Artificial Lift
Equipment such as pumpjacks, ESPs, and gas lift used to lift fluids to surface once reservoir pressure can no longer flow the well naturally.
Artificial lift is any mechanical method used to bring oil and water to the surface after the reservoir no longer has enough natural pressure to flow on its own. The familiar pumpjack (a rod pump) is the classic example, but operators also use electric submersible pumps (ESPs), gas lift that injects gas to lighten the fluid column, and other systems chosen to fit the well.
Most wells flow naturally early in life, then need lift as pressure falls along the decline curve. Installing and running lift is an operating cost borne by the working interest and is a common reason for a workover. It keeps a well producing for years, sometimes decades, after the early flush has passed.
For a royalty owner, the pumpjack quietly nodding in a field is what keeps a mature well — and the check tied to it — alive long after the big initial rates are gone.