Definition - What does Electromagnetic Caliper mean?
Electromagnetic Caliper is an in situ measurement of inside diameter of the tubing or casing by using an electromagnetic technique. With the measurement of electromagnetic thickness, which is generally measured at the same time, an alternating magnetic field is generated by the coil centered present inside the casing. The phase shift that is introduced by casing is measured by other tools which farther up the tool. The signal penetrates into the casing less than tenth of one millimeter at a high frequency and phase shift is related to the internal diameter of the casing.
Petropedia explains Electromagnetic Caliper
An Electromagnetic Caliper measures the inside diameter of casing with the help of electromagnetic techniques. The measurements do not correspond to the nonmagnetic scales unlike the ultrasonic or the mechanical caliper. It is considered as a disadvantage when determining the true internal diameter, but it is also considered as an advantage in the process of determining the corrosion. The Electromagnetic Caliper logs are the logging tools are used to measure and generate an alternating magnetic field in the tubing or casing, which is used for measuring the internal diameter of the tubing or casing.