Patent ID: 9611717
Date: 2017-04-04
CPC Classifications: E21B

Claim:
1. A wellhead assembly comprising: a wellhead housing having an axis; a wellhead hanger disposed in the housing; a valve bore in a sidewall of the wellhead hanger, the valve bore having a diameter less than a radial width of the sidewall; a valve body axially selectively reciprocal in the valve bore between open and closed positions; a first groove on an outer diameter of the valve body containing a first seal, the first seal being annular and removable with the valve body; a second groove on an outer diameter of the valve body containing a second seal, the second seal being annular and removable with the valve body; upper and lower annulus access circuits in the sidewall of the wellhead hanger that each intersect the valve bore at axially spaced apart locations and that are in communication with one another when the valve body is in the open position and that are out of communication when the valve body is in the closed position, a valve body pressure source selectively in communication with opposing ends of the valve body and for selectively axially reciprocating the valve body between the open and closed positions; an override head secured to an upper end of the valve body; an override assembly selectively positioned on top of the wellhead hanger, the override assembly having an override bore, a piston in the override bore, and a latching assembly coupled to the piston for axial movement with the piston, the latching assembly having a latch on a lower end that is engageable with the override head; a fluid pressure down stroke passage leading to the override bore above the piston for stroking the piston and the latching assembly downward; a fluid pressure up stroke passage leading to the override bore below the piston for stroking the piston upward; wherein in the event of failure of the valve body pressure source, fluid pressure supplied to the down stroke passage causes the latch to move downward and couple to the override head, and fluid pressure subsequently supplied to the up stroke passage lifts the valve body upward.