Changes

==Measured depth==

==Measured depth==

''Measured depth'' (MD), or ''drilled to depth'' (DD), is the depth measured (by driller or logger) to any feature of a well, whether a casing point, a [[Overview_of_routine_core_analysis#Sidewall_core_analysis]]sidewall core, or a significant geological marker. To use this depth in interpreting geological structure, the depth must be corrected to subsea depth or ground elevation (or rig floor or kelly bushing elevation) using information commonly found on log headers. For example, drilled depth minus kelly bushing elevation equals subsea elevation.

''Measured depth'' (MD), or ''drilled to depth'' (DD), is the depth measured (by driller or logger) to any feature of a well, whether a casing point, a [[Overview_of_routine_core_analysis#Sidewall_core_analysis]]sidewall core]], or a significant geological marker. To use this depth in interpreting geological structure, the depth must be corrected to subsea depth or ground elevation (or rig floor or kelly bushing elevation) using information commonly found on log headers. For example, drilled depth minus kelly bushing elevation equals subsea elevation.

==True vertical depth==

==True vertical depth==