Magnetoelastic Measurement of Vibration of Downhole Tools

A principle for measurement of the vibration force of a downhole tool based on the use of magnetoelastic characteristics of ferromagnetic materials is proposed. The features of the construction of sensitive elements in the form of inductive and mutually inductive converters of a desired physical parameter are presented. The errors are estimated with respect to optimal cable transmission of information signal. An ultrahigh-frequency approach for calculation of the vibrational force based on varactor frequency tuning is proposed. Aiming at an increase in the efficiency of the measurement of vibration force, several widespread bridge measuring circuits are analyzed with a choice depending on the requirements for measurement accuracy and range of the desired parameter.