Retainer valve

An apparatus for controlling fluid flow in a pipe extending from a rig through a subsea blowout preventer into a subsea well, comprising:

• a control valve connected to a lower portion of the pipe that extends into the subsea well;
• a retainer valve connected to an upper portion of the pipe above the subsea well, the retainer valve comprising:
• an elongated body adapted to be positioned within the subsea blowout preventer, the elongated body having an end adapted for connection to the pipe, a flow passage for fluid communication with the pipe, and an outer surface for engagement with a sealing member in the subsea blowout preventer;
• a first chamber defined within the elongated body and connected to receive pressure from one side of the sealing member;
• a second chamber defined within the elongated body and connected to receive pressure from another side of the sealing member;
• and
• a valve supported in the elongated body for movement in response to pressure differential between the first and second chambers, the valve being movable between an open position to permit fluid flow through the flow passage and a closed position to prevent fluid flow through the flow passage;
• and
• a latch releasably connecting the control valve to the retainer valve.

A method for controlling fluid flow in a pipe extending from a rig through a subsea blowout preventer into a subsea well, the subsea blowout preventer having a sealing member, the method comprising:

• providing a retainer valve in the pipe such that a flow passage in the retainer valve is in fluid communication with the pipe;
• operating a movable member in the retainer valve to open the flow passage such that fluid can flow through the flow passage or close the flow passage such that fluid is prevented from flowing through the flow passage;
• venting a first chamber in the retainer valve to pressure on one side of the sealing member in the subsea blowout preventer;
• venting a second chamber in the retainer valve to pressure on another side of the sealing member in the subsea blowout preventer;
• and
• creating pressure differential between the first chamber and the second chamber to move the movable member.

An apparatus for controlling fluid flow in a pipe extending from a rig through a subsea blowout preventer into a subsea well, comprising:

• a control valve connected to a lower portion of the pipe that extends into the subsea well;
• a retainer valve connected to an upper portion of the pipe above the subsea well, the retainer valve comprising:
• an elongated body adapted to be positioned within the subsea blowout preventer, the elongated body having an end adapted for connection to the pipe, a flow passage for fluid communication with the pipe, and an outer surface for engagement with a sealing member in the subsea blowout preventer;
• a first chamber defined within the elongated body and connected to receive pressure from above the sealing member;
• a second chamber defined within the elongated body and connected to receive pressure from below the sealing member;
• and
• a valve supported in the elongated body for movement in response to pressure differential between the first and second chambers, the valve being movable between an open position to permit fluid flow through the flow passage and a closed position to prevent fluid flow through the flow passage;
• and
• a latch releasably connecting the control valve to the retainer valve, and
• wherein the retainer valve further comprises a sleeve having a first surface for communication with a fluid pressure control line, the sleeve adapted to be moved by pressure in the fluid pressure control line to actuate the valve,
• wherein the retainer valve further comprises a piston disposed between the first and second chambers and coupled to the sleeve, the piston adapted to be moved by pressure differential between the first and second chambers.

An apparatus for controlling fluid flow in a pipe extending from a rig through a subsea blowout preventer into a subsea well, comprising:

• a control valve connected to a lower portion of the pipe that extends into the subsea well;
• a retainer valve connected to an upper portion of the pipe above the subsea well, the retainer valve comprising:
• an elongated body adapted to be positioned within the subsea blowout preventer, the elongated body having an end adapted for connection to the pipe, a flow passage for fluid communication with the pipe, and an outer surface for engagement with a sealing member in the subsea blowout preventer;
• a first chamber defined within the elongated body and connected to receive pressure from above the sealing member;
• a second chamber defined within the elongated body and connected to receive pressure from below the sealing member;
• and
• a valve supported in the elongated body for movement in response to pressure differential between the first and second chambers, the valve being movable between an open position to permit fluid flow through the flow passage and a closed position to prevent fluid flow through the flow passage;
• and
• a latch releasably connecting the control valve to the retainer valve,
• wherein the retainer valve further comprises a bleed valve adapted to bleed trapped pressure between the retainer valve and the control valve.