Patent ID: 8500127

Claim:
A wellhead assembly with an axis, comprising: an outer wellhead member having a bore; an inner wellhead member adapted to be located in the bore; opposing seal surfaces in the bore and on an exterior portion of the inner wellhead member; a seal ring between the inner and outer wellhead members having an inner annular member and an outer annular member circumscribing a portion of the inner annular member, the inner and outer annular members being secured to each other by threads, the threads terminating below upper ends of the inner and outer annular members, defining a slot between the inner and outer annular members above the threads; an annular energizing ring having a lower end insertable into the slot, so that when the lower end of the energizing ring is inserted into the slot the inner and outer annular members of the seal ring above the threads are urged radially outward into sealing engagement with the seal surfaces of the inner and outer wellhead members, and the lower end of the energizing ring forms metal-to-metal sealing engagements with wall surfaces of the inner and outer annular members that define the slot; and wherein the threads define a pathway for fluid to flow from the bore below the seal ring into the slot and into contact with the lower end of the energizing ring, wherein fluid pressure in the bore below the seal ring produces a force within the slot to urge the inner annular member of the seal ring inward and the outer annular member of the seal ring outward.