Downhole pump assembly

Abstract

The invention pertains to oil production pumping equipment in particular to submersible downhole pumps with rod drives to simultaneously and separately lift reservoir fluids to the surface from two reservoirs of a single well. The downhole pump assembly comprises a drive, upper and lower oil-well sucker-rod pumps each connected with its own rod string. In addition to this the unit is equipped with the body, crossbar and joint hollow rod string the latter being attached to the upper part of the crossbar to the bottom of which the rod strings of the upper and lower oil-well sucker-rod pumps are fixed, moreover, the rod string of the upper oil-well sucker-rod pump being made hollow and interconnected with the hollow plunger of the upper oil-well sucker-rod pump and the channel in the crossbar with the joint hollow rod string, and the rod string of the lower oil-well sucker-rod pump is installed between the cylinder of the upper oil-well sucker-rod pump and the downhole pump assembly body, moreover, the upper oil-well sucker-rod pump being offset from the longitudinal downhole pump assembly body axis. Coaxiality of the lower oil-well sucker-rod pump is achieved through the use of the rod crossover shoe, S-shaped rod and non-central pipe sub. The lower plunger pump rod has a shaped cross-section. As a result a standard pumping unit and two oil-well sucker-rod pumps are used and both enhanced reliability of the downhole pump assembly and increased overhaul life of its operation are achieved.

1 . A downhole pump assembly comprises a rod drive, tubing string, upper and lower oil-well sucker-rod pumps each connected with its own rod strings, characterized in that the downhole pump assembly is equipped with the body, crossbar and joint hollow rod string the latter being attached to the upper part of the crossbar to the bottom of which the rod strings of the upper and lower oil-well sucker-rod pumps are fixed, moreover, the rod string of the upper oil-well sucker-rod pump being made hollow and interconnected with the hollow plunger of the upper oil-well sucker-rod pump and the channel in the crossbar with the joint hollow rod string, and the rod string of the lower oil-well sucker-rod pump is installed between the cylinder of the upper oil-well sucker-rod pump and the downhole pump assembly body, moreover, the upper oil-well sucker-rod pump being offset from the longitudinal downhole pump assembly body axis. 
     
     
         2 . A downhole pump assembly according to  claim 1 , characterized in that the rod string of the lower oil-well sucker-rod pump includes a rod. 
     
     
         3 . A downhole pump assembly according to  claim 1 , characterized in that the axes of the lower oil-well sucker-rod pump and the downhole pump assembly match. 
     
     
         4 . A downhole pump assembly according to  claim 1 , characterized in that the rod string of the lower oil-well sucker-rod pump between the crossbar and the lower oil-well sucker-rod pump is equipped with a non-central rod crossover shoe. 
     
     
         5 . A downhole pump assembly according to  claim 1 , characterized in that the rod string of the lower plunger pump is sigmoid bended. 
     
     
         6 . A downhole pump assembly according to  claim 1 , characterized in that the lower oil-well sucker-rod pump is displaced relative to the downhole pump assembly body axis to the opposite side from the upper oil-well sucker-rod pump. 
     
     
         7 . A downhole pump assembly according to  claim 1 , characterized in that the cross-section of the lower oil-well sucker-rod pump rod connected to the crossbar can be different, for instance, flat, oval, moon-shaped, etc. and the rod position relative to the crossbar is fixed. 
     
     
         8 . A downhole pump assembly according to  claim 6 , characterized in that the downhole pump assembly body is connected with the lower oil-well sucker-rod pump by means of a non-central pipe sub. 
     
     
         9 . A downhole pump assembly according to  claim 1 , characterized in that the rod string of the upper oil-well sucker-rod pump includes a rod. 
     
     
         10 . A downhole pump assembly according to  claim 1 , characterized in that there are centralizers on the rods.