Tandem wellbore safety valve apparatus and method of valving in a wellbore

In a tandem safety valve for connection into a tubing string for use in a wellbore, the tandem safety valve having a pair of valves connected in series in a housing, each of the valves including a flow tube, biased into a fail-safe normally closed position, the flow tube for selectively opening and closing each of the pair of valves against fluid flow in the tubing string, the housing including an hydraulic actuation cylinder in fluid flow communication with a normal-operation fluid pressure source, and a locking hydraulic actuation cylinder in fluid flow communication with a locking fluid pressure source, an apparatus for selectively locking open, and selectively opening and closing, each of the pair of valves of the tandem safety valve, the apparatus comprising:

• a normal-operation actuator means coupled to the normal-operation hydraulic cylinder to selectively and releasably engage the flow tube and valve for selectively opening and closing each valve;
• latch means for selectively and releasably securing the normal-operation actuator to the flow tube;
• locking dog means for selectively and releasably securing the flow tube to the housing wherein each valve is selectively maintained in a locked-open condition;
• and
• locking actuator means coupled to the locking hydraulic actuation cylinder to selectively release the normal-operation actuator means from engagement with the latch means and the locking dog means, wherein the locking dog means can engage the housing to secure the flow tube to the housing in a locked-open position;
• and
• wherein each of the pair of valves is operable in a plurality of conditions, the plurality of conditions including:
• a normal-operation condition in which the normal-operation actuator means is engaged with the latch means, and normal-operation actuator means and the flow tube are movable to open and close the valve member against fluid flow through the tandem safety valve;
• a locked-open condition in which the normal-operation actuator means is disengaged from the latch means and the locking dog means is engaged with the housing to maintain the flow tube stationary relative to the housing, wherein the valve is locked open to fluid flow through the tandem safety valve;
• and
• a locking condition in which the locking actuator means is engaged with the latch means to release the normal-operation actuator means and urge the flow tube into the locked-open condition;
• and
• a fail-safe closed condition in which the normal-operation actuator means and the locking actuator means are disengaged from the latch means and the valve is maintained in a closed position to block fluid flow through the tandem safety valve.

A safety valve for use in a wellbore to selectively permit fluid flow through a tubing string in the wellbore, the safety valve comprising:

• a housing;
• a valve member disposed in the housing to selectively block fluid flow through the safety valve;
• a flow tube disposed in the housing and selectively engageable with the valve member;
• a latch member secured to the flow tube to selectively and releasably engage a normal-operation actuator;
• a locking dog coupled to the latch member to selectively maintain the flow tube stationary relative to the housing, wherein the valve member is maintained in an open position to permit fluid flow through the safety valve;
• and
• a locking actuator to selectively engage the latch member to disengage the normal-operation actuator from the latch member.

A safety valve for use in a wellbore to selectively permit fluid flow through a tubing string in the wellbore, the safety valve comprising:

• a housing;
• a valve member disposed in the housing to selectively block fluid flow through the safety valve;
• a flow tube disposed in the housing and selectively engageable with the valve member;
• a latch member secured to the flow tube to selectively and releasably engage a normal-operation actuator, the normal operation actuator in communication with and responsive to fluid pressure from a normal-operation fluid pressure source;
• a cam member coupled to the latch member to selectively maintain the flow tube stationary relative to the housing, wherein the valve member is maintained in an open position to permit fluid flow through the safety valve;
• and
• a locking actuator to selectively engage the latch member to disengage the normal-operation actuator from the latch member, the locking actuator in communication with and responsive to fluid pressure from a locking fluid pressure source.

A method of valving to control fluid flow in a tubing string in a wellbore, the tubing string including a tandem safety valve, the method comprising the steps of:

• assembling at the surface a tubing string including a pair of safety valves, including an uppermost safety valve and a lowermost safety valve, connected in series in the tubing string, the uppermost and lowermost safety valves including:
• a housing;
• a valve member disposed in the housing to selectively block fluid flow through the safety valve;
• a flow tube disposed in the housing and selectively engageable with the valve member;
• a latch member secured to time flow tube to selectively and releasably engage a normal-operation actuator;
• a locking dog coupled to the latch member to selectively engage the housing to maintain the flow tube stationary relative to the housing, wherein the valve member is maintained in a locked-open position to permit fluid flow through the safety valve;
• and
• a locking actuator to selectively engage the latch member to disengage the normal-operation actuator from the latch member;
• running the tubing string including the pair of safety valves to a selected depth in the wellbore;
• locking open the lowermost safety valve by actuating the locking actuator of a lowermost safety valve to engage the latch member and to urge the flow tube into a locked-open condition wherein the flow tube is releasably secured to the housing by the locking dog wherein the valve member of the lowermost safety valve permits fluid flow through the lowermost safety valves;
• normally operating an uppermost of the pair of safety valves by actuating the normal-operation actuator of the uppermost pair of the valves to engage the latch member and locking dog to selectively open and close the valve member of the uppermost of the pair of the valves to selectively permit fluid flow through the pair of safety valves.

A safety valve for use in a wellbore to selectively permit fluid flow through a tubing string in the wellbore, the safety valve comprising:

• a housing for connection into the tubing string;
• a flapper valve secured to the housing for movement between an open and a closed position;
• a tube member longitudinally movable in the housing to move the flapper valve from the open to the closed position;
• a normal-operation cylinder and piston, the normal-operation piston being stationary relative to the housing and the normal-operation cylinder being movable relative to the normal-operation piston responsive to fluid pressure from a normal-operation fluid pressure source;
• a locking cylinder and piston, the locking piston being stationary relative to the housing and the locking cylinder being movable relative to the locking piston responsive to fluid pressure from a locking fluid pressure source;
• a normal-operation actuator coupled to the normal-operation cylinder and piston;
• a latch coupled to the tube member to selectively and releasably engage the normal-operation actuator;
• a locking member coupled to the latch to selectively maintain the tube member stationary relative to the housing, wherein the flapper is maintained in the open position without fluid pressure from the normal-operation and locking fluid pressure sources;
• and
• a locking actuator coupled to the locking cylinder and piston to selectively engage the latch and disengage the normal-operation actuator from the latch.

A safety valve for use in a wellbore to selectively permit fluid flow through a tubing string in the wellbore, the safety valve comprising:

• a housing for connection into the tubing string;
• a flapper valve secured to the housing for movement between an open and a closed position;
• a tube member longitudinally movable in the housing to move the flapper valve from the open to the closed position;
• a biasing member coupled between the housing and the tube member to urge the tube member to a fail-safe condition, wherein the flapper is in the closed position;
• a normal-operation cylinder and piston, the normal-operation piston being stationary relative to the housing and the normal-operation cylinder being movable relative to the housing responsive to fluid pressure from a normal-operation fluid pressure source;
• a locking cylinder and piston, the locking piston being stationary relative to the housing and the locking cylinder being movable relative to the housing responsive to fluid pressure from a locking fluid pressure source;
• a normal-operation actuator coupled to the normal-operation cylinder and piston, the normal-operation actuator being selectively engageable with the tube member to move the tube member and flapper valve between the open and closed positions;
• and
• a locking actuator coupled to the locking cylinder and piston to selectively engage the tube member to disengage the normal-operation actuator from the tube member and move the tube member to a releasably locked position in which the flapper valve is in the open position and the tube member is releasably maintained stationary relative to the housing without fluid pressure from the locking and normal-operation fluid pressure sources, the tube member being released from the releasably locked position by engagement of the normal-operation actuator with the tube member.

A safety valve for use in a wellbore to control fluid flow in a tubing string in the wellbore, the safety valve comprising:

• a housing for connection in the tubing string;
• a valve disposed in the housing and movable between an open position and a closed position;
• a tube longitudinally movable in the housing to move the valve between the open and closed positions, the tube including a latch and locking member, the locking member for selective engagement with the housing;
• an annulus defined between the housing and the flow tube;
• a normal-operation actuator disposed in the annulus for selective and releasable engagement with the latch, wherein the normal-operation actuator and the tube selectively move the valve between the open and closed positions;
• a locking actuator disposed in the annulus for selective engagement with the latch, wherein the valve is moved to the open position and the flow tube is releasably secured against movement relative to the housing by the locking member.

A tandem safety valve for use in a wellbore to control fluid flow in a tubing string in the wellbore, the tandem safety valve including:

• a pair of independently actuable safety valves connected in series in the tubing string, each safety valve including:
• a housing for connection into the tubing string;
• a flapper valve secured to the housing for movement between an open and a closed position;
• a tube member longitudinally movable in the housing to move the flapper valve from the open to the closed position;
• a normal-operation cylinder and piston, the normal-operation piston being stationary relative to the housing and the normal-operation cylinder being movable relative to the housing responsive to fluid pressure from a normal-operation fluid pressure source;
• a locking cylinder and piston, the locking piston being stationary relative to the housing and the locking cylinder being movable relative to the housing responsive to fluid pressure from a locking fluid pressure source;
• a normal-operation actuator coupled to the normal-operation cylinder and piston;
• a latch coupled to the tube member to selectively and releasably engage the normal-operation actuator;
• a locking member coupled to the latch to selectively maintain the tube member stationary relative to the housing, wherein the flapper is maintained in the open position without fluid pressure from the normal-operation and locking fluid pressure sources;
• and
• a locking actuator coupled to the locking cylinder and piston to selectively engage the latch and disengage the normal-operation actuator from the latch.

A safety valve for use in a wellbore to selectively permit fluid flow through a tubing string in the wellbore, the safety valve comprising:

• a housing for connection into the tubing string;
• a flapper valve secured to the housing for movement between an open and a closed position;
• valve-operation means for moving the flapper valve from the open to the closed position;
• a normal-operation cylinder and piston, the normal-operation piston being stationary relative to the housing and the normal-operation cylinder being movable relative to the normal-operation piston responsive to fluid pressure from a normal-operation fluid pressure source;
• a locking cylinder and piston, the locking piston being stationary relative to the housing and the locking cylinder being movable relative to the locking piston responsive to fluid pressure from a locking fluid pressure source;
• a normal-operation actuator coupled to the normal-operation cylinder and piston;
• a latch coupled to the valve-operation means to selectively and releasably engage the normal-operation actuator;
• a locking member coupled to the latch to selectively maintain the valve-operation means stationary relative to the housing, wherein the flapper is maintained in the open position without fluid pressure from the normal-operation and locking fluid pressure sources;
• and
• a locking actuator coupled to the locking cylinder and piston to selectively engage the latch and disengage the normal-operation actuator from the latch.

A method of valving to control fluid flow in a tubing string in a wellbore, the method comprising the steps of:

• providing a safety valve including:
• a valve member movable between an open and a closed position;
• a latch member selectively coupled to the valve member to selectively and releasably engage a normal-operation actuator;
• a locking dog coupled to the latch member to selectively engage the housing to maintain the valve member stationary relative to the housing, wherein the valve member is maintained in a locked-open position to permit fluid flow through the safety valve;
• and
• a locking actuator to selectively engage the latch member to disengage the normal-operation actuator from the latch member;
• running a tubing string including the safety valve to a selected depth in the wellbore;
• normally operating the safety valve by actuating the normal-operation actuator to engage the latch member and locking dog to selectively open and close the valve member to selectively permit fluid flow through the safety valve;
• locking open the safety valve by actuating the locking actuator to engage the latch member and urge the flow tube into a locked-open condition, wherein the flow tube is releasably secured to the housing by the locking dog wherein the valve member permits fluid flow through the safety valve.

A method of valving to control fluid flow in a tubing string in a wellbore, the method comprising the steps of:

• providing a safety valve including:
• a housing for connection into the tubing string;
• a valve member disposed in the housing to selectively block fluid flow through the safety valve;
• a flow tube disposed in the housing and selectively engageable with the valve member;
• a latch member secured to the flow tube to selectively and releasably engage a normal-operation actuator;
• a locking dog coupled to the latch member to selectively engage the housing to maintain the flow tube stationary relative to the housing, wherein the valve member is maintained in a locked-open position to permit fluid flow through the safety valve;
• and
• a locking actuator to selectively engage the latch member to disengage the normal-operation actuator from the latch member;
• running a tubing string including the safety valve to a selected depth in the wellbore;
• normally operating the safety valve by actuating the normal-operation actuator to engage the latch member and locking dog to selectively open and close the valve member to selectively permit fluid flow through the safety valve;
• locking open the safety valve by actuating the locking actuator to engage the latch member and urge the flow tube into a locked-open condition, wherein the flow tube is releasably secured to the housing by the locking dog wherein the valve member permits fluid flow through the safety valve.