ACID TREATMENT OF AN OIL EXPLOITATION WELL BOTTOM-HOLE AREA Russian patent published in 2012 - IPC E21B43/27 

FIELD: oil producing industry.

SUBSTANCE: invention belongs to the oil producing industry and may be used for acid treatment of an oil exploitation well bottom-hole area characterized by the uncapped productive formation with carbonate reservoir rock. Acid treatment of an oil exploitation well bottom-hole area technique involves running-in of a flexible flush-joint coiled tubing unit along the annular space with the subsequent injection into the well, advance of the flexible flush-joint coiled tubing up to the well bottom, oil injection up to the full change of killing fluid to the oil, removal of flexible flush-joint coiled pipes of a coiled tubing unit up to the roof of the productive accumulation, shutting-in a well, injection of soldering acid solution to the bottom-hole area through the flexible flush-joint coiled pipes of a coiled tubing, pulling of the bottom part of flexible flush-joint coiled pipes of a coiled tubing unit to 0.8-1.2 m and injection of soldering acid solution up to the reach of productive formation bottom, running of the bottom part of flexible flush-joint coiled pipes of a coiled tubing unit to the centre of the well and curing within the period of 2-3 hours., gradual pulling of the bottom part of flexible flush-joint coiled pipes of a coiled tubing unit to the well bottom and simultaneous oil injection with the borehole fluid drainage through the annular space, flushing-out of well with oil, removal of the bottom part of flexible flush-joint coiled pipes of a coiled tubing unit and closing of the annular space, carrying out of advancing and closing operations and launching of a well. The aforementioned adaptation requires a well with the uncapping productive formation with the permeability not less than 0.01 mcm², formation pressure not less than or equal to 7 MPa, productivity index not exceeding 0.1 m³/day*atm. Immediately prior to processing, the well production rate within the bottom-hole pressure conditions should be not less than or equal to 1.5 MPa, while the formation dispersion should be not less than or equal to5.5 MPa. Within the processing the acid volume should be not less than 0.5-1 m³ for 1 m of the perforated load. Productive formation interval is perforated no sooner than in a year prior to such processing with perforation of the productive formation interval amounting to more than 10m.

EFFECT: efficiency enhancement of acid treatment of an oil exploitation well bottom-hole area.

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