Pulsed eddy current casing inspection tool

A method of downhole logging a well having one or more well tubulars, comprising:

• suspending a housing in the one or more well tubulars by a support cable, the housing including a first transmitter, a second transmitter and a third transmitter positioned in longitudinally spaced-apart relation and being operable to generate magnetic fields, the first transmitter having a first length, the second transmitter having a second length and the third transmitter having a third length;
• selectively firing the first transmitter, the second transmitter and the third transmitter in at least one of multiple transmission modes to generate magnetic fields to stimulate pulsed eddy currents in the one or more well tubulars wherein a first transmission mode of the multiple transmission modes is the simultaneous firing of the first transmitter, the second transmitter and the third transmitter and in that first transmission mode the first transmitter, the second transmitter and the third transmitter function like a single transmitter having a length approximately equal to the sum of the first, second and third lengths;
• sensing with a first receiver positioned in the housing decaying magnetic fields created by the pulsed eddy currents;
• and
• determining a parameter of interest of the one or more well tubulars from the sensed decaying magnetic fields.

A method of manufacturing a downhole logging tool for inspecting one or more well tubulars, comprising:

• fabricating a housing adapted to be supported in the well casing by a support cable;
• positioning a first transmitter, a second transmitter and a third transmitter in longitudinally spaced-apart relation in the housing, the first transmitter, the second transmitter and third transmitter being operable to generate magnetic fields, the first transmitter having a first length, the second transmitter having a second length and the third transmitter having a third length;
• positioning a first receiver in the housing to sense decaying magnetic fields created by the pulsed eddy currents;
• and
• operatively coupling driving circuitry to the first transmitter, the second transmitter and the third transmitter to selectively fire the first transmitter, the second transmitter and the third transmitter in multiple transmission modes to generate magnetic fields to stimulate pulsed eddy currents in the one or more well tubulars wherein a first transmission mode of the multiple transmission modes is the simultaneous firing of the first transmitter, the second transmitter and the third transmitter and in that first transmission mode the first transmitter, the second transmitter and the third transmitter function like a single transmitter having a length approximately equal to the sum of the first, second and third lengths.