WELL-KILLING FOAMING COMPOSITION Russian patent published in 2003 - IPC

FIELD: oil and gas production. SUBSTANCE: invention relates to foaming compositions for killing wells in order to perform pullout of hole at abnormally low formation pressures. Composition consists of foam-former based on aqueous solution of lignosulfonate reagent (4-20%), hydrocarbon fluid as foam stabilizer (12-31%), 1:(0.5-2.0) mixture of crushed three-day barley germs with powdered lignosulfonate reagent selected from industrial-grade lignosulfonate, condensed sulfite-alcohol distillery dregs, ferrochrome-lignosulfonate, and lignase as solid phase (3-10%), and aqueous calcium chloride solution with density 1120-1280 kg/cu.m (the balance), said lignosulfonate reagent solution having concentration 1130 kg/cu.m and said lignosulfonate being selected from as above. EFFECT: increased multiplicity of foam with preserved stability, enhanced blocking properties, reduced filtration into formation due to accelerated creation of low-permeable filtration barrier, reduced natural permeability of producing formations after unblocking, and decreased well development time. 2 cl, 15 ex