Abstract: Included are methods and systems for marine geophysical surveying. A system includes a streamer; a sensor package coupled to the streamer, wherein the sensor package comprises a primary orientation sensor and a complimentary orientation sensor, wherein the complimentary orientation sensor comprises a magnetometer, wherein the primary orientation sensor and the complimentary orientation sensor are capable of collecting data indicative of the orientation of the streamer; and geophysical sensors distributed on the streamer.

Abstract: An electromagnetic survey acquisition system includes a sensor cable and a source cable, each deployable in a body of water, and a recording system. The sensor cable includes an electromagnetic sensor thereon. The source cable includes an electromagnetic antenna thereon. The recording system includes a source current generator, a current sensor, and an acquisition controller. The source current generator powers the source cable to emit an electromagnetic field from the antenna. The current sensor is coupled to the source current generator. The acquisition controller interrogates the electromagnetic sensor and the current sensor at selected times in a synchronized fashion.

Abstract: Disclosed are methods and systems for enabling anti-twist functionality in marine geophysical streamers. An embodiment discloses a method comprising: towing a streamer behind a survey vessel in a body of water, wherein the streamer comprises rotation sensors and streamer rotation devices; receiving data from at least one rotation sensor indicative of streamer twist; and rotating a portion of the streamer with at least one streamer rotation device to reduce the streamer twist based, at least in part on the data.

Abstract: An apparatus is disclosed that includes a solid-core streamer with particle motion sensors disposed within the solid core. Some embodiments may additionally include one or more pressure sensors that are disposed outside of the solid core. In some embodiments, the apparatus may also include one or more electromagnetic sensors. Also disclosed are various methods of operating an apparatus that includes a streamer with particle motion sensors disposed within the solid core of the streamer.

Abstract: Disclosed are methods and systems for controlling spread and/or depth in a geophysical survey. An embodiment discloses a submersible deflector, comprising: an upper portion comprising an upper fin section and upper foils disposed below the upper fin section, wherein at least one slot is defined between the upper foils; and a lower portion coupled to the upper portion and disposed below the upper portion, wherein the lower portion comprises a lower fin section and lower foils disposed above the lower fin section, wherein at least one slot is defined between the lower foils. Also disclosed are marine geophysical survey systems and methods of performing geophysical surveys.

Abstract: Disclosed are methods and systems for controlling spread and/or depth in a geophysical survey. An embodiment discloses a submersible deflector, comprising: an upper portion comprising an upper fin section and upper foils disposed below the upper fin section, wherein at least one slot is defined between the upper foils; and a lower portion coupled to the upper portion and disposed below the upper portion, wherein the lower portion comprises a lower fin section and lower foils disposed above the lower fin section, wherein at least one slot is defined between the lower foils. Also disclosed are marine geophysical survey systems and methods of performing geophysical surveys.

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: 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: Depth and tilt control systems for geophysical sensor streamers and methods of use are discussed. Such systems may include a plurality of tilt sensors disposed at spaced apart locations along the geophysical sensor streamer, each tilt sensor having a first tilt sensing element arranged to measure tilt of the geophysical sensor streamer proximate the associated spaced apart location, a plurality of LFD control devices, each disposed proximate one of the tilt sensors along the geophysical sensor streamer, and a plurality of microcontrollers, each microcontroller in signal communication with at least one of the LFD control devices and its associated tilt sensor, wherein each microcontroller is capable of utilizing the tilt measured by the associated tilt sensor to selectively operate the associated LFD control device to cause the geophysical sensor streamer to align with a selected depth profile.

Abstract: Depth and tilt control systems for geophysical sensor streamers and methods of use are discussed. Such systems may include a plurality of tilt sensors disposed at spaced apart locations along the geophysical sensor streamer, each tilt sensor having a first tilt sensing element arranged to measure tilt of the geophysical sensor streamer proximate the associated spaced apart location, a plurality of LFD control devices, each disposed proximate one of the tilt sensors along the geophysical sensor streamer, and a plurality of microcontrollers, each microcontroller in signal communication with at least one of the LFD control devices and its associated tilt sensor, wherein each microcontroller is capable of utilizing the tilt measured by the associated tilt sensor to selectively operate the associated LFD control device to cause the geophysical sensor streamer to align with a selected depth profile.

Abstract: An electromagnetic survey acquisition system includes a sensor cable and a source cable, each deployable in a body of water, and a recording system. The sensor cable includes an electromagnetic sensor thereon. The source cable includes an electromagnetic antenna thereon. The recording system includes a source current generator, a current sensor, and an acquisition controller. The source current generator powers the source cable to emit an electromagnetic field from the antenna. The current sensor is coupled to the source current generator. The acquisition controller interrogates the electromagnetic sensor and the current sensor at selected times in a synchronized fashion.

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: This disclosure is related to the field of streamers. In one embodiment, a streamer may include a group of particle motion sensors. In some embodiments, at least two of the particle motion sensors in the group are movable relative to one another within the streamer, and the two particle motion sensors are configured to measure motion along a particular axis. In some embodiments, the streamer may additionally include a plurality of pressure sensors.

Abstract: An electromagnetic survey acquisition system includes a sensor cable and a source cable, each deployable in a body of water, and a recording system. The sensor cable includes an electromagnetic sensor thereon. The source cable includes an electromagnetic antenna thereon. The recording system includes a source current generator, a current sensor, and an acquisition controller. The source current generator powers the source cable to emit an electromagnetic field from the antenna. The current sensor is coupled to the source current generator. The acquisition controller interrogates the electromagnetic sensor and the current sensor at selected times in a synchronized fashion.

Abstract: Disclosed are methods and systems for calibration of an accelerometer used in a geophysical sensor while deployed in the water. An embodiment may include towing a streamer behind a survey vessel in a body of water, wherein the streamer comprises an accelerometer; causing at least a portion of the streamer to twist; receiving data from the accelerometer at a selected plurality of times during the twist; and based at least in part on the data, determining at least one calibration parameter of the accelerometer.

Abstract: Disclosed are methods and systems for enabling anti-twist functionality in marine geophysical streamers. An embodiment discloses a method comprising: towing a streamer behind a survey vessel in a body of water, wherein the streamer comprises rotation sensors and streamer rotation devices; receiving data from at least one rotation sensor indicative of streamer twist; and rotating a portion of the streamer with at least one streamer rotation device to reduce the streamer twist based, at least in part on the data.

Abstract: The present disclosure describes various geophysical survey systems and methods for mapping an electric potential field. At least one illustrative embodiment includes an electromagnetic (EM) source and geophysical survey cables that each includes multiple electrodes spaced apart along each geophysical survey cable's length, and multiple data acquisition units that each obtains measurements indicative of an electric potential between two the electrodes. A modeling module is included and configured to calculate a reference potential at a selected electrode for each of the plurality of geophysical survey cables, as well as a calculation module to combine signals representative of the measurements to produce signals indicative of the electric potential of each electrode relative to the reference potential.

Abstract: A method for marine electromagnetic surveying includes transmitting a first electromagnetic field oriented in a first direction into a body of water. A second electromagnetic field oriented in a second direction is transmitted into the body of water, wherein the second direction is substantially transverse to the first direction. A parameter related to electromagnetic field amplitude is detected at a plurality of longitudinally and laterally spaced apart positions behind a vessel. The components of the detected electromagnetic field parameter are resolved into components along the first and second directions by using the geometrical symmetries and asymmetries of the transmitting source. Systems for implementing such methods are also provided.

Abstract: Electromagnetic streamer cables and methods of use. Example systems include: a first electrode, the first electrode at a first location along the streamer cable; a second electrode at a second location along the streamer cable; a first sensor module electrically coupled to the first electrode and second electrode, the first sensor module configured to measure a voltage across the first and second electrodes; a third electrode at a third location between the first and second electrodes; a fourth electrode at a fourth location along the streamer cable, the fourth location distal to the second location; and a second sensor module electrically coupled to the third electrode and fourth electrode, the second sensor module configured to measure a voltage across the third and fourth electrodes.

Abstract: An apparatus is disclosed that includes a solid-core streamer with particle motion sensors disposed within the solid core. Some embodiments may additionally include one or more pressure sensors that are disposed outside of the solid core. In some embodiments, the apparatus may also include one or more electromagnetic sensors. Also disclosed are various methods of operating an apparatus that includes a streamer with particle motion sensors disposed within the solid core of the streamer.