Abstract: The disclosure relates to a system for detection and delineation of an object that is at least partly buried in seabed, the system comprising: a marine vehicle (1,10); a controlled electric dipole source (3) mounted on the marine vehicle; a first receiver electrode pair (4) comprising vertical receiver electrodes (4a, 4b) mounted on the marine vehicle, the vertical receiver electrodes (4a4b) separated from one another in the vertical direction of the AUV (1); a 3 axes magnetometer assembly; wherein the receiver pair (4) is configured to measure electric field and the 3-axes magnetometer assembly is configured to measure magnetic field. The disclosure further relates to a method of detection and delineation of an object that is at least partly buried in seabed.

Abstract: The disclosure relates to a system for measuring electric and/or magnetic field of an object, the system comprising: an underwater vehicle comprising: a plurality of links (2a-2d) that are connected to one another by joint modules for generating a flexural motion of the underwater vehicle: wherein the flexural motion devices enable movement of the underwater vehicle and control of the orientation and/or location of the underwater vehicle, wherein the plurality of the links define a hull having a first end (4a) and a second end (4b): a sensor arrangement comprises: a first electrode (6a) mounted on the first end (4a) of the hull: a second electrode (6b) mounted on the second end (4b) of the hull: the first and the second electrode configured to measure electric field of an object, the electric field data sampled with sampling frequencies between 1 and 300 Hz; and/or a first single, 2-, or 3-axes magnetometers (7a) mounted inside the first end (4a) of the underwater vehicle: a second single, 2-, or 3-axes magne

Abstract: The disclosure relates to a system for tracking an object that is at least partly buried in seabed, the system comprising: An Autonomous Underwater Vehicle (AUV) having a hull, a controlled electric dipole source mounted on the hull of the AUV; first sensor assembly mounted on the hull in the proximity of starboard side of the AUV (1); second sensor assembly mounted on the hull in the proximity of port side of the AUV; wherein the first and the second sensor assemblies are configured to measure magnetic field from electromagnetic energy transmitted from the controlled electric dipole source. The disclosure further relates to a method of tracking an object that is at least partly buried in seabed.

Abstract: A system and method for detection and delineation of conductive bodies situated upon or beneath the seafloor, comprising: at least one source Autonomous Underwater Vehicle (AUV) having a hull and at least one receiver (AUV) having a hull, the source AUV comprising: at least one controlled electric dipole source mounted on the hull of the source AUV; at least one first magnetometer mounted inside the hull of the source AUV; the receiver AUV comprising; at least one first receiver electrodes; at least one second receiver electrodes; at least one second magnetometers mounted inside the hull of the AUV; measurement electronics hosted inside the receiver AUV; wherein the first and the second magnetometers are configured to measure the magnetic field and the first and the second receiver electrodes are configured to measure electric field in a horizontal direction relative to the AUV, x-direction, and a vertical direction relative to the AUV, z-direction, when electromagnetic energy is transmitted from the controll

Abstract: A pressure sensor configured for biological pressure measurement at a distal end portion of an elongated member comprises a dissolvable hydrophilic material coated on a surface of the pressure sensor. A guide wire for biological pressure measurement may include a tube extending along a longitudinal axis of the guide wire; and a pressure sensor for biological pressure measurement, at least a portion of the pressure sensor being mounted within the tube. The pressure sensor comprises a pressure sensor membrane facing a top side of the tube. A circumferential wall of the tube includes at least six openings: a first distal opening, a second distal opening located on a right side of the tube, a third distal opening located on a left side of the tube, a first proximal opening, a second proximal opening located on a right side of the tube, and a third proximal opening located on a left side of the tube.

Abstract: A method for preparing a sensor wire includes: providing a sensor wire configured for biological pressure measurement and including: an elongated member; and a pressure sensor configured for biological pressure measurement, the pressure sensor being mounted at a distal end portion of the elongated member, wherein a dissolvable hydrophilic material is coated on a surface of the pressure sensor; and submerging the pressure sensor in saline solution, whereby the hydrophilic material dissolves and causes the saline solution to contact the pressure sensor.

Abstract: Inversion of enhanced-sensitivity controlled source electromagnetic data can include combining measured controlled source electromagnetic (CSEM) data onto a common set of virtual receiver positions for each of a plurality of positions of a source along a survey path, determining a steering vector that enhances a sensitivity of the measured CSEM data to a subsurface resistivity variation, and performing an inversion using the measured CSEM data and modeled CSEM data, each having the steering vector applied thereto as a data weight, to better identify the subsurface resistivity variation.

Abstract: A pressure sensor configured for biological pressure measurement at a distal end portion of an elongated member comprises a dissolvable hydrophilic material coated on a surface of the pressure sensor. A guide wire for biological pressure measurement may include a tube extending along a longitudinal axis of the guide wire; and a pressure sensor for biological pressure measurement, at least a portion of the pressure sensor being mounted within the tube. The pressure sensor comprises a pressure sensor membrane facing a top side of the tube. A circumferential wall of the tube includes at least six openings: a first distal opening, a second distal opening located on a right side of the tube, a third distal opening located on a left side of the tube, a first proximal opening, a second proximal opening located on a right side of the tube, and a third proximal opening located on a left side of the tube.

Abstract: A guide wire for biological pressure measurement includes a tube extending along a longitudinal axis of the guide wire; and a pressure sensor for biological pressure measurement, at least a portion of the pressure sensor being mounted within the tube. The pressure sensor comprises a pressure sensor membrane facing a top side of the tube. A circumferential wall of the tube includes at least six openings: a first distal opening, a second distal opening located on a right side of the tube, a third distal opening located on a left side of the tube, a first proximal opening, a second proximal opening located on a right side of the tube, and a third proximal opening located on a left side of the tube. The first distal opening is larger than the second and third distal openings, and the first proximal opening is larger than the second and third proximal openings.

Abstract: Electromagnetic (EM) inversion includes determining an electric field associated with EM data within a predetermined sensitivity area around each of a plurality of source positions, iteratively inverting the electric field for a subsurface resistivity EM model indicative of a subterranean formation for each of a plurality of EM electrical resistivity data cells within each of the predetermined sensitivity areas, and storing results of the iterative inversion. A linear system of equations comprising a Jacobian matrix is generated based on the iterative inversion, the linear system of equations is stored, and the linear system of equations is solved at each iteration of the iterative inversion to update the subsurface resistivity EM model until a convergence criterion is met. A resistivity map based on the updated subsurface resistivity EM model can be produced.

Abstract: A method and apparatus for a streamer having a total field magnetometer (“TFM”). A streamer includes a plurality of TFMs in proximity with one another and distributed symmetrically about an axis of the streamer. A streamer includes a first subset of TFMs in a streamer section and in proximity with one another; a second subset in the streamer section and in proximity with one another; wherein the first subset is not in proximity with the second subset. A method includes towing a streamer through a body of water, the streamer comprising first and second TFMs; acquiring magnetic data with the first and the second TFMs; and reducing noise in the data based on at least one of: averaging data from the first and the second TFMs; filtering data from the first and the second TFMs; estimating motion of the first TFM; and estimating rotation of the first TFM.

Abstract: Methods of geophysical prospecting are described herein. In the described methods, a data set of electromagnetic readings from a marine geophysical survey is obtained and loaded into a computer processing system. Using the computer processing system, a high-frequency subset of the data is selected based on a frequency threshold, and a seawater resistivity map is resolved from the subset for a seawater portion of the survey by inversion. The seawater resistivity map can subsequently be used to resolve a resistivity map of the seabed from the data set by inversion.

Abstract: Method for transmitting signals on a transmission channel (103), comprising the steps of detecting (S101) a channel occupancy of a transmission channel (103) by processing data from a receiving path (105) after an activation of a transmission path (111); and deactivating (S102) the transmission path (111) on the basis of the detected channel occupancy.

Abstract: A method and system for estimation of electromagnetic earth responses in a marine electromagnetic survey. A method may comprise estimating initial values of the electromagnetic earth responses and ambient noise applicable to the marine electromagnetic survey; and processing electromagnetic data based on the initial values of the electromagnetic earth responses and the ambient noise to obtain a joint estimation of updated values of the electromagnetic earth responses and the ambient noise, wherein the electromagnetic data was acquired with one or more electromagnetic sensors, wherein the electromagnetic data contains measurements of an electromagnetic field.

Abstract: A resistivity profile can be generated directly from measured electromagnetic field data from a marine survey. A series of transformations can be applied to remove a conductivity dependency from a boundary value problem such that an inversion method may no longer be required to generate the resistivity profile.

Abstract: Electromagnetic (EM) inversion includes determining an electric field associated with EM data within a predetermined sensitivity area around each of a plurality of source positions, iteratively inverting the electric field for a subsurface resistivity EM model indicative of a subterranean formation for each of a plurality of EM electrical resistivity data cells within each of the predetermined sensitivity areas, and storing results of the iterative inversion. A linear system of equations comprising a Jacobian matrix is generated based on the iterative inversion, the linear system of equations is stored, and the linear system of equations is solved at each iteration of the iterative inversion to update the subsurface resistivity EM model until a convergence criterion is met. A resistivity map based on the updated subsurface resistivity EM model can be produced.

Abstract: Inversion of enhanced-sensitivity controlled source electromagnetic data can include combining measured controlled source electromagnetic (CSEM) data onto a common set of virtual receiver positions for each of a plurality of positions of a source along a survey path, determining a steering vector that enhances a sensitivity of the measured CSEM data to a subsurface resistivity variation, and performing an inversion using the measured CSEM data and modeled CSEM data, each having the steering vector applied thereto as a data weight, to better identify the subsurface resistivity variation.

Abstract: A method and apparatus for a streamer having a total field magnetometer (“TFM”). A streamer includes a plurality of TFMs in proximity with one another and distributed symmetrically about an axis of the streamer. A streamer includes a first subset of TFMs in a streamer section and in proximity with one another; a second subset in the streamer section and in proximity with one another; wherein the first subset is not in proximity with the second subset. A method includes towing a streamer through a body of water, the streamer comprising first and second TFMs; acquiring magnetic data with the first and the second TFMs; and reducing noise in the data based on at least one of: averaging data from the first and the second TFMs; filtering data from the first and the second TFMs; estimating motion of the first TFM; and estimating rotation of the first TFM.

Abstract: Methods of geophysical prospecting are described herein. In the described methods, a data set of electromagnetic readings from a marine geophysical survey is obtained and loaded into a computer processing system. Using the computer processing system, a high-frequency subset of the data is selected based on a frequency threshold, and a seawater resistivity map is resolved from the subset for a seawater portion of the survey by inversion. The seawater resistivity map can subsequently be used to resolve a resistivity map of the seabed from the data set by inversion.

Abstract: Method for transmitting signals on a transmission channel (103), comprising the steps of detecting (S101) a channel occupancy of a transmission channel (103) by processing data from a receiving path (105) after an activation of a transmission path (111); and deactivating (S102) the transmission path (111) on the basis of the detected channel occupancy.