Retaining apparatus for use in a wellhead assembly and method for using the same

A method for retaining an apparatus within the central bore of a wellhead assembly, the method comprising:

• providing a first retaining means within the bore of the wellhead assembly;
• providing a second retaining means within the bore of the wellhead assembly;
• providing the apparatus with an engagement assembly for engaging with the second retaining means within the bore of the wellhead assembly;
• positioning the apparatus within the bore of the wellhead assembly so as to be retained by the first retaining means;
• engaging the engagement assembly with the second retaining means;
• applying a preload to the apparatus against the second retaining means to urge the apparatus toward the first retaining means;
• providing an actuator movable longitudinally within the central bore of the wellhead assembly, movement of the actuator in a first direction causing the engagement ring to move into engagement with the groove and movement of the actuator in a second direction causing the engagement ring to move out of engagement with the groove, the method comprising moving the actuator in the first direction to engage the engagement ring with the groove;
• providing a loading assembly, the loading assembly being movable longitudinally within the bore of the wellhead assembly, with the apparatus positioned within the bore of the wellhead assembly and the engagement assembly engaged with the second retaining means, movement of the loading assembly in a first direction causing the loading assembly to bear against the second retaining means and urge the apparatus against the first retaining means, thereby applying the preload to the apparatus, the method comprising moving the loading assembly in the first direction to bear against the second retaining means;
• and,
• the apparatus comprises a housing, movement of the loading assembly in the first direction is obtained by rotation of the loading assembly with respect to the housing.

An internal tree cap for installation in the central bore of a wellhead assembly, the wellhead assembly comprising first and second retaining means within the bore of the wellhead, the internal tree cap comprising:

• a cap housing for location within the bore of the wellhead;
• a first engagement assembly for engaging with the first retaining means in the bore of the wellhead to thereby retain the cap housing within the bore of the wellhead;
• a second engagement assembly for engaging with the second retaining means in the bore of the wellhead;
• a preload assembly operable when the cap housing is located within the bore of the wellhead, the preload assembly when operated bearing against the second retaining means to urge the cap housing towards the first retaining means, the preload assembly thereby applying a preload to the cap housing between the first and second retaining means.

A wellhead assembly comprising:

• first and second retaining means within the bore of the wellhead;
• an internal tree cap retained in the bore of the wellhead, the internal tree cap comprising:
• a cap housing for location within the bore of the wellhead;
• a first engagement assembly for engaging with the first retaining means in the bore of the wellhead to thereby retain the cap housing within the bore of the wellhead;
• a second engagement assembly for engaging with the second retaining means in the bore of the wellhead;
• a preload assembly operable when the cap housing is located within the bore of the wellhead, the preload assembly when operated bearing against the second retaining means to urge the cap housing towards the first retaining means, the preload assembly thereby applying a preload to the cap housing between the first and second retaining means.

An apparatus for use in a wellhead, the wellhead having a central bore and first and second retaining means within the bore of the wellhead, the apparatus comprising:

• a housing for location within the bore of the wellhead;
• at least one seal mounted externally on a portion of the housing and adapted for sealing engagement with the wellhead;
• a first engagement assembly associated with the first retaining means in the bore of the wellhead to thereby support the housing within the bore of the wellhead;
• a second engagement assembly for engaging with the second retaining means in the bore of the wellhead to thereby retain the housing within the bore of the wellhead;
• a preload assembly operable when the housing is located within the bore of the wellhead to apply a preload to that portion of the housing on which the at least one seal is mounted below the second retaining means, the preload assembly comprises a loading member movable so as to be brought to bear against the second engagement assembly once the second engagement assembly is engaged with the second retaining means to urge the housing toward the first retaining means within the wellhead, to thereby provide the preload;
• the loading member is a loading ring movable longitudinally with respect to the housing;
• and,
• a threaded connection secures the loading ring to the housing, rotation of the loading ring with respect to the housing causing the loading ring to move longitudinally with respect to the housing.

A retaining apparatus for use in a wellhead, the wellhead having a central bore and a first retaining means with a support shoulder in the central bore and a second retaining means with a groove, the apparatus comprising:

• a well component within the central bore adapted to be supported by the support shoulder;
• seals disposed around a part of the well component and engaging the wellhead;
• a housing adapted for location within the bore of the wellhead;
• at least one seal mounted externally on a portion of the housing and adapted for sealing engagement with the wellhead;
• the housing engaging the well component;
• a first engagement assembly associated with the support shoulder of the first retaining means in the bore of the wellhead to thereby support the housing within the bore of the wellhead;
• a second engagement assembly for engaging with the groove of the second retaining means in the bore of the wellhead to thereby retain the housing within the bore of the wellhead;
• the second engagement assembly including a locking ring disposed on the housing and adapted to project into the groove to thereby retain the housing within the bore of the wellhead;
• a preload assembly operable when the housing is located within the bore of the wellhead to apply a preload to that portion of the housing on which the at least one seal is mounted below the second retaining means, the preload assembly comprises a loading member movable so as to be brought to bear against the second engagement assembly once the second engagement assembly is engaged with the second retaining means to urge the housing toward the first retaining means within the wellhead, to thereby provide the preload;
• the loading member is a loading ring movable longitudinally with respect to the housing;
• a threaded connection secures the loading ring to the housing, rotation of the loading ring with respect to the housing causing the loading ring to move longitudinally with respect to the housing;
• and
• a retainer securing the loading member to the housing as the loading member moves longitudinally.

An internal tree cap for installation in the central bore of a horizontal tree with a tubing hanger, the horizontal tree comprising a retaining profile within the bore of the horizontal tree, and the tubing hanger having seals around a part of the tubing hanger, the internal tree cap comprising:

• a cap housing for location within the bore of the horizontal tree;
• at least one seal mounted externally on a portion of the cap housing and adapted for sealing engagement with the horizontal tree;
• the cap housing engaging the tubing hanger in the bore of the horizontal tree to thereby support the cap housing within the bore of the horizontal tree;
• an engagement assembly on the internal tree cap engaging the retaining profile in the bore of the horizontal tree;
• and
• a force assembly operable when the cap housing is located within the bore of the horizontal tree, the force assembly when operated bearing against the engagement assembly to urge the cap housing towards the tubing hanger, the force assembly thereby applying a force on the cap housing portion between the retaining profile and the tubing hanger.

A wellhead assembly comprising:

• first and second retainers within the bore of the wellhead assembly;
• an internal tree cap retained in the bore of the wellhead assembly, the internal tree cap comprising:
• a cap housing for location within the bore of the wellhead assembly;
• at least one seal mounted externally on a portion of the cap housing;
• a first engagement assembly supported by the first retainer in the bore of the wellhead assembly;
• a second engagement assembly for engaging the second retainer in the bore of the wellhead assembly to thereby retain the cap housing within the bore of the wellhead assembly;
• a preload assembly operable when the cap housing is located within the bore of the wellhead assembly, the preload assembly when operated moving axially bearing against the second engagement assembly and engaging the cap housing to urge the cap housing portion in an axial direction away from the second engagement assembly and against the first retainer, the preload assembly thereby applying a preload to the cap housing portion between the first and second retainers.

A wellhead assembly having a wellhead, the wellhead assembly comprising:

• a horizontal tree having a central bore therethrough, a landing shoulder, and first and second profiles in the central bore;
• a tubing hanger landed on the landing shoulder and having seals disposed around a part of the tubing hanger;
• a first locking ring on the tubing hanger projecting into the first profile retaining the tubing hanger within the central bore;
• an internal tree cap disposed within central bore and engaging the tubing hanger;
• at least one seal mounted around an external portion of the internal tree cap;
• a second locking ring on the internal tree cap projecting into the second profile retaining the internal tree cap within the central bore;
• and
• a loading member engaging the internal tree cap and movable longitudinally with respect to the internal tree cap causing a downward force on the tubing hanger to prevent longitudinal movement of the tubing hanger part.

A wellhead assembly comprising:

• a spool tree having a bore with first and second retaining means;
• an internal tree cap retained in the bore of the spool tree, the internal tree cap comprising:
• a cap housing for location within the bore of the spool tree;
• at least one seal mounted externally around a portion of the cap housing;
• a first engagement assembly associated with the first retaining means in the bore of the spool tree to thereby support the cap housing within the bore of the spool tree;
• a second engagement assembly for engaging with the second retaining means in the bore of the spool tree to retain the cap housing within the bore of the spool tree;
• a force assembly operable when the cap housing is located within the bore of the spool tree and including a securing means, the force assembly when operated bearing against the second retaining means to urge the cap housing portion towards the first retaining means, the force assembly thereby applying a force to the cap housing portion between the first and second retaining means;
• wherein:
• the spool tree is a horizontal tree having the bore therethrough and including a landing shoulder disposed in the bore of the horizontal tree and first and second profiles in a wall forming the bore of the spool tree;
• a tubing hanger landed on the landing shoulder, the landing shoulder and tubing hanger forming the first retaining means;
• seals disposed around an external part of the tubing hanger;
• a first locking ring on the tubing hanger projecting into the first profile retaining the tubing hanger within the bore;
• the internal tree cap having a downwardly facing shoulder forming the first engagement means and engaging the tubing hanger supported on the landing shoulder;
• the second engagement means including a second locking ring on the internal tree cap projecting into the second profile forming the second retaining means to retain the internal tree cap within the bore;
• and
• a loading member engaging the internal tree cap and movable longitudinally with respect to the internal tree cap causing a downward force on the internal tree cap portion and tubing hanger part to thereby prevent the cap housing portion and tubing hanger part from moving longitudinally with respect to the spool tree.