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: A sensor streamer stretch section. At least some of the example embodiments are methods including measuring at least one parameter related to noise while towing the sensor streamer through a body of water with a towing vessel, and adjusting at least one of a spring constant and a damping coefficient of a stretch section disposed proximate the sensor streamer such that the measured parameter is minimized.

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: 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: A method for towing marine geophysical sensor streamers in a body of water includes moving a towing vessel at a selected speed along the surface of the body of water. At least one geophysical sensor streamer is towed by the vessel at a selected depth in the water. A velocity of the streamer in the water is measured at at least one position along the streamer. The selected speed of the towing vessel is adjusted if the measured velocity is outside of a selected range.

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: 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: 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: 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: 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: A marine electromagnetic sensor cable system includes a first sensor cable subsystem including at least a first sensor cable segment. The first sensor cable segment includes a plurality of spaced apart electrodes which electrically contact a body of water when the first sensor cable segment is immersed therein, and an electrical conductor coupled to each electrode, each electrical conductor extending from one longitudinal end of the sensor cable segment to the other. The system includes a first signal processing module electrically coupled to a longitudinal end of the first sensor cable segment, and including a voltage measuring circuit electrically connected between two or more electrodes from the first plurality of electrodes. Marine electromagnetic surveys are conducted using the marine electromagnetic sensor cable system.

Abstract: A disclosed electromagnetic survey system includes one or more streamer(s) having multiple electromagnetic sensors and motion sensing units. Each motion sensing unit has one or more accelerometer(s) to measure motion perpendicular to an axis of the streamer, and a rotation sensor to measure rotation about the axis. The measurements of the accelerometer are adjusted based on measurements from the rotation sensor. The survey system also includes one or more processor(s) that determine, for each electromagnetic sensor, a motion signal based on the adjusted measurements. A described electromagnetic survey method includes processing acceleration and rotational motion measurements to obtain an orientation of motion sensing units as a function of time. The measured acceleration is manipulated based on the orientation to obtain one or more velocity signal(s) for each motion sensing unit. Interpolation is performed on the velocity signals to determine at least one velocity signal for each electromagnetic sensor.

Abstract: An electromagnetic sensor cable has components including a first sensor cable segment having a plurality of spaced apart electrodes on the first sensor cable segment an electrical conductors coupled to the electrodes such that at least one of the electrodes is electrically connectible at at least one longitudinal end of the first sensor cable segment. The sensor cable includes a second sensor cable segment configured substantially the same as the first sensor cable segment. A first signal processing and configuration module has signal processing circuitry configured to perform at least one of measuring voltages across selected pairs of electrodes, and communicating signals representative of voltages measured across selected pairs of electrodes. The cable components are each configured to connect at the lateral ends one to another.

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: 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.