Pumpjack

A pumpjack, also known as a nodding donkey, horsehead pump, walking beam pump, or beam pump, is a surface-mounted reciprocating piston pump used to mechanically lift liquid, typically crude oil, out of an oil well when there is insufficient pressure for the oil to flow to the surface naturally. It is a common form of artificial lift.

The pumpjack consists of a high-torque electric motor driving a crank, which in turn oscillates a walking beam. One end of the walking beam is connected to a polished rod, which extends down into the well and is attached to a sucker rod string. The sucker rod string operates a downhole pump assembly. As the walking beam moves up and down, it pulls and pushes the sucker rod string, activating the downhole pump, which draws oil into the pump cylinder and lifts it to the surface.

The stroke length and pumping speed of the pumpjack can be adjusted to optimize production. The size of the pumpjack is determined by the depth of the well, the weight of the fluid being lifted, and the desired production rate.

Pumpjacks are typically used in mature oil fields where the reservoir pressure has declined to the point where natural flow is no longer viable. They are a relatively simple and reliable technology, although they can be visually obtrusive and require regular maintenance. While other artificial lift methods exist, the pumpjack remains a widely used and recognizable symbol of the oil industry.