WITSML realtime header component object. The header is only transmitted with the first realtime, when the header changes or when a retransmit is requested. Human recognizable context for the well that contains the wellbore. Human recognizable context for the wellbore that contains the tubular. Name of contractor who provided the service. Log run number. This should normally be a number; however some legacy systems encode other information in this value. The bottom hole assembly run number associated with this log. Identifies the pass within the run. Date and time that the realtime was created. Comments about the realtime. The definition of a group of channels.