PACKING ASSEMBLY FOR GEOTHERMAL WELLHEAD CASING

A geothermal wellhead assembly (22) has a casing head (26). An inner casing (12) within the casing head has a restrained lower end portion and an unrestrained upper end portion extending above the casing head. An expansion spool (28) is mounted on the upper end of the casing head and receives the upper end portion of the inner casing. An expansion sleeve (92) fits within the expansion spool. The outer surface (94) of the expansion sleeve is adjacent the inner surface (60) of the expansion spool and an annular space (98) is defined by the inner surface (96) of the expansion sleeve and the outer surface (76) of the inner casing. A packing assembly (108) is mounted within the annular space and extends in sealing relation between the inner casing and the expansion sleeve. The packing assembly is movable with the upper end portion of the inner casing as the inner casing moves longitudinally in response to temperature changes within the wellhead.