14.7.5.1 MdReference
Topic Version  1  Published  09/11/2015  
For Standard  RESQML v2.0.1 
Reference location for the measured depth datum (MdDatum).
The type of local or permanent reference datum for vertical gravity based (i.e., elevation and vertical depth) and measured depth coordinates within the context of a well. This list includes local points (e.g., kelly bushing) used as a datum and vertical reference datums (e.g., mean sea level).
Name 
Data Type 
Notes 

ground level 

kelly bushing 

mean sea level 
A tidal datum. The arithmetic mean of hourly heights observed over the National Tidal Datum Epoch (19 years). 

derrick floor 

casing flange 
A flange affixed to the top of the casing string used to attach production equipment. 

arbitrary point 
This value should not be used for drilled wells. All reasonable attempts should be made to determine the appropriate value. 

crown valve 

rotary bushing 

rotary table 

sea floor 

lowest astronomical tide 
The lowest tide level over the duration of the National Tidal Datum Epoch (19 years). 

mean higher high water 
A tidal datum. The average of the higher high water height of each tidal day observed over the National Tidal Datum Epoch (19 years). 

mean high water 
A tidal datum. The average of all the high water heights observed over the National Tidal Datum Epoch (19 years). 

mean lower low water 
A tidal datum. The average of the lower low water height of each tidal day observed over the National Tidal Datum Epoch (19 years ). 

mean low water 
A tidal datum. The average of all the low water heights observed over the National Tidal Datum Epoch (19 years). 

mean tide level 
A tidal datum. The arithmetic mean of mean high water and mean low water. Same as halftide level. 

kickoff point 
This value is not expected to be used in most typical situations. All reasonable attempts should be made to determine the appropriate value. 