L

LEM

Lateral Entry Module 
 

Licence block

A part of the continental shelf located in a certain sector. The block is demarcated and positioned according to a further coordinate specification and usually divided into smaller areas. 
 

Lifting

A tanker load of crude. 
 

Liftings costs

Production costs. 
 

Liner

Thinly perforated casing through which the oil or gas flows in order to get into the production tubing.
Also a joint to lower into the wellbore in order to seal off an especially porous point where mud is lost or where water penetrates. 
 

Logging/mud analyses

A continual analysis of the drilling slag that circulates in the well. The purpose is to log any trace of oil or gas. 
 

Loss of returns/circulation

Disappeared drilling mud. 
 

Lost circulation material

Those materials added to the drilling mud so they can penetrate into the cracks in the subsoil where the drilling mud otherwise may disappear. 
 

LWD (Logging While Drilling)

A variation of Measurement While Drilling.