Patents by Inventor Stian Hegna

Stian Hegna has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20130325427
    Abstract: Methods and systems for computing notional source signatures from modeled notional signatures and measured near-field signatures are described. Modeled near-field signatures are calculated from the modeled notional signatures. Low weights are assigned to parts of a source pressure wavefield spectrum where signatures are less reliable and higher weights are assigned to parts of the source pressure wavefield spectrum where signatures are more reliable. The part of the spectrum where both sets of signatures are reliable can be used for quality control and for comparing the measured near-field signatures to modeled near-field signatures. When there are uncertainties in the input parameters to the modeling, the input parameters can be scaled to minimize the differences between measured and modeled near-field signatures.
    Type: Application
    Filed: May 30, 2012
    Publication date: December 5, 2013
    Applicant: PGS Geophysical AS
    Inventors: Stian Hegna, Fabien Julliard
  • Publication number: 20130322205
    Abstract: Techniques are disclosed relating to determining or executing a survey pattern for a marine seismic survey vessel. The survey pattern may be determined based on a determined subsurface illumination area. The subsurface illumination area may be identifiable from primary reflections and higher-order reflections detected by sensors disposed in a sensor streamer configuration that may be towed behind the survey vessel. The sensor streamer configuration may include a plurality of streamers.
    Type: Application
    Filed: May 31, 2012
    Publication date: December 5, 2013
    Inventors: Martin Widmaier, Walter Sollner, Stian Hegna, Steve Bishop
  • Publication number: 20130322208
    Abstract: Systems and methods for imaging subterranean formations using primary and multiple reflections are described. An exploration-seismology vessel tows a seismic source, a receiver acquisition surface located beneath a free surface, and a source acquisition surface positioned at a depth below the source. The receiver acquisition surface is used to measure pressure and normal velocity wavefields and the source acquisition surface is used to measure direct, down-going, source pressure wavefields generated by the source. The down-going source pressure wavefields in combination with the down-going pressure wavefields and up-going pressure wavefields computed from the pressure and velocity wavefields are used to compute images of the subterranean formation associated with primary reflections and multiple reflections.
    Type: Application
    Filed: May 31, 2012
    Publication date: December 5, 2013
    Applicant: PGS Geophysical AS
    Inventors: Walter Sollner, Norman Daniel Whitmore, JR., Stian Hegna, Charles Lameloise, Rune Tonnessen, Gregg Parkes
  • Patent number: 8596409
    Abstract: A disclosed seismic source assembly includes a body having a cavity and a seismic source positioned in the cavity. The cavity is in fluid communication with the water via an aperture oriented in a first direction. One or more surfaces of the body define a water contact significantly larger than an area of the aperture and on a side opposite the first direction. A described method includes forming a source assembly by: providing a cavity having an aperture for transmitting seismic waves; rigidly attaching a base to a side of the cavity opposite the aperture, where a transverse area of the base is significantly larger than an area of the aperture; and positioning a seismic source in the cavity. The source assembly is submerged in the water and triggered.
    Type: Grant
    Filed: October 12, 2011
    Date of Patent: December 3, 2013
    Assignee: PGS Geophysical AS
    Inventors: Gregory Ernest Parkes, Stian Hegna
  • Patent number: 8600680
    Abstract: Recorded seismic data are represented as a convolution of operators representing a reflectivity series of the earth and a seismic wavelet. The recorded seismic wavelet is represented as a convolution of operators representing a receiver ghost, a source ghost, a ghost-free source system response, an earth filter response, and a receiver system response. The operator representing the receiver ghost is removed from the convolution representing the seismic wavelet. The operator representing the source ghost is removed from the convolution representing the seismic wavelet. The operator representing the ghost-free source response is removed from the convolution representing the seismic wavelet. The operator representing the earth filter response is removed from the convolution representing the seismic wavelet. The operator representing the seismic wavelet is removed from the convolution representing the recorded seismic data.
    Type: Grant
    Filed: April 5, 2011
    Date of Patent: December 3, 2013
    Assignee: PGS Geophysical AS
    Inventors: Gregory Ernest Parkes, Stian Hegna, Anthony James Day
  • Publication number: 20130201791
    Abstract: Seismic data are acquired using a seismic source comprising a plurality of seismic sub-sources disposed in a body of water at a plurality of depths and activated with different time delays. Far-field signatures are determined for the plurality of seismic sub-sources at each of the plurality of depths. A composite ghost-free far-field signature of the seismic source is determined from the far-field signatures for the plurality of seismic sub-sources at each of the plurality of depths and different time delays.
    Type: Application
    Filed: February 7, 2012
    Publication date: August 8, 2013
    Inventors: GREGORY ERNEST PARKES, STIAN HEGNA
  • Patent number: 8456950
    Abstract: Three-axis velocity data, obtained along with pressure data in a marine seismic survey, are rotated to a ray direction. Plane wave decomposition is applied in the ray direction to the rotated velocity data. The pressure data and the velocity data are combined to generate at least one of up-going and down-going wave fields. The at least one of up-going and down-going wave fields are used in a time-space domain to image the earth's subsurface.
    Type: Grant
    Filed: July 30, 2010
    Date of Patent: June 4, 2013
    Assignee: PGS Geophysical AS
    Inventor: Stian Hegna
  • Publication number: 20130092469
    Abstract: A disclosed seismic source assembly includes a body having a cavity and a seismic source positioned in the cavity. The cavity is in fluid communication with the water via an aperture oriented in a first direction. One or more surfaces of the body define a water contact significantly larger than an area of the aperture and on a side opposite the first direction. A described method includes forming a source assembly by: providing a cavity having an aperture for transmitting seismic waves; rigidly attaching a base to a side of the cavity opposite the aperture, where a transverse area of the base is significantly larger than an area of the aperture; and positioning a seismic source in the cavity. The source assembly is submerged in the water and triggered.
    Type: Application
    Filed: October 12, 2011
    Publication date: April 18, 2013
    Applicant: PGS GEOPHYSICAL AS
    Inventors: Gregory Ernest PARKES, Stian Hegna
  • Publication number: 20130088938
    Abstract: A disclosed subsurface imaging method begins by obtaining initial signals from a geophysical survey that has been acquired with multiple geophysical energy sources actuated in a plurality of firing sequences, each sequence having a known time delay between the firing times of each source. The initial signals are grouped into gathers of signals acquired from multiple firing sequences. For each gather, initial estimates of the first and second source wave fields are determined. Quieted signals for the first source are then generated to represent the initial signals minus a current estimate of the second source wave field. A coherent energy separation operation is applied to the quieted signals to obtain a refined estimate for the first source wave field.
    Type: Application
    Filed: October 10, 2011
    Publication date: April 11, 2013
    Inventors: Peter Aaron, Stian Hegna, Gregory Parkes
  • Patent number: 8345510
    Abstract: A method for acquisition and processing of marine seismic signals to extract up-going and down-going wave-fields from a seismic energy source includes deploying at least two marine seismic energy sources at different depths in a body of water. These seismic energy sources are actuated with known time delays that are varied from shot record to shot record. Seismic signals from sources deployed at different depths are recorded simultaneously. Seismic energy corresponding to each of the sources is extracted from the recorded seismic signals. Up-going and down-going wave-fields are extracted from the sources deployed at different depths using the extracted seismic energy therefrom. A method includes the separated up-going and down-going wave-fields are propagated to a water surface or a common reference, the up-going or the down-going wave-field is 180 degree phase shifted, and the signals from these modified up-going and down-going wave-fields are summed.
    Type: Grant
    Filed: June 2, 2009
    Date of Patent: January 1, 2013
    Assignee: PGS Geophysical AS
    Inventors: Stian Hegna, Gregory Ernest Parkes
  • Publication number: 20120307591
    Abstract: Disclosed are apparatus and methods for seismic exploration using pressure changes caused by sea-surface variations as a low-frequency seismic energy source. One embodiment relates to a method which obtains dual wave-fields measured below a sea surface. The measured dual wave-fields are decomposed into a down-going wave-field and an up-going wave-field at a selected observation level. Seismic images are then generated using the down-going and up-going wave-fields. Other embodiments, aspects, and features are also disclosed.
    Type: Application
    Filed: May 31, 2011
    Publication date: December 6, 2012
    Inventors: Stian HEGNA, Walter SÖLLNER
  • Publication number: 20120259553
    Abstract: Recorded seismic data are represented as a convolution of operators representing a reflectivity series of the earth and a seismic wavelet. The recorded seismic wavelet is represented as a convolution of operators representing a receiver ghost, a source ghost, a ghost-free source system response, an earth filter response, and a receiver system response. The operator representing the receiver ghost is removed from the convolution representing the seismic wavelet. The operator representing the source ghost is removed from the convolution representing the seismic wavelet. The operator representing the ghost-free source response is removed from the convolution representing the seismic wavelet. The operator representing the earth filter response is removed from the convolution representing the seismic wavelet. The operator representing the seismic wavelet is removed from the convolution representing the recorded seismic data.
    Type: Application
    Filed: April 5, 2011
    Publication date: October 11, 2012
    Inventors: Gregory Ernest Parkes, Stian Hegna, Anthony James Day
  • Publication number: 20120033526
    Abstract: Seismic data are acquired by actuating a first source at a first time and one or more additional seismic sources each with their own characteristic times with respect to a time of signal recording, the sources substantially collocated and at different depths. A first wavefield is determined that would occur if the first source were actuated at a selected time with respect to an initiation time of the recordings and being time adjusted for the water depth. One or more additional wavefields are determined that would occur if the one or more additional sources were each actuated at said selected time with respect to said initiation time, and being time adjusted for water depths of the one or more additional sources. The first wavefield and the one or more additional wavefields are combined to determine a deghosted source wavefield corresponding to actuation of a single seismic energy source.
    Type: Application
    Filed: August 5, 2010
    Publication date: February 9, 2012
    Inventors: STIAN HEGNA, GREGORY ERNEST PARKES
  • Publication number: 20120026829
    Abstract: Three-axis velocity data, obtained along with pressure data in a marine seismic survey, are rotated to a ray direction. Plane wave decomposition is applied in the ray direction to the rotated velocity data. The pressure data and the velocity data are combined to generate at least one of up-going and down-going wave fields. The at least one of up-going and down-going wave fields are used in a time-space domain to image the earth's subsurface.
    Type: Application
    Filed: July 30, 2010
    Publication date: February 2, 2012
    Inventor: Stian Hegna
  • Publication number: 20120002502
    Abstract: In a first embodiment the invention comprises a method for gathering geophysical data, including towing geophysical data gathering equipment behind a survey vessel in a body of water, said equipment including an array of sensor streamers extending behind said vessel, and determining a geodetic location of a streamer steering reference point at a forward end of the sensor streamers and a reference direction. At least one sensor streamer included in said array of sensor streamers is laterally deflected in response to the determined geodetic location of said streamer steering reference point and the determined reference direction.
    Type: Application
    Filed: July 2, 2010
    Publication date: January 5, 2012
    Inventors: Øyvind Hillesund, Stian Hegna
  • Publication number: 20110242937
    Abstract: A measured pressure field, a measured vertical velocity field, and two measured orthogonal horizontal velocity fields are obtained. A programmable computer is used to perform the following. A scaling factor is determined from water acoustic impedance, the measured pressure field, and the horizontal velocity fields. One of the measured pressure field and measured vertical velocity field is combined with one of the measured vertical velocity field scaled by the scaling factor and the measured pressure field scaled by the scaling factor, generating one of up-going and down-going pressure and velocity wavefields.
    Type: Application
    Filed: March 30, 2010
    Publication date: October 6, 2011
    Inventors: Walter Söllner, Stian Hegna
  • 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
  • Publication number: 20100165792
    Abstract: A seismic streamer includes at least one elongated strength member. The seismic streamer further includes a substantially rigid sensor holder coupled to the strength member and fixed in position relative to the strength member. The streamer includes at least one particle motion sensor coupled to the sensor holder and fixed in position relative to the sensor holder.
    Type: Application
    Filed: December 26, 2008
    Publication date: July 1, 2010
    Inventors: Andre Stenzel, Qyvind Hillesund, Nils Lunde, Stian Hegna
  • 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
  • Publication number: 20100008184
    Abstract: A method for acquisition and processing of marine seismic signals to extract up-going and down- going wave-fields from a seismic energy source includes deploying at least two marine seismic energy sources at different depths in a body of water. These seismic energy sources are actuated with known time delays that are varied from shot record to shot record. Seismic signals from sources deployed at different depths are recorded simultaneously. Seismic energy corresponding to each of the sources is extracted from the recorded seismic signals. Up-going and down-going wave-fields are extracted from the sources deployed at different depths using the extracted seismic energy therefrom. A method includes the separated up-going and down-going wave-fields are propagated to a water surface or a common reference, the up-going or the down-going wave-field is 180 degree phase shifted, and the signals from these modified up-going and down-going wave-fields are summed.
    Type: Application
    Filed: June 2, 2009
    Publication date: January 14, 2010
    Inventors: Stian Hegna, Gregory Ernest Parkes