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

FIELD: oil and gas industry.

SUBSTANCE: well abandonment method includes running in of tubes to the well, placing of cement plug from the bottomhole up to the well head. A part of the casing string is cut in the formation interval where crossflow between layers is found through borehole annulus and 10 m above it. Then a macaroni string blinded from downwards is run in to the well from the well head up to the bottomhole. Then a fibre-optical cable is run in to the macaroni string. Thereafter the string is run in to the bottomhole and a cement plug is placed by pressurised plugging from the bottomhole up to the wellhead using high temperature cement. The string is removed from the well; the bottomhole is poured by high temperature cement up to the wellhead. Upon abandonment temperature distribution is recorded for the well bore on quarter basis.

EFFECT: invention allows reducing process duration and improving reliability of the method implementation due to increase in strength of the cement plug with removal of the casing string part in the interval where crossflow is possible as well as available control over reliability in the well abandonment process.

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