The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 19, 2011
Filed:
Feb. 12, 2007
Harald Westerdahl, Dal, NO;
Svein Erling Johnstad, Bønes, NO;
Brian Anthony Farrelly, Rådal, NO;
Multifield Geophysics AS, Laksevag, NO;
Abstract
A method for analyzing acquired electromagnetic measurements (R) made at or in a sea () over a seafloor () with rock formations () having relatively low resistivity (ρ) for detecting a possibly underlying petroleum bearing reservoir formation () having relatively high resistivity (ρ), 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 (ρ).