Abstract: Methods and systems of correcting operation of multiple modules are described. The methods include generating a first dual-tone signal in a first module and transmitting the first dual-tone signal to a second module. A second dual-tone signal is generated in the second module and transmitted to the first module. The first module determines a first phase of the received second dual-tone signal and the second module determines a second phase of the received first dual-tone signal. Operation of one or both of the first and second modules is corrected based on the determined first phase and the determined second phase.

Abstract: Methods and systems of correcting operation of multiple modules are described. The methods include generating a first dual-tone signal in a first module and transmitting the first dual-tone signal to a second module. A second dual-tone signal is generated in the second module and transmitted to the first module. The first module determines a first phase of the received second dual-tone signal and the second module determines a second phase of the received first dual-tone signal. Operation of one or both of the first and second modules is corrected based on the determined first phase and the determined second phase.

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 fo

Abstract: A method for estimating a property of an earth formation penetrated by a borehole, the method comprising generating a first transient electromagnetic fields with a transmitter on a carrier located outside of the borehole and receiving associated signals, calculating a bucking coefficient using the measured signals, conveying the carrier through a borehole, generating a second transient electromagnetic field and receiving associated signals, calculating, a bucked signal using the bucking coefficient and the downhole signals, calculating synthetic formation signals, calculating synthetic formations signals by applying a Duhamel's integral to the measured signals and the synthetic formation signals, calculating a synthetic bucked signal, and performing an inversion of a formation model to estimate a property of the formation such that an inverted synthetic bucked signal and an inverted bucked signal coincide within a predetermined range.

Abstract: Methods and systems for estimating properties of formations penetrated by boreholes are provided, 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 from the transmitter, generating a transient electromagnetic field with the transmitter, obtaining a total signal from signals received by the first receiver and the second receiver, performing a bucking calculation to obtain a pipe signal, applying a correction scheme to the total signal to generate a corrected formation property signal, wherein the correction scheme is Vcorr=Vmeas?P*Vmeas, wherein Vcorr is a correction signal, Vmeas is the total signal, and P is the pipe signal, estimating a formation property from corrected formation property signal to select a model of the formation, and adjusting a drilling operation based on the estimated property of the formation.

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.

Abstract: Methods and systems for estimating properties of formations penetrated by boreholes are provided, 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 from the transmitter, generating a transient electromagnetic field with the transmitter, obtaining a total signal from signals received by the first receiver and the second receiver, performing a bucking calculation to obtain a pipe signal, applying a correction scheme to the total signal to generate a corrected formation property signal, wherein the correction scheme is Vcorr=Vmeas?P*Vmeas, wherein Vcorr is a correction signal, Vmeas is the total signal, and P is the pipe signal, estimating a formation property from corrected formation property signal to select a model of the formation, and adjusting a drilling operation based on the estimated property of the formation.

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.

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 fo

Abstract: A method for estimating a property of an earth formation penetrated by a borehole, the method comprising generating a first transient electromagnetic fields with a transmitter on a carrier located outside of the borehole and receiving associated signals, calculating a bucking coefficient using the measured signals, conveying the carrier through a borehole, generating a second transient electromagnetic field and receiving associated signals, calculating, a bucked signal using the bucking coefficient and the downhole signals, calculating synthetic formation signals, calculating synthetic formations signals by applying a Duhamel's integral to the measured signals and the synthetic formation signals, calculating a synthetic bucked signal, and performing an inversion of a formation model to estimate a property of the formation such that an inverted synthetic bucked signal and an inverted bucked signal coincide within a predetermined range.

Abstract: An apparatus for estimating a property of an earth formation penetrated by a borehole includes: a borehole carrier; a first switchable-magnet; a first energy storage device coupled to the first switchable magnet; a second switchable-magnet; a second energy storage device coupled to the second switchable-magnet; at least one voltage source having a first polarity and a second polarity opposite of the first polarity; and an electrical circuit configured to charge the first energy storage device and the second energy storage device at the same time and to sequentially discharge the first energy storage device and the second energy storage device, the electrical circuit being further configured to charge the first and second energy storage devices to the first polarity and then charge the first and second energy storage devices to the second polarity after the first and second energy storage devices are discharged.