LOCAL HYDRAULIC RESERVOIR FRACTURING METHOD Russian patent published in 2005 - IPC

FIELD: oil production, particularly methods for stimulating oil production.

SUBSTANCE: method involves performing deep perforation through all intervals of formation to be treated; assembling sectional charge with central channel for tool set passage; lowering charge into well and combusting sections thereof formed of compositions providing charge burning in aqueous, oil-and-water and acid medium to form combustion products; increasing pressure and temperature inside the well; performing control of charge section burning in real time mode during fast combustion thereof; recording behavior characteristics of the charge and estimating the pattern of action exerted on the formation and bottomhole formation zone response to the action. Composite rod formed of material providing rod integrity during mechanical and heat load application during charge lowering/lifting and combustion process is used for charge assemblage. Composite rod has inner channel extending along central axis thereof adapted for passing power lead of ignition unit and wire with heat-resistant insulation connecting borehole cable with electronic unit adapted for controlling and recording behavior characteristics of the charge. Electronic unit is connected with lower part of lower rod and spaced a distance from charge sections. The distance is selected to prevent direct action of charge combustion products on the electronic unit. Besides, gas flow distributor is arranged between lower charge section and electronic unit to provide maximal directed action onto formation to be treated. Inner charge cavity is filled with surfactant for the full structure height to provide additional differential pressure drawdown and mechanical impurities removal as a result of surfactant foaming during charge burning. Perforation is performed through all formation intervals by means of perforator with 30-45° phasing so that vertically inclined spiral cracks around well bore in bottomhole zone are formed after charge combustion. The cracks are restricted from closing during following hydraulic fracturing and provide hydrodynamic communication between well and formation. For charge assemblage upper and lower rods connected to both ends of load-bearing rod part are used, wherein upper rod is lengthen up to 2.0-2.5 m, lower one is extended up to 1.0-1.5 m.

EFFECT: reduced accident risk, decreased thermal impact action on borehole cable, possibility of well normal operation after treatment thereof due to prevention of pump clogging with mechanical impurities and pyrobitumens during well operation starting and increased perfection of reservoir drilling-in.

2 dwg