F

Field

A gathering of rocks containing hydrocarbons. It is also another term for reservoir. 
 

Fish

An object that by accident has been dropped in the borehole. 
 

Fishing

An attempt to pick up the lost equipment out of the borehole.
Also see overshot
 

Flare

To burn off undesired gasses. Also the flame that is generated during flaring. 
 

Flash point

The point where the gas/oxygen concentration is high enough to cause it to burn. 
 

Float equipment

Check valves that allow fluids to flow downwards but not upwards through the casing. 
 

Flow Control Equipment

A mechanism on conventional wireline with the sole purpose to direct and control the flow of produced or injected fluids in the production tubing. 
 

Formation

A term that is often used to describe a rock that drill-technically speaking is of uniform character, for instance a hard-formation. 
 

Formation damage

When the permeability is reduced in reservoir rocks due to drillings or fluids close to the well. 
 

Formation water

See produced water
 

Fractional destillation

A process that causes crude to split (decompose) into fluids by using the different fractions. This is the main process in all oil refining.