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:
Feb. 03, 2015
Filed:
Dec. 23, 2009
David Alumbaugh, Berkeley, CA (US);
Edward Nichols, Clamart, FR;
Nestor Cuevas, Berkeley, CA (US);
Schlumberger Technology Corporation, Sugar Land, TX (US);
Abstract
Methods and related systems are described for measuring naturally occurring electromagnetic fields both at the earth's surface as well as downhole. These fields originate from currents in the ionosphere above the earth, and are the same fields as employed by known magnetotelluric geophysical methods based on surface measurements. Some embodiments are especially useful in horizontal wells that are uncased at depth, although some embodiments are also useful in normal vertical wells that are both uncased or cased with a conductive liner. The method includes receiving downhole electromagnetic survey data of the naturally occurring electromagnetic fields obtained using a downhole receiver deployed at a first location in a borehole. A second set of electromagnetic survey data of the naturally occurring electromagnetic fields is also received that has been obtained using a receiver deployed at a second location. A transfer function is estimated between the first and second locations for portions of the electromagnetic fields based on the two sets of electromagnetic survey data.