Dual metal seal system

摘要

A wellhead seal assembly has a primary seal and a secondary seal, each seal forming a metal-to-metal seal between inner and outer wellhead members. A primary metal seal ring has inner and outer walls separated by a slot. A secondary metal seal is located below the seal ring and has a bottom portion that contacts an upward facing shoulder of a hanger. A primary energizing exerts downward force on the primary seal, causing a secondary energizing ring, located below the primary energizing ring, to energize the secondary seal. Once the secondary seal is energized, thus stopping downward movement of the (primary seal and secondary energizing ring, the primary energizing ring energizes the primary seal.

主权项

1. A wellhead sealing assembly, comprising:
a first seal member, the first seal member having inner and outer annular walls to define a slot therebetween, the first seal member having first seal threads protruding from a first seal member surface; a first energizing ring concentric with the first seal member and moveable between an upper and a lower position, the first energizing ring slidingly engaging the inner and outer walls to occupy the slot while moving from the upper to the lower position; a second seal member concentric with and located below the first seal member, the second seal member having second seal threads protruding from a second seal member surface, the first seal threads and the second seal threads threadingly engaging and passing through one another so that the second seal member can slidingly move axially along the seal assembly; a second energizing ring concentric with and located between the first and second seal members, the first seal member and second energizing ring being integrally formed of the same material and being moveable between a first and a second position, the second energizing ring and the second seal member having mating cylindrical surfaces that slide against one another while moving from the first to the second position, the second seal energizing ring moving from the first position to the second position in response to downward movement of the first seal member; and a delaying apparatus, the delaying apparatus preventing the first energizing ring from moving to the lower position until after the second energizing ring has moved to the second position.