The drilling fluid 124 where {TAIL ~ the base fluid} has {HEAD ~ a nitrogen content} of less than about 1 weight percent 
The drilling fluid 124 where { TAIL ~ the base fluid } has { HEAD ~ a nitrogen content } of less than about 1 weight percent
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH