Damage to steel surfaces caused by friction and improper lubrication.

A tubular, perforated device attached to the bottom of sucker-rod pump that helps to prevent gas lock.

The device works on the principle that gas, being lighter than oil, rises.

As well fluids enter the anchor, the gas breaks out of the fluid and exits from the anchor through perforations near the top.

The remaining fluids enter the pump through a mosquito bill (a tube with the anchor), which has an opening near the bottom.

In this way, all or most of the gas escapes before the fluids enter the pump.

A well into which gas in injected for the purpose of maintaining or supplementing pressure in an oil reservoir.

More commonly called a gas injection well.

A process in which gas becomes entrained in a liquid.

The use of the energy that raises from the expansion of compressed gas in a reservoir to move crude oil to a wellbore.

Also call reservoir drive mechanism.

The process of raising or lifting fluid from a well by injecting gas down the well through tubing or through the tubing-casing annulus.

Injected gas aerates the fluid to make it exert less pressure than the formation does; consequently, the higher formation pressure forces the fluid out of the wellbore.

Gas may be injected continuously or intermittently, depending on the producing characteristics of the well and the arrangement of the gas-lift equipment.