公开(公告)号：EP1987375A4

公开(公告)日：2012-05-09

申请号：EP07709226

申请日：2007-02-12

Applicant: MULTIFIELD GEOPHYSICS AS

Inventor： WESTERDAHL HARALD ,  JOHNSTAD SVEIN ERLING ,  FARRELLY BRIAN ANTHONY

IPC: G01V3/12 ,  G01V3/38

CPC classification number: G01V3/12 ,  G01V3/083 ,  Y02A90/344

Abstract: 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 (&rgr;3) for detecting a possibly underlying petroleum bearing reservoir formation (2) having relatively high resistivity (&rgr;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 calculated back to a recalculated field (F0(x)) to one or more offsets (x) being shorter than the large offset (xL); that the recalculated field (P0(X)) is subtracted from the field (P(x)) for possibly highlighting a field which arising due to the possibly petroleum bearing reservoir formation (2) having relatively high resistivity (&rgr;2).

公开(公告)号：CA2642633C

公开(公告)日：2013-07-02

申请号：CA2642633

申请日：2007-02-12

Applicant: MULTIFIELD GEOPHYSICS AS

Inventor： WESTERDAHL HARALD ,  JOHNSTAD SVEIN ERLING ,  FARRELLY BRIAN ANTHONY

IPC: G01V3/12 ,  G01V3/38

Abstract: 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 (.rho.3) for detecting a possibly underlying petroleum bearing reservoir formation (2) having relatively high resistivity (.rho.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 calculated back to a recalculated field (F0(x)) to one or more offsets (x) being shorter than the large offset (xL); that the recalculated field (P0(X)) is subtracted from the field (P(x)) for possibly highlighting a field which arising due to the possibly petroleum bearing reservoir formation (2) having relatively high resistivity (.rho.2).

公开(公告)号：CA2642633A1

公开(公告)日：2007-08-23

申请号：CA2642633

申请日：2007-02-12

Applicant: MULTIFIELD GEOPHYSICS AS

Inventor： WESTERDAHL HARALD ,  FARRELLY BRIAN ANTHONY ,  JOHNSTAD SVEIN ERLING

IPC: G01V3/12 ,  G01V3/38

公开(公告)号：BRPI0707773A2

公开(公告)日：2011-05-10

申请号：BRPI0707773

申请日：2007-02-12

Applicant: MULTIFIELD GEOPHYSICS AS

Inventor： WESTERDAHL HARALD ,  JOHNSTAD SVEIN ERLING ,  FARRELY BRIAN ANTHONY

IPC: G01V3/12 ,  G01V3/38

公开(公告)号：MX2008010284A

公开(公告)日：2008-10-21

申请号：MX2008010284

申请日：2007-02-12

Applicant: MULTIFIELD GEOPHYSICS AS

Inventor： JOHNSTAD SVEIN ERLING ,  WESTERDAHL HARALD ,  FARRELLY BRIAN ANTHONY

IPC: G01V3/12 ,  G01V3/38

Abstract: Un método para analizar mediciones (R) electromagnéticas adquiridas hechas en o sobre un mar (4) sobre un fondo (1) de mar con formaciones rocosas (3) que tienen resistividad (?3) relativamente baja para detectar una formación (2) subyacente de depósito que tiene posiblemente petróleo que tienen resistividad (?2) relativamente, alta en donde un transmisor (5) electromagnético de baja frecuencia colocado en el mar (4) emite un campo (P) electromagnético que se propaga en el mar (4) en las rocas (3,2) y en el aire (0) por arriba del mar; en donde los sensores electromagnéticos (6) se colocan con desviaciones deseadas (x) en el mar (4) para medir el campo electromagnético (P(x) ) en tanto que se propaga el campo, caracterizado en que se miden uno o más componentes del campo electromagnético (P) al menos en una desviación grande (XL) desde el transmisor (5) donde el campo (P) tiene solo esencialmente su origen desde el campo que se propaga como un campo (P0) a través del aire (0); en que el uno o más componentes del campo electromagnético (P) medido a la desviación grande (XL) se calcula de regreso a un campo recalculado (F0(X)) a una o más desviaciones (x) que son más cortas que la desviación grande (XL); en que el campo recalculado (P0(X) ) se substrae del campo (P(X)) para resaltar posiblemente un campo que surge debido a la formación (2) de depósito que tiene posiblemente petróleo que tiene resistividad (?2) relativamente alta.