FORMULATION FOR TREATING CRITICAL AREA OF CARBONATE RESERVOIR AND A METHOD OF ACID TREATMENT OF CRITICAL AREA OF FORMATION Russian patent published in 2007 - IPC C09K8/72 E21B43/27 

FIELD: oil and gas production.

SUBSTANCE: invention relates to formulations and methods of acid treatment of critical area of formation with carbonate reservoirs and can be used (i) to intensify oil inflow, to increase intake capacity of well, and completing wells via acid treatment of carbonate reservoir and (ii) as perforation medium in secondary exposal of formation with carbonate reservoir. Formulation for treating carbonate reservoirs comprises, wt %: hydrochloric acid 7-19, surfactant 0.1-3.0, solvent 10-45, orthophosphoric acid 4-14, and water - the balance. In a method of acid treatment critical area of formation with carbonate reservoir, above-indicated formulation is injected into borehole and forced into depth of formation with the aid squeezing fluid, after which process pause is performed. Before and/or after introduction of acid formulation, optionally containing oil-soluble demulsifier hydrocarbon solvent can be injected. Use of formulation enhances efficiency of treating critical area of formation with carbonate reservoir owing to increased formulation permeation depth into formation and creates branched network of fluid-conducting channels owing to reduced velocity of interaction of formulation with formation rock. Formulation is characterized by reduced corrosion activity toward construction steel and cement stone behind oil string of well. Formulation also reduces probability of clogging formation pores with insoluble iron compounds and prevents arising of leaking in cement ring behind oil string of well.

EFFECT: improved performance characteristics of formulation.

4 cl, 3 tbl