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.
A type of artificial lift, a gas lift, injects compressed gas into the well to reestablish pressure, making it produce. Even if a well is producing without artificial gas lift, a form of natural gas lift is utilized. In an artificial gas lift, the compressed gas is injected down the casing tubing annulus, entering the well at numerous entry points called gas-lift valves. As the gas enters the tubing at these different stages, it forms bubbles, lightens the fluids, and lowers the pressure. The injected gas reduces the pressure on the bottom of the well by decreasing the viscosity of the fluids in the well. This process encourages fluids to flow more easily to the surface.