METHOD OF INTERVAL-BY-INTERVAL TREATMENT OF PRODUCING FORMATION WITH OPEN HORIZONTAL BOREHOLE Russian patent published in 2015 - IPC E21B43/27 E21B33/138 

FIELD: oil and gas industry.

SUBSTANCE: invention refers to oil producing industry. The method of interval-by-interval treatment of producing formation with open horizontal borehole includes running in of tubular column blinded from below with packers and filtering components in between, closing treatment interval with packers, determination of the interval injectivity and injection of acid composition to this interval. At that injection of acid composition with agents influencing completeness and solution velocity of the rock in acid is performed proportionally with increase in volume of each next portion and flushing by hydrocarbon solvent in volume of 30-50% of volume of the injected acid compound. Before injection to the treatment interval of the first portion of acid composition with injectivity more than 1.0 m³/(MPa·h) free-flowing highly-viscous material is injected additionally to the treatment interval in order to reduce injectivity at least 1.5 times for the reaction period of all portions of the acid compound with the rock; at that volume of the first portion of the acid composition is defined on condition of complete rock solving in the treatment interval up to increase in the well radius of at least 1.5-2.0 times. Volume of each next portion of the acid composition is defined by the following formula: where V_ai is volume for injection of the i^th portion of acid composition, m³; V_a1 is volume for injection of the 1^st portion of acid composition, m³; a is rock solubility factor by unit mass of the acid composition; ρ_a is density of the acid composition, kg/m³; ρ_r is rock density, kg/m³. Injection of acid composition portions is repeated until total volume of 0.2-0.5 m³ is obtained per running meter of the treatment interval, at that substance retarding acid effect at least 5-100 times is added to the last portion of the acid composition.

EFFECT: increased oil production per 30-50% due to increased filtration area.