{TAIL ~ An annular groove} is formed in {HEAD ~ the bore} of the wellhead housing above the casing hanger 
{ TAIL ~ An annular groove } is formed in { HEAD ~ the bore } of the wellhead housing above the casing hanger
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH