Tail pipe head leakage well secondary well completion pipe string

The utility model relates to a secondary well completion pipe string for a drilling liner head leakage well. The secondary well completion pipe string mainly comprises an expansion hanger, a drilling liner string, a sealing plug and the like. The expansion hanger is composed of an expansion cone, an expansion hanging barrel, a sealing hanging element, a cone bearing shaft, a recyclable sealing plug, a double-male connector, an outlet falling object preventing device, a tail pipe nipple, a center pipe and the like. The recoverable sealing plug is limited in the double-male connector and is in sealing fit with the double-male connector, and after the expansion hanger is hung in a sitting mode, the expansion hanger is pulled out of a hole along with the central pipe to be recovered. During operation, the sealing plug is inserted into a tie-back barrel of an original well tail pipe hanger, the expansion hanger generates permanent plastic deformation, the sealing hanging element is compressed in an annular space o