Casing hanger is classified into two kinds, i. e. The threaded (mandrel) and the slipped; slip casing hanger consists of G, W, WD, WE and other types, WD hanger is applicable for connection of casing head and surface casing and keeps the slip closing the casing fast in use of outer force, W hanger adopts self-weight energized sealing structure and WE & G hanger is manual-energized sealing structure