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1. (WO2017156101) METHOD AND APPARATUS FOR ACTIVE SUPPRESSION OF PIPE SIGNALS IN TRANSIENT ELECTROMAGNETIC MEASUREMENTS

Pub. No.:    WO/2017/156101    International Application No.:    PCT/US2017/021323
Publication Date: Fri Sep 15 01:59:59 CEST 2017 International Filing Date: Thu Mar 09 00:59:59 CET 2017
IPC: G01V 3/12
G01N 33/24
Applicants: BAKER HUGHES, A GE COMPANY, LLC
Inventors: MORRIS, Steven Allen
Title: METHOD AND APPARATUS FOR ACTIVE SUPPRESSION OF PIPE SIGNALS IN TRANSIENT ELECTROMAGNETIC MEASUREMENTS
Abstract:
Methods and systems for estimating properties of formations including conveying a carrier through a borehole having a first transmitter, a second transmitter collocated with the first transmitter, a first receiver, and a second receiver, the first receiver positioned a first distance from the first transmitter and the second receiver positioned a second distance therefrom, generating a transient electromagnetic field with the first transmitter, generating a suppression signal with the second transmitter, the suppression signal configured to suppress a response received by the first and second receivers that is caused by the transient electromagnetic field interacting with the carrier, measuring a signal with suppressed pipe signal at the first and second receivers, the measured signal representing the formation response to the transient electromagnetic field, estimating a formation property from the measured signal to select a model, and adjusting a drilling operation based on the estimated property of the formation.