Patent ID: 9341039
Filing Date: 2016-05-17
CPC Classification: E21B,F16J

Claim Text:
1. A wellhead assembly comprising: a wellhead housing having a bore with an axis; a casing hanger landed in the bore, defining an annular seal pocket between the casing hanger and the wellhead housing; a seal assembly that seals within the seal pocket, comprising: an upper seal having inner and outer seal surfaces that seal between the casing hanger and the wellhead housing, the upper seal having a depending extension member below the inner and outer seal surfaces; a lower seal, comprising: a lower seal retaining ring; a cylindrical member extending from the extension member to the lower seal retaining ring; an outer seal stack between the lower seal retaining ring and the extension member and having an inner diameter in engagement with the cylindrical member; the outer seal stack having compliant sealing elements that move to a set position, sealing between a surface of the wellhead housing and the cylindrical member; an inner seal stack coaxial with the outer seal stack between the lower seal retaining ring and the extension member, the inner seal stack having an outer diameter smaller than the inner diameter of the outer seal stack and in engagement with the cylindrical member; the inner seal stack having compliant sealing elements that move to a set position, sealing between a surface of the casing hanger and the cylindrical member; and the outer seal stack and the inner seal stack being movable to the set position in response to an axial force applied by downward movement of the upper seal member relative to the lower seal member along a load path through the extension member, the outer and inner seal stacks and the lower seal retaining ring, the load path bypassing the cylindrical member.