5 of 5 codes

Code Means Normalised Valid
GL Ground level always
DF Derrick floor always
KB Kelly bushing always
RT Rotary table always
GR Ground always

Columns that use these codes

Dataset Column Meaning
Full Wellbore Database (ASCII) elevation_code Which point the elevation was measured from. Depths are relative to it.
Wellbore Form Dates elevation_code Which point the elevation was measured from. Depths are relative to it.

Where this mapping came from: RRC manual WBA091, COBOL 88-level values on WB-ELEVATION-CODE