DOWN HOLE EJECTION UNIT Russian patent published in 2018 - IPC E21B43/25 E21B28/00 E21B43/16 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas industry, in particular to downhole jet devices, and is designed to extract formation fluids from wells with simultaneous stimulating effect on a near well bore area of a productive formation. Down hole ejection unit formation fluid production from the well comprises an ejector pump installed on the inner tubing string (tubing). In this case, the ejector pump includes a housing in which a nozzle and a mixing chamber with a diffuser are installed coaxially to the inner string (tubing), in parallel with which axial channels are provided for supplying the working flow. Wherein, to feed the ejected flow, the channels in the housing are axial, from the upper end they are connected to the receiving chamber of the ejector pump, and from the lower end – with the suction cavity of the housing of the downhole ejection unit, in which a moveable plate is also located. Plate opens when the pressure drops and acts as a back pressure valve. In this case, a nozzle-cavitator is used as the nozzle, consisting of a first input section, made in the form of a conoidal nozzle for the maximum value of the speed coefficient and the flow rate of the flowing liquid, the radius of rounding, equal to 2÷5 diameters of the smallest cross-section (2÷5 d); a second cylindrical section of diameter d, of length l_c=2÷3d; a third conically divergent section with an opening angle of 13°30' and a length of l_l=8÷12d. Wherein the cavitation flow regime in the flow section of the ejector pump reduces to finding the ejection coefficient at which cavitation occurs, according to the given mathematical expression.

EFFECT: technical result is an increase in the well production rate, an increase in the recovery factor of the reservoir fluid, the possibility of regulating the value of draw-down pressure, and a reduction in operating costs.

1 cl, 2 dwg