WO2008085063A1 - Method for data acquisition - Google Patents

Method for data acquisition Download PDF

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Publication number
WO2008085063A1
WO2008085063A1 PCT/NO2008/000009 NO2008000009W WO2008085063A1 WO 2008085063 A1 WO2008085063 A1 WO 2008085063A1 NO 2008000009 W NO2008000009 W NO 2008000009W WO 2008085063 A1 WO2008085063 A1 WO 2008085063A1
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WO
WIPO (PCT)
Prior art keywords
source
receiver
regime
horizontal
survey
Prior art date
Application number
PCT/NO2008/000009
Other languages
French (fr)
Inventor
Mikhail Boulaenko
Original Assignee
Rocksource Geotech As
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Rocksource Geotech As filed Critical Rocksource Geotech As
Publication of WO2008085063A1 publication Critical patent/WO2008085063A1/en

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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

Definitions

  • the present invention relates to geophysical mapping and more specifically to the prospecting for hydrocarbons and minerals.
  • Controlled source electromagnetic (CSEM) sounding is a well known geophysical method for mapping resistivity of the subsurface (see e.g. Spies and Frischknecht, 2001, Electromagnetic methods in applied geophysics, Edited by M Nabhigian, pages 288- 293).
  • the concept of the present invention is based on use of specially designed source transmitter and/or receiver which allows for effective collection of multi-dimensional resistivity data.
  • the object of the present invention is to improve the accuracy of subsurface resistivity mapping by obtaining more information by combining different transmitter configuration and/or receiver configurations in a simple and practical way.
  • the present invention relates to a data acquisition method for effective collection of controlled source electromagnetic data.
  • the acquisition method is based on joint use of horizontal loop and horizontal dipole sources and/or joint use of horizontal loop and horizontal dipole receivers.
  • the same wires are used to form the loop and dipole configurations by means of commutation devices.
  • a grid of receivers of arbitrary size can be used for EM filed recordings.
  • the present invention relates to a method for controlled source electromagnetic data acquisition, the method comprises use of multi-regime source and/or receiver operation where a physical system is able to perform as a horizontal loop source and as a horizontal electric dipole source and/or is able to perform as a horizontal loop receiver and as a horizontal electric dipole receiver.
  • the remote data acquisition according to the invention can be performed according to the following steps:
  • the present invention also relates to a method for controlled source electromagnetic data acquisition, the method further comprises use of multi-regime receiver operation where a physical receiver system is able to perform as a horizontal loop receiver and as a horizontal electric dipole receiver.
  • the remote data acquisition can be performed according to the following steps: • Deploying at least one receiver in the survey area
  • loop and dipole sources are beneficial due to different radiation pattern and thus different sensitivity to the resistivity distribution of the underground.
  • Horizontal loop source will provide good sensitivity to conductive features, while horizontal dipole source will give good sensitivity to resistors.
  • Joint use of the sources will help to resolve ambiguity in interpretation and will help in estimation of electrical anisotropy of underground formations.
  • Fig. 1 shows source loop(s) and /or receiver loop(s) comprising four wire segments placed on the ground.
  • Fig. 2 shows a grid of 225 receivers deployed on land.
  • the data acquisition system consists of one or several source loops and one or several receiver stations.
  • the source loop and/or receiver loop(s) comprise of at least three, typically, four wire segments (fig. 1) placed on the ground to form a rectangle and connected through commutation devices at points A,B,C,D.
  • the source and/or receiver is able to operate in three regimes: i)
  • the wires are connected at points B,C, and D, to form a horizontal loop.
  • the electric current is fed to the wires AB and DA and point A. ii) All the wires are disconnected. Wire AB is connected to the ground at point B. In case of a source system the current is fed to wire AB at point A, the current source is grounded at point A. iii) All the wires are disconnected. Wire AD is connected to the ground at point D. In case of the source system the current is fed to wire AD at point A, the current source is grounded at point A.
  • the data acquisition is performed by a single deployment of the loop, and consequent operation of the source in regimes i,ii, and iii.
  • the EM field is recorded by one or more receivers.
  • the data acquisition is performed by deployment of one ore more loops, and consequent operation of the receiver in regimes i,ii, and iii for each loop.
  • a controlled source EM survey is performed on land.
  • a grid of 225 receivers is deployed on land with 50 meters spacing between receivers (Fig. T).
  • the data acquisition is performed by deploying the multi regime source loop in position 1 and operating it in regimes i, ii, and iii.
  • the process is repeated for loop positions from 2 to 25.
  • the collected data is interpreted using joint 3D inversion of multi-regime dataset.
  • a controlled source EM survey is performed on land.
  • a grid of 225 receivers is deployed on land with 50 meters spacing between receivers (Fig. T).
  • the data acquisition is performed by deploying the multi regime source loops in all positions and operating it in regimes i, ii, and iii where several collocated wires are used to form loop and dipole sources.
  • a dipole source is formed between points Al and B5, a loop source is formed via point A1,B5,C25, and D21, etc.
  • the collected data is interpreted using joint 3D inversion of multi-regime dataset.
  • the survey can be performed at repeated time intervals. In an embodiment of the invention the survey can be performed by using frequency domain methods. In another embodiment of the invention the survey can be performed by using time domain methods.
  • the determination of subsurface fluid flow can comprise joint processing and/or inversion of resistivity mapping data sets collected at different time intervals.
  • Seismic data can be used in addition to resistivity data during the process of characterization of a geological formation.
  • gravity data can be used in addition to resistivity data during the process of characterization of a geological formation.
  • magnetic data can be used in addition to resistivity data during the process of characterization of a geological formation.

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  • 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)
  • Geophysics And Detection Of Objects (AREA)

Abstract

Method for geophysical prospecting based on electromagnetic data analysis with joint use of horizontal loop and horizontal dipole source datasets. The data is collected either by means of multi-regime source system which is able to operate as a horizontal loop and horizontal grounded wire source and/or a multi-regime receiver system which is able to operate as a horizontal loop and horizontal dipole receiver system. The method provides for rapid data acquisition and reduces ambiguity in interpretation due to joint use of either different source types or receiver types or both. Furthermore the joint use of the sources provides for estimation of anisotropy of geological formation due to different current directions induced in the ground by two source types.

Description

Method for data acquisition
The present invention relates to geophysical mapping and more specifically to the prospecting for hydrocarbons and minerals.
Controlled source electromagnetic (CSEM) sounding is a well known geophysical method for mapping resistivity of the subsurface (see e.g. Spies and Frischknecht, 2001, Electromagnetic methods in applied geophysics, Edited by M Nabhigian, pages 288- 293).
The concept of the present invention is based on use of specially designed source transmitter and/or receiver which allows for effective collection of multi-dimensional resistivity data.
The object of the present invention is to improve the accuracy of subsurface resistivity mapping by obtaining more information by combining different transmitter configuration and/or receiver configurations in a simple and practical way.
The present invention relates to a data acquisition method for effective collection of controlled source electromagnetic data. The acquisition method is based on joint use of horizontal loop and horizontal dipole sources and/or joint use of horizontal loop and horizontal dipole receivers. The same wires are used to form the loop and dipole configurations by means of commutation devices. A grid of receivers of arbitrary size can be used for EM filed recordings.
The present invention relates to a method for controlled source electromagnetic data acquisition, the method comprises use of multi-regime source and/or receiver operation where a physical system is able to perform as a horizontal loop source and as a horizontal electric dipole source and/or is able to perform as a horizontal loop receiver and as a horizontal electric dipole receiver.
The remote data acquisition according to the invention can be performed according to the following steps:
• Deploying a grid of receivers in the survey area • Deploying at least one source in the first operational position
• Operating the source in the regime corresponding to horizontal loop source
• Operating the source in the regime corresponding to horizontal electric dipole source along a selected direction
• Operating the source in the regime corresponding to horizontal electric dipole source perpendicular to the direction selected at the previous step
• Performing joint inversion of multi regime EM dataset
Various embodiments are given in claims 2 to 11.
The present invention also relates to a method for controlled source electromagnetic data acquisition, the method further comprises use of multi-regime receiver operation where a physical receiver system is able to perform as a horizontal loop receiver and as a horizontal electric dipole receiver.
According to the invention the remote data acquisition can be performed according to the following steps: • Deploying at least one receiver in the survey area
• Deploying one source in the survey area
• Operating the receiver in the regime corresponding to horizontal loop receiver
• Operating the receiver in the regime corresponding to horizontal electric dipole receiver along a selected direction • Operating the receiver in the regime corresponding to horizontal electric dipole receiver perpendicular to the direction selected at the previous step
• Performing joint inversion of multi regime EM dataset
Various embodiments are given in claims 13 to 22.
The use of loop and dipole sources is beneficial due to different radiation pattern and thus different sensitivity to the resistivity distribution of the underground. Horizontal loop source will provide good sensitivity to conductive features, while horizontal dipole source will give good sensitivity to resistors. Joint use of the sources will help to resolve ambiguity in interpretation and will help in estimation of electrical anisotropy of underground formations.
The data acquisition system will now be explained in more detail with reference to the accompanying drawings which shows examples of the present invention: Fig. 1 shows source loop(s) and /or receiver loop(s) comprising four wire segments placed on the ground. Fig. 2 shows a grid of 225 receivers deployed on land. The data acquisition system consists of one or several source loops and one or several receiver stations. The source loop and/or receiver loop(s) comprise of at least three, typically, four wire segments (fig. 1) placed on the ground to form a rectangle and connected through commutation devices at points A,B,C,D. The source and/or receiver is able to operate in three regimes: i) The wires are connected at points B,C, and D, to form a horizontal loop. In case of a source system, the electric current is fed to the wires AB and DA and point A. ii) All the wires are disconnected. Wire AB is connected to the ground at point B. In case of a source system the current is fed to wire AB at point A, the current source is grounded at point A. iii) All the wires are disconnected. Wire AD is connected to the ground at point D. In case of the source system the current is fed to wire AD at point A, the current source is grounded at point A.
For the multi-regime source, the data acquisition is performed by a single deployment of the loop, and consequent operation of the source in regimes i,ii, and iii. The EM field is recorded by one or more receivers. For the multi-regime receiver, the data acquisition is performed by deployment of one ore more loops, and consequent operation of the receiver in regimes i,ii, and iii for each loop.
Example 1
In the example below, a controlled source EM survey is performed on land. A grid of 225 receivers is deployed on land with 50 meters spacing between receivers (Fig. T). The data acquisition is performed by deploying the multi regime source loop in position 1 and operating it in regimes i, ii, and iii. The process is repeated for loop positions from 2 to 25. The collected data is interpreted using joint 3D inversion of multi-regime dataset.
Example 2
In the example below, a controlled source EM survey is performed on land. A grid of 225 receivers is deployed on land with 50 meters spacing between receivers (Fig. T). The data acquisition is performed by deploying the multi regime source loops in all positions and operating it in regimes i, ii, and iii where several collocated wires are used to form loop and dipole sources. For example: a dipole source is formed between points Al and B5, a loop source is formed via point A1,B5,C25, and D21, etc. The collected data is interpreted using joint 3D inversion of multi-regime dataset.
According to the invention it is possible to deploy several source systems simultaneously. In one embodiment of the invention several collocated source systems are used to form arbitrary loop and dipole sources utilizing commutation devices.
According to the invention it is possible to deploy several receiver systems simultaneously. In one embodiment of the invention several collocated receiver systems are used to form arbitrary loop and dipole receivers utilizing commutation devices.
The following features and embodiments of the invention apply both for source systems and receiver systems:
The survey can be performed at repeated time intervals. In an embodiment of the invention the survey can be performed by using frequency domain methods. In another embodiment of the invention the survey can be performed by using time domain methods.
Furthermore, the determination of subsurface fluid flow can comprise joint processing and/or inversion of resistivity mapping data sets collected at different time intervals. Seismic data can be used in addition to resistivity data during the process of characterization of a geological formation. In a further embodiment gravity data can be used in addition to resistivity data during the process of characterization of a geological formation. In another embodiment of the method according to the invention magnetic data can be used in addition to resistivity data during the process of characterization of a geological formation.

Claims

C l a i m s
1.
5 A method for controlled source electromagnetic data acquisition, c h a r a c t e r i z e d i n that the method further comprises adoption of multi-regime source operation where a physical source system is able to perform as a horizontal loop source and as a horizontal electric dipole source. 0
2.
The method according to claim 1, wherein the remote data acquisition is performed according to the following steps: s • Deploying a grid of receivers in the survey area
• Deploying the source in the first operational position
• Operating the source in the regime corresponding to horizontal hoop source
• Operating the source in the regime corresponding to horizontal electric dipole source along a selected direction 0 • Operating the source in the regime corresponding to horizontal electric dipole source perpendicular to the direction selected at the previous step
• Performing joint inversion of multi regime EM dataset
5 3.
The method according to any of claims 1 to 2, wherein several source systems are deployed simultaneously
4. o The method according to any of claims 1 to 3, wherein several collocated source systems are used to form arbitrary loop and dipole sources utilizing commutation devices.
5. 5
The method according to any of claims 1 to 4, wherein the survey is performed at repeated time intervals. The method according to any of claims 1 to 5, wherein the survey is performed by using frequency domain methods.
7.
The method according to any of claims 1 to 5, wherein the survey is performed by using time domain methods.
8.
The method according to any of claims 1 to 7, wherein the determination of subsurface fluid flow comprises joint processing and/or inversion of resistivity mapping data sets collected at different time intervals.
9.
The method according to any of claims 1 to 8, wherein seismic data are used in addition to resistivity data during the process of characterization of a geological formation, or
10.
The method according to any of claims 1 to 9, wherein gravity data are used in addition to resistivity data during the process of characterization of a geological formation.
11. The method according to any of claims 1 to 10, wherein magnetic data are used in addition to resistivity data during the process of characterization of a geological formation.
12. A method for controlled source electromagnetic data acquisition, c h a r a c t e r i z e d i n that the method further comprises adoption of multi-regime receiver operation where a physical receiver system is able to perform as a horizontal loop receiver and as a horizontal electric dipole receiver.
13.
The method according to claim 12, wherein the remote data acquisition is performed according to the following steps: • Deploying one receiver in the survey area
• Deploying one source in the survey area
• Operating the receiver in the regime corresponding to horizontal loop receiver
• Operating the receiver in the regime corresponding to horizontal electric dipole receiver along a selected direction
• Operating the receiver in the regime corresponding to horizontal electric dipole receiver perpendicular to the direction selected at the previous step
• Performing joint inversion of multi regime EM dataset
14.
The method according to any of claims 12 to 13, wherein several receiver systems are deployed simultaneously
15.
The method according to any of claims 12 to 14, wherein several collocated receiver systems are used to form arbitrary loop and dipole receivers utilizing commutation devices.
16.
The method according to any of claims 12 to 15, wherein the survey is performed at repeated time intervals.
17. The method according to any of claims 12 to 16, wherein the survey is performed by using frequency domain methods.
18.
The method according to any of claims 12 to 16, wherein the survey is performed by using time domain methods.
19.
The method according to any of claims 12 to 18, wherein the determination of subsurface fluid flow comprises joint processing and/or inversion of resistivity mapping data sets collected at different time intervals.
20.
The method according to any of claims 12 to 19, wherein seismic data are used in addition to resistivity data during the process of characterization of a geological formation.
21.
The method according to any of claims 12 to 20, wherein gravity data are used in addition to resistivity data during the process of characterization of a geological formation.
22.
The method according to any of claims 12 to 21, wherein magnetic data are used in addition to resistivity data during the process of characterization of a geological formation.
PCT/NO2008/000009 2007-01-11 2008-01-09 Method for data acquisition WO2008085063A1 (en)

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NO20070209 2007-01-11

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2182389A2 (en) * 2008-11-03 2010-05-05 MTEM Limited Method for acquiring controlled source electromagnetic survey data to assist in attenuating correlated noise
WO2013173782A1 (en) * 2012-05-17 2013-11-21 Deep Imaging Technologies, Inc. A system and method using near and far field ulf and elf interferometry synthetic aperture radar for subsurface imaging
US9846255B2 (en) 2013-04-22 2017-12-19 Exxonmobil Upstream Research Company Reverse semi-airborne electromagnetic prospecting
CN110187394A (en) * 2019-06-20 2019-08-30 甘肃省地震局（中国地震局兰州地震研究所） Double field source electromagnetic depth methods obtain the anisotropic method and device of formation resistivity

Citations (3)

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US4633182A (en) * 1983-03-03 1986-12-30 Instytut Gornictwa Naftowego I Gazownictwa Method and system for direct prospecting of hydrocarbon deposits
US5563513A (en) * 1993-12-09 1996-10-08 Stratasearch Corp. Electromagnetic imaging device and method for delineating anomalous resistivity patterns associated with oil and gas traps
US6603313B1 (en) * 1999-09-15 2003-08-05 Exxonmobil Upstream Research Company Remote reservoir resistivity mapping

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4633182A (en) * 1983-03-03 1986-12-30 Instytut Gornictwa Naftowego I Gazownictwa Method and system for direct prospecting of hydrocarbon deposits
US5563513A (en) * 1993-12-09 1996-10-08 Stratasearch Corp. Electromagnetic imaging device and method for delineating anomalous resistivity patterns associated with oil and gas traps
US6603313B1 (en) * 1999-09-15 2003-08-05 Exxonmobil Upstream Research Company Remote reservoir resistivity mapping

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
NAGENDRA PRATAP SINGHET ET AL.: "Effective skin depth of EM fields due to large circular loop and electric dipole sources", EARTH PLANET SPACE, vol. 55, 2003, pages 301 - 313 *

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2182389A2 (en) * 2008-11-03 2010-05-05 MTEM Limited Method for acquiring controlled source electromagnetic survey data to assist in attenuating correlated noise
EP2182389A3 (en) * 2008-11-03 2011-11-02 MTEM Limited Method for acquiring controlled source electromagnetic survey data to assist in attenuating correlated noise
WO2013173782A1 (en) * 2012-05-17 2013-11-21 Deep Imaging Technologies, Inc. A system and method using near and far field ulf and elf interferometry synthetic aperture radar for subsurface imaging
CN104471443A (en) * 2012-05-17 2015-03-25 深层成像技术有限公司 A system and method using near and far field ulf and elf interferometry synthetic aperture radar for subsurface imaging
US9638826B2 (en) 2012-05-17 2017-05-02 Deep Imaging Technologies Inc. Method using near and far field ULF and ELF interferometry synthetic aperture radar for subsurface imaging
US10254428B2 (en) 2012-05-17 2019-04-09 Deep Imaging Technologies, Inc. Using near and far field ULF and ELF interferometry synthetic aperture radar for subsurface imaging
US9846255B2 (en) 2013-04-22 2017-12-19 Exxonmobil Upstream Research Company Reverse semi-airborne electromagnetic prospecting
CN110187394A (en) * 2019-06-20 2019-08-30 甘肃省地震局（中国地震局兰州地震研究所） Double field source electromagnetic depth methods obtain the anisotropic method and device of formation resistivity

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