Pumpjacks

Pumpjack

A pumpjack is a device that is used to create pressure to mechanically lift liquid (typically oil) out of a well when there is not enough pressure downhole to pull it from downhole. A common staple in oil rich areas, a pumpjack has many other names like sucker rod pump or SRP, grasshopper pump, jack pump, or beam pump. Pumpjacks are typically found with onshore wells that are struggling to produce oil, in order to increase production.

Pumpjack Size

Several factors play into the size of a pump jack, like depth and weight of liquid to be removed from the well. The deeper and thicker the liquid, the more power required to extract it. Deeper extraction requires more power to lift, as the discharge column/head is heavier. Although pump sizes vary, they generally produce from around 5-40 liters of liquid per stroke. This liquid is often a combination of water and crude oil.

Pumpjack Facts

Historically, the pumpjack was often employed in 18th and 19th century marine steam engine designs. A pumpjack converts the rotary mechanism from the motor to a vertical reciprocating motion. This drives the pump shaft and results in the familiar nodding motion. The engineering term for this mechanism is a walking beam.

Water Well Pumpjacks

Even though the flow rate for an old fashioned hand pump water well is considerably lower than a jet pump, pumpjacks can be used to efficiently produce water from water wells. The technology is simple, using a low horsepower electric motor with a parallel bar double cam lift. Though the setup is a much smaller scale than a traditional oil well, it works well because it can sit on top of an existing hand pumped well head. In an emergency, the hand pump is still an option by attaching a manual handle to the top of the wellhead rod, and hand rotating the pumpjack cam to it's lowest position.

Downhole

The downhole pump is located at the bottom of the tubing, and has two ball check valves. There is a standing valve (stationary) and a traveling valve. Fluid from the reservoir comes through the formation to the bottom of the borehole through perforations in the cement and casing. The traveling valve is closed and the standing valve is open when the rods at the pump end travel upwards. The pump barrel fills with fluid while the traveling piston lifts contents of the barrel up. As the rods push down, the traveling valve releases (opens) and the standing valve closes. The piston reaches the end of the stroke and the cycle starts over.