Patent ID: 8066061

Claim:
A seal for a wellhead for providing a metal-to-metal seal between a casing head and a tubing head, the casing head and tubing head each having a tapered wall surface adapted for engagement with the seal, comprising: an annular seal member having an upper and a lower end and an inner wall surface and an outer wall surface; an upper tapered sealing flank disposed on the outer wall surface of the seal member and adjacent the upper end of the annular seal member; a lower tapered sealing flank disposed on the outer wall surface of the seal member and adjacent the lower end of the annular seal member; the upper and lower tapered sealing flanks having a first diameter before engagement with the tapered wall surfaces of the casing head and the tubing head; the upper and lower tapered sealing flanks having a second diameter after engagement with the tapered wall surfaces of the casing head and the tubing head, with the second diameter being smaller than the first diameter; after the seal member is removed from engagement with the tapered wall surfaces of the tubing head and the casing head, the upper and lower tapered sealing flanks have a third diameter, the third diameter being substantially the same as the first diameter; and at least one annular relief groove disposed on the upper tapered sealing flank, and at least one annular relief groove disposed on the lower tapered sealing flank.