Independently retrievable subsea tree and tubing hanger system

A method for servicing a subsea well, said well comprising a wellhead housing supported on a seabed, a tree disposed above and removably connected to said wellhead housing, said tree having an internal bore, a fine alignment key for aligning said tree with said wellhead housing, and a plurality of ports selected from the group comprising:

• at least one radial production port for communication of said bores with an external production line;
• at least one annular access port for communication of said bores with an annular access line;
• and
• at least one additional port for hydraulic connection to said internal bore;
• a tubing hanger disposed in said internal bore of said tree and having a production tubing string extending downwardly therefrom, and an annular tubing string extending downwardly therefrom, said tubing hanger further comprising slidably engagable gates each with a gate port and wherein said gates are moveable to selectively open and close at least one of said ports, said method comprising the steps of:
• a. engaging at least one of said slidably engagable gates in an axial motion to apply pressure against a means for retracting or extending outer seals for said ports;
• b. camming against said means for retracting or extending at least one outer seals causing motion perpendicular to the motion of said slidably engagable gate thereby retracting or extending said at least one outer seal for said outer port;
• c. maintaining an inner contact using said slidably engagable gate having a port disposed therein, to alternatively provide a blocking position by engaging said gate with an inner seal and an unblocking position by aligning said gate port with at least one of said production port, said annular access port, and said additional port for fluid communication with the tubing hanger and the tree;
• and
• d. when in the blocked position, removing said tree from said wellhead housing while said tubing hanger remains engaged to said production tubing string.

A method for servicing a subsea well, said well comprising a wellhead housing supported on a seabed;

• a tree disposed above and removably connected and aligned with said wellhead housing, said tree having an internal bore, a plurality of ports comprising;
• at least one radial production port for communication of aid bores with an external production line;
• at least one annular access port for communication of said bores with an annular access line;
• and
• at least one additional port for hydraulic connection to said internal bore;
• a tree cap with a tree cap internal bore in fluid communication with said tree, a tubing hanger disposed in said internal bore of said tree and having a production tubing string extending downwardly therefrom, and an annular tubing string extending downwardly therefrom, said tubing hanger further comprising slidably engagable gates each with a gate port, and wherein said gates open and close said production port, said annular access port and said additional port;
• said method comprising the steps of:
• a. engaging at least one of said slidably engagable gates in an axial motion to apply pressure against a means for retracting or extending outer seals for said ports;
• b. camming against said means for retracting or extending at least one outer seal causing motion perpendicular to the motion of said slidably engagable gate thereby retracting or extending said at least one outer seal for said outer port;
• c. maintaining an inner contact using said slidably engagable gate having a port disposed therein, to alternatively provide a blocking position, by engaging said gate with an inner seal and an unblocking position by aligning said gate port with at least one of said production port, said annular access port, and said additional port for fluid communication with the tubing hanger and the tree;
• d. disconnecting said tree cap from said tree and said tubing hanger;
• and
• e. using a running tool to pull said tubing hanger from said wellhead by manipulating said slidably engagable gates in an axial direction to retract said outer seals and through the use of a lost motion dog, disconnecting said tubing hanger from said wellhead.