Annulus check valve with tubing plug back-up

A method for installing a tubing hanger in a subsea wellhead, the tubing hanger having a production bore and an offset tubing annulus bore extending therethrough, the wellhead being in communication with a vessel at the surface via a riser which contains a blowout preventer, the method comprising:

• (a) installing a valve in the annulus bore;
• (b) securing the tubing hanger to a running tool;
• (c) opening the valve with the running tool, securing the running tool to a monobore conduit, lowering the tubing hanger through the riser with the conduit, and setting the tubing hanger in the wellhead;
• then
• (d) installing a retrievable production plug in the production bore;
• (e) releasing the running tool from the tubing hanger and closing the valve;
• then
• (f) determining if the valve leaks;
• and if so,
• (g) installing an annulus plug in the annulus bore;
• wherein step (c) includes:
• closing the blowout preventer around the conduit while the running tool is engaged with the tubing hanger, creating a chamber within the riser which communicates with the vessel through a choke and kill line incorporated with the riser;
• and
• providing an annulus passageway in the running tool for communicating the tubing annulus bore with the chamber, and thereby with the vessel through the choke and kill line.

A method for installing a tubing hanger in a subsea wellhead, the tubing hanger having a production bore and an offset tubing annulus bore extending therethrough, the wellhead being in communication with a vessel at the surface via a riser which contains a blowout preventer, the method comprising:

• (a) installing a check valve in the annulus bore;
• (b) securing the tubing hanger to a running tool;
• (c) opening the check valve with the running tool, securing the running tool to a monobore conduit, lowering the tubing hanger through the riser with the conduit, and setting the tubing hanger in the wellhead;
• then
• (d) installing a retrievable production plug in the production bore;
• (e) releasing the running tool from the tubing hanger and closing the check valve;
• then
• (f) determining if the check valve leaks;
• and if so,
• (g) installing an annulus plug in the annulus bore;
• and wherein step (g) comprises retrieving the check valve, then installing the annulus plug.

A method for installing a tubing hanger in a subsea wellhead, the tubing hanger having a production bore and an offset tubing annulus bore extending therethrough, the wellhead being in communication with a vessel at the surface via a riser which contains a blowout preventer, the method comprising:

• (a) installing a check valve in the annulus bore;
• (b) securing the tubing hanger to a running tool;
• (c) opening the check valve with the running tool, securing the running tool to a monobore conduit, lowering the tubing hanger through the riser with the conduit, and setting the tubing hanger in the wellhead;
• then
• (d) installing a retrievable production plug in the production bore;
• (e) releasing the running tool from the tubing hanger and closing the check valve;
• then
• (f) determining if the check valve leaks, and if so,
• (g) installing an annulus plug in the annulus bore;
• and wherein
• step (c) comprises while connecting the running tool to the tubing hanger, moving a seat of the check valve downward with a stinger incorporated with the running tool.

A tubing hanger assembly for landing in a wellhead of a subsea well, comprising:

• a production bore extending through the tubing hanger assembly;
• an annulus bore extending through the tubing hanger assembly offset from the production bore;
• a check valve located in the annulus bore for preventing upward flow through the annulus bore while the check valve is in a closed position;
• a profile in the annulus bore for receiving an annulus plug in the event the check valve fails;
• and wherein
• the check valve secures within the profile in the annulus bore and is adapted to be retrieved and replaced by the annulus plug in the event the check valve fails.

A tubing hanger assembly for landing in a wellhead of a subsea well, comprising:

• a production bore extending through the tubing hanger assembly;
• an annulus bore extending through the tubing hanger assembly offset from the production bore;
• a check valve located in the annulus bore for preventing upward flow through the annulus bore while the check valve is in a closed position;
• a profile in the annulus bore for receiving an annulus plug in the event the check valve fails;
• wherein
• the check valve has a seat, a movable element which engages the seat, and a spring which urges the movable element upward into engagement with the seat;
• and wherein
• the movable element is adapted to be selectively pushed out of engagement with the seat by a running tool while the tubing hanger is being lowered into the wellhead.

A tubing hanger assembly for landing in a wellhead of a subsea well, comprising:

• a production bore extending through the tubing hanger assembly;
• an annulus bore extending through the tubing hanger assembly offset from the production bore;
• a check valve located in the annulus bore for preventing upward flow through the annulus bore while the check valve is in a closed position;
• a profile in the annulus bore for receiving an annulus plug in the event the check valve fails;
• wherein
• the check valve has a seat, a movable element which engages the seat, and a spring which urges the movable element upward into engagement with the seat;
• and wherein
• the movable element is adapted to be selectively pushed out of engagement with the seat by the annulus plug when being installed in the profile.

A tubing hanger assembly for landing in a wellhead of a subsea well, comprising:

• a production bore extending through the tubing hanger assembly;
• an annulus bore extending through the tubing hanger assembly offset from the production bore;
• a check valve located in the annulus bore for preventing upward flow through the annulus bore while the check valve is in a closed position;
• a profile in the annulus bore for receiving an annulus plug in the event the check valve fails;
• wherein
• the check valve has a seat located below the profile, a movable element which engages the seat, and a spring which urges the movable element upward into engagement with the seat;
• and wherein the tubing hanger assembly further comprises:
• a rod which protrudes upward from the movable element past the seat;
• a retainer mounted to the rod above the movable element, the retainer and the rod being movable from an operational position with the retainer located above the seat to a latched position wherein the retainer is located below and pressed against the seat by the spring, preventing the movable element from sealing against the seat.

A tubing hanger assembly for landing in a wellhead of a subsea well, comprising:

• a production bore extending through the tubing hanger assembly;
• an annulus bore extending through the tubing hanger assembly offset from the production bore;
• a check valve located in the annulus bore for preventing upward flow through the annulus bore while the check valve is in a closed position;
• a profile in the annulus bore for receiving an annulus plug in the event the check valve fails;
• wherein
• the check valve has a seat located below the profile, a movable element which engages the seat, and a spring which urges the movable element upward into engagement with the seat;
• and wherein the tubing hanger assembly further comprises:
• a rod which protrudes upward from the movable element past the seat for engagement by a running tool stinger to selectively hold the check valve in an open position.

In a subsea well having a wellhead, a riser secured to the wellhead and extending upward to a vessel, a blowout preventer mounted in the riser and having a choke and kill line, an assembly for installing a tubing hanger in the wellhead, comprising:

• a tubing hanger adapted to be secured to a string of tubing and having a production bore and an annulus bore offset from the production bore;
• a check valve located in the annulus bore for preventing upward flow through the annulus bore while the check valve is in a closed position;
• a string of conduit having a passage therethrough, the conduit adapted to be lowered from the vessel through the riser;
• a running tool connected to the string of conduit and to the tubing hanger;
• the running tool having a production sleeve which engages the production bore and communicates the production bore with the passage in the string of conduit;
• the running tool having an annulus sleeve which engages the annulus bore and a stinger which moves the check valve to an open position;
• wherein
• lifting the running tool from the tubing hanger after installation of the tubing hanger and closing the blowout preventer around the conduit enables the check valve to be monitored in the closed position through the choke and kill line;
• and wherein
• the annulus bore has a profile for receiving an annulus plug in the event the check valve fails.