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1. (WO2017155777) METHOD AND APPARATUS FOR MEASUREMENT OF PIPE SIGNALS FOR DOWNHOLE TRANSIENT ELECTROMAGNETIC PROCESSING

Pub. No.:    WO/2017/155777    International Application No.:    PCT/US2017/020367
Publication Date: Fri Sep 15 01:59:59 CEST 2017 International Filing Date: Fri Mar 03 00:59:59 CET 2017
IPC: G01V 3/26
E21B 47/00
G01V 3/38
Applicants: BAKER HUGHES, A GE COMPANY, LLC
Inventors: MORRIS, Steven Allen
Title: METHOD AND APPARATUS FOR MEASUREMENT OF PIPE SIGNALS FOR DOWNHOLE TRANSIENT ELECTROMAGNETIC PROCESSING
Abstract:
Methods and systems for estimating properties of earth formations including conveying a carrier through a borehole having a transmitter, a first receiver, and a second receiver, the first receiver positioned a first distance from the transmitter and the second receiver positioned a second distance therefrom, generating with the transmitter a transient electromagnetic field, receiving a first measured signal at the first receiver, receiving a second measured signal at the second receiver, obtaining a total signal from the first measured signal and the second measured signal, determining a bucking coefficient, performing a bucking calculation employing the bucking coefficient, the first measured signal, and the second measured signal to extract a pipe signal, suppressing the pipe signal from the total signal to obtain a formation signal, estimating a formation property from the formation signal, and adjusting a drilling operation based on the estimated property of the formation.