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

FIELD: oil and gas industry.

SUBSTANCE: the well abandonment method includes running in of a pipe string to the well, placing of a cement plug from the bottomhole up to the well head. When cement sheath is available behind the casing string, geophysical investigations are carried out and length of non-cemented part of the casing string is determined. Picking-up of the casing string is made with the load equal to the dead weight of the removed part of the casing string. A pipe of the casing string is cut off at distance of 5-10 m above the lower end of the non-cemented part of the casing string. The non-cemented part of the casing string is removed. Then a pipe string of small diameter with perforated openings and a plug at the end is run in from the well head up to the bottomhole. At that total are of the perforated openings twice exceeds the inner cross-section area of the pipe string of small diameter. Thereafter a fibre-optical cable and additional string pipe are run in to the pipe string of small diameter up to the downhole. Then a cement plug is installed by back-plugging under pressure from the bottomhole up to the well head with use of high-temperature cement with addition of fibre, temperature distribution is fixed periodically in the well bore after its abandonment.

EFFECT: higher efficiency and reliability of the well abandonment.

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