PLUGGING MATERIAL FOR REPAIR OF OIL AND GAS WELLS Russian patent published in 2020 - IPC C09K8/467 C09K8/12 E21B33/138 

FIELD: oil, gas and coke-chemical industries.

SUBSTANCE: invention relates to oil and gas industry. Backfill material for repair of oil and gas wells contains phenol-formaldehyde resin (35.0–67.5 wt. %), plasticiser (20.0–30.0 wt. %), hardener (5.0–15.0 wt. %), hardener modifier (5.0–15.0 wt. %) and corrosion inhibitor (1.0–5.0 wt. %). Resin used is a resol type phenol-formaldehyde resin. Plasticizing agent used is monoethylene glycol (MEG), or diethylene glycol (DEG), or triethylene glycol (TEG). Curing agent used is 5–24 % solution of hydrochloric acid. Resorcinol or pyrocatechol is used as curing agent modifier. Corrosion inhibitor used is ICU-128 corrosion inhibitor, which is a solution of oxyethylated quaternary pyridinium ammonium salts.

EFFECT: technical result consists in enabling control of hardening time, control of strength after hardening, as well as in the absence of action on the casing string in the well.

1 cl, 1 tbl, 3 ex