LOCALISATION METHOD OF LEAKAGE AREAS OF PRODUCTION STRING Russian patent published in 2009 - IPC E21B33/14 

FIELD: oil-and-gas production.

SUBSTANCE: before lowering of protecting string on it is installed holder, packer unit, it is connected supporting column to protecting string by means of disconnector, it is lowered protecting string with disconnector into production string, it is suspended protecting string in production by means of action on holder, progressively it is unloaded weight of protecting string to walls of production string, after what by means of packer unit, which is located lower than leakage area, it is separated annular space between protecting and production strings, it is localised leakage area, it is disconnected by means of disconnector protecting string from supporting excluding its rotation and it is lifted the latter. Localisation of leakage area of production string is implemented by means of pumping of cement mortar into protecting string, forcing through it by squeezing plug into annular space between protecting and production strings, using at that overlapped to packer unit cementation clutch, up to stop of squeezing plug and pressure jump at wellhead ensured by disconnection of tubal and annular space by stop sleeve of cementation clutch, it is uplifted supporting column over top pipe of protecting string, breaking hydraulical connection, there are leached excess of cement mortar and is implemented flushing of space over top of protecting string by means of direct or back-flushing, after extraction of supporting column there are drilled out elements of cementation clutch excluding rotation of its operating details, blocked in protecting string.

EFFECT: method provides localisation of leakage area of production string at repair of wells with several intervals of leakage in layers, inclined to absorption, overlap of sealing procedures of protecting string with suspension of protecting string on production string, acceleration of wells' repair process.

6 dwg