METHOD AND DEVICE FOR ASSESSING TECHNICAL CONDITION OF CASING STRINGS Russian patent published in 1999 - IPC

FIELD: oil and gas production industry. SUBSTANCE: method can be used for detection of defects and untightness of casing strings in wells. According to method, Introduced into casing string being investigated through lubricator is well probe with magnetizing coils for generation of alternating magnetic field and with receiving converters for generation of signal in reaction to disturbance of eddy current in pipe of casing string. Well head is hermetically sealed. Winch of logging hoist is partly braked so as to equalize braking moment and moment produced by gravity force of well probe and logging cable lowered into well. Lowering of well instrument is effected by means of collars with circular slots and overflow valves, which are in contact with internal surface of pipes of casing string installed above unit of magnetizing coils and receiving converters, by applying positive flow of liquid or gas injected through point of untightness of casing string. Application of aforesaid method improves efficiency in detecting faults in casing strings. EFFECT: higher efficiency. 3 cl, 1 dwg