Expandable Liner Hanger Axial Load Capacity
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Solution Overview
Problem
Current expandable liner hangers face challenges in supporting substantial axial loads from longer and heavier tubing strings, especially at elevated temperatures, where mechanical properties of elastomeric seals can yield, and traditional designs are sensitive to temperature changes.
Innovation Solution
The design separates axial load bearing gripping and sealing functions into distinct sub-assemblies, using hardened metal features with stress-relief notches to prevent cracking during radial expansion, and employs annular sealing members and circumferential ridges with hardened teeth to enhance load capacity independently of external or internal pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional expandable liner hangers use elastomeric seals for gripping and sealing, then sealing function is achieved, but axial load capacity decreases under substantial loads and elevated temperatures
Solution Approach 1:
The hanger system is divided into separate functional components: a gripping sub-assembly with hardened metal features (teeth, ridges) for axial load bearing, and a separate sealing sub-assembly with elastomeric seals for sealing function. This segmentation allows each component to be optimized independently - the gripping features handle mechanical loads without temperature-sensitive materials, while seals focus solely on sealing performance.
Solution Approach 2:
The elastomeric sealing components are extracted from the axial load bearing function. The gripping and sealing sub-assemblies are designed to operate independently, with the sealing sub-assembly positioned within the gripping sub-assembly. This extraction eliminates the conflict between load-bearing requirements and seal performance under thermal stress.
2Strength
If the liner hanger is expanded radially outward to increase gripping and sealing contact, then engagement with casing is improved, but cracking can occur in hardened features during expansion
Solution Approach 1:
The hardened gripping features are pre-formed with integrated stress-relief notches before the expansion process. These notches are strategically positioned to preemptively address stress concentration points that would otherwise cause cracking during radial expansion. The preliminary inclusion of these stress-relief features ensures structural integrity is maintained throughout the expansion operation.
3Strength
If the setting tool wall thickness is increased to support high axial loads, then load capacity is improved, but equivalent circulating density increases and deployment speed decreases
Solution Approach 1:
The setting tool is designed with segmented, thin-walled construction that maintains structural adequacy through strategic reinforcement only at critical load-bearing locations. The separation of gripping and sealing functions allows the tool to be optimized for rapid deployment with reduced overall wall thickness, while still providing sufficient strength through localized features.
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
This approach increases axial load capacity while maintaining low equivalent circulating density, allowing for rapid deployment and operation in deep wells, and reduces reliance on elastomeric seals' mechanical properties, thus improving stability and durability at elevated temperatures.
Implementation Method 1
Expandable liner hangers can be expanded by use of hydraulic pressure to drive an expanding cone, wedge, or 'pig,' through the liner hanger
Implementation Method 2
The ridges, when expanded, penetrate the casing with a plurality of hardened teeth to grippingly engage the expandable liner hanger
Data Source
AI summary
A high-axial load bearing assembly is provided for use with a radially expandable tool such as an expandable liner hanger. Exemplary embodiments of axial load bearing assemblies operate independently of external casing pressure and internal tubing pressure. The assemblies do not rely on movable slips or the physical characteristics of the sealing members to grip the casing and bear the axial load. The gripping and sealing functions are largely separated between gripping and sealing sub-assemblies. Hardened metal features which undergo radial expansion during deployment are provided with expansion stress-relief features.