Patent ID: 8413730
Filing Date: 2013-04-09
Classification: E21B

Abstract:
1. A wellhead assembly, comprising: a wellhead housing having a bore with a longitudinal axis therein and an installed lower casing hanger mounted therewith, the wellhead housing having in the bore a load ring groove with an upward and inward facing support shoulder above an upper end of the lower casing hanger, the support shoulder having an inner diameter that is the same as an inner diameter of the bore above the load ring groove; an upper casing hanger for securing to a string of casing and lowering into the wellhead housing; an inward-biased split, resilient load ring carried in a retracted initial position on the upper casing hanger, the load ring being movable radically outward to a set position in engagement with the wellhead housing; an actuator carried with the upper casing hanger below the load ring so that the load ring moves from the initial position toward an expanded position in contact with the wellhead housing when the actuator lands on the lower casing hanger and casing weight is applied to the load ring via the upper casing hanger and the actuator; the actuator including a resilient, axially compressible mechanism having a compression stiffness greater than a resistance to radial expansion of the load ring so that the actuator expands the load ring before being compressed under the weight of the casing string; wherein in the event the load ring is pushed into contact with the wellhead housing with the load ring misaligned above the support shoulder, continued lowering of the upper casing hanger causes the compressible mechanism to contact to enable the load ring to move further downward in the wellhead housing and into engagement with the support shoulder of the wellhead housing.