Abstract: A method and apparatus for installing casing hangers in a wellbore utilizing an externally activated gripping system to temporarily bind wearbushings secured to casing and tubing hangers in order to lock-down such hangers during various wellbore drilling activities, thereby minimizing the size of landing shoulders and eliminating additional lock down equipment and simplifying running procedures.

Abstract: A joint for joining the ends of two pipes has a socket (or box) on the end of one pipe into which the end of the other pipe is inserted. The part of the socket which surrounds the inserted pipe has an external tapered surface. A correspondingly tapered sleeve surrounds the socket and can be moved axially to apply a compressive force to the taper on the socket which is thus compressed inward against the inserted pipe end to frictionally grip the inserted pipe end.

Abstract: A method and apparatus for a seal assembly for a unitized wellhead system for land or platform applications utilizes a friction grip technology to create maintainable metal-to-metal seals with finely-controlled contact stresses, lock-down casing and tubing hangers, support test loads to minimize the size of landing shoulders required, and to rotationally lock casing hangers to provide simplified running procedures. The system can be used in combination with a friction grip clamping assembly to greatly streamline the wellhead design.

Abstract: A clamp for clamping two concentric tubes, typically two concentric tubes in an oil or gas well. The clamp has two axially movable tapered components which can be pulled over one another in an axial direction to provide a contraction of internal diameter which grips the smaller diameter tube. In one embodiment, a spacer is fitted to allow the tapered components to be held apart until the tubes have been correctly positioned. The spacer is then removed, and the tapered components are drawn together to effect the clamping. A hydraulic ram can be provided to separate the tapered components should readjustment be required. In another embodiment, the larger diameter tube is made with a relatively thin wall, so that it can be distorted inwards to grip the smaller tube.

Abstract: A centralizer assembly for centralizing casing inside a riser includes a locking element to move generally radially outward from the casing toward the riser in response to a change in pressure in the annulus between the casing and the riser. The locking element may be a first wedge shaped element adapted for movement in a radial direction from the casing toward the riser and a second wedge shaped element adapted to move generally axially along the casing and adapted for engaging the first wedge shaped element in response to a pressure activated driver. The driver may be a rupture device that ruptures when the pressure in the annulus reaches a predetermined threshold. Ratchet teeth are included between the elements for engaging and locking the wedge shaped elements in position once driven by the driver.