Plug installation system for deep water subsea wells

An apparatus for engaging a plug in a wellhead passage of a subsea wellhead assembly, comprising:

• a tubular housing adapted to be sealingly connected to an upper end of a subsea wellhead assembly;
• an axially moveable stem carried in the housing and having at least two portions that telescope relative to each other for movement between a retracted position and an extended position into the wellhead passage;
• a hydraulically actuated engaging member mounted to the stem for selectively installing or retrieving the plug;
• and
• a plurality of fluid passages extending between the engaging member and an upper end portion of the housing that selectively receive and vent hydraulic fluid for actuating the engaging member into and out of engagement with the plug.

An apparatus for engaging a plug in a wellhead passage of a subsea wellhead assembly, comprising:

• a tubular housing having a closed upper end and a lower end adapted to be connected to a wellhead passage of a subsea wellhead assembly;
• a stem carried within the housing for axial movement relative to the housing, the stem having a piston portion located within a piston chamber within the housing;
• a hydraulically actuated engaging member mounted to a lower end of the stem for engaging a plug in the wellhead passage;
• a piston port extending through the housing for supplying hydraulic fluid to the piston chamber to move the stem from a retracted position to an extended position with the engaging member extending from the housing into the wellhead passage;
• an engaging member chamber located in the housing below and isolated from the piston chamber;
• an engaging member port extending through the housing;
• and
• a rigid tube stationarily secured within the housing, having an upper end in communication with the engaging member port, the tube extending through the piston portion of the stem and having an open lower end in communication with the engaging member chamber for supplying hydraulic fluid to the engaging member to engage the plug.

A method for engaging a plug within a wellhead passage of a subsea wellhead assembly, comprising:

• (a) providing a tubular housing, an axially moveable stem carried within the housing, an engaging member connected to the stem, and a fluid passage extending through the stem to the engaging member;
• (b) connecting the housing to a subsea wellhead assembly;
• (c) extending the stem, causing the engaging member to move into the wellhead passage;
• and
• (d) supplying hydraulic fluid through the fluid passage to the engaging member to selectively lock or unlock the engaging member with the plug.