Annular Seal Assembly With Axial Load Decoupling
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Solution Overview
Problem
Existing wellhead annular seal systems face challenges in maintaining seal integrity due to relative movement between the lockdown ring and wellhead housing, leading to degradation under pressure loads, as they often allow play between components to facilitate installation, which compromises sealing performance.
Innovation Solution
An annular seal system with an actuator ring having both rigid and flexible components, forming separate load paths to ensure the hanger's fixed position while allowing variability in the lockdown ring's position, decoupling axial loads through a flexible support member that absorbs or limits transfer of reactive forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If play is allowed between components to facilitate installation, then ease of operation is improved, but seal integrity deteriorates due to relative movement under pressure loads
Solution Approach 1:
The actuator ring is segmented into a rigid portion and a flexible portion, allowing each segment to perform different functions: the rigid portion maintains fixed positioning for seal integrity, while the flexible portion accommodates installation variability through controlled deformation
Solution Approach 2:
The actuator ring's flexibility parameter is optimized to allow controlled deformation within a specific range during installation, then maintain rigidity under operating pressure loads, effectively changing its mechanical properties based on operational phase
2Reliability
If the seal assembly is constrained to maintain fixed position, then seal integrity is improved, but adaptability deteriorates due to inability to accommodate positional variation
Solution Approach 1:
The actuator ring is divided into rigid and flexible portions, where the rigid portion ensures fixed positioning for seal integrity while the flexible portion provides positional adaptability during installation and operation
Solution Approach 2:
The actuator ring transitions from a static, fully rigid structure to a dynamic structure with both rigid and flexible portions, allowing it to adapt its stiffness characteristics based on operational requirements
3Device complexity
If axial loads are transferred directly to the seal assembly, then structural simplicity is improved, but seal performance deteriorates due to degradation under reactive forces
Solution Approach 1:
The load path is segmented into two separate paths: one through the rigid portion of the actuator ring for axial loads, and another through the flexible portion for reactive forces, preventing direct transfer of damaging loads to the seal assembly
Solution Approach 2:
The flexible portion of the actuator ring acts as an intermediary element that absorbs and mitigates reactive forces between the seal assembly and the locking mechanism, protecting the seal from degradation
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
The system maintains seal integrity by reducing play between components, enhancing the sealing system's performance under pressure loads by decoupling axial loads, thereby preventing degradation and ensuring accurate positioning.
Implementation Method 1
the flexible portion of the actuator ring adapted to axially compress to allow positional variation between the lockdown ring and the wellhead housing
Data Source
AI summary
An annular seal system for sealing between a casing hanger and a wellhead housing, the system including an actuator ring having a rigid portion and a flexible portion, and a lockdown ring positioned adjacent the actuator ring. The annular seal system further includes a seal assembly capable of moving between a de-energized position and an energized position, wherein the seal assembly in the de-energized position has a defined a space between the seal assembly and the rigid portion of the actuator ring, wherein the seal assembly in the energized position has the space closed, wherein the rigid portion of the actuator ring is to contact a surface of the casing hanger, wherein the flexible portion of the actuator ring is to push the lockdown ring into engagement with the wellhead, and wherein the flexible portion of the actuator ring adapted is to axially compress to allow positional variation between the lockdown ring and the wellhead housing.