METHOD FOR DETERMINING LEAKAGE INTERVAL OF PIPE STRING AND WELL PLUG FOR ITS IMPLEMENTATION Russian patent published in 2024 - IPC E21B47/117 E21B33/12 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas industry and can be used to determine leakage interval of emergency coiled tubing strings, tubing installed above pumping equipment. In particular, disclosed is a method for determining the leakage interval of a pipe string, characterized by the fact that a well plug is pre-installed in the start-up device – a wellhead lubricator, filling the pipe string above the well plug with a liquid, after which a punching pressure is created to push the well plug along the pipe string until the pressure increase at the wellhead is fixed when the plug reaches the leakage interval and is closed by self-sealing collars, after which fluid pumping is stopped and location of leakage interval of pipe string is determined with subsequent lifting of pipe string for replacement of defective section. Well plug consists of a hollow shaft closed from below with a plug with a lower striker, at least two self-sealing collars passing from below and located above and below the collars of the upper and lower centralizers, respectively. To drain the liquid when lifting the pipe string, a load is lowered into the pipe string, under the action of which the well plug is lowered until the knock-down valve interacts and breaks down and the self-sealing collars are arranged below the knock-down valve.

EFFECT: high accuracy of determining location of leakage interval.

2 cl, 2 dwg