Abstract: Disclosed are apparatus and methods acoustic node positioning during a marine survey. In one embodiment, positions of a plurality of nodes are calibrated using acoustic transceivers. In addition, changes in the positions of the nodes are tracked using accelerometers. In another embodiment, a traveling wave is detected, and an effect of the traveling wave is projected on steering devices in a projected path of the traveling wave. Time-dependent control signals are computed and applied to the steering devices to maintain a local streamer geometry. Other embodiments, aspects, and features are also disclosed.

Abstract: A method and system for controlling the shape and separation of an arrangement of streamers towed behind a survey vessel. Each streamer is steered laterally by lateral steering devices positioned along its length at specific nodes. Each streamer is driven by its lateral steering devices to achieve a specified separation from a neighboring streamer. One of these actual streamers, used as a reference by the other actual streamers, is steered to achieve a specified separation from an imaginary, or ghost, streamer virtually towed with the actual streamers.

Abstract: Computational systems and methods, to be carried out by the computational systems for determining streamer-depth bias during exploration-seismology experiments are disclosed. An exploration-seismology vessel tows a number of streamers that form a smoothly varying data acquisition surface located beneath a fluid surface. In one aspect of this disclosure, the method determines a set of image points that represent a profile of the fluid surface above each streamer. The image points are determined based on pressure and velocity wavefields measured at dual sensors of the streamer. The method then determines an elevation parameter of the image points that minimizes DC offset in a spectral domain of the image points. The elevation parameter corresponds to the streamer-depth bias and can be used to correct for the streamer-depth bias in subsequent calculations of a fluid-surface profile.

Abstract: A seismic survey system for recording seismic data underwater. The system includes first plural buoys configured to descend to a first predetermined depth (H1) in water, at least one buoy having a seismic receiver for recording the seismic data; a first vessel configured to launch the first plural buoys; and a first acoustic system attached to the first vessel and configured to detect a position of the at least one buoy while underwater. The at least one buoy is instructed to maintain the first predetermined depth (H1) underwater while recording the seismic data.

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: To determine a position of an object in a positioning network associated with a marine survey arrangement, images of targets on the object in the positioning network are captured with a plurality of cameras. Based on known positions of the plurality of cameras and known separation between the targets, positions of the targets are computed by processing the images. A position of the object is derived based on the positions of the targets.

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 determining geodetic position of at least one point on a geophysical sensor streamer towed by a vessel in a body of water includes determining geodetic positions of a plurality of locations along a first geophysical sensor streamer towed at a first depth in the body of water. A lateral offset is caused between the first geophysical sensor streamer and a second geophysical sensor streamer towed at a second depth in the body of water. A distance is measured between at least two selected points along the first geophysical sensor streamer and a selected point along the second geophysical sensor streamer. A depth is measured at at least one point along the second geophysical sensor streamer. A geodetic position is determined at a selected point along the second geophysical sensor using the depth measurement, a direction of the lateral offset and the measured distances.

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: 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: A technique includes obtaining first measurements acquired by sensors of a towed seismic streamer, which are indicative of an inclination of the streamer. Based at least in part on the measurements, a shape of the streamer while in tow is determined.

Abstract: Computing device and method for generating an image of a subsurface. The method calculates an offset shift of measured offsets between a seismic source and plural receivers of a streamer. The method includes receiving seismic data recorded underwater by the plural receivers; selecting two pairs of traces from the plural traces and for each pair, calculating a quantity Y that depends on measured offsets of receivers for which the traces were selected, and a quantity X that depends on travel-times and the measured offsets of the receivers for which the traces were selected; calculating a linear relation Y=aX+b, where “a” is a constant and “b” is related to the offset shift; estimating the offset shift from “b”; correcting the measured offsets of the receivers based on the offset shift; and calculating the image of the subsurface based on the corrected offsets.

Abstract: Disclosed are apparatus and methods for streamer positioning during marine seismic exploration. In one embodiment, a designated location for each of one or more transponders is determined based on a survey area, and each transponder is anchored to a sea floor at its own designated location. A marine seismic survey is then performed over the survey area with a marine-towed seismic sensor array, where multiple transceivers are moved along with the seismic sensor array during the marine seismic survey. Signals are communicated between the plurality of transceivers and each transponder so as to determine positions of the plurality of transceivers. Other embodiments, aspects, and features are also disclosed.

Abstract: Systems and methods for automatic steering of marine seismic towing vessels are described. One system comprises a towing vessel, a seismic source, and optionally one or more seismic streamers towed by the towing vessel; a steering sub-system for steering the vessel, the sub-system including a vessel steering algorithm for calculating an optimum vessel steering path; and a controller to produce a difference between a measured position of a tracking point with a pre-plot position of the tracking point, and calculate a set point based on the difference to the steering algorithm. It is emphasized that this abstract is provided to comply with the rules requiring an abstract, allowing a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b).

Abstract: A seismic streamer system and associated methods for estimating the shape of a laterally steered seismic streamer. The streamer is divided into a series of contiguous streamer segments by lateral-steering devices. Heading sensors positioned in forward and aft portions of each segment produce heading readings. Each segment is modeled as having a linear shape in the forward portion and a curved shape in the aft portion. The shape of the segment is estimated according to the model from the heading readings on the segment.

Abstract: A data collection system 100 for estimating a corrected sound speed between a first point and a second point comprises a subsea acoustic transponder beacon (106) disposed at a fixed position relative to a seabed (108), and an acoustic transceiver (214) immersed below a sea surface (104) and above the acoustic beacon (106). A processing resource (200) is also operably coupled to the acoustic transponder (214), the acoustic transceiver (214) being arranged to traverse a path above the acoustic beacon (106) and communicate with the acoustic beacon (106). The processing resource (200) is also arranged to collect time-of-flight data associated with the communication between the acoustic transceiver (214) and the acoustic beacon (106).

Abstract: A method for determining a longitudinal position of at least one geophysical sensor on a towed marine streamer includes measuring a parameter related to tension at least one position along the streamer. A change in length of the streamer is determined using the measured parameter. The longitudinal position of the at least one sensor is determined. A marine streamer includes at least one geophysical sensor and at least one tension sensor capable of measuring a parameter related to axial tension.

Abstract: Method and system for determining positions of underwater sensors. The method includes sending a Doppler variant signal from a moving source; recording the signal with the at least one seismic sensor; evaluating a frequency drift of the recorded signal; and determining a position of the at least one seismic sensor based on the evaluated frequency drift and a source movement relative to the at least one sensor.

Abstract: A method and system for controlling the shape and separation of an arrangement of streamers towed behind a survey vessel. Each streamer is steered laterally by lateral steering devices positioned along its length at specific nodes. Each streamer is driven by its lateral steering devices to achieve a specified separation from a neighboring streamer. One of these actual streamers, used as a reference by the other actual streamers, is steered to achieve a specified separation from an imaginary, or ghost, streamer virtually towed with the actual streamers.

Abstract: According to a preferred aspect of the instant invention, there is provided a system and method for using satellite communications satellites to control and receive data from a land cableless seismic system. The satellite transmission could transmit control signals (e.g. turn on/off) and receive signals from the remote seismograph units (seismic data, quality control parameters, status, location, etc.) which would subsequently be retransmitted to a processing center or other surface facility.

Abstract: The geodetic position of a point on a streamer towed by a vessel in a body of water may be determined. Geodetic positions of a plurality positions along at least two of a plurality streamers towed in the body of water may be determined. Positions may be selected from the plurality of positions. Distances between pairs of the selected positions and between each of the selected positions and the point may be determined. Geodetic position of the point may be determined using the geodetic positions and distances.

Abstract: A technique includes receiving data acquired by a seismic sensor on a spread of at least one streamer. The data are indicative of a seismic source signature that is produced by a source seismic to penetrate into the Earth to acquire geophysical information in connection with a seismic survey. The technique includes processing the data to determine a position on the streamer relative to a reference position not disposed on the streamer.

Abstract: A method of controlling a streamer positioning device (18) configured to be attached to a marine seismic streamer (12) and towed by seismic survey vessel (10) and having a wing and a wing motor for changing the orientation of the wing. The method includes the steps of: obtaining an estimated velocity of the streamer positioning device, calculating a desired change in the orientation of the wing using the estimated velocity of the streamer positioning device, and actuating the wing motor to produce the desired change in the orientation of the wing. The invention also involves an apparatus for controlling a streamer positioning device including means for obtaining an estimated velocity of the streamer positioning device, means for calculating a desired change in the orientation of the wing using the estimated velocity of the streamer positioning device, and means for actuating the wing motor to produce the desired change in the orientation of the wing.

Abstract: A method and system for controlling the shape and separation of an arrangement of streamers towed behind a survey vessel. Each streamer is steered laterally by lateral steering devices positioned along its length at specific nodes. Each streamer is driven by its lateral steering devices to achieve a specified separation from a neighboring streamer. One of these actual streamers, used as a reference by the other actual streamers, is steered to achieve a specified separation from an imaginary, or ghost, streamer virtually towed with the actual streamers.

Abstract: A technique includes receiving data indicative of acoustic measurements acquired by receivers disposed on a seismic receiver spread including at least one streamer. The technique includes processing the data in a machine to determine a depth and/or shaped of the spread.

Abstract: In seismic survey for icy waters, streamers are towed behind a vessel under the water's surface to avoid ice. GPS readings may not be consistently obtained because the ice prevents a tail buoy with a GPS receiver from trailing from streamer at the surface. Instead, a device tows on the streamer under the water's surface. The streamer's absolute position is tracked by intermittently bringing the towed device toward the surface so GPS readings can be obtained. The streamer's absolute position can then be used in conjunction with compass readings and can correlate various seismic sensor signals obtained along the streamer during the survey. The compass readings can be corrected for declination using declinometer readings, which can be compensated for iron effects from the vessel or other device carrying the declinometer.

Abstract: A method for determining a longitudinal position of at least one geophysical sensor on a towed marine streamer includes measuring a parameter related to tension at least one position along the streamer. A change in length of the streamer is determined using the measured parameter. The longitudinal position of the at least one sensor is determined. A marine streamer includes at least one geophysical sensor and at least one tension sensor capable of measuring a parameter related to axial tension.

Abstract: One embodiment of the invention concerns a probe that couples to a seismic vessel via a tow cable. When deploying probes from a seismic vessel that is towing source arrays and streamers, the probe and its tow cable can tangle with elements of the towed seismic spread. However, a cable guide may be used to lessen the risk for such entanglement by guiding the tow cable into the water at a distance removed from the seismic spread. Also, the probe may be steerable to steer the probe and tow cable away from the seismic spread. Other embodiments are described herein.

Abstract: A distributed optical acoustic sensor is provided along a structure in a body of water. The distributed optical acoustic sensor is used to detect acoustic waves generated by at least one acoustic source for positioning of at least one object in relation to the structure.

Abstract: To performing positioning of survey equipment, measurements of acoustic signals reflected from at least one boundary of a marine environment are received. The reflected acoustic signals are reflected from the at least one boundary in response to acoustic signaling originated by an acoustic source. A positioning model is updated based on the measurements of the acoustic signals, wherein the positioning model contains information relating to positions of components of a positioning system that includes the acoustic source and acoustic receiver.

Abstract: A system includes a subterranean survey data acquisition network and a processor. The network has first nodes that are distributed along a length of the network between a first end of the network and a second end of the network. Each of the first nodes is capable of being either in a state in which the first node is transparent to the network or in a state in which the first node is visible to the network. The processor is adapted to communicate with the closest visible first node relative to the first end, and the processor is adapted to, based on the communication, determine whether the closest visible first node is the closest first node of all of the first nodes relative to the first end.

Abstract: A method comprising determining coordinates of a first point rigidly attached to a rigid body floating on the sea surface in a desired coordinate reference frame; measuring orientation parameters of the rigid floating body to determine 3D offset in the coordinate reference frame of the first point to any point on or rigidly attached to the body; applying a 3D coordinate shift from the first point to a second point rigidly attached to the body, thus determining coordinates of the second point in the desired reference frame; determining a distance from the second point to one or more devices that are components of a seismic acquisition spread, by comparing transmission times of a signal to recording times of transmitted signals and multiplying by a signal propagation rate; and determining relative positions of components of the spread to each other and to devices rigidly attached to the rigid body.

Abstract: The present invention provides a method and apparatus for determining the position of a seismic cable being used to perform a marine seismic survey. The apparatus includes at least one seismic sensor and a plurality of sources deployed in a manner that is structurally independent of the seismic sensors and adapted to provide a positioning signal distinguishable from a seismic survey signal to the seismic sensors.

Abstract: The invention relates to a method for acquiring seismic data at a plurality of positions spread out over a zone on the seabed which includes transmitting acoustic waves in the water layer above the zone by a plurality of sources, —for each of the acquisition positions, dropping from the surface a seismic acquisition equipment, the equipment comprising a seismic acquisition unit and autonomous guiding equipment adapted to receive whilst descending acoustic signals from the sources and to control its trajectory according to the received acoustic signals so as to direct said equipment towards said position, —performing the seismic acquisition, —causing the acquisition equipments to move up to the surface, and —retrieving the acquisition equipments on the surface.

Abstract: A method of obtaining information about the positions of sources in a marine seismic source array that has N seismic sources, including at least Nunique types of sources that are nominally non-identical to one another, where 1?Nunique?N?1. The method comprises measuring the pressure field at M independent locations of the N sources, where M>Nunique, and obtaining information about the positions of sources from the M pressure measurements and from the constraint that at least two of the sources are nominally identical to one another.

Abstract: A method of obtaining information about the positions of sources in a marine seismic source array, comprises: determining respective notional signatures for m selected seismic sources, where m<n, where n is the number of sources of the array actuated to generate an output; and obtaining information about the travel between one of the m selected seismic sources and one of the n?m unselected seismic sources from the determined notional signatures. The m seismic sources are selected as sources whose positions, relative to one another, are expected to be close to their nominal positions. The effect of the n?m unselected seismic sources is ignored in the calculation of the nominal signatures for the m sources, and this gives rise to anomalies in the nominal signatures for the m sources. The determined travel time may be converted to a distance, so that information about the positions of the n?m unselected seismic sources may be obtained from the anomalies.

Abstract: An apparatus includes a towed seismic acquisition system and a ranging system. The ranging system is adapted to use electromagnetic ranging signals to indicate a location of one or more points on the towed seismic acquisition system.

Abstract: A method for marine seismic surveying includes towing seismic sensors in a plurality of streamers in the water, actuating a seismic energy source in the water at selected times and detecting seismic signals at the sensors resulting from the actuation of the source. A data trace is created for each of the detected signals. At least one Fresnel zone is determined for at least some of the seismic data traces. A contribution of each of the traces to each one of a plurality of bins defined in a predetermined pattern is computed, based on the Fresnel zone associated with each trace. Based on the computed contributions, a maximum lateral distance between corresponding seismic sensors is determined that will result in a contribution sum above a selected threshold.

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: Methods and related systems are described for use with hydraulic fracturing and other oilfield applications. A tool body is positioned in a wellbore at a location near a subterranean rock formation being fractured. The tool body contains a plurality of deployable continuous fibers. At least some of the deployable continuous fibers are deployed into fractures within a subterranean rock formation. Each deployed fiber is continuous from the tool body to the rock formation. The number of deployable continuous fibers provides sufficient redundancy to make at least a target measurement relating to the fracturing process.

Abstract: Methods and systems for determining position of marine seismic spread components are disclosed. One method comprises exposing an underwater marine seismic spread component to an optical device, and calculating geometry of the spread component using at least some of the data obtained by the optical device, for example travel time for an optical signal to travel to and return from one or more spread elements in the spread component. The optical device may comprise one or more laser scanners, cameras, or laser scanners and cameras. The spread component may be a marine seismic source, a marine seismic streamer cable, and the like. This abstract allows a searcher or other reader to quickly ascertain the subject matter of the disclosure. It will not be used to interpret or limit the scope or meaning of the claims.

Abstract: To perform quality control with respect to positioning of survey hardware, survey navigation data is acquired regarding components of the survey hardware used to perform a survey operation with respect to a subterranean structure. Error statistics according to the survey navigation data are determined in real time. An action is effected in response to the error statistics.

Abstract: A technique includes disposing a particle motion sensor on a spread of at least one streamer and using the particle motion sensor to acquire a measurement of a signal, which is transmitted from an acoustic transmitter. The technique includes determining a heading of the particle motion sensor based at least in part on the measurement.

Abstract: A system includes a subterranean survey data acquisition network and a processor. The network has first nodes that are distributed along a length of the network between a first end of the network and a second end of the network. Each of the first nodes is capable of being either in a state in which the first node is transparent to the network or in a state in which the first node is visible to the network. The processor is adapted to communicate with the closest visible first node relative to the first end, and the processor is adapted to, based on the communication, determine whether the closest visible first node is the closest first node of all of the first nodes relative to the first end.

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 moving seismic streamer steering devices to target positions are disclosed. One method comprises calculating forces required to steer one or more seismic streamer steering devices in a seismic spread to target positions, the calculated forces based wholly or in part on information in modulated underwater acoustic transmissions, and steering the streamer steering devices to the target positions using the calculated forces. It is emphasized that this abstract is provided to comply with the rules requiring an abstract, which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Abstract: To determine a position of an object in a positioning network associated with a marine survey arrangement, images of targets on the object in the positioning network are captured with a plurality of cameras. Based on known positions of the plurality of cameras and known separation between the targets, positions of the targets are computed by processing the images. A position of the object is derived based on the positions of the targets.

Abstract: A method for marine seismic surveying includes determining at least an initial depth of a plurality of spaced apart seismic sensors in a body of water. The sensors each include a substantially collocated pressure responsive sensor and motion responsive sensor. A ghost time delay is determined for each sensor based on the at least an initial depth. Seismic signals detected by each motion responsive sensor and each pressure responsive sensor are cross ghosted. The at least initial depth is adjusted, and the determining ghost time delay and cross ghosted seismic signals are repeated until a difference between the cross ghosted motion responsive signal and the cross ghosted pressure responsive signal falls below a selected threshold.

Abstract: Systems and methods for determining inline skew of one or more seismic streamers are disclosed. One system embodiment includes a seismic streamer including a plurality of receivers, a skew detector adapted to detect inline skew of the streamer, and a receiver selector adapted to select which receivers in the streamer to use in data acquisition based on the detected streamer inline skew. It is emphasized that this abstract is provided to comply with the rules requiring an abstract, which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Abstract: Methods and apparatus for acquiring marine seismic data are described. One method comprises selecting tow depth of one or more marine seismic streamers based at least in part on lack of or presence of currents at different depths, and allowing the current to contribute to steering the streamers to desired lateral positions at the selected tow depth. It is emphasized that this abstract is provided to comply with the rules requiring an abstract, which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.