Patents by Inventor Svein Erling Johnstad
Svein Erling Johnstad 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).
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Patent number: 9176254Abstract: A geophysical sensor cable has one or more sensor cable sections. Each of the sensor cable sections is provided with seismic and electromagnetic sensors arranged along said cable. The seismic sensors include a hydrophone and a seismic component receiver for seismic vector measurements while the sensor cable is at the sea-floor. The electromagnetic sensors include both E-field sensors and H-field sensors. The E-field sensors include pairs of first and second electrodes arranged with different positions along the cable and connected to a voltage amplifier. The H-field sensors include three mutually orthogonally arranged H-field component sensors.Type: GrantFiled: March 16, 2009Date of Patent: November 3, 2015Assignee: MULTIFIELD GEOPHYSICS ASInventor: Svein Erling Johnstad
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Patent number: 8299794Abstract: A method for electromagnetic geophysical surveying of rock formations (1) under a sea-floor (3) comprising the following steps: *—towing first and second alternating field (E1, E2) emitting sources (s1, S2) in first and second depths below the sea surface, said first field (E1) having a first phase (?1);—said second alternating field (E2) given a second phase (?2) different from said first phase (?1), said sources (S1, S2) constituting a phased array emitter antenna with directivity for transmitting a major proportion of the combined electromagnetic energy downwards;—said first and second fields (E1, E2) for propagating partly down through the sea-floor (3) and being reflected and/or refracted through said rock formations (1) and partly propagating back through the seafloor (3);—said first and said second fields (E1, E2) for merging to a total field and being measured by electromagnetic receivers (r1, r2, . . . , rn) recording corresponding field registrations (Er1(t), Er2(t), Er3(t), . . . , Ern(t)).Type: GrantFiled: May 16, 2007Date of Patent: October 30, 2012Assignee: Norsk Hydro ASAInventors: Brian Anthony Farrelly, Svein Erling Johnstad
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Patent number: 7982465Abstract: A method for analyzing acquired electromagnetic measurements (R) made at or in a sea (4) over a seafloor (1) with rock formations (3) having relatively low resistivity (?3) for detecting a possibly underlying petroleum bearing reservoir formation (2) having relatively high resistivity (?2), wherein a low frequency electromagnetic transmitter (5) arranged in the sea (4) emits an electromagnetic field (P) propagating in the sea (4), in the rocks (3, 2) and in the air (0) above the sea; wherein electromagnetic sensors (6) are arranged with desired offsets (x) in the sea (4) for measuring the electromagnetic field (P(x)) while the field propagates, characterized in that one or more component of the electromagnetic field (P) is measured at least one large offset (xL) from the transmitter (5) where the field (P) essentially only has its origin from the field propagating as a field (P0) through the air (0); that the one or more components of the electromagnetic field (P) measured at the large offset (xL) is calculatType: GrantFiled: February 12, 2007Date of Patent: July 19, 2011Assignee: Multifield Geophysics ASInventors: Harald Westerdahl, Svein Erling Johnstad, Brian Anthony Farrelly
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Publication number: 20110158043Abstract: A geophysical sensor cable has one or more sensor cable sections. Each of the sensor cable sections is provided with seismic and electromagnetic sensors arranged along said cable. The seismic sensors include a hydrophone and a seismic component receiver for seismic vector measurements while the sensor cable is at the sea-floor. The electromagnetic sensors include both E-field sensors and H-field sensors. The E-field sensors include pairs of first and second electrodes arranged with different positions along the cable and connected to a voltage amplifier. The H-field sensors include three mutually orthogonally arranged H-field component sensors.Type: ApplicationFiled: March 16, 2009Publication date: June 30, 2011Applicant: MULTIFIELD GEOPHYSICS ASInventor: Svein Erling Johnstad
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Patent number: 7812611Abstract: A method for determining electrical properties of a submarine petroleum fluid-bearing formation (1) under overburden geological layers (2) of thickness (s) under a seafloor (3) of a sea. The method includes: *arranging one or more transmitter antennas (9) in the sea, and arranging one or more electromagnetic receivers (8) in the sea, *the sea having a shallow sea depth (d) of 50-350 meters; *using the transmitter antenna (9) transmitting electromagnetic signals (10) of one or more pulses (11) having frequency of very low frequency between 0.01 Hz and 0.Type: GrantFiled: January 9, 2006Date of Patent: October 12, 2010Assignee: Norsk Hydro ASAInventors: Svein Erling Johnstad, Brian Anthony Farrelly
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Publication number: 20090278541Abstract: A method for analysing acquired electromagnetic measurements (R) made at or in a sea (4) over a seafloor (1) with rock formations (3) having relatively low resistivity (?3) for detecting a possibly underlying petroleum bearing reservoir formation (2) having relatively high resistivity (?2), wherein a low frequency electromagnetic transmitter (5) arranged in the sea (4) emits an electromagnetic field (P) propagating in the sea (4), in the rocks (3, 2) and in the air (0) above the sea; wherein electromagnetic sensors (6) are arranged with desired offsets (x) in the sea (4) for measuring the electromagnetic field (P(x)) while the field propagates, characterized in that one or more component of the electromagnetic field (P) is measured at least one large offset (xL) from the transmitter (5) where the field (P) essentially only has its origin from the field propagating as a field (P0) through the air (0); that the one or more components of the electromagnetic field (P) measured at the large offset (xL) is calculatType: ApplicationFiled: February 12, 2007Publication date: November 12, 2009Applicant: Multifield Geophysics ASInventors: Harald Westerdahl, Svein Erling Johnstad, Brian Anthony Farrelly
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Publication number: 20090267608Abstract: A method for determining electrical properties of a submarine petroleum fluid-bearing formation (1) under overburden geological layers (2) of thickness (s) under a seafloor (3) of a sea (4), said method comprising the following steps: arranging one or more transmitter antennas (9) in said sea (4), and arranging one or more electromagnetic receivers (8) in said sea (4), said sea having a shallow sea depth (d) of 50-350 meters; using said transmitter antenna (9) transmitting electromagnetic signals (10) of one or more pulses (11) having frequency of very low frequency between 0.01 Hz and 0.Type: ApplicationFiled: January 9, 2006Publication date: October 29, 2009Inventors: Svein Erling Johnstad, Brian Anthony Farrelly
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Publication number: 20090243617Abstract: A method for electromagnetic geophysical surveying of rock formations (1) under a sea-floor (3) comprising the following steps: * —towing first and second alternating field (E1, E2) emitting sources (s1, S2) in first and second depths below the sea surface, said first field (E1) having a first phase (?1); —said second alternating field (E2) given a second phase (?2) different from said first phase (?1), said sources (S1, S2) constituting a phased array emitter antenna with directivity for transmitting a major proportion of the combined electromagnetic energy downwards; —said first and second fields (E1, E2) for propagating partly down through the sea-floor (3) and being reflected and/or refracted through said rock formations (1) and partly propagating back through the seafloor (3); —said first and said second fields (E1, E2) for merging to a total field and being measured by electromagnetic receivers (r1, r2, . . . , rn) recording corresponding field registrations (Er1(t), Er2(t), Er3(t), . . . , Ern(t)).Type: ApplicationFiled: May 16, 2007Publication date: October 1, 2009Inventors: Brian Anthony Farrelly, Svein Erling Johnstad
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Patent number: 7456632Abstract: A method for monitoring a high-resistivity reservoir rock formation (2) below one or more less resistive formations (3). The method includes transmitting an electromagnetic signal (S) propagating from near a seafloor or land surface (1) by means of an electromagnetic transmitter (5) powered by a voltage signal generator (G). The electromagnetic signal (S) propagates from the seafloor (1) and is guided along a conductive string (7) to the high-resistive formation (2), and propagates as a guided-wave electromagnetic signal (S2) at a relatively higher speed (V2) inside the high-resistivity formation (2) than a propagation speed (V3) in the less resistive formations (3).Type: GrantFiled: March 22, 2004Date of Patent: November 25, 2008Assignee: Norsk Hydro ASAInventors: Svein Erling Johnstad, Fan-Nian Kong, Harald Westerdahl
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Patent number: 7453265Abstract: A device for monitoring the position of an oil/water contact (OWC, 22) between an oil-continuous fluid (2o) overlying a water-continuous fluid (2w) inside a casing pipe (7). The device includes a transmitter (5) for a generating an electromagnetic signal (ST) and the transmitter (5) is provided with electrical energy (GT) from a voltage signal generator (G). The transmitter (5) is arranged inside the casing pipe (7) in the oil-continuous fluid (2o) and above the oil-water contact (22). The electromagnetic wave signal (ST) partly propagates downwards from the transmitter (5), is partly reflected from the oil-water contact (22), and is partly reflected by the end of the casing, giving rise to an upward propagating, reflected electro-magnetic signal (SR).Type: GrantFiled: March 19, 2004Date of Patent: November 18, 2008Assignee: Norsk Hÿdro ASAInventors: Svein Erling Johnstad, Fan-Nian Kong, Harald Westerdahl
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Patent number: 7453763Abstract: The invention includes a geographical sensor apparatus for use under water in the sea, including a plurality of seismic sensors (1) for sensing seismic waves associated with underground formations, and a plurality of EM-sensors constituted preferably by electrodes (4) for sensing electromagnetic waves associated with the underground formations. In a preferred receiver cable configuration embodiment of the invention, the geophysical sensor apparatus includes a seismic receiver cable with a linear array of a plurality of seismic sensors (1) and EM-sensors arranged inside a flexible outer skin (25), with the EM-sensors having electrodes on the outside of the outer skin. The cable is operated on the seafloor by a surface vessel, the vessel towing an electromagnetic transmitter antenna in addition to the seismic source.Type: GrantFiled: June 18, 2004Date of Patent: November 18, 2008Assignee: Norsk Hydro ASAInventor: Svein Erling Johnstad