Artificial lift is a method used to lower the producing bottom hole pressure (BHP) on the formation to obtain a higher production rate from the well. This can be done with a positive-displacement downhole pump, such as a beam pump or a progressive cavity pump (PCP), to lower the flowing pressure at the pump intake. Artificial lift is needed in wells when there is insufficient pressure in the reservoir to lift the produced fluids to the surface but is often used in naturally flowing wells (which do not technically need it) to increase the flow rate above what would flow naturally.
Artificial lift in detail
Artificial lift is a process used on oil wells to increase pressure within the reservoir and encourage oil to the surface. When the natural drive energy of the reservoir is not strong enough to push the oil to the surface, artificial lift is employed to recover more production.
While some wells contain enough pressure for oil to rise to the surface without stimulation, most don't, requiring an artificial lift. In fact, 96% of the oil wells in the US require an artificial lift from the very beginning.