TREATMENT METHOD OF BOTTOM-HOLE FORMATION ZONE Russian patent published in 2013 - IPC E21B43/27 C09K8/74 

FIELD: oil and gas industry.

SUBSTANCE: acid treatment method of a bottom-hole formation zone involves pumping to the formation of emulsion and water solution of an acid; at that, first, water solution of acid is pumped, and pumping of water solution of acid and emulsion is performed in a series-and-alternating mode, and emulsion containing the following components, wt %, is used as emulsion: acid 5.0-40.0; emulsifier - anionic or nonionic, or cationic surface-active substance, or their mixture 1.0-10.0; hydrocarbon solvent 5.0-40.0; decomposer - primary or secondary alcohol or their mixture 0.1-5.0; corrosion inhibitor 0.01-0.05 and water is the rest. Emulsion can contain viscosity regulator in the quantity of 0.01-6.0 wt %. Water solution of acid with concentration of 3.0-24.0% is used.

EFFECT: deceleration of a reaction of acid with rock of the formation, enlarging the treatment coverage range as to thickness and depth of the formation using an emulsion, preserving stability, reducing intensity of acid corrosion and having washing effectiveness in relation to asphaltene-resin-wax-bearing deposits.

3 cl, 3 tbl, 29 ex