FOAM-FORMING COMPOSITION FOR PERFORATION OF PRODUCING STRATA Russian patent published in 2003 - IPC

FIELD: oil and gas production. SUBSTANCE: invention, in particular, relates to secondary exposing of permeability-nonuniform mudded strata by perforation under low formation pressure conditions. Perforation composition comprises, wt %: foam former based on lignosulfonate reagent aqueous solution with density 1130 kg/cu.m, 4-20; acid reagent, 7-50; potassium or calcium chloride, 3-24; water (the balance), and, additionally, (i) filler in the form of 1:(2-4) mixture of divided three-day barley germs and powdered lignosulfonate reagent selected from group including: technical lignosulfonate, condensed sulfite-alcohol distillery dregs, lignopol, and lignase, 1-5; and (ii) diesel fuel or gas condensate, 10-29. Lignosulfonate reagent for above-named foam former is selected as indicated for powdered lignosulfonate reagent and acid reagent is 20% aqueous solution of hydrochloric acid or sulfamic acid or mixture of 20% aqueous solutions selected from group: hydrochloric acid and hydrofluoric acid, hydrochloric acid and potassium or ammonium, or hydroammonium hydrofluoride, hydrofluoric acid and sulfamic acid, sulfamic acid and potassium or ammonium, or hydroammonium hydrofluoride. EFFECT: enhanced efficiency of secondary perforation exposing of stratum due to use of elevated-stability foam possessing improved blocking and demudding properties allowing achievement of high hydrodynamic relation between borehole and producing stratum and ensuring integrity of casing pipe and cement ring. 3 cl, 30 ex