METHOD OF WELL ABANDONMENT Russian patent published in 2014 - IPC E21B33/13 E21B47/05 

FIELD: oil and gas industry.

SUBSTANCE: method of well abandonment with behind-the-casing flows includes running in of the tubing string and installation of cement plugs in the casing string. With geophysical investigations availability of a cement sheath is defined behind the production casing and seal failures are found in the production casing. Then when cement sheath is not detected behind the production casing and seal failures are found in the production casing the cement sheath is grown behind the production casing and failures in the production casing are sealed by plugging. Quality of the production casing plugging is determined by repeated geophysical investigations. Then, small-diameter string plugged from below is lowered from wellhead to bottom. Then additional string is run in from the well bottomhole and a cement plug is installed by pressurised plugging from the bottomhole up to the wellhead using high-temperature cement with addition of fibres in quantity of 0.2% of the dry cement weight. The additional string is removed from the well; the borehole is poured by high temperature cement up to the wellhead. Thereupon the string of low diameter is filled with antifreeze. Then a fibre-optical cable is run in to the macaroni string. Upon the well abandonment temperature distribution is recorded periodically in the well borehole.

EFFECT: higher efficiency and reliability of the well abandonment.

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