Sequential retrieval mechanism for bi-directional wellhead annulus packoff

Abstract

A wellhead annulus packoff and an associated method is disclosed. A retainer lock mechanism of the wellhead annulus packoff is to sit at least partly within a first indentation of a hanger. The retainer lock mechanism includes a bottom surface and a side surface so that the bottom surface is to be associated with a lower energizing ring and the side surface is to be engaged in an energized state with a first side of the seal element. A second side of the seal element is to abut with a surface of a housing and a slot of the seal element is to abut with the lower energizing ring in the energized state of the wellhead annulus packoff.

What is claimed is: 
     
         1 . A method for a wellhead annulus packoff, comprising:
 providing a retainer lock mechanism to sit at least partly within an indentation of a hanger;   enabling the retainer lock mechanism to be associated with a first side of a seal element in an energized state of the wellhead annulus packoff; and   enabling at least one leg, comprised in a second side of the seal element, to abut within at least one recess of a surface of a housing in the energized state of the wellhead annulus packoff.   
     
     
         2 . The method of  claim 1 , further comprising:
 enabling, with the wellhead annulus packoff in the energized state, the retainer lock mechanism to be in an engaged position between the hanger, the seal element, and a lower energizing ring; and   enabling, with the wellhead annulus packoff in a de-energized state, the retainer lock mechanism to be in a disengaged position.   
     
     
         3 . The method of  claim 1 , further comprising:
 providing the seal element with two legs; and   enabling the two legs to be recessed within different recesses of the housing.   
     
     
         4 . The method of  claim 1 , further comprising:
 associating a mechanical conditional operator between the seal element and a lower energizing ring; and   causing the mechanical conditional operator to disengage during energizing of the wellhead annulus packoff.   
     
     
         5 . The method of  claim 1 , further comprising:
 enabling a surface of the retainer lock mechanism to be between the seal element and with a lower energizing ring; and   landing the lower energizing ring and the retainer lock mechanism into an annular space between the hanger and the housing, with contact associated with the retainer lock mechanism, the seal element, and the lower energizing ring occurring at least with inclusion of the surface of the retainer lock mechanism.   
     
     
         6 . The method of  claim 1 , further comprising:
 engaging the retainer lock mechanism with a first indentation of the hanger during energizing of the wellhead annulus packoff, the engaging to use at least one inclined top surface of the retainer lock mechanism;   disengaging the retainer lock mechanism from the first indentation of the hanger during de-energizing of the wellhead annulus packoff, the disengaging to be supported by the at least one inclined top surface of the retainer lock mechanism; and   transferring, using the at least one inclined top surface of the retainer lock mechanism, a vertical upwards force from a lower energizing ring into a neck of the hanger in the energized state of the wellhead annulus packoff.   
     
     
         7 . The method of  claim 1 , further comprising:
 abutting a bottom surface of the retainer lock mechanism with a lifting surface of a lower energizing ring;   limiting, by at least the bottom surface and a side surface of the retainer lock mechanism, a top surface of the lower energizing ring or the second side of the seal element from asserting pressure against the housing during de-energizing of the wellhead annulus packoff.   
     
     
         8 . The method of  claim 1 , further comprising:
 removing the wellhead annulus packoff with a first de-energizing force or forces that is less than a second de-energizing force or forces, the second de-energizing force or forces associated with removal the wellhead annulus packoff in an application comprising the wellhead annulus packoff installed while being devoid of the retainer lock mechanism.   
     
     
         9 . The method of  claim 1 , further comprising:
 determining an elevation of the seal energizing ring within an annular space comprising the wellhead annulus packoff; and   providing one or more surfaces of the retainer lock mechanism to enable the determined elevation of the seal energizing ring within an annular space.   
     
     
         10 . The method of  claim 1 , further comprising:
 providing multiple seal stages to be above the retainer lock mechanism;   associating the multiple seal stages with the seal element via one or more surfaces of the retainer lock mechanism; and   enabling, using the one or more surfaces, the retainer lock mechanism to be removed with the multiple seal stages during de-energizing of the wellhead annulus packoff.   
     
     
         11 . A wellhead annulus packoff, comprising:
 a retainer lock mechanism to sit at least partly within an indentation of a hanger and to be associated with a first side of a seal element in an energized state of the wellhead annulus packoff, wherein a second side of the seal element comprises at least one leg to abut within at least one recess of a surface of a housing.   
     
     
         12 . The wellhead annulus packoff of  claim 11 , wherein the retainer lock mechanism is to be in an engaged position between the hanger, the seal element, and a lower energizing ring, with the wellhead annulus packoff in the energized state; and wherein the retainer lock mechanism is to be in a disengaged position, with the wellhead annulus packoff in a de-energized state. 
     
     
         13 . The wellhead annulus packoff of  claim 11 , further comprising:
 at least two legs of the seal element to be recessed within different recesses of the housing.   
     
     
         14 . The wellhead annulus packoff of  claim 11 , further comprising:
 a mechanical conditional operator between the seal element and a lower energizing ring, the mechanical conditional operator to disengage during energizing of the wellhead annulus packoff.   
     
     
         15 . The wellhead annulus packoff of  claim 11 , further comprising:
 a surface of the retainer lock mechanism to be associated between the seal element and a lower energizing ring, and to allow landing of the lower energizing ring and the retainer lock mechanism into an annular space between the hanger and the housing.   
     
     
         16 . The wellhead annulus packoff of  claim 11 , further comprising:
 at least one inclined top surface of the retainer lock mechanism to enable one or more of:   an allowance for the retainer lock mechanism to disengage from the first indentation of the hanger during de-energizing of the wellhead annulus packoff;   an allowance for the retainer lock mechanism to engage the first indentation of the hanger during energizing of the wellhead annulus packoff; or   a transfer of a vertical upwards force from a lower energizing ring into a neck of the hanger in the energized state of the wellhead annulus packoff.   
     
     
         17 . The wellhead annulus packoff of  claim 11 , further comprising:
 a bottom surface of the retainer lock mechanism to abut with a lifting surface of a lower energizing ring, the bottom surface and a side surface of the retainer lock mechanism to limit a top surface of the lower energizing ring or the second side of the seal element from asserting pressure against the housing during de-energizing of the wellhead annulus packoff.   
     
     
         18 . The wellhead annulus packoff of  claim 11 , further comprising:
 the wellhead annulus packoff being removable with a first de-energizing force or forces that is less than a second de-energizing force or forces, the second de-energizing force or forces associated with removal of the wellhead annulus packoff in an application comprising the wellhead annulus packoff installed while being devoid of the retainer lock mechanism.   
     
     
         19 . The wellhead annulus packoff of  claim 11 , further comprising:
 one or more surfaces of the retainer lock mechanism to enable a determined elevation of a lower energizing ring within an annular space comprising the wellhead annulus packoff.   
     
     
         20 . The wellhead annulus packoff of  claim 11 , further comprising:
 multiple seal stages above the retainer lock mechanism, the multiple seal stages associated with each other and with the seal element via one or more surfaces of the retainer lock mechanism, the one or more surfaces to enable the retainer lock mechanism to be removed with the multiple seal stages during de-energizing of the wellhead annulus packoff.