METHOD OF WELL WATER PRODUCTION ZONE ISOLATION Russian patent published in 2014 - IPC E21B33/138 

FIELD: oil-and-gas industry.

SUBSTANCE: proposed method comprises making the mortar to be injected to well and forced into interval to be isolated. After injection of mortar into well in amount of 10% of total amount, portion of fibro fibers is added thereto under mortar jet. First portion of fibro fibers is fed in 3 mm length, minimum, and in minimum amount of 1 kg per 1 m of mortar. At insignificant increase in injection pressure, 2^nd, 3^rd and 4^th portions of fibro fibers (6, 12, 18 mm-long) are added in portions of 2-5 kg per 1m of mortar till pressure of 70-90% of permissible pressure to operating string or to pools. Injection is terminated to force mortar with fibro fibers, process fluid to permissible pressure to string or to pools. Solution residues are washed off by back-flushing. Well is closed for mortar hardening period.

EFFECT: higher efficiency of isolation, fast process.