DUAL-TRANSMITTER WITH SHORT SHIELDS FOR TRANSIENT MWD RESISTIVITY MEASUREMENTS

摘要

Systems, devices, and methods for evaluating an earth formation. Method embodiments may include conveying a carrier in a borehole, the carrier including a conducting tubular having a plurality of transmitters and a receiver non-collocated with the plurality of transmitters; inducing a first current in the earth formation using a first transmitter of the plurality of transmitters; measuring with the receiver a first time-dependent transient electromagnetic (TEM) signal induced by the formation responsive to the first current; inducing a second current in the earth formation using a second transmitter of the plurality of transmitters; measuring with the receiver a second TEM signal induced by the formation responsive to the second current; and using at least one processor to estimate a value of a resistivity property of the earth formation using a bucked signal derived from the first time-dependent TEM signal, the second time-dependent TEM signal, and a bucking coefficient K(t).