Flow completion system

A flow completion system for controlling the flow of fluid from a well bore, the flow completion system comprising:

• a tubing spool which includes a central bore that extends axially therethrough and a production outlet which communicates with the central bore;
• a tubing hanger which is supported in the central bore and which includes a production bore that extends axially therethrough and a production passageway that communicates between the production bore and the production outlet, the tubing hanger supporting a tubing string which extends into the well bore and defines a tubing annulus surrounding the tubing string;
• a first closure member which is positioned in the production bore above the production passageway;
• a first annular seal which is positioned between the tubing hanger and the central bore above the production passageway;
• wherein the first closure member and the first seal comprise a first pressure-containing barrier between the well bore and a surrounding environment;
• a second closure member which is positioned in the production bore above the first closure member;
• a second annular seal which is positioned between the tubing hanger and the central bore above the first seal;
• wherein the second closure member and the second seal comprise a second pressure-containing barrier between the well bore and the environment;
• wherein both the first and the second barriers are associated with the tubing hanger;
• and
• a tree cap which comprises an annular non-metallic body and means for securing the body to the tubing hanger or the tubing spool;
• wherein the securing means comprises:
• a plurality of collet fingers which are secured to the body;
• a lock mandrel which includes a camming surface;
• and
• a number of locking dogs which are disposed generally radially in the body and which each comprise a first end which is adapted to be engaged by the camming surface and a second end which is adapted to contact one or more of the collet fingers;
• wherein actuation of the lock mandrel will force the locking dogs radially outwardly against the collet fingers to lock the collet fingers in a corresponding groove that is formed on the tubing hanger or the tubing spool.

A flow completion system for controlling the flow of fluid from a well bore, the flow completion system comprising:

• a tubing spool which includes a central bore that extends axially therethrough and a production outlet which communicates with the central bore;
• a tubing hanger which is supported in the central bore and which includes a production bore that extends axially therethrough and a production passageway that communicates between the production bore and the production outlet, the tubing hanger supporting a tubing string which extends into the well bore and defines a tubing annulus surrounding the tubing string;
• a first closure member which is positioned in the production bore above the production passageway;
• a first annular seal which is positioned between the tubing hanger and the central bore above the production passageway;
• wherein the first closure member and the first seal comprise a first pressure-containing barrier between the well bore and a surrounding environment;
• a second closure member which is positioned in the production bore above the first closure member;
• a second annular seal which is positioned between the tubing hanger and the central bore above the first seal;
• wherein the second closure member and the second seal comprise a second pressure-containing barrier between the well bore and the environment;
• wherein both the first and the second barriers are associated with the tubing hanger;
• and
• a tree cap which comprises:
• an annular non-metallic body;
• means for securing the body to the tubing hanger or the tubing spool;
• a landing ring which is movably secured to the body;
• and
• means for adjusting landing ring axially relative to the body;
• wherein when the tree cap is secured to the tubing hanger or the tubing spool, the landing ring engages a tubing hanger locking mandrel which is slidably mounted on the tubing hanger;
• whereby the landing ring maintains the position of the tubing hanger locking mandrel fixed relative to the tubing hanger.

A flow completion system for controlling the flow of fluid from a well bore, the flow completion system comprising:

• a tubing spool which includes a central bore that extends axially therethrough and a production outlet which communicates with the central bore;
• a tubing hanger which is supported in the central bore and which includes a production bore that extends axially therethrough and a production passageway that communicates between the production bore and the production outlet, the tubing hanger supporting a tubing string which extends into the well bore and defines a tubing annulus surrounding the tubing string;
• a first closure member which is positioned in the production bore above the production passageway;
• a first annular seal which is positioned between the tubing hanger and the central bore above the production passageway;
• wherein the first closure member and the first seal comprise a first pressure-containing barrier between the well bore and a surrounding environment;
• a second closure member which is positioned in the production bore above the first closure member;
• a second annular seal which is positioned between the tubing hanger and the central bore above the first seal;
• wherein the second closure member and the second seal comprise a second pressure-containing barrier between the well bore and the environment;
• wherein both the first and the second barriers are associated with the tubing hanger;
• a BOP which is removably connectable to the top of the tubing spool and which includes a BOP bore, a set of BOP rams, and at least one choke and kill line that communicates with a portion of the BOP bore which is located below the BOP rams;
• and
• a tubing hanger running tool which is removably connectable to the top of the tubing hanger and which includes a cylindrical outer surface portion, a production port that communicates with the production bore, and an annulus port that comprises a first end which communicates with an annulus bore that extends through the tubing hanger and communicates with the tubing annulus and a second end which communicates with the outer surface portion;
• wherein the BOP rams are adapted to sealingly engage the outer surface portion above the second end of the annulus port;
• whereby fluid communication between the tubing annulus and the BOP choke and kill line may be established through the annulus bore, the annulus port and the portion of the BOP bore which is located below the first BOP rams.