A downhole sucker rod pumping unit

Abstract

The invention relates to downhole sucker rod pump assemblies comprising a stationary flexible long-length tube having disposed therein a movable flexible long-length rod, connected at opposite ends to a surface drive and to an operating element of a submersible piston pump or screw pump. An annulus between the rod and the tube is filled with a lubricant from a channel at the wellhead end. The lower and upper ends of the tube are connected to a wellhead pipe and a pumping pipe. At the lower end of the rod is a box filled with a liquid which provides protection for the seal of a plunger pump. The flexible long-length rod is capable of rotating or reciprocating movement. The result is an increase in the operating reliability of a deep-well pump, an increase in the time between repairs and a decrease in the energy consumed when the pump is operating.

1 . A downhole sucker-rod pumping unit, comprising:
 a surface power drive;   a tubing string with a mounted borehole pump, said borehole pump having a driven operating element connected to a sucker rod;   wherein the sucker rod comprises a fixed flexible tube and a movable flexible rod, the movable flexible rod being connected at a first end to the surface power drive by a wellhead polished rod and at a second end to the driven operating element as a plunger of the borehole pump by a pumping polished rod;   an annular space between the movable flexible rod and the fixed flexible tube for receiving a lubricating fluid from a channel at a wellhead end;   a wellhead pipe branch and a pumping pipe branch at respective upper and lower ends of the fixed flexible tube, the length of said branches being longer than a maximum plunger pump stroke of the borehole pump, and;   a sealing unit of the pumping polished rod, said pumping polished rod connected at a lower end to a packing unit having a bucket filled with a fluid the specific weight of which is higher than that of a pumped out fluid for protecting the sealing unit of the polished rod in select positions.   
     
     
         2 . A downhole sucker-rod pumping unit according to  claim 1 , wherein the availability in the annular space for receiving the lubricating fluid from the channel creates an excess pressure. 
     
     
         3 . A downhole sucker-rod pumping unit according to  claim 1 , wherein a bypass valve is calibrated for a design pressure at the connection of the annular space with the cavity of the upturned bucket. 
     
     
         4 . A downhole sucker-rod pumping unit, comprising:
 a surface power drive;   a tubing string with a mounted borehole pump, said borehole pump having a driven operating element connected to a sucker rod;   wherein the sucker rod comprises a fixed flexible tube and a movable flexible rod, the movable flexible rod being connected at a first end to the surface power drive by a wellhead polished rod and at a second end to the driven operating element as a shaft of a progressing cavity by a pumping polished rod;   an annular space between the movable flexible rod and the fixed flexible tube for receiving a lubricating fluid from a channel at a wellhead end;   a wellhead pipe branch and a pumping pipe, an upper end of the wellhead pipe branch being attached to a sealing unit of the pumping polished rod and with an upturned bucket filled with the lubricating fluid.   
     
     
         5 . A downhole sucker-rod pumping unit according to  claim 4 , wherein the availability in the annular space for receiving the lubricating fluid from the channel creates an excess pressure. 
     
     
         6 . A downhole sucker-rod pumping unit according to  claim 4 , wherein a bypass valve is calibrated for a design pressure at the connection of the annular space with the cavity of the upturned bucket.