FIELD: mining, drilling.
SUBSTANCE: invention relates to the mining industry, particularly to the research of the drilling wells, and can be used in detecting the loose or caught-on pipe parts in a well. The recording of the quantity which characterises the condition of the pipe metal, is performed, where the time-dependent electromagnetic field falloff (EMF) generated by square-wave impulse applied to the pipe, is used as a quantity. The time-dependent EMF curves are recorded at the equal intervals along the pipe length, and the conclusion on localisation of the FP is made using the quantity's change. The data are stored. Then, the bore is exposed to tensioning or twisting and the EMF is repeatedly measured at the entire pipe length. The stored and newly received EMF curves are compared, and the FP localisation is calculated with use of recorded quantities and the Maxwell formula.
EFFECT: reliability and precision of procedure for detecting free point in bore are increased while cost of emergency works is reduced.
4 cl, 1 ex
