LOCATOR OF PERFORATION HOLES AND COUPLINGS OF FERROMAGNETIC CASINGS Russian patent published in 2002 - IPC

FIELD: well logging, specifically, equipment for nondestructive test of technical condition of ferromagnetic casings in wells. SUBSTANCE: locator of perforation holes and couplings of ferromagnetic casings comprises down-hole logging instrument and ground part connected by means of logging cable. Down-hole logging instrument houses even number n of induction converters, n/2 differential amplifiers, adding unit, n+1 analog keys, controller, analog-to-digital converter, transmitter, unit processing telemetering information and computer. Induction converters are anchored by means of non-magnetic inserts over circumference of steel frame of down-hole logging instrument. Signal coils of each pair of adjacent induction converters are connected one to inverting input and the other to non-inverting input of corresponding differential amplifiers. Second outputs of n signal coils are connected through resistors to n corresponding inputs of adder. Outputs of all differential amplifiers and adder are connected to inputs of analog keys. Controller which output is connected to transmitter is connected to first and second ports of analog keys through control bus and communication bus. Output of transmitter is connected to one end of logging cable. Second end of logging cable is connected to input of unit processing telemetering information which output is coupled to input port of ground computer. Unit processing telemetering information and computer present ground information processing, recording and reading device. EFFECT: raised precision and functional reliability of locator. 4 dwg