WO2008062024A2 - Method of and apparatus for processing electromagnetic data - Google Patents
Method of and apparatus for processing electromagnetic data Download PDFInfo
- Publication number
- WO2008062024A2 WO2008062024A2 PCT/EP2007/062659 EP2007062659W WO2008062024A2 WO 2008062024 A2 WO2008062024 A2 WO 2008062024A2 EP 2007062659 W EP2007062659 W EP 2007062659W WO 2008062024 A2 WO2008062024 A2 WO 2008062024A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- source
- airwave
- receiver
- water
- reflection
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
- G01V3/12—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with electromagnetic waves
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
- G01V3/08—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices
- G01V3/083—Controlled source electromagnetic [CSEM] surveying
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
- Y02A90/30—Assessment of water resources
Definitions
- the present invention relates to a method of and an apparatus for processing electromagnetic data, for example obtained by means of marine controlled source electromagnetic sounding.
- Marine controlled source electromagnetic (mCSEM) sounding is a technique that can detect offshore hydrocarbon reserves or reserves below inland bodies of water such as lakes. Also known as SeaBed Logging (SBL) (Eidesmo et al., 2002; Ellingsrud et al., 2002), the technique uses a horizontal electric dipole (HED) antenna as a source, emitting an alternating current (AC) typically in the range of 0.01 Hz to 10 Hz. The HED source is towed some 20-4Om above the sea floor while an array of stationary receivers deployed on the sea bottom records the resulting electromagnetic (EM) field.
- HED horizontal electric dipole
- AC alternating current
- the main principle exploited in mCSEM/SBL surveying is that hydrocarbon saturated reservoirs typically are between 5 and 100 times more resistive than the host sediments.
- Such a reservoir will guide EM energy over long distances with low attenuation.
- the electric fields at the receivers at long source-receiver separations will be larger in magnitude than the more-attenuated background electromagnetic fields caused by the host sediments.
- the air layer is known to create a problem, namely the source-induced airwave component.
- the airwave component is dominated by the signal component that diffuses upwards from the source 1 to the sea surface 3 and then propagates through the air at the speed of light with no attenuation, before diffusing back down through the seawater column 2 of depth z b to the sea bottom 4 where it is picked up by the receivers 5.
- the airwave component is of no particular concern to marine electromagnetic practitioners in the deep water environment due to the two-way attenuation of the signal.
- the airwave signal may be dominant at intermediate to long offsets so that the signal from the subsurface, possibly containing valuable information about a resistive hydrocarbon reservoir, is hardly distinguishable.
- the electromagnetic field radiated by the HED source can be considered to consist of two different modes: one transverse electric (TE) mode component and one transverse magnetic (TM) mode component.
- the response of the sea water (and the subsurface) to the source signal is generally very different for the TE and TM mode components.
- the airwave component is known to be predominantly caused by the TE mode component of the source, since the TE mode component is efficiently inductively coupled across the sea water/air interface.
- the TM mode component is known to couple less well across the sea water/air interface, and therefore does not contribute significantly to the airwave component for the finite offsets recorded in mCSEM/SBL surveys.
- p is the dipole moment
- ⁇ is the azimuth angle
- k 0 ⁇ ( ⁇ 0 ⁇ 0 ) 1/2
- ⁇ 0 is the wavenumber in air
- co is the circular frequency
- ⁇ 0 is the magnetic permeability in a vacuum
- ⁇ 0 is the electric permittivity in a vacuum.
- Equation 1 was recently used by Constable and Weiss (2006) to demonstrate the behaviour of the airwave. Constable and Weiss (2006) noted that equation 1 describes the propagation (including attenuation) vertically upwards of the source-side signal from the source through the water column to the sea surface. This upward travelling signal at the sea surface induces an airwave component travelling horizontally through air. The airwave leaks signals into the water column, travelling vertically downward (including attenuation) through the water column to the receiver.
- a method of processing electromagnetic data relating to a region of the earth covered by water and obtained by at least one electromagnetic receiver in response to at least one electromagnetic source comprising providing the electromagnetic data and removing from the electromagnetic data an airwave contribution having a first component propagating without reflection from the at least one source to the at least one receiver and at least one second component whose propagation path from the at least one source to the least one receiver includes at least one vertical portion at at least one of the at least one source and the at least one receiver and which has at least one reflection from at least one of the water surface and the interface between the region and the water.
- the airwave contribution may be removed by subtraction.
- the at least one second component may comprise a plurality of components having propagation paths at the at least one source with different numbers of reflections.
- the airwave contribution may be proportional to:
- the at least one second component may comprise a plurality of components having propagation paths at the at least one receiver with different numbers of reflections.
- the airwave contribution may be proportional to:
- F(x r ) is a function that accounts for the downward field propagation of the source induced airwave from the sea surface to the receiver at location x r , e.g.,
- R r and R 5 are reflection coefficients at the receiver and source side, respectively.
- the seabed conductivity ⁇ 2 may be obtained in several way, for instance by inversion of
- the electromagnetic data may be controlled source electromagnetic data.
- the at least one source may comprise a horizontal electric dipole.
- the method may comprise analysing the processed data for hydrocarbon reserves.
- a drilling method comprising performing a method as defined above and controlling drilling in accordance with the result of the analysis.
- a production method comprising performing a method as defined above and controlling hydrocarbon production in accordance with the result of the analysis.
- an apparatus arranged to perform a method according the first aspect of the invention.
- a computer program arranged to control a computer to perform a method according to the first aspect of the invention.
- a computer-readable medium carrying a program according to the fifth aspect of the invention.
- Figure 1 is a cross-sectional diagram illustrating an mCSEM data-gathering arrangement and an airwave
- Figures 2(a) to 2(f) are diagrams illustrating reflections and reverberations of a field from a HED source inducing an airwave;
- Figures 3(a) to 3(c) are diagrams illustrating a downgoing field from the airwave at a receiver with reflections and reverberations;
- Figures 4(a) to 4(c) are diagrams illustrating three models used during airwave analysis
- Figures 5 and 6 are graphs illustrating amplitude in volts per metre and phase in radians of a radial component of electric fields against source-receiver separation
- Figures 7 to 9 are graphs similar to Figures 5 and 6 for a finite water column model.
- Figure 10 is a graph similar to Figures 5 and 6 for models with and without a hydrocarbon reservoir
- Figure 11 is a graph of normalised amplitude of the radial electric fields against offset in kilometres
- Figure 12 is a graph similar to Figures 5 and 6 of models with and without a reservoir after subtracting the effect of the airwave;
- Figure 13 is a graph similar to Figure 1 1 after subtracting the effect of the airwave.
- an asymptotic, space domain extension of the airwave expression is provided that includes the effect of the seabed.
- the vertically upward travelling TE mode from the source in addition to inducing an airwave component at the sea surface, sets up a reverberation sequence of signals between the sea surface and the sea bottom. Each time a signal in the reverberation sequence hits the surface, a new airwave component is induced.
- the vertically downgoing TE signal from the source to the seabed sets up a reverberation sequence, in which each signal induces an airwave component at the sea surface.
- the initially vertically downgoing signal will reverberate between the seabed and the sea surface.
- a formula for the generalised airwave is derived, in the special case that the seabed conductivity is constant and the seabed depth is the same at the source and receiver sides.
- the source induced airwave is modified due to source side and receiver side seabed reflections and water column reverberations.
- the generalised airwave response of a water layer with varying thickness is then numerically compared with the response obtained from full modeling of Maxwell's equations. For large offsets where the airwave dominates the water layer due to a HED source, the generalised asymptotic airwave modeling is an excellent approximation to the exact airwave.
- Figures 2a to 2f illustrate how the source induced airwave is modified due to the seabed reflection and its associated reverberations.
- the seabed 4 at depth z b has conductivity ⁇ 2 .
- the signal at the sea surface 3 is represented by
- Figure 2d shows that the downward diffusing signal from the source 1 to the seabed 4 is reflected into an upward travelling signal which induces an airwave component at the sea surface 3.
- This water column signal is represented asymptotically as exp(ikz s )Rexp[2ik(z b -z s )],
- Figures 2e and 2f show that the initially downgoing source signal depicted in Figure 2b can reverberate once and twice before the airwave is induced.
- the terms are, respectively:
- s_1 + Rexp[2ik(z b -z s )] 1-Rexp(2ikz b ) (3) is a filter that represents the source-side modification upon the airwave due to the seabed.
- Figures 3a to 3c how the airwave is modified at the receiver side, due to the seabed reflection and its associated reverberations.
- Figure 3a shows that the airwave hits the receiver 5 at depth z r , then is reflected at the seabed 4 and returns upwards to the receiver. The process is described asymptotically as:
- Figures 3b and 3c account for one and two reverberations in the water column, described mathematically as:
- Equation 6 The derivation of equation 6 is based on the conjecture that the HED source in the water column will set up a reflection and reverberation sequence of vertically travelling modes, where each TE mode component at the sea surface 3 will asymptotically induce airwave components. At the receiver side, the airwave components reflect and reverberate in a similar manner to that on the source side.
- Equation 1 we demonstrate the validity of equation 1 and calculate the airwave response for the seawater half-space model bounded by air (Figure 4a).
- equation 6 we verify equation 6 by taking into account the effect of a finite water layer (Figure 4b). The verification is achieved by comparing the responses given in equations 1 and 6 with full numerical modeling of Maxwell's equations for layered media, as described in L ⁇ seth (2000).
- An HED source directed in the radial direction with a frequency of 0.25 Hz and a unit dipole moment is used for all of the models.
- the receivers are situated on the seabed along a line in the same plane as the source.
- Figure 5 shows graphs of amplitude and phase of the radial component of the electric field versus source-receiver separation for the water half-space model.
- the dashed curve gives the airwave component modeled according to equation 1
- the dotted curve shows the response obtained from full EM modeling.
- the solid curve gives the amplitude of the difference between the signals.
- the source depth is now 25 m above the receiver level.
- equation 1 describes the airwave for the water half-space model with sufficient accuracy.
- equation 1 the airwave expression in equation 1 is calculated for a relatively shallow receiver depth of 10 m. A good approximation to the numerically obtained results is given for offsets greater than 1-2 km.
- equation 1 shows good agreement with the responses obtained from full numerical modelling of the electric field for offsets greater than 3-4 km. In this case, the direct field is probably more influential than the airwave component at offsets less than about 3 km.
- the airwave problem in marine CSEM data analysis and interpretation can be illustrated by using the simple 1 D model in Figure 4c. From top to bottom, the model consists of five layers: a nonconductive air layer, a 100-m-thick layer of seawater, a
- FIG. 10 shows graphs of the amplitude and phase of the radial component of the electric field versus offset for the model with a reservoir (dotted curve) and the reference model without a reservoir (solid curve), together with the generalized airwave (dot-dashed curve). The depth of the water layer is shallow, so the airwave dominates the received signal for offsets greater than about 3 km. This is seen from both the amplitude and phase curves.
- the phase is constant for offsets greater than about 4 km, showing where the airwave dominates the field measurements.
- the reservoir model and the nonreservoir model are hardly distinguishable for all offsets.
- the electric amplitude varies over a large range with offset, it is useful to consider the normalized electric amplitude.
- the curve in Figure 1 1 displays the normalized electric amplitude, which is close to unity for all offsets. Therefore, a geophysical interpreter cannot determine reliably whether a resistive hydrocarbon-saturated layer is present in the subsurface. This example clearly demonstrates the problem of the airwave in shallow water.
- the technique described hereinbefore may be used to model and subtract the airwave effect from the recorded electric field, as suggested by Lu et al. (2005), to enhance the response from the reservoir.
- the solid curves in Figure 12 show the amplitude and phase of the electric field versus offset for the five-layer reservoir model discussed above, after modelling according to equation 6 and subtracting the airwave effect.
- Amplitude and phase of the reference electric field, obtained by subtracting the airwave effect from the electric-field data from the nonreservoir model, are displayed by the dashed curves. Observe the large separation of the curves in the 4-10 km offset range, indicating a significant signal from the resistive layer buried 2 km below the seabed.
- the airwave modeling for the electric field is given in equation (6).
- the airwave modeling for the magnetic field is straightforward to derive using the same principle.
- the total air wave response at the receiver location x r for the source at x s is
- the airwave contribution removal technique described herein may be used on electromagnetic data, for example obtained by means of mCSEM techniques.
- a plurality of receivers are disposed on the seabed above the region which is to be explored.
- One or more sources such as horizontal electric dipoles, are towed in the water above the receivers while being actuated and the resulting measurements made by the receivers are stored for subsequent processing.
- the processing comprises or includes a step for removing or at least reducing the contribution from the airwave recorded at each receiver in respect of the or each source.
- An optional preliminary step comprises normalisation as described hereinbefore.
- the airwave contribution is then determined in accordance with equation 6 and optionally in accordance with equation 7.
- the airwave contribution is at least partially removed by subtracting the contribution determined in accordance with these equations.
- the processed data may then be further processed and analysed in order to provide information about any hydrocarbon deposits or reservoirs in the region of interest. If appropriate, MT measurements as described hereinbefore may be used in order to determine apparent conductivity in accordance with equation 8 so as to determine the reflection coefficient at the lower interface of the water column. This may be used in determining airwave contribution.
- This technique may be used in circumstances where the airwave contribution is problematic. For example, this technique may be used for relatively shallow water columns in relation to the frequency of the electromagnetic waves used during measurement.
- the resulting information about hydrocarbon reserve may then be used for a variety of purposes depending on the application.
- the processed data may be used to identify new hydrocarbon reservoirs and to assess the quantities of hydrocarbons present in such reservoirs together with their locations.
- the drilling of wells may then be controlled or directed in order to extract, or optimise the extraction of, the hydrocarbons.
- the quantity of hydrocarbons remaining during production may be determined and used to control production, for example to optimise draining of a reservoir.
- processing techniques are performed by suitably programmed computers.
- a standard type of computer for example of the type typically used for processing hydrocarbon exploration data, may be used and the processing techniques may be encoded as suitable application programs for controlling such computers to perform the processing techniques.
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Remote Sensing (AREA)
- Life Sciences & Earth Sciences (AREA)
- Electromagnetism (AREA)
- Environmental & Geological Engineering (AREA)
- Geology (AREA)
- General Life Sciences & Earth Sciences (AREA)
- General Physics & Mathematics (AREA)
- Geophysics (AREA)
- Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)
- Geophysics And Detection Of Objects (AREA)
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB0909891A GB2458394B8 (en) | 2006-11-22 | 2007-11-21 | Method of and apparatus for processing electromagnetic data |
NO20092363A NO343082B1 (en) | 2006-11-22 | 2009-06-19 | Processing of electromagnetic data including removing the airwave contribution |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB0623279.7 | 2006-11-22 | ||
GBGB0623279.7A GB0623279D0 (en) | 2006-11-22 | 2006-11-22 | Air wave modeling for MCSEM/SBL surveying |
Publications (2)
Publication Number | Publication Date |
---|---|
WO2008062024A2 true WO2008062024A2 (en) | 2008-05-29 |
WO2008062024A3 WO2008062024A3 (en) | 2008-11-27 |
Family
ID=37636313
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/EP2007/062659 WO2008062024A2 (en) | 2006-11-22 | 2007-11-21 | Method of and apparatus for processing electromagnetic data |
Country Status (4)
Country | Link |
---|---|
GB (2) | GB0623279D0 (en) |
NO (1) | NO343082B1 (en) |
RU (1) | RU2423728C2 (en) |
WO (1) | WO2008062024A2 (en) |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2010084117A1 (en) | 2009-01-20 | 2010-07-29 | Statoil Asa | Method of and apparatus for processing csem data, program, storage medium, computer and use of method |
US9195783B2 (en) | 2010-08-16 | 2015-11-24 | Exxonmobil Upstream Research Company | Reducing the dimensionality of the joint inversion problem |
US9453929B2 (en) | 2011-06-02 | 2016-09-27 | Exxonmobil Upstream Research Company | Joint inversion with unknown lithology |
US9494711B2 (en) | 2011-07-21 | 2016-11-15 | Garrett M Leahy | Adaptive weighting of geophysical data types in joint inversion |
US9702995B2 (en) | 2011-06-17 | 2017-07-11 | Exxonmobil Upstream Research Company | Domain freezing in joint inversion |
US9846255B2 (en) | 2013-04-22 | 2017-12-19 | Exxonmobil Upstream Research Company | Reverse semi-airborne electromagnetic prospecting |
US10379255B2 (en) | 2010-07-27 | 2019-08-13 | Exxonmobil Upstream Research Company | Inverting geophysical data for geological parameters or lithology |
US10591638B2 (en) | 2013-03-06 | 2020-03-17 | Exxonmobil Upstream Research Company | Inversion of geophysical data on computer system having parallel processors |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2385923A (en) * | 2002-05-24 | 2003-09-03 | Statoil Asa | Method for electromagnetic wavefield resolution |
WO2005010560A1 (en) * | 2003-06-26 | 2005-02-03 | Exxonmobil Upstream Research Company | Method for removing air wave effect from offshore frequency domain controlled-source electromagnetic data |
WO2005096020A1 (en) * | 2004-04-03 | 2005-10-13 | Statoil Asa | Method and apparatus for deriving a calibration filter for electromagnetic data |
GB2415511A (en) * | 2004-06-26 | 2005-12-28 | Statoil Asa | Processing electromagnetic data |
-
2006
- 2006-11-22 GB GBGB0623279.7A patent/GB0623279D0/en not_active Ceased
-
2007
- 2007-11-21 RU RU2009123488/28A patent/RU2423728C2/en active
- 2007-11-21 WO PCT/EP2007/062659 patent/WO2008062024A2/en active Application Filing
- 2007-11-21 GB GB0909891A patent/GB2458394B8/en not_active Expired - Fee Related
-
2009
- 2009-06-19 NO NO20092363A patent/NO343082B1/en not_active IP Right Cessation
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2385923A (en) * | 2002-05-24 | 2003-09-03 | Statoil Asa | Method for electromagnetic wavefield resolution |
WO2005010560A1 (en) * | 2003-06-26 | 2005-02-03 | Exxonmobil Upstream Research Company | Method for removing air wave effect from offshore frequency domain controlled-source electromagnetic data |
WO2005096020A1 (en) * | 2004-04-03 | 2005-10-13 | Statoil Asa | Method and apparatus for deriving a calibration filter for electromagnetic data |
GB2415511A (en) * | 2004-06-26 | 2005-12-28 | Statoil Asa | Processing electromagnetic data |
Non-Patent Citations (2)
Title |
---|
AMUNDSEN ET AL: "Decomposition of electromagnetic fields into upgoing and downgoing components" GEOPHYSICS,, vol. 71, no. 5, 28 August 2006 (2006-08-28), pages G211-G223, XP002488358 cited in the application * |
NORDSKAG JANNICHE IREN ET AL: "Asymptotic airwave modeling for marine controlled-source electromagnetic surveying" November 2007 (2007-11), GEOPHYSICS; GEOPHYSICS NOVEMBER/DECEMBER 2007, VOL. 72, NR. 6, PAGE(S) F249 - F255 , XP002492816 the whole document * |
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2010084117A1 (en) | 2009-01-20 | 2010-07-29 | Statoil Asa | Method of and apparatus for processing csem data, program, storage medium, computer and use of method |
US20120011130A1 (en) * | 2009-01-20 | 2012-01-12 | Statoil Asa | Method of and apparatus for processing csem data, program, storage medium, computer and use of method |
US10677951B2 (en) | 2009-01-20 | 2020-06-09 | Statoil Petroleum As | Method of and apparatus for processing CSEM data, program, storage medium, computer and use of method |
US10379255B2 (en) | 2010-07-27 | 2019-08-13 | Exxonmobil Upstream Research Company | Inverting geophysical data for geological parameters or lithology |
US9195783B2 (en) | 2010-08-16 | 2015-11-24 | Exxonmobil Upstream Research Company | Reducing the dimensionality of the joint inversion problem |
US9453929B2 (en) | 2011-06-02 | 2016-09-27 | Exxonmobil Upstream Research Company | Joint inversion with unknown lithology |
US9702995B2 (en) | 2011-06-17 | 2017-07-11 | Exxonmobil Upstream Research Company | Domain freezing in joint inversion |
US9494711B2 (en) | 2011-07-21 | 2016-11-15 | Garrett M Leahy | Adaptive weighting of geophysical data types in joint inversion |
US10591638B2 (en) | 2013-03-06 | 2020-03-17 | Exxonmobil Upstream Research Company | Inversion of geophysical data on computer system having parallel processors |
US9846255B2 (en) | 2013-04-22 | 2017-12-19 | Exxonmobil Upstream Research Company | Reverse semi-airborne electromagnetic prospecting |
Also Published As
Publication number | Publication date |
---|---|
GB2458394A8 (en) | 2013-08-07 |
GB2458394B (en) | 2011-03-23 |
RU2423728C2 (en) | 2011-07-10 |
GB0623279D0 (en) | 2007-01-03 |
NO20092363L (en) | 2009-08-18 |
NO343082B1 (en) | 2018-10-29 |
GB0909891D0 (en) | 2009-07-22 |
GB2458394A (en) | 2009-09-23 |
GB2458394B8 (en) | 2013-08-07 |
WO2008062024A3 (en) | 2008-11-27 |
RU2009123488A (en) | 2010-12-27 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
Andreis et al. | Controlled-source electromagnetic sounding in shallow water: Principles and applications | |
Ellingsrud et al. | Remote sensing of hydrocarbon layers by seabed logging (SBL): Results from a cruise offshore Angola | |
US7362102B2 (en) | Electromagnetic surveying for resistive or conductive bodies | |
US8315804B2 (en) | Method of and apparatus for analyzing data from an electromagnetic survey | |
CA2564159C (en) | Electromagnetic surveying for hydrocarbon reservoirs | |
US20070288211A1 (en) | Electromagnetic Surveying for Resistive or Conductive Bodies | |
WO2008062024A2 (en) | Method of and apparatus for processing electromagnetic data | |
Chen et al. | Three methods for mitigating airwaves in shallow water marine controlled-source electromagnetic data | |
Darnet et al. | Detecting hydrocarbon reservoirs from CSEM data in complex settings: Application to deepwater Sabah, Malaysia | |
EP2087379B1 (en) | A method of mapping hydrocarbon reservoirs in shallow waters and also an apparatus for use when practising the method | |
Nordskag et al. | Asymptotic airwave modeling for marine controlled-source electromagnetic surveying | |
WO2005096020A1 (en) | Method and apparatus for deriving a calibration filter for electromagnetic data | |
US20100271029A1 (en) | Method and Device for Induced Polarization Mapping of Submarine Hydrocarbon Reservoirs | |
WO2005096019A1 (en) | Electromagnetic data processing | |
US10416334B2 (en) | CSEM survey method | |
Daud et al. | Air waves effect on sea bed logging for shallow water application | |
Rauf et al. | Prediction of double stacking hydrocarbon using Marine Controlled Source Electromagnetic method | |
Ansari et al. | Relationship of resistivity contrast and thickness depth of hydrocarbon for seabed logging application | |
Khairuddin et al. | Airwaves effect in Sea Bed Logging for shallow water environment | |
Røsten et al. | Electromagnetic Seabed Logging-A Proven Tool For Direct Hydrocarbon Identification | |
Sasaki et al. | Near-surface effects on 3D marine CSEM responses: Implications for reducing uncertainty in energy resource exploration | |
Nordskag et al. | TE and TM Decomposition. Marine EM Surveying by Use of Gradiometers | |
Ridyard et al. | Electromagnetic prospect scanning: The next frontier for exploration using SeaBed Logging |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 07822794 Country of ref document: EP Kind code of ref document: A2 |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
ENP | Entry into the national phase |
Ref document number: 0909891 Country of ref document: GB Kind code of ref document: A Free format text: PCT FILING DATE = 20071121 |
|
WWE | Wipo information: entry into national phase |
Ref document number: 0909891.4 Country of ref document: GB |
|
ENP | Entry into the national phase |
Ref document number: 2009123488 Country of ref document: RU Kind code of ref document: A |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 07822794 Country of ref document: EP Kind code of ref document: A2 |