PROCEDURE FOR DEVELOPMENT OF OIL DEPOSIT Russian patent published in 2010 - IPC E21B43/20 E21B7/06 

FIELD: oil and gas production.

SUBSTANCE: deposit is drilled out with vertical and/or inclined boreholes. Product is withdrawn via producers, while working agent is pumped via pressure wells. Further an offshoot is drilled from the vertical or slant hole of the producer and production is withdrawn from both boreholes. During drilling the offshoot a kick-off interval of the offshoot is chosen below zones of loss and intensive water inflows, below zones of unstable rock sloughing and below fluid level in the borehole. The offshoot is predrilled in the interval of dense, impermeable, inflow-free beds. In the interval of offshoot kick-off cement sheath after the flow string of the vertical borehole is solid and single eliminating annulus cross flow. When making the offshoot, the interval from a kick-off "window" to a "head" of the flow string of the off-shoot is arranged in dense, impermeable and inflow-free intervals, leaving it uncased at distance 0.5-10 m and free form the cement sheath.

EFFECT: increased rate of mineral withdrawal, and raised yield of oil deposit.

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