OIL WELL PUMPING UNIT FOR DUAL RESERVOIR PUMPING Russian patent published in 2008 - IPC E21B43/14 

FIELD: oil production, particularly oil well pumping units for oil obtaining from a multiple-zone well.

SUBSTANCE: pumping unit comprises lift string with adapting bush connected to lower end thereof. Upper pump unit cylinder and solid case are secured to adapting bush by upper ends thereof. The solid case is arranged outside cylinder and spaced apart therefrom. Radial channels are created in adapting bush over upper pump cylinder level. Lower ends of upper pump cylinder and case are fixed in sub provided with radial and vertical channels, as well as with rod sealing unit. The rod connects pistons of upper and lower pumps. The rod is solid and has diameter not less than lower pump piston diameter. Upper end of lower pump cylinder is secured to lower sub part through solid pipe. Stem with filter attached to stem end and packer to be installed between upper and lower reservoirs is secured to lower part of lower pump cylinder body. Upper pump outlet is linked to hollow rod string included in gathering facilities, which accumulates product from upper reservoir. Lower pump outlet is communicated with lift string interior through vertical sub channels and annular space between upper pump cylinder and upper pump case, as well as through radial channels of adapting bush. Lift string is communicated with gathering facilities, which accumulate product from lower reservoir, at well head.

EFFECT: simplified pumping unit installation in well, possibility to treat well bottom zone without unit lifting and packer releasing, as well as well bottom zone treatment, upper and lower horizon killing and liquid drainage from pipes as unit is lifted to ground surface when repair works take place.

6 cl, 1 dwg