The tieback member of this invention is used in the contingency that {HEAD ~ the tieback threads} in {TAIL ~ the casing hanger} become damaged 
in
The tieback member of this invention is used in the contingency that { HEAD ~ the tieback threads } in { TAIL ~ the casing hanger } become damaged
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH