[0019] A seal assembly 22 for use with a casing hanger 24 that includes a pair of split rings 28, 32 held together by a threaded fastener 38. Torqueing the fastener 38 axially compresses one of the rings 28, 32 so that it expands radially inward into sealing engagement with a wall of wellbore 46 casing, and radially outward against an inner wall of a wellhead housing 14. Support grommets 50 are provided where the fastener 38 enters and exits the compressible ring 32. Protrusions 52 on a side of the support grommets 50 project into the compressible ring 32 and create a sealing interface between each support grommet 50 and compressible ring 32. O- rings 56 line inner circumferences of the support grommets 50 to seal between the support grommets 50 and fasteners 38. A threaded end on a lower end of the fastener 38 has a diameter less than an inner diameter of the O-rings 56 to prevent damaging the O-rings 56 during assembly.
