INTERVAL TREATMENT METHOD OF BOTTOM-HOLE ZONE OF OIL-GAS WELL FORMATIONS Russian patent published in 2014 - IPC E21B43/27 

FIELD: oil and gas industry.

SUBSTANCE: in interval treatment method of buttonhole zone of oil-gas formations in a well equipped with a production tubing a sand plug is washed up from the upper treated producing formation. The sand plug is left for the period or moisture removal from it. Thereafter to an unkilled gas well, up to the sand plug head, a flexible tube is run in and acid composition is injected to it through the upper treated formation. By inert gas the acid composition is flushed to the bottomhole zone of the upper treated formation to a depth of the colmataged zone. The acid composition is left for the period of its reaction with colmataging particles in the bottomhole zone of the upper treated formation. Gas influx is induced from the upper treated formation. Reaction products are removed with gas through annular space between the flexible tube and the production string until productivity of the upper treated formation is restored completely. The gas well borehole is washed up to the bottom of the medium treated producing formation with removal of the sand plug upper part. The flexible tube is run in to the partially washed sand plug and the above acid treatment operations are repeated for the medium interval of the formation. The gas well borehole is washed up to the bottom of the lower treated producing formation with removal of the sand plug remaining part. The flexible tube is run in to the remaining part of the sand plug and the above acid treatment operations are repeated for the lower interval of the formation. The gas well borehole is washed up to the bottomhole with removal of the sand plug remaining part. The gas well is worked by flaring.

EFFECT: improved reliability of the treated producing formations isolation at interval acid treatment of each formation with reduced costs of repair works.

3 ex, 3 dwg