{TAIL ~ Wellbore WB} contains a conventional drill pipe DP extending from the surface S to the lower end of {HEAD ~ the wellbore} 
{ TAIL ~ Wellbore WB } contains a conventional drill pipe DP extending from the surface S to the lower end of { HEAD ~ the wellbore }
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD