A technique facilitates failsafe closure of a valve used in, for example, a subsea test tree. The technique utilizes a valve combined with a cutter oriented to sever well equipment passing through an interior passage of the valve. The valve is operatively coupled with an actuation system having an actuator piston which controls cutting and valve closure. The failsafe valve and the cutter are shifted to an open position by applying pressure in a control fluid chamber to shift the actuator piston. However, the actuator piston, and thus the valve and cutter, are biased toward a closed position via pressure applied in a pressure chamber and a gas precharge chamber. The combined pressure ensures adequate force for shearing of the well equipment and closure of the valve when hydraulic control pressure is lost. In some applications, additional closing force may be selectively provided to the actuator piston.

A downhole component includes a body and a stress riser formed in the body. The stress riser being positioned and shaped to promote a full fracture of the body while maintaining a structure of the body to bear force in at least one direction. A downhole system having a tubular string disposed in a borehole.

A plug for isolating a wellbore. The plug can include a body having a first end and a second end, wherein the body is formed from one or more composite materials and adapted to receive a setting tool through the first end thereof, at least one malleable element disposed about the body, at least one slip disposed about the body, at least one conical member disposed about the body, and one or more shearable threads disposed on an inner surface of the body, adjacent the second end thereof, wherein the one or more shearable threads are adapted to receive at least a portion of a setting tool that enters the body through the first end thereof, and wherein the one or more shearable threads are adapted to engage the setting tool when disposed through the body and adapted to release the setting tool when exposed to a predetermined axial force.

The well system includes a casing and production tubing and a control unit that can receive measurements of temperature and pressure of fluid in the tubing-casing annulus (TCA). A subsurface safety valve (SSSV) connected to the tubing can switch to an open or closed state in response to a change in pressure of the fluid. An expected thermal expansion or contraction of the TCA fluid is calculated based on the received measurements, and the control unit determines, based on the expected thermal expansion or contraction and on a calculated TCA volume, a volume necessary to be added to or released from the TCA to maintain the fluid within an optimal pressure range. The control unit can also receive an indication of an emergency condition and transmit a signal to activate a release valve to release from the TCA a volume of fluid sufficient to cause the SSSV to close.

A downhole actuator typically for a downhole tool such as a valve, and typically for incorporation in a string of tubulars in an oil or gas well has a central axis with radially movable counterweights on opposite sides of the axis, which move radially outward to change the activation state of the actuator. The counterweights are supported by link arms which control the movement of the counterweights in response to centrifugal force created by rotation of the body, for example, during rotary drilling operations of the string. Radial outward movement of the counterweights typically transmits axial forces between sleeves at the upper and lower ends of the counterweights, so when the counterweights move radially outward, the upper and lower sleeves approach one another, which typically triggers the actuator.

A casing mill having a main body with cutter bases with cutters mounted on the cutter bases. The cutter bases are moved radially by operating arms which are rotatably attached to the main body, which are in turn moved by an operating mechanism in response to fluid flow through. One or more of the operating arms are extended to form a cutout arm, which enables cutting an initial window in a casing string, from which milling can continue. The operating arms are mounted to the main body by pins, which are held in the main body by a pin retaining arrangement.

A method and apparatus including a subsurface tool, such as a flapper closure valve, that has an integrally formed body and that includes at least one of an internal void located within the body of the flapper closure plate; and an indentation extending from an exterior surface of the body of the flapper closure plate, the indentation having an opening defining a first dimension along a first direction at the exterior surface of the body, the indentation defining an indentation surface extending within the body, the indentation surface defining a second dimension along the first direction within the body, the second dimension being greater than the first dimension. In one or more exemplary embodiments, the flapper closure plate is at least partially manufactured using an additive manufacturing process.

A differential fill valve assembly for application in float collars or shoes in a well casing can provide a mechanism for releasing a flapper valve by advancing and activating sleeve of the valve assembly. The valve assembly includes a backpressure flapper valve and an activating sleeve slidably disposed within a housing. The activating sleeve initially maintains the flapper valve in an open position. The activating sleeve provides at least one ramp on an inner surface thereof. Fluid flow through the activating sleeve generates a pressure differential, across the activating sleeve that produces a net force on the activating sleeve to drive the activating sleeve downward, releasing the backpressure flapper valve.

A technique facilitates control over fluid flow via controlled operation of an injection valve. The technique enables control over operation of the injection valve in a variety of subsurface applications. The injection valve comprises a flapper which may be selectively shifted to and held in an open position. Depending on the operational configuration of the injection valve, the flapper may be shifted to the open position via fluid flow along a primary flow passage. However, the injection valve also may be shifted to the open position via a separate actuator controllable via pressure applied independently of fluid flow along the primary flow passage.

A valve assembly includes a valve body that defines an internal flow passageway between an inlet and an outlet, and a valve seat disposed in the valve body with a sealing surface perpendicular to the flow passageway. The valve assembly further includes a clapper pivotally correlated to the valve seat having a closed configuration extending across the valve seat configured to substantially close off the flow passageway, and an open configuration configured to substantially allow fluid flow in the flow passageway from the inlet to the outlet through the valve body. An annular valve seat seal is disposed within an annular groove formed in a surface of the valve seat, where the annular valve seat seal is disposed at an interface between the valve seat and the clapper when the clapper is in the closed configuration.