Patents Represented by Attorney E. Eugene Thigpen
  • Patent number: 7957906
    Abstract: A calculated vertical velocity sensor signal is determined from a recorded pressure sensor signal. A constructed vertical velocity sensor signal is determined as a linear combination of the calculated vertical velocity sensor signal and a recorded vertical velocity sensor signal in dual-sensor seismic streamer data, using a mixture coefficient as a proportionality constant. An upgoing pressure wavefield component is determined as one half of a difference of the recorded pressure sensor signal and the constructed vertical velocity sensor signal, as a function of the mixture coefficient. An error in the upgoing pressure wavefield component is determined by propagating errors in the recorded pressure sensor signal and constructed vertical velocity sensor signal terms. A value of the mixture coefficient is determined that minimizes the error in the upgoing pressure wavefield component.
    Type: Grant
    Filed: May 7, 2008
    Date of Patent: June 7, 2011
    Assignee: PGS Geophysical AS
    Inventor: Neil Turnbull
  • Patent number: 7957904
    Abstract: A method for mapping sub-surface resistivity contrasts comprising making multi-channel transient electromagnetic (MTEM) measurements using at least one electric source with grounded input current electrodes or one magnetic source with current in a wire loop or multi loop and at least one electric field or magnetic field receiver, measuring the resultant earth response simultaneously at each receiver using a known recording system, measuring the system response by measuring directly the current in the wire at the source using effectively the same recording system, using the measured system response to recover the impulse response of the earth from each measured earth response, and creating from such impulse responses a sub-surface representation of resistivity contrasts.
    Type: Grant
    Filed: December 13, 2005
    Date of Patent: June 7, 2011
    Assignee: MTEM Ltd.
    Inventors: Anton Ziolkowski, Bruce Hobbs, Graham Dawes, David Wright
  • Patent number: 7957221
    Abstract: A method for determining upgoing pressure components of seismic signals from signals detected by combined pressure responsive sensors and motion responsive seismic sensors disposed in a plurality of laterally spaced apart streamers includes determining a threshold time at which angle of incidence error in the motion responsive signals in the cross-line direction falls below a selected threshold. Below the threshold time, the motion responsive signals are corrected for angle of incidence in the in-line and cross-line directions. Above the threshold time, the motion responsive signals are corrected for angle of incidence only in the in-line direction. Both sets of incidence corrected measured motion responsive signals, and the pressure responsive signals are used to determine upgoing or downgoing pressure components or upgoing or downgoing motion components of the measured motion responsive and pressure responsive seismic signals.
    Type: Grant
    Filed: November 14, 2008
    Date of Patent: June 7, 2011
    Assignee: PGS Geophysical AS
    Inventors: Tilman Klüver, Hocine Tabti, Anthony James Day
  • Patent number: 7929373
    Abstract: A time-dependent arrival angle is determined at a single receiver station in a towed streamer. Up-going and down-going pressure wavefields are calculated from pressure and vertical particle velocity wavefields measured at the receiver station. Extrapolated up-going and down-going pressure wavefields are generated from the up-going and down-going pressure wavefields displaced by a time delay based upon the time-dependent arrival angle.
    Type: Grant
    Filed: November 19, 2008
    Date of Patent: April 19, 2011
    Assignee: PGS Geophysical AS
    Inventor: Frederick James Barr, Jr.
  • Patent number: 7926614
    Abstract: A marine seismic streamer includes a jacket substantially covering an exterior of the streamer. At least one strength member is disposed along the length of the jacket. A sensor mount is coupled to the strength member. At least one particle motion sensor is suspended within the sensor mount at a selected location along the jacket. The at least one particle motion sensor is suspended in the jacket by at least one biasing device. A mass of the particle motion sensor and a force rate of the biasing device are selected such that a resonant frequency of the particle motion sensor within the sensor jacket is within a predetermined range. The sensor mount is configured such that motion of the jacket, the sensor mount and the strength member is substantially isolated from the particle motion sensor.
    Type: Grant
    Filed: October 17, 2008
    Date of Patent: April 19, 2011
    Assignee: PGS Americas, Inc.
    Inventors: Stig Rune Lennart Tenghamn, Andre Stenzel
  • Patent number: 7881153
    Abstract: A paravane for a seismic acquisition system includes a float, a frame suspended from the float, deflectors affixed to the frame, and means for coupling a tow rope to a lead-in functionally extending between a forward end and an aft end of the frame. The paravane includes means for selectively changing an effective position along the lead-in of the means for coupling the tow cable.
    Type: Grant
    Filed: August 21, 2007
    Date of Patent: February 1, 2011
    Assignee: PGS Geophysical AS
    Inventors: Jan Erik Stokkeland, Ole-Fredrik Semb
  • Patent number: 7881158
    Abstract: A seismic vibrator includes a transducer, a reactive mass, a base plate to couple motion of the reactive mass to subsurface formations and a linkage system configured to couple motion of the transducer to the reactive mass and the base plate. The linkage system cooperates with the reactive mass and the transducer to define a first resonant frequency and a second resonant frequency within a range of 1 to 300 Hz.
    Type: Grant
    Filed: June 30, 2008
    Date of Patent: February 1, 2011
    Assignee: PGS Geophysical AS
    Inventor: Stig Rune Lennart Tenghamn
  • Patent number: 7881159
    Abstract: A seismic streamer includes at least one array of sensors each disposed in a sensor holder at longitudinally spaced apart locations. A longitudinal orientation of at least one sensor or at least one sensor holder is different from that of the other sensors along the length of the array.
    Type: Grant
    Filed: December 18, 2006
    Date of Patent: February 1, 2011
    Assignee: PGS Geophysical AS
    Inventors: Stian Hegna, Øyvind Hillesund
  • Patent number: 7872942
    Abstract: A pressure wavefield and a normal velocity wavefield measured on a smoothly shaped acquisition surface by towed dual-sensor marine seismic streamers are decomposed into up-going and down-going pressure and particle velocity components on an observation level between the acquisition surface and a sea surface of undetermined shape. The up-going and down-going pressure and particle velocity components are extrapolated iteratively in steps from the observation level toward the sea surface. An image point and a reflection coefficient of the sea surface at the image point are determined from the iteratively extrapolated up-going and down-going pressure and particle velocity components.
    Type: Grant
    Filed: October 14, 2008
    Date of Patent: January 18, 2011
    Assignee: PGS Geophysical AS
    Inventor: Walter Söllner
  • Patent number: 7869303
    Abstract: A method for identifying a position of a source of noise in a marine seismic record includes defining, for at least one shot record, a set of possible noise source positions. A difference between travel time of noise from each possible noise source position to each of a plurality receiver position for the at least one shot record is determined. Signals from at least a subset of the receiver positions are time-aligned with respect to the difference between travel times for each possible noise source position. The time-aligned signals are then stacked. The noise source position is determined from the stacked, time-aligned signals. This result can then be used to construct a model of the noise at the receiver position.
    Type: Grant
    Filed: August 14, 2007
    Date of Patent: January 11, 2011
    Assignee: PGS Geophysical AS
    Inventor: Jack Dewayne Kinkead
  • Patent number: 7835225
    Abstract: Signals detected by particle motion sensors in a towed dual sensor marine seismic streamer are scaled to match signals detected by pressure sensors in the streamer. The pressure sensor signals and the scaled particle motion sensor signals are combined to generate up-going and down-going pressure wavefield components. The up-going and down-going pressure wavefield components are extrapolated to a position just below a water surface. A first matching filter is applied to the extrapolated down-going pressure wavefield component. The filtered down-going pressure wavefield component is subtracted from the extrapolated up-going pressure wavefield component, generating an up-going pressure wavefield component with attenuated particle motion sensor noise. A second matching filter is applied to the extrapolated up-going pressure wavefield component.
    Type: Grant
    Filed: October 11, 2006
    Date of Patent: November 16, 2010
    Assignee: PGS Geophysical AS
    Inventors: Walter Söllner, Xiao-Ping Li, Martin Widmaier
  • Patent number: 7834632
    Abstract: A receiver streamer system for marine electromagnetic surveying includes a first streamer, and a second streamer disposed substantially parallel to and spaced apart from the first streamer. A first pair of electrodes is associated with the first streamer and a second pair of electrodes is associated with the second streamer. Each of the first and second pairs of electrodes is functionally associated with a voltage measuring circuit configured to measure voltage along an inline direction. At least one electrode on each of the first and second streamers is configured and associated with a voltage measuring circuit to make voltage measurements in a cross-line direction.
    Type: Grant
    Filed: December 3, 2007
    Date of Patent: November 16, 2010
    Assignee: PGS Geophysical AS
    Inventors: Stig Rune Lennart Tenghamn, Eivind Fromyr, Marit Ronaess, Rune Johan Magnus Mattsson, Ulf Peter Lindqvist, Lena Kristina Frenje Lund, Anders Göran Mattsson, Toril Margrethe Bruun Vaage
  • Patent number: 7830747
    Abstract: Three data subsets are obtained in three selected azimuthal directions from seismic data in heterogeneous, anisotropic media. Azimuthal velocities are determined for each of the data subsets. A linear system of equations in the three selected azimuthal directions and the three determined azimuthal velocities is solved for three independent parameters. An azimuthal time migration velocity function is constructed from the three solved independent parameters. A time migration traveltime function is constructed from the constructed azimuthal time migration velocity function.
    Type: Grant
    Filed: November 1, 2006
    Date of Patent: November 9, 2010
    Assignee: PGS Geophysical AS
    Inventor: Walter Söllner
  • Patent number: 7822515
    Abstract: An ocean bottom cable system includes a sensor cable configured to be extended from a vessel to the bottom of the body of water. The sensor cable includes a plurality of seismic sensor units at spaced apart locations. A lead in cable is coupled at a to at least one of the vessel and a buoy, and to an aft lead in cable segment. The segment includes a cable loop to compensate water-caused motion of the lead in cable substantially without moving the sensor units. A first swivel is disposed between a forward end of the sensor cable and an aft end of the aft lead in cable segment. The first swivel enables relative rotation between the sensor cable and the segment. At least a second swivel is disposed between the second end of the lead in cable and a forward end of the aft lead in segment.
    Type: Grant
    Filed: July 30, 2007
    Date of Patent: October 26, 2010
    Assignee: PGS Americas, Inc.
    Inventors: Nicholas C. George, Ole-Fredrik Semb
  • Patent number: 7800976
    Abstract: A lateral force and depth control device for a marine streamer includes a housing configured to be coupled within the streamer. A control surface is mounted to the housing such that a rotary orientation and an angle of attack of the control surface with respect to the housing are changeable. The device includes means for moving the control surface to a selected rotary orientation with respect to the housing. The device includes means for moving the control surface to a selected angle of attack with respect to the housing. A removable coupling is provided to couple the control surface to the means for moving to a selected rotary orientation and means for moving to a selected angle of attack.
    Type: Grant
    Filed: June 28, 2007
    Date of Patent: September 21, 2010
    Assignee: PGS Geophysical AS
    Inventors: Jan Erik Stokkeland, Jon Falkenberg
  • Patent number: 7795873
    Abstract: A method for measuring the electromagnetic response of formations below the bottom of a body of water includes positioning at least one electromagnetic transmitter and at least one electromagnetic receiver in the body of water each at a selected depth below the water surface. A transient electric current is passed through the at least one transmitter. An electromagnetic signal is detected at the at least one electromagnetic receiver. The depths are selected so that substantially all electromagnetic response to the current passed through the transmitter from the air above the body of water in the detected electromagnetic signal occurs before the beginning of a response originating in the formations below the water bottom.
    Type: Grant
    Filed: July 15, 2008
    Date of Patent: September 14, 2010
    Assignee: MTEM Ltd
    Inventors: Antoni Marjan Ziolkowski, David Allan Wright
  • Patent number: 7768869
    Abstract: A method is disclosed for deghosting and water surface multiple reflection attenuation in marine seismic data. The method includes decomposing data acquired at two water depths with sensors that measure the same parameter into upgoing and downgoing wavefield components. The decomposing includes, in one embodiment, transforming the data into the spatial Fourier domain and separating the upgoing and downgoing wavefield components in the transformed data. A substantially multiple-free wavefield is then determined from the decomposed wavefield components.
    Type: Grant
    Filed: May 5, 2005
    Date of Patent: August 3, 2010
    Assignee: PGS Americas, Inc.
    Inventors: Peter M. van den Berg, Jacob T. Fokkema
  • Patent number: 7751277
    Abstract: An estimated frequency-wavenumber spectrum is generated by applying a first Anti-leakage Fourier transform method to unaliased frequency components in temporal-transformed seismic data and applying a second Anti-leakage Fourier transform method to aliased frequency components in the temporal-transformed seismic data. The second Anti-leakage Fourier transform method applies an absolute frequency-wavenumber spectrum extrapolated from unaliased frequencies to aliased frequencies to weight frequency-wavenumber components of the aliased frequencies. An inverse temporal and spatial Fourier transform is applied to the estimated frequency-wavenumber spectrum, generating trace interpolation of the seismic data.
    Type: Grant
    Filed: March 17, 2008
    Date of Patent: July 6, 2010
    Assignee: PGS Geophysical AS
    Inventor: Michel Albert Schonewille
  • Patent number: 7737698
    Abstract: A detector for a marine electromagnetic survey system includes a housing arranged to minimize turbulence when the housing is towed through a body of water, and to minimize motion of the housing in any direction other than the tow direction. The housing includes at least one of an electric field and a magnetic field sensing element associated therewith.
    Type: Grant
    Filed: September 13, 2006
    Date of Patent: June 15, 2010
    Assignee: PGS Geophysical AS
    Inventors: Stig Rune Lennart Tenghamn, Rune Johan Magnus Mattsson, Peter Gunnar Krylstedt, Mattias Fredrik Karlsson, Ulf Peter Lindqvist, Per Anders Davidsson
  • Patent number: 7733740
    Abstract: A seismic streamer includes a jacket covering an exterior of the streamer. At least one strength member extends along the length of and disposed inside the jacket. At least one seismic sensor is mounted in a housing affixed to the at least one strength member. A void filling material fills the interstices inside the jacket. The housing is configured to isolate the at least one sensor from pressure variations in the void filling material, and the housing is configured to couple the at least one sensor to a body of water outside the streamer.
    Type: Grant
    Filed: March 30, 2007
    Date of Patent: June 8, 2010
    Assignee: PGS Geophysical AS
    Inventors: Oyvind Hillesund, Stian Hegna