Wellhead Metal Seal with Energizing Ring Having Trapped Fluid Reliefs

A wellhead assembly, comprising:

• a wellhead housing having a bore with a longitudinal axis, the bore having an inner seal surface;
• a hanger landed in the bore, the hanger having an outer seal surface;
• a set of wickers s formed on at least one of the seal surfaces;
• a metal seal ring having annular inner and outer legs separated by an annular slot;
• an energizing ring that inserts into the slot, the energizing ring having inner and outer diameter surfaces that extend upward from a lower rim of the energizing ring and slide against the inner and outer legs of the seal ring when the energizing ring is moved downward in the slot to radially deform the outer leg outward in sealing engagement with the inner seal surface and the inner leg inward into sealing engagement with the outer seal surface;
• at least one inner diameter relief on the inner diameter surface and at least one outer diameter relief on the outer diameter surface, the inner diameter and outer diameter reliefs extending upward from the lower rim a selected distance less than an axial dimension of the inner and outer diameter surfaces, the inner diameter and the outer reliefs having circumferential dimensions less than 360 degrees;
• and wherein
• the outer diameter relief is located on a same radial line as the inner diameter relief, defining a bridge of narrower radial thickness in the lower rim than a remaining portion of the lower rim.

A method of setting a seal between a seal surface of a hanger and a seal surface of a wellhead having an axis, at least one of the seal surfaces having a set of wickers, the seal having a metal seal ring with annular inner and outer legs separated by an annular slot, the seal having an energizing ring with inner and outer diameter surfaces that extend upward from a lower end of the energizing ring;

• the method comprising:
• providing at least one partially circumferential relief extending upward from the lower end of the energizing ring on a lower section of at least one of the inner and outer diameter surfaces;
• moving the energizing ring downward in the slot, radially deforming the inner and outer legs of the seal ring to embed an upper section of one of the walls into sealing engagement with the set of wickers;
• and
• preventing a lower section of said one of the walls adjacent the relief from sealing engagement with the set of wickers to allow trapped liquid in a lower section of the wickers to flow out.