Plug installation system for deep water subsea wells

In a subsea well apparatus having a production tree, a tubing hanger, a passage that extends vertically through the tubing hanger and the tree, and a plug located in the passage within the tubing hanger, a device for removing the plug, comprising:

• a housing;
• a connector having a released position and a locked position for releasably connecting the housing to an upper end of the production tree;
• an axially extensible stem in the housing;
• a drive mechanism mounted to the housing for moving the stem from a retracted position to an extended position within the production passage of the tubing hanger;
• and
• a retrieval member mounted to the stem for engaging the plug while the stem is being moved to the extended position and pulling it upwardly in the passage the stem is being moved when in the retracted position.

In a subsea well apparatus having a production tree with an external profile on an upper end, a tubing hanger, a passage that extends vertically through the tubing hanger and the tree, and a plug located within a plug profile in the passage within the tubing hanger, a device for removing the plug, comprising:

• a housing and connector adapted to be lowered on a lift line onto the upper end of the tree;
• the connector having a ROV connector interface for engagement by an ROV to enable the ROV to move the connector from a released position to a locked position releasably engaging the external profile on the tree;
• an axially extensible stem in the housing;
• a drive mechanism mounted to the housing and having an ROV drive interface for engagement by the ROV to enable the ROV to move the stem from a retracted position to an extended position within the production passage of the tubing hanger;
• and
• a retrieval member mounted to the stem for engaging the plug while the stem is being moved to the extended position and pulling it upwardly in the passage while the stem is being moved to the retracted position.

A method for retrieving a plug in a passage of a subsea wellhead assembly, comprising:

• (a) mounting an axially movable stem within a housing and connecting a retrieval member to the stem;
• then
• (b) lowering the housing on a lift line and sealingly connecting the housing to an upper end of a subsea wellhead assembly while the stem is in a retracted position;
• (c) axially moving the stem downward into the passage and causing the retrieval member to engage the plug;
• then
• (d) moving the stem upward along with the plug.

A method for completing a subsea well having a wellhead housing and at least one casing hanger suspended therein, the method comprising:

• (a) from a floating platform, connecting a drilling riser to the wellhead housing;
• (b) lowering a string of tubing through the drilling riser on a string of conduit and setting a tubing hanger within the wellhead housing;
• (c) lowering a perforating gun through the conduit and tubing and perforating the well;
• then
• (d) lowering a plug through the conduit and setting the plug within a plug profile provided in the tubing hanger;
• then
• (e) disconnecting the drilling riser from the wellhead housing;
• then
• (f) lowering a tree on a lift line and connecting the tree to the wellhead housing;
• (g) at the platform, mounting an axially movable stem within a housing and connecting a retrieval member to the stem;
• then
• (h) lowering the housing on a lift line and sealingly connecting the housing to an upper end of the tree while the stem is in a retracted position;
• (i) axially moving the stem downward into the passage and causing the retrieval member to engage the plug;
• (j) moving the stem upward along with the plug;
• and
• (k) disconnecting the housing from the tree and retrieving the housing to the platform.