Abstract: The present invention provides a method of calculating the load capacity of a wellhead system. The method comprises determining a first contact stress at a first interface between an annular component and a collar and equating a radial deflection of an inner surface of the annular component with a radial deflection of an outer surface of the collar. The method uses a first contact stress and the axial movement of the annular component to determine a contact stress at a gripping interface between a gripping surface and an inner tubular member. The method also equates a radial deflection of the outer surface of the inner tubular member with (i) a radial deflection of the gripping surface plus (ii) a depth of penetration of a ridge of the outer surface of the inner tubular member into the gripping surface (iii) a radial dimension of an initial gap between the outer surface of the inner tubular member and the inner surface of the outer tubular member.

Abstract: This invention relates to a method of determining a grip coefficient in a wellhead system.

Abstract: A crown plug for a tree of an oil/gas well/wellhead has a securement arrangement for securing the crown plug within the tree. The main body of the crown plug comprises a solid body creating the barrier within the production bore. The solid body creates a robust, strong and reliable barrier. The crown plug is retained within the outer member through inward distortion which secures the crown plug. The securement arrangement arises from an inward radial force that distorts the outer member inwardly to grip a component located within the outer member. The outer member elastically deforms and the outer member returns to a released position once the clamping force is released. Two concentric oppositely arranged tapered surfaces move axially to create the inwardly directed force. The clamping force and the solid body together provide an improved crown plug which is easy and reliable to operate.

Abstract: A mudline connector including a compression adaptor which can be elastically deformed onto an internal tubular member. The compression adaptor deflects inwardly to grip upper and lower sealing mandrels, providing axial and bending load support and creating a seal to isolate bore pressure from an outer annulus. The clamping arrangement provides a sealed connection between two well casing sections extending in opposite axial directions. The well casings are gripped and held in an end to end configuration by a radial load applied internally by a compression ring. The connector is activated by introducing pressure to activate pistons which in turn provide an axial thrust to stroke the internally tapered compression ring along the externally tapered compression collar, effectively creating an interference fit therebetween. This deflects the inner surface of the compression collar inwardly, deflecting the compression adaptor inwardly to grip the outer surfaces of the upper and lower sealing mandrels.

Abstract: A mudline connector including a compression adaptor which can be elastically deformed onto an internal tubular member. The compression adaptor deflects inwardly to grip upper and lower sealing mandrels, providing axial and bending load support and creating a seal to isolate bore pressure from an outer annulus. The clamping arrangement provides a sealed connection between two well casing sections extending in opposite axial directions. The well casings are gripped and held in an end to end configuration by a radial load applied internally by a compression ring. The connector is activated by introducing pressure to activate pistons which in turn provide an axial thrust to stroke the internally tapered compression ring along the externally tapered compression collar, effectively creating an interference fit therebetween. This deflects the inner surface of the compression collar inwardly, deflecting the compression adaptor inwardly to grip the outer surfaces of the upper and lower sealing mandrels.

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 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.

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.