RECOVERY METHOD OF HIGH-VISCOSITY OIL DEPOSIT BY STEAM CYCLIC EFFECT Russian patent published in 2017 - IPC E21B43/24 E21B43/14 E21B43/267 E21B43/27 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to development of high-viscosity oil deposits with steam cyclic effect containing impermeable interlayers using hydraulic fracturing cracks (HF). The method includes drilling a vertical well in high-viscosity oil deposit, supporting the vertical well with a casing string, casing perforating in the production formation interval, pumping steam and gas carrier through the well into the production formation, lowering the tubing string with a pump, and taking the heated product from the well. A vertical well opens the deposit of high-viscosity oil, represented by the upper and lower parts of the formation separated by an impermeable interlayer. In this case, the casing string is perforated in the well in front of the upper part of the production formation and in the cap of the impermeable interlayer. After that, hydraulic fracturing is performed by pumping 20% hydrochloric acid at a flow rate of 1.5 m³/min at the rate of 2 m³ per 1 m of the formation with the fracturing crack. Then, salt water with density of 1180 kg/m³ is pumped into the fracturing crack in the volume of the injected acid at a flow rate of 0.8 m³/min. Then, the fracturing crack is supported by pumping a crosslinked gel with a proppant mixture at a flow rate of 2.0 m³/min in the following ratio %: proppant fraction 16/20 mesh - 60%; cylindrical proppant of fraction 12/16 mesh - 20%; RCP proppant fraction 16/30 mesh - 20%. After the hydraulic fracturing, the bottom of the production formation is perforated. To reduce heat losses at the beginning of the steam cyclic effect, the well is warmed by steam circulating until the condensate outlet from the return line stops. A pipe string with a bottom-up non-return valve, a lock support of the plug-in rod pump, a lower relief valve, a lower packer, an upper relief valve, and an upper packer is lowered into the well. The pipes string is placed in the well so that the upper packer is opposite the cap of the upper part of the production formation, and the lower packer is opposite the cap of the lower part of the production formation. Then, an insert rod pump is lowered into the pipes string on the rod column, which is fixed in the lock support, then the steam is pumped in a volume of 40 tons per day for 14 days. After that, the well is closed and kept for 14 days for impregnation. Then, the heated high-viscosity oil is taken, after the production rate is reduced to a cost-effective level for this well, the steam injection cycles and the selection of the heated high-viscosity oil are repeated.

EFFECT: increase deposit coverage; increase efficiency of steam-thermal effect on the formation; exclude overheating of the upper part of the formation; reduce heat losses along the well bore.

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