Downhole deployment valves

A valve for use in a wellbore, the valve comprising:

• a housing having a bore;
• a valve member moveable between a first position permitting tool passage through the bore and a second position obstructing the bore through the housing;
• and
• a sealing structure disposed along an interface between the valve member and a valve seat, the sealing structure being a convex feature formed on one of the valve member or the valve seat that is configured to mate with a concave feature formed on the other one of the valve member or the valve seat when the valve member is in the second position.

A method for selectively isolating a zone in a wellbore, the method comprising:

• positioning a valve in the wellbore, the valve having a housing with a bore, a valve member, a valve seat, and a seat ring disposed in a trough formed in the valve seat;
• selectively isolating the zone in the wellbore by moving the valve member between a first position permitting tool passage through the bore and a second position obstructing the bore through the housing;
• moving the seat ring in the trough from an extended position to a retracted position as the valve member moves to the second position, the seat ring being biased toward the extended position;
• and
• creating a sealing interface between the valve member and the seat ring when the valve member is in the second position.

A valve for use in a wellbore, the valve comprising:

• a housing having a bore;
• a valve member pivotable around a pivot point between an open position and a closed position, the valve member being configured to obstruct the bore of the housing as the valve member engages a valve seat in the closed position;
• and
• a hinge member that is attached to the valve member at the pivot point, the hinge member being slidably connected to the housing by a connection member inserted through a slot formed in the hinge member, wherein there is relative movement between the connection member and the slot formed in the hinge member as the hinge member moves relative to the housing.

A valve for use in a wellbore, the valve comprising:

• a housing having a bore;
• a valve member pivotable around a pivot point between an open position and a closed position, the valve member being configured to obstruct the bore of the housing as the valve member engages a valve seat in the closed position;
• a hinge member that is attached to the valve member at the pivot point, the hinge member being slidably connected to the housing;
• and
• a sealing element disposed at an interface between the valve member and the valve seat, wherein the valve member contacts the sealing element at a first stage of the closed position, and a gap is formed between the valve member and the valve seat.

A method of selectively isolating a zone in a wellbore, the method comprising:

• positioning a valve in the wellbore, the valve having a housing, a valve member, and a slidable hinge member;
• selectively isolating the zone in the wellbore by moving the valve member from an open position to a closed position, the valve member being configured to obstruct a bore of the housing as the valve member engages a valve seat in the closed position;
• creating a seal between the valve member and a sealing element disposed at an interface between the valve member and the valve seat at a first stage of the closed position;
• creating a seal between the valve member and the valve seat at a second stage of the closed position;
• and
• moving the hinge member along a longitudinal axis of the housing as the valve member moves between the open position and the second stage of the closed position.