Patent ID: 7232524

Claim:
A hydraulically-operated crude oil pump, comprising: an upper pumping section having an upper bladder within an upper housing defining an upper space therebetween; a lower pumping section having a lower bladder within a lower housing defining a lower space therebetween; a hydraulic pump driven by an electric motor to pump hydraulic fluid from a hydraulic fluid reservoir; a crude oil inlet and a crude oil outlet, the upper and lower spaces being in selective fluid communication with the crude oil inlet and crude oil outlet; and a directional control valve in fluid communication with the upper bladder and the lower bladder, to selectively control the flow of hydraulic fluid between the upper pumping section and the lower pumping section, wherein the upper bladder expands when hydraulic fluid flows inside the upper bladder to pump crude oil from the upper space through the crude oil outlet to surface, the upper bladder being adapted to contract to allow crude oil to enter the upper space from the crude oil inlet when hydraulic fluid flows into the lower bladder, and wherein the lower bladder expands when hydraulic fluid flows inside the lower bladder to pump crude oil from the lower space through the crude oil outlet to surface thereby pumping crude oil into the inlet of the pump and out of the crude oil outlet to the surface.