic sensor in operational communication with a voltage measuring circuit disposed inside the jacket, and at least one wire coil. The at least one wire coil is in signal communication with the voltage measuring circuit, and the voltage measuring circuit is configured to determine motion-induced voltages imparted to the at least one electromagnetic sensor in the streamer.

Abstract: The present invention relates to streamer cables. One embodiment of the present invention relates to a method for preparing a streamer cable. The method may comprise retrofitting the streamer cable with a solid void-filler material, where the streamer cable was configured as a liquid-filled streamer cable. The retrofitting may comprise introducing a void-filler material into the streamer cable when the void-filler material is in a liquid state and curing or otherwise solidifying the void-filler material to a solid state. In another embodiment, the present invention relates to a streamer cable comprising an outer skin and-at least one sensor positioned within the outer skin. The streamer cable may also comprise a solid void-filler material positioned between the outer skin and the at least one sensor, wherein the solid void-filler material is coupled to the at least one sensor.

Abstract: A method for determining a sail plan for a towed-array marine seismic survey, includes: dividing a survey area into a regular grid of tiles; and identifying a subset of the tiles as nodes around which continuously curved sail lines are defined. The nodes define regular pattern further including: a first subpattern of nodes; and a second subpattern of nodes offset from the first subpattern. In alternative aspects, a computer-readable program storage medium may be encoded with instructions that, when executed by a processor, perform the method, or a computing apparatus may be programmed to perform the method. A method for conducting a towed array marine survey includes: traversing a plurality of continuously curved sail lines across a survey area, each sail line being relative to a node; and acquiring seismic data while traversing the continuously curved sail lines.

Abstract: The technique disclosed herein includes a method and apparatus for controlling streamer steering devices to maintain a coil streamer shape that gives coverage for a coil shooting plan. The technique uses solved positions and a target coil streamer shape identified in the shooting plan to determine steering instructions to the streamer steering devices along the streamer.

Abstract: Methods and systems for improving azimuth distribution in a seismic acquisition system are described. A survey acquisition system includes a plurality of streamers towed by a plurality of streamer vessels, including a first streamer vessel and a second streamer vessel and a plurality of sources towed by a plurality of source vessels. The plurality of streamer vessels and plurality of source vessels are configured relative to one another such that the plurality of source vessels are positioned at one or more predetermined inline distances behind a portion of the first streamer vessel and are also positioned at one or more predetermined inline distances in front of a portion of the second streamer vessel. The plurality of streamer vessels and plurality of source vessels are also spaced apart from one another in a cross-line direction.

Abstract: A seismic streamer system for acquiring seismic data includes a plurality of first cable sections each employing a first sensor configuration therein, and at least one second cable section operatively connected to one or more of the first cable sections and employing a second sensor configuration therein. In various embodiments of the streamer system, one or more of the second cable sections are sparsely integrated into a streamer, a streamer array, and/or a seismic spread. The first sensor configuration may, e.g., include a conventional hydrophone distribution, and the second sensor configuration may, e.g., include multicomponent sensors such as at least one of a particle velocity sensor, a pressure gradient sensor, an accelerometer, and a combination thereof. The present invention is useful for attenuating noise in the measured seismic data as well as deghosting the data.

Abstract: A marine node for recording seismic waves underwater. The node includes a spherical body made of a material that has a density similar to a density of the water so that the body is buoyant neutral; a first sensor located in the body and configured to record three dimensional movements of the node; a second sensor located in the body and configured to record pressure waves propagating through the water; and one or more cables connected to the first and second sensors and configured to exit the body to be connected to an external device. The body is coupled to the water.

Abstract: To acquire near-zero offset survey data, a survey source and a first streamer attached to the survey source are provided, where the first streamer has at least one survey receiver. A second streamer separate from the survey source and the first streamer includes survey receivers. Near-zero offset data is measured using the at least one survey receiver of the first streamer.

Abstract: A technique for processing seismic data acquired in a seismic survey conducted in the presence of a rough sea includes receiving a first dataset that is derived from data acquired by a first set of seismic sensors generally towed at a first depth in the seismic survey and receiving a second dataset that is derived from data acquired by a second set of seismic sensors generally towed at a second depth that is different than the first depth in the seismic survey. The first dataset is indicative of at least pressure measurements, and the second dataset is indicative of at least crossline particle motion measurements. The technique includes determining crossline particle motion measurements in the presence of a relatively flat sea surface based at least in part on the crossline measurements that are indicated by the second dataset and the pressure measurements that are indicated by the first dataset.

Abstract: A disclosed geophysical survey cable includes a signal amplifier coupled between two electrodes spaced apart along the length of the geophysical survey cable (the electrodes being coupled to the signal amplifier by a first conductor pair), and a noise amplifier coupled to a second conductor pair positioned substantially parallel to the first conductor pair. The geophysical survey cable further includes a combiner that combines a noise signal provided by the noise amplifier with a sensor signal provided by the signal amplifier to provide a sensor signal with a reduced noise component.

Abstract: A method of acquiring marine seismic data using an acoustic source to generate an acoustic signal, a portion of which is reflected at one or more subsurface formation interfaces as a seismic signal, includes: a) sailing a surface vessel along a sinusoidal sail line which lies over an area to be surveyed while towing one or more seismic streamers, each streamer including a plurality of hydrophones to receive the reflected seismic signals, where the streamer follows the sinusoidal sail line while seismic data is acquired. In one embodiment, the method further comprises b) dividing the area to be surveyed using a grid to form a plurality of bins; c) collating the seismic signals using the plurality of bins; and, d) repeating step a) to populate each bin with seismic data, where a range of offsets associated with each event varies between adjacent cross-line and in-line bins.

Abstract: A method for determining quality of signals acquired using marine seismic streamers having pressure responsive sensors and motion responsive sensors includes cross ghosting pressure responsive seismic signals and contemporaneously acquired motion responsive seismic signals. First filters are determined that cause the cross ghosted pressure responsive signals to substantially match the cross ghosted motion responsive signals. Second filters are determined that cause the cross ghosted motion responsive signals to substantially match the cross ghosted pressure responsive signals. The first and second filters are convolved and the convolution is used to determine signal quality.

Abstract: A sensor streamer stretch section includes at least one spring. A means for coupling the spring at each end to at least one of a sensor streamer and a lead in cable is included. A cable is coupled at its ends to the means for coupling. The cable is capable of carrying at least one of electrical and optical signals. The cable is formed such that the cable undergoes substantially no axial strain when the shock cord is elongated. An adjustable damper is coupled between the means for coupling at each end of the stretch section.

Abstract: Methods and systems for survey designs are disclosed. In one embodiment, a method of towing an array of marine streamers is disclosed, wherein: the array includes a plurality of receivers, the array includes a plurality of steering devices, and the array is towed along a first portion of a coil sail path; steering the array of marine streamers along two or more depths; and steering the array of marine streamers to a slant angle while maintaining the array of marine streamers at their respective two or more depths.

Abstract: Control mechanisms, computer software and methods for driving vibrational source arrays underwater. An incoherent acquisition scheme drives individual source elements simultaneously and incoherently while a coherent acquisition scheme drives high-frequency individual source elements simultaneously and incoherently and low-frequency individual source elements simultaneously and coherently. Thus, denser coverage and an increased energy input is achieved for the source arrays.

Abstract: Control mechanisms, computer software and methods for driving vibrational source arrays underwater. An incoherent acquisition scheme drives individual source elements simultaneously and incoherently while a coherent acquisition scheme drives high-frequency individual source elements simultaneously and incoherently and low-frequency individual source elements simultaneously and coherently. Thus, denser coverage and an increased energy input is achieved for the source arrays.

Abstract: A method of deploying a seismic recorder array on a seafloor is disclosed. The seismic recorder array comprises a plurality of removable seismic data recorders. The method comprises the step of forming the seismic recorder array by connecting a plurality of recorder housings in series, wherein adjacent recorder housings are connected by a connector cable. The recorder housings are configured to retain the removable seismic data recorders. The method comprises the step of loading the plurality of removable seismic data recorders in the recorder housings, and lowering the seismic recorder array into water until the seismic recorder array is positioned on the seafloor underlying the water. The method comprises the step of operating the seismic data recorders to detect seismic signal reflections and to record seismic data representing the reflections.

Abstract: A method for acquiring three-dimensional seismic data for sub-surface geologic features wherein a seismic source array is moved along a survey pattern having a plurality of source lines of unequal lengths that are substantially parallel to each other and intersect a receiver line. The survey pattern can be repeated in an overlapping and interleaved fashion to survey a larger area.

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: An ocean bottom seismic cable recording apparatus comprising a plurality of seismic node casings (1), said node casings being separated from each other by separate stress member sections (2), each stress member section having acoustic decoupling arrangements (3) at each end connecting to said seismic node casings (1), and where each seismic node casing comprising an autonomous sensor capsule (5) for sensing and recording seismic data, and wherein the autonomous sensor capsule (5) is removable from said seismic node casing (1), and wherein each seismic node casing (1) further comprising an inner compartment (4) accommodating the autonomous sensor capsule (5).

Abstract: Some embodiments of the disclosed invention include a method for acquiring marine seismic data using solid streamers in a curved pattern. Streamers can be towed in a curved pattern within a body of water. While being towed in the curved patter the source may be fired and response data can be collected by the streamers as they are towed through the water in the curved/circular pattern. These streamers can be solid streamers and can be filled with a gel like substance. Moreover, the streamers can be placed at various known depths within the body of water.

Abstract: A disclosed digital sensor includes a pair of piezoelectric sensors that respond to acceleration and pressure in opposite ways, a pair of digital transducer circuits each employing a quantized feedback path to obtain digital sensor signals for the piezoelectric sensors, and a combiner circuit that combines the digital sensor signals to produce a compensated digital output signal. The compensated digital output signal may be a pressure compensated acceleration signal, an acceleration compensated pressure signal, or both. Also disclosed is a signal detection method that includes configuring a pair of piezoelectric membranes in a piezoelectric sensor to respond to acceleration and pressure in opposite ways, and based on their responses, producing at least one of a digital pressure compensated acceleration signal and a digital acceleration compensated pressure signal. The digital signals may be produced in part by applying a quantized feedback signal to at least one of the piezoelectric membranes.

Abstract: A disclosed data acquisition system includes one or more streamers having multiple spaced apart sensor units. At least one sensor unit includes at least one digital sensor employing a quantized feedback loop to produce a digital output signal. A data recording system collects and stores data from the sensor units. The quantized feedback loop may be adapted to exert a quantized force on the sensing element. A described method for acquiring data includes deploying at least one streamer having multiple spaced apart sensor units, where at least a portion of the sensor units include a digital sensor employing a quantized feedback loop to produce a digital output signal. A stimulus event is triggered. Data is received from the sensor units and stored.

Abstract: A system is proposed for conducting efficient marine seismic surveys in different climatic conditions for water depths of 0-500 meters, in near-shore zones and on the land for obtaining seamless profiles. The system includes at least one bottom module (BM) and onboard devices located on a vessel. The BM can be submerged from the vessel onto a bottom ground and lifted up on the board. The BM includes a case provided with roundings on its upper surface and its bottom area, to which case are mounted damping elements, a hydrophone and a geophone block for receiving seismic data, a vacuum port, a hermetic electrical socket, and equipment arranged inside the case, including—a clock generator,—a digital compass providing angle data,—an interface board essentially reading the seismic and angle data and transmitting thereof to the onboard devices, and—a recorder board communicating with the geophones, hydrophone, and interface board.

Abstract: A marine cable for seismic surveys is described with a plurality of ceramic pressure sensors (901-904) arranged in groups of at least two pressure sensors with a group output being representative of the vertical pressure gradient at the group location, and an inclinometric system including one or more transducers for determining the orientation of the sensors of the group in order to determine their true vertical separation.

Abstract: Disclosed are methods and systems for controlling spread and/or depth in a geophysical survey. An embodiment discloses a method for geophysical surveying, comprising: towing two streamers laterally spaced apart through a body of water at a depth of at least about 25 meters, each of the streamers comprising geophysical sensors disposed thereon at spaced apart locations; maintaining lateral separation of at least about 150 meters between the two streamers using at least two submersible deflectors, the two submersible deflectors being individually coupled to one of the two streamers; and detecting signals using the two geophysical sensors while the two streamers are towed at the depth of at least about 25 meters.

Abstract: The present invention relates to a streamer cable for use in marine seismic exploration. Further, a method for reducing noise generation in marine seismic exploration is described, as well as a method for the preparation of the said seismic cables.

Abstract: Marine surveys using vertically oriented sensor streamers. At least some embodiments are vertically oriented sensor streamers where each sensor streamer includes: an elongated outer jacket; a plurality of hydrophones coupled to the outer jacket, each hydrophone of the plurality of hydrophones longitudinally spaced along the outer jacket; a plurality of three-axis motion detectors, each three-axis motion detector of the plurality of three-axis motion detectors longitudinally spaced along the outer jacket; and a plurality of electrodes coupled to the outer jacket, each electrode of the plurality of electrodes longitudinally spaced along the outer jacket, and the plurality of electrodes electrically exposed outside the outer jacket. Other embodiments may also comprise a plurality of electrodes on each sensor streamer, the electrodes for measuring electromagnetic energy.

Abstract: A technique is designed for conducting a seismic survey. The technique utilizes a plurality of vibrator arrays employed to conduct a seismic survey utilizing low frequency and high frequency vibrators in each vibrator array. The plurality of vibrator arrays continuously sweeps low frequency signals via low frequency vibrators. While sweeping low frequency signals, high-frequency vibrators emit high-frequency signals in an alternating pattern between vibrator arrays to enhance the seismic survey.