U

Ultra deepwater

Operations carried out at 5000 ft (1525 meters) of depth or more 
 

Underbalanced drilling

Drilling under conditions where the pressure from inside of the well, created by drilling fluids, are lower than the pressure in the oil or gas formation. 
 

Underground injection

Injecting gasses or fluids into a reservoir in the sub soil through a bore hole. Underground injection may be used as part of EOR or in water flooding processes or to get rid off production water. 
 

Uplift

The yearly amount of oil a company is allowed to extract from a field without having to pay taxes of the value of the oil. 
 

Upstream

The Exploration or Production areas of the oil and gas industry. Also see Downstream