Oil derrick vs pump jack
The oil derrick pump is known colloquially as a sucker rod pump, named for the plunger-like mechanics it uses to pump oil from underground wells up to the surface. It uses a series of gears and cranks to pump a polished rod up and down an oil well in a piston-like motion, albeit much slower. This design is used to conserve energy while bringing a continuous, reliable flow of oil from deep wells to the surface.
How an Oil Derrick works
Oil derrick vs pump jack
Oil well pumpjacks
How Do Oil Pumpjacks Work?