BOREHOLE ROD PUMP Russian patent published in 2021 - IPC F04B47/00 

FIELD: oil production.

SUBSTANCE: invention relates to a technique for oil production and can be used for lifting oil from a well with a sucker rod pump, including oil with a high gas content. The effect is solved by the described downhole sucker rod pump containing a stepped cylinder with a suction valve, equipped with a bypass channel with a valve, a hollow plunger with a delivery valve. What is new is that the upper stage of the cylinder is made with a large diameter and length with a value not less than the length of the plunger and an additional hollow plunger is placed in it, which is connected from the bottom by a hollow rod to the plunger and a discharge valve, and from above is connected to the rod string, the bypass channel is made in the bottom of the upper stage of the cylinder.

EFFECT: increasing the filling factor of the cylinder and the efficiency of the pump.

1 cl, 2 dwg