METHOD AND DEVICE FOR OIL EXTRACTION AT LOW FORMATION PRESSURE Russian patent published in 2016 - IPC E21B43/25 E21B43/18 E21B28/00 E21B43/16 F15B21/12 

FIELD: oil and gas industry.

SUBSTANCE: oil extraction method at low formation pressure, at which a packer and a jet pump with an annular nozzle and an annular diffuser are installed on the lower end of the tubing string, which are separated with a low-pressure chamber with a central suction duct. Liquid is supplied via the tubing to the jet pump. The annular free liquid jet is formed in the low-pressure chamber, at the interval between the annular nozzle and the annular diffuser. Therefore, reduction of static pressure in the low-pressure chamber is achieved. Inflow of oil to it is provided through the central suction duct, and pressure fluctuations are created with certain frequency in the low-pressure chamber. Primary pressure fluctuations are generated with certain frequency in a free annular liquid jet due to direction of this jet to sharp edges of the annular diffuser and primary pressure fluctuations are amplified in the low-pressure chamber, the natural frequency of which is tuned with resonance to frequency of primary pressure fluctuations.

EFFECT: improving formation efficiency of pressure fluctuations in the under-packer area of the well without any disturbance of continuous supply of working liquid via a supply duct.

2 cl, 1 dwg