Statoil Asa

Statoil Petroleum As

Other

Norskhydro Asa

Den Norske Stats Oljeselskap A.s.

Equinor Energy As

Electromagnetic Geoservices As

Multifield Geophysics As

Norgas Geotekniske Institut

Norges Geotekniske Insitutt

Norges Geotekniske Institutt

Harald Westerdahl

Fan-nian Kong

Svein Ellingsrud

Terje Eidesmo

Lasse Amundsen

Mark Thompson

Svein Erling Johnstad

Stale Johansen

Per Magnus Sparrevik

Vidar Sten-Halvorsen

Peter Hanssen

Brian Anthony Farrelly

Einar St&oslash;len

Stephen Walter Hayes

Christian Madshus

Ben King

Svend Østmo

Klaus Tronstad

Marit Stustad Guttormsen

Fan-Nian Kong

A method for use in surveying a subsurface region beneath a body of water by detecting compressional, P, waves propagating through the body of water includes locating one or more sensor systems in the water at or close to the subsurface region, using the or each sensor system to detect P waves in the water, and translating all or a portion of the data representing the detected P waves to a higher level above the subsurface region. In the method, the effects of S waves, propagating in the subsurface and converted at the water/subsurface interface into P waves propagating in the water or along the seabed interface, in the translated data is reduced.

P/S wave measurement and compensation

A method of at least partially deghosting recorded seismic s-waves, wherein recorded seismic data is provided, wherein the recorded seismic data has been recorded at a receiver located beneath the Earth's surface, and wherein the recorded seismic data includes s-wave data. The method may include the steps of finding a model of the Earth's crust for use in deghosting the recorded seismic data using the s-wave data, wherein the model includes at least one region and wherein the model includes the Earth's surface and the location of the receiver, using the model to find a deghosting operator that, when applied to the s-wave data, at least partially deghosts the s-wave data, and applying the deghosting operator to the s-wave data to at least partially deghost the s-wave data.

Method for deghosting seismic data

A sensor system for deployment on or close to the seabed in marine seismic surveys includes a central hub, and a plurality of arms coupled to the central hub. Each arm has a degree of freedom of movement with respect to the central hub. The system further includes at least one seismic sensor mounted to each of said arms.

Seismic sensor recording system

A method for use in surveying a subsurface region beneath a body of water by detecting S waves propagating through the subsurface region. The method comprises using a first sensor configuration to detect mixed S and P waves on or in the subsurface region, using a second sensor configuration located on or in relatively close proximity to the subsurface region to detect P waves in the water, and using the P waves detected in the water to compensate the detected mixed S and P waves, and thereby attenuate the effects of P waves in the mixed S and P waves.

An apparatus for conducting a marine seismic survey is disclosed. The apparatus includes a plurality of sensors configured to measure water pressure, a horizontal derivative of the pressure in two orthogonal directions, vertical particle velocity or acceleration of the water, and a horizontal derivative of the vertical particle velocity or acceleration in two orthogonal directions.

Apparatus for marine seismic survey

A method of providing seismic data (such as marine seismic data). A seismic source is actuated at a plurality of source locations (S, S). For each source location, a multicomponent seismic measurement is performed at least one receiver location (S). A reconstructing method is applied to each multicomponent measurement to obtain additional data corresponding to source locations additional to the source locations at which the source was actuated (S). The additional data are output and/or used (S).

Method of providing seismic data

A method for analyzing acquired electromagnetic measurements (R) made at or in a sea () over a seafloor () with rock formations () having relatively low resistivity (&#x3c1;) for detecting a possibly underlying petroleum bearing reservoir formation () having relatively high resistivity (&#x3c1;), wherein a low frequency electromagnetic transmitter () arranged in the sea () emits an electromagnetic field (P) propagating in the sea (), in the rocks () and in the air () above the sea; wherein electromagnetic sensors () are arranged with desired offsets (x) in the sea () 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 (x) from the transmitter () where the field (P) essentially only has its origin from the field propagating as a field (P) through the air (); that the one or more components of the electromagnetic field (P) measured at the large offset (x) is calculated back to a recalculated field (F(x)) to one or more offsets (x) being shorter than the large offset (x); that the recalculated field (P(X)) is subtracted from the field (P(x)) for possibly highlighting a field which arising due to the possibly petroleum bearing reservoir formation () having relatively high resistivity (&#x3c1;).

Electromagnetic method on shallow water using a controlled source

A method for monitoring a high-resistivity reservoir rock formation () below one or more less resistive formations (). The method includes transmitting an electromagnetic signal (S) propagating from near a seafloor or land surface () by means of an electromagnetic transmitter () powered by a voltage signal generator (G). The electromagnetic signal (S) propagates from the seafloor () and is guided along a conductive string () to the high-resistive formation (), and propagates as a guided-wave electromagnetic signal (S) at a relatively higher speed (V) inside the high-resistivity formation () than a propagation speed (V) in the less resistive formations (). The guided-wave electromagnetic signal (S) gives rise to an upward refracting electromagnetic signal (R) having the relatively lower propagation speed (V) in the less resistive formations () and having an exit angle nearer to the normal (N) to the interface between the high-resistivity formation () and the lower-resistivity formation (), and gives rise to a steeply rising refraction wave front (F). The refracted electromagnetic wave front (F) includes refracted electromagnetic signals (R) detected along an array of sensor antennas (, . . . ,) positioned along the seafloor. The array having a direction away from the transmitter ().

Method for monitoring low-resistivity formation using polarized waves

A device for monitoring the position of an oil/water contact (OWC,) between an oil-continuous fluid () overlying a water-continuous fluid () inside a casing pipe (). The device includes a transmitter () for a generating an electromagnetic signal (ST) and the transmitter () is provided with electrical energy (G) from a voltage signal generator (G). The transmitter () is arranged inside the casing pipe () in the oil-continuous fluid () and above the oil-water contact (). The electromagnetic wave signal (S) partly propagates downwards from the transmitter (), is partly reflected from the oil-water contact (), and is partly reflected by the end of the casing, giving rise to an upward propagating, reflected electro-magnetic signal (S). The device also includes a sensor () for detecting the reflected electromagnetic signal (S), and the sensor () is also arranged above the oil-water contact (), providing a sensor signal (R) to a receiver () for receiving the sensor signal (R) and further to an analyzing device () for analyzing the sensor signal (R), e.g. with respect to two-way propagation time or amplitude in order to calculate an elevation level for the oil-water contact.

Device for monitoring of oil-water interface

The present invention relates to a system and apparatus for detecting and recovering hydrocarbons located in a subterranean reservoir In some embodiments, an electromagnetic field is applied by a transmitter positioned on a seabed and detected by antenna also positioned on the seabed.

Method and apparatus for recovering hydrocarbons from subterranean reservoirs

A method for mapping a submarine or subterranean reservoir by conducting an electromagnetic survey using an electromagnetic field in the form of a wave. An electromagnetic field is applied by a transmitter on the seabed and detected by antennae. The nature of the detected reflected waves is used to determine whether the reservoir contains water or hydrocarbons, which may then be produced from a well that penetrates the reservoir.

Electromagnetic surveying for mapping the content of subterranean reservoirs

A system for investigating subterranean strata. An electromagnetic field is applied using a dipole antenna transmitter and this is detected using a dipole antenna receiver. Phase information is extracted from a refracted wave response and used to identify the presence and/or nature of a subterranean reservoir.

Electromagnetic method and apparatus for determining the nature of subterranean reservoirs using refracted electromagnetic waves

A system for investigating subterranean strata. An electromagnetic field is applied using a fixed dipole antenna transmitter and this is detected using a dipole antenna receiver. The receiver is moved from one location to another in dependence upon the strength of the detected signal.

Electromagnetic methods and apparatus for determining the content of subterranean reservoirs

Methods and devices are disclosed for determining if hydrocarbons or water is present in a subterranean reservoir are described. Certain embodiments involve an electromagnetic field applied by a transmitter on the seabed and detected by at least one antenna also on the seabed, wherein a refracted wave component is sought in the wave field response, and is analyzed to determine the nature and contents of the resevoir.

Method and apparatus for determining the nature of subterranean reservoirs using refracted electromagnetic waves

A method for investigating subterranean strata. An electromagnetic field is applied using a dipole antenna transmitter and this is detected using a dipole antenna receiver. Phase information is extracted from a refracted wave response and used to identify the presence and/or nature of a subterranean reservoir.

Growing community of inventors

Dal, Norway

Harald Westerdahl