Abstract: A wellhead assembly having a tubular magnetized in at least one selected location, and a sensor proximate the magnetized location that monitors a magnetic field from the magnetized location. The magnetic field changes in response to changes in mechanical stress of the magnetized location, so that signals from the sensor represent loads applied to the tubular. Analyzing the signals over time provides fatigue loading data useful for estimating structural integrity of the tubular and its fatigue life. Example tubulars include a low pressure housing, a high pressure housing, conductor pipes respectively coupled with the housings, a string of tubing, a string of casing, housing and tubing connections, housing and tubing seals, tubing hangers, tubing risers, and other underwater structural components that require fatigue monitoring, or can be monitored for fatigue.

Abstract: A seal seals an annulus in a subsea assembly between a wellhead and a casing hanger landed on a shoulder within a bore of the wellhead. The seal includes a casing hanger seal ring disposed within the annulus. The seal ring engaged with an inner diameter surface of the wellhead, and engaged with an outer diameter surface of the casing hanger so that the seal ring prevents flow through the annulus. A lockdown slip ring is secured to a lower end of the seal ring so that, when the seal ring is energized, the lockdown slip ring engages a substantially smooth inner diameter surface portion of the wellhead and a substantially smooth outer diameter surface portion of the casing hanger to limit upwards axial movement of the casing hanger.

Abstract: A wellhead assembly having an outer tubular, an inner tubular inserted into the outer tubular, an annular space between the inner and outer tubulars, a lock ring in the annular space, and an activation ring that axially strokes between the lock ring and one of the tubulars. The lock ring selectively locks together the inner and outer tubulars when the activation ring slides between the lock ring and the one of the tubulars. The surface of the activation ring that contacts lock ring is contoured so that an interface surface between the activation ring and lock ring when the lock ring is in its locked position, is offset an angle from an axis of the wellhead that is less than an offset between the axis of the wellhead and an interface surface between the activation ring and lock ring when the activation ring is stroking downward.

Abstract: A wellhead assembly for use subsea includes a high pressure housing landed within a low pressure housing. The low pressure housing is an annular member that mounts into the sea floor and having an inner surface engaging the high pressure housing along a loading interface. Upper and lower sockets are formed along axially spaced apart portions of the outer surface of the high pressure housing. As the high pressure housing inserts into the low pressure housing, the high pressure housing sockets engage corresponding sockets formed along axially spaced apart sockets on portions of the inner surface of the low pressure housing. The sockets each have cylindrically shaped outer surfaces, and when engaged with one another define the loading interface. The sockets are strategically located on the upper and lower portions of the housings to maximize their distance apart.

Abstract: A wellhead seal assembly that forms a metal-to-metal seal between inner and outer wellhead members. A metal seal ring has inner and outer legs separated by a slot. An extension of seal ring contacts an upward facing shoulder of the inner wellhead member. An energizing ring with a tapered nose is moved into the slot. The tapered nose has a downward facing stop shoulder that contacts an upper end of inner leg when the energizing ring is in its lower position.

Abstract: A dart launcher launches a dart by placing the dart within a launcher bore formed within a launcher body. The launcher body also defines a central bore coupled inline with a tubing string and in fluid communication with the launcher bore. The launcher bore is formed at an angle to the central bore. A release assembly is coupled to the launcher body and includes a release rod protruding into the launcher bore to selectively release the dart. A visual indicator assembly is coupled to the launcher body downstream from the release assembly and includes a flapper protruding into the launcher bore. The release assembly is actuated by the dart rotating the flapper to rotate an arm from a non-released position to a released position.

Abstract: An anti-rotation device prevents an inner wellhead housing from rotating within an outer wellhead housing. The anti-rotation device provides cam rollers within the inner wellhead housing that wedge between opposing surfaces of the inner wellhead housing and outer wellhead housing to arrest either clockwise or counter-clockwise rotation of the inner wellhead housing. The cam rollers are circumferentially spaced apart around the inner wellhead housing.

Abstract: A seal seals an annulus in a subsea assembly between a wellhead and a casing hanger landed on a shoulder within a bore of the wellhead. The seal includes a casing hanger seal ring disposed within the annulus. The seal ring engaged with an inner diameter surface of the wellhead, and engaged with an outer diameter surface of the casing hanger so that the seal ring prevents flow through the annulus. A nose ring is secured to a lower end of the seal ring so that, when the seal ring is energized, a conical surface of the nose ring engages a mating conical profile formed in the inner diameter surface portion of the wellhead and the nose ring engages a surface opposite the conical surface with a substantially smooth outer diameter surface portion of the casing hanger to limit upwards axial movement of the casing hanger.

Abstract: An acoustic modem located on a blowout preventer stack communicates with a running tool acoustic modem located on a subsea running tool disposed within a subsea wellhead, tree or tubing spool. The acoustic modem and the running tool acoustic modern transmit and receive acoustic signals through a column of fluid in the blowout preventer stack. The acoustic modem is communicatively coupled to a subsea electronics module located on the blowout preventer stack and further communicatively coupled to a central control unit located on a platform at the surface. The running tool acoustic modem is communicatively coupled to a controller that receives data from sensors on the running tool and sends operational signals to functions of the running tool. An operator at the surface may control the running tool through the acoustic modems, and the running tool may communicate the running tool status to the operator through the acoustic modems.

Abstract: A seal seals an annulus in a subsea assembly between a wellhead and a casing hanger landed on a shoulder within a bore of the wellhead. The seal includes a casing hanger seal ring disposed within the annulus. The seal ring engaged with an inner diameter surface of the wellhead, and engaged with an outer diameter surface of the casing hanger so that the seal ring prevents flow through the annulus. A lockdown slip ring is secured to a lower end of the seal ring so that, when the seal ring is energized, the lockdown slip ring engages a substantially smooth inner diameter surface portion of the wellhead and a substantially smooth outer diameter surface portion of the casing hanger to limit upwards axial movement of the casing hanger.

Abstract: An anti-rotation device prevents an inner wellhead housing from rotating within an outer wellhead housing. The anti-rotation device provides cam rollers within the inner wellhead housing that wedge between opposing surfaces of the inner wellhead housing and outer wellhead housing to arrest either clockwise or counter-clockwise rotation of the inner wellhead housing. The cam rollers are circumferentially spaced apart around the inner wellhead housing.