Pgs Geophysical As

Pgs Geophyiscal As

Pgs Geopysical As

Ulf Peter Lindqvist

Andras Robert Juhasz

Gustav Göran Mattias Südow

Rune Johan Magnus Mattsson

Stig Rune Lennart Tenghamn

Robert Andras Juhasz

Lars Erik Magnus Björnemo

Carl Joel Gustav Skogman

Oliver Colin Peppe

Lars Erik Magnus Bjornemo

Marit Ronaess

Kenneth Karlsen

Robert A P Fernihough

Anders Göran Mattsson

James Ewan Mackay

Prawin K Bhadani

Per Anders Davidsson

Mattias Fredrik Karlsson

Svein Torleif Vaage

Toril Margrethe Bruun Vaage

Lena Kristina Frenje Lund

Eivind Fromyr

Richard Samuel Bailie

Peter Gunnar Krylstedt

Lena Kristina Frenje

Anders Goran Mattsson

Robert Fernihough

Lena Kristina Lund

Anders Goeran Mattsson

Rune Johan Mattsson

Stig Rune Tenghamn

Measured marine survey data can be processed analogously to modeled marine survey data analogously and a misfit can be calculated between the processed measured marine survey data and the processed modeled marine survey data. A model parameter in the modeled marine survey data can be updated based on the misfit. The model parameter can be a parameter of a subsurface location.

Analogous processing of modeled and measured marine survey data

A system and method is provided for identifying degrading electrodes in a marine electromagnetic survey system. A system may comprise a sensor array operable for use in a marine electromagnetic survey system, wherein the sensor array comprises a plurality of electrodes. The system may comprise a shunt resistor connected to the electrodes and a processor operable to vary a resistance of the shunt resistor in the presence of a voltage across the electrodes. A method for identifying degrading electrodes may comprise measuring an electric field in a body of water with a pair of electrodes, wherein a shunt resistor is connected between the pair of electrodes. The method may comprise varying a resistance of the shunt resistor. The method may comprise measuring a voltage across the shunt resistor while varying the resistance of the shunt resistor to obtain measured voltages for different shunt resistor values. The method may comprise comparing the measured voltages of the different shunt resistor values to calculate resistance of the pair of electrodes.

Identification of degrading electrodes in a marine electromagnetic survey system

Aspects described herein provide for a sensor assembly having an electrically isolated cable segment that may be used for geophysical prospecting. The sensor assembly generally includes a first cable segment comprising at least one electromagnetic (EM) sensor, and a second cable segment connected to the first cable segment and electrically isolated from the first cable segment. The second cable segment may be free of electrically conductive components. Alternatively, the second cable segment may have electrically conductive components that are not electrically connected to the first cable segment. The electrically isolated cable segment may reduce or eliminate undesired signal cross-feed from the EM source to the first cable segment, which may aid in maintaining data quality.

Electrically isolated streamer section

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.

Adjustable sensor streamer stretch section for noise control for geophysical sensor streamers

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.

Method and system for streamer depth control

Disclosed are methods and systems that include a multiple-tube electrode assembly. An embodiment discloses an electrode assembly, comprising: a carrier body comprising an elongated support; and electrically conducting surfaces longitudinally spaced along the carrier body, wherein the electrically conducting surfaces are electrically coupled in parallel.

Electrode assembly for marine electromagnetic geophysical survey sources

Disclosed are methods and systems for conditioning electrodes while deployed in the sea with a marine electromagnetic survey system. An embodiment of the method may comprise deploying electrodes in seawater during a marine electromagnetic survey. The method further may comprise coupling at least one of the electrodes to a controllable current/voltage source while the electrodes are deployed in the seawater. The method further may comprise sending a first conditioning signal from the controllable current/voltage source to the at least one of the electrodes coupled to the controllable current/voltage source.

System and method for in-sea electrode conditioning

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.

Noise suppression by adaptive speed regulations of towed marine geophysical streamer

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.

Acquisition system and method for towed electromagnetic sensor cable and source

Disclosed are methods and systems for suppression of noise in electromagnetic surveying that includes stacking two or more frames of electromagnetic data. An example embodiment discloses a method for suppressing swell-induced noise in an electromagnetic survey, comprising: measuring an electromagnetic field parameter at one or more positions to provide an electromagnetic signal, the electromagnetic signal comprising a swell-induced portion; and stacking two or more frames of the electromagnetic signal to provide a stacked signal in which the swell-induced portion is suppressed, wherein the swell-induced portion is out of phase between the two or more frames.

Method and system for suppressing swell-induced electromagnetic noise

A marine electromagnetic survey source includes a power cable configured to couple to a high voltage power supply at one axial end and to a head unit at the other axial end. The head unit includes equipment configured to output a lower voltage at higher current than the current imparted thereto by high voltage power supply. The head unit has an electrically conductive exterior coupled to one output terminal of the equipment. An electromagnetic antenna cable having an electrode thereon is coupled to the head unit and configured to receive the output of another terminal of the head unit equipment. In some implementations, electromagnetic fields are induced in formations by conducting current to the equipment. Marine geophysical surveys are conducted utilizing such induction of electromagnetic fields.

Power converter and electrode combinations for electromagnetic survey source

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.

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Segeltorp, Sweden

Ulf Peter Lindqvist