Subsea production test valve assembly

In a subsea test assembly securable within a blowout preventer stack above a subterranean well and positionable between upper and lower portions of a tubular conduit in fluid communication with a production zone within the well, the test assembly including an upper subassembly carriable with the upper conduit portion, a lower subassembly carriable with the lower conduit portion, and valve means including a rotatable ball valve member and a pivotable flapper member in the lower subassembly each manipulatable between opened and closed positions for controlling fluid flow within the conduit, the improvement comprising:

• the upper subassembly including an upper housing and a first plurality of rigid downwardly extending dog members fixedly secured to the upper housing;
• the lower subassembly including a lower housing and a second plurality of rigid upwardly extending dog members fixedly secured to the lower housing;
• the first plurality of dog members each being positionable between a latch position for latching the upper and lower subassemblies and an unlatch position for unlatching the upper and lower subassemblies upon rotational movement of the first plurality of dog members with respect to the second plurality of dog members;
• and
• an axially movable fluid responsive piston member movable from an open valve position to a closed valve position for structurally engaging the flapper member upon movement from the closed valve position to the opened valve position to open the flapper and retain the flapper member open when in the open valve position;
• ball operating means interconnecting the piston member and the ball valve member for rotating the ball valve member between opened and closed positions in response to movement of the piston member;
• and
• locking means movable relative to the second plurality of dog members from a lock position for limiting rotational movement of the first plurality of dog members with respect to the second plurality of dog members to an unlock position for allowing the first plurality of dog members to rotate relative to the second plurality of dog members and unlatch the upper subassembly from the lower subassembly.

A method of operating a subsea test assembly securable within a blowout preventer stack above a subterranean well and positionable between upper and lower portions of a tubular conduit in fluid communication with a production zone within the well, the test assembly including an upper subassembly carriable with the upper conduit portion, a lower subassembly carriable with the lower conduit portion, and valve means in the lower subassembly manipulatable between opened and closed positions to control fluid flow within the conduit, the method comprising:

• fixedly securing a first plurality of rigid dog members to an upper housing of the upper subassembly;
• fixedly securing a second plurality of rigid dog members to a lower housing of the lower subassembly;
• axially and rotatably moving the upper housing relative to the lower housing for latching the first plurality of dog members to the second plurality of dog members;
• thereafter axially moving a locking member relative to latched first and second dog members for locking the first plurality of dog members to the second plurality of dog members and retaining the upper subassembly latched to the lower subassembly.