Lag
Lag time
Laminar
Laminar flow
Last reading
Lateral curve
Lateral device
Laterolog
Latitude
Latitude correction
Lava
Lay down pipe
Leak, leakage
Lease
Least-squares fit
Lens
Liberated gas
Limestone
Limestone device
Limestone sonde
Line
Liner
Liner hanger
Line wiper
Liquefied natural gas
Liquefied petroleum gas
Liquid
Liquid-junction potential
Lithification
Litho-Density Log
Lithologic log
Lithology
Lithostatic load
Little slam
Live oil
Log
Logarithmic grid
Logging cable
Logging tool
Log scale insert
Log zero
Longitudinal wave
Long normal curve
Long-spaced sonic log
Long string
Lose returns
Lost circulation
Lost-circulation material
Low explosive
LR
Lubricator