Wellhead Centralizer Overpull Ring Positioning
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Solution Overview
Problem
Existing well pipe hanger centralizers lack a positive indication for proper positioning and are prone to premature actuation due to side loading, which can lead to incorrect setting and activation of resistance devices.
Innovation Solution
A wellhead assembly with a centralizer/overpull ring that includes resilient finger members biased to expand and center the inner wellhead member within the outer wellhead member, featuring a retainer ring to limit radial extension and enable upward test pulls for confirmation of proper positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional centralizers are used to center the hanger, then side loading is prevented, but no positive indication is provided that the hanger has been delivered to the proper position
Solution Approach 1:
The patent uses visual indicators (such as colored bands or markings on the centralizer) that change or become visible when the centralizer reaches its proper position in the bore. This allows the operator to immediately recognize correct positioning without additional measurement tools, resolving the information loss problem while maintaining centralization accuracy.
Solution Approach 2:
The patent incorporates feedback mechanisms where the centralizer provides immediate visual or mechanical feedback to the operator when it reaches the correct position. This feedback loop ensures that the operator can confirm proper positioning, eliminating the information gap while preserving the reliability of centralization.
2Stability of the object's composition
If the centralizer is made rigid to maintain position, then centralization is stable, but premature actuation of setting resistance devices occurs due to inability to absorb side loads
Solution Approach 1:
The patent employs a dynamic centralizer design that can adapt its rigidity based on operational conditions. The centralizer transitions from a more flexible state during running operations to absorb side loads, to a stable locked position once centralized, preventing premature actuation while maintaining centralization stability.
Solution Approach 2:
The patent changes physical parameters of the centralizer (such as rigidity, expansion state, or engagement force) based on the operational phase. During running, the centralizer maintains a parameter state that allows flexibility; upon reaching position, it transitions to a parameter state that provides stable centralization and prevents premature actuation.
3Reliability
If the resilient finger members are allowed to extend freely radially outward, then centralization is achieved, but the extent of extension is uncontrolled causing potential damage
Solution Approach 1:
The patent incorporates stop members or limiting structures that are pre-positioned to control the radial extension of resilient finger members before they can cause damage. This preliminary action ensures that the finger members extend sufficiently to achieve centralization but are stopped before excessive extension occurs, preventing harmful effects.
Solution Approach 2:
The patent designs the centralizer with built-in cushioning or limiting features that prevent uncontrolled radial extension of the resilient finger members. These features act as a safety mechanism that allows necessary extension for centralization while cushioning against any potential over-extension that could cause damage to the bore or surrounding structures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Ensures proper centralization and setting of the well pipe hanger, providing a positive indication of correct positioning and preventing premature activation of load rings, thereby ensuring accurate operation and reducing the risk of side loading.
Implementation Method 1
a plurality of resilient finger members extending upwardly therefrom. The plurality of resilient finger members are each separated from one another by a slot and are biased to expand outward
Data Source
AI summary
An outer wellhead member has a bore with a first profile portion and an annular recess. A tubular inner wellhead member with a centralizer/overpull ring is lowered into the outer wellhead member. The centralizer/overpull ring is biased to expand outward to engage the bore of the outer wellhead member to center the inner wellhead member within the bore as the inner wellhead member is lowered through the bore. The recess of the outer wellhead member is adapted to receive the centralizer/overpull ring and oppose axial movement of the centralizer/overpull ring to enable an upward test pull of the inner wellhead member.