OIL-WELL SUCKER-ROD PUMP FOR MARGINAL WELL Russian patent published in 2002 - IPC

FIELD: devices for lifting fluid from oil wells, mainly, marginal wells. SUBSTANCE: oil-well sucker-rod pump has cylinder with plunger. Cylinder consists of single-type bushings with internal bore on one end and external bore on the other end, and assembled without clearance and forming an internal groove in tubular case. Plunger is made in the form of piston with thread on lower end whose upper part projects over cylinder through head of sucker rod and has weight rod with guide ribs. Cylinder and pressure valve unit are enclosed in additional tubular case, and annular space between inner diameter of additional tubular case and outer diameter cylinder communicates with tubing string and serves a channel for fluid passage. Invention is designed for marginal wells for lifting of low- and high-viscosity oil with the help of drive in the form of beam pumping units. EFFECT: higher efficiency. 6 dwg