Expandable Threaded Connection With Metal-to-Metal Seal After Expansion
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Solution Overview
Problem
Existing expandable threaded connections in wellbore operations face limitations in handling high tensile loads and are not suitable for high-temperature environments, particularly when elastomeric seals fail, necessitating a connection with a metal-to-metal seal that offers improved efficiency and load-bearing capacity.
Innovation Solution
The design features a threaded connection with a 'V' shaped pin end and a thicker box end, allowing for metal-to-metal sealing engagement, where the pin end has a varying inner diameter and wall thickness, enabling efficient radial expansion and forming a new seal after deformation, providing greater resistance to tensile loads and maintaining sealing under pressure differentials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If elastomeric seals are used in threaded connections, then sealing is provided under normal conditions, but the connection becomes unsuitable for high-temperature environments and certain wellbore fluids
Solution Approach 1:
The patent transitions from elastomeric sealing materials to metal-to-metal sealing surfaces, fundamentally changing the material parameter and sealing mechanism. The metal sealing surfaces engage through direct contact with sufficient compressive force, eliminating temperature and fluid compatibility limitations of elastomeric materials while maintaining sealing reliability under extreme wellbore conditions.
Solution Approach 2:
The threaded connection integrates metal sealing surfaces with threaded engagement geometry, creating a composite sealing system that combines the advantages of metallic durability and threaded load-bearing capacity. This composite approach provides both mechanical strength and environmental resilience in high-temperature, high-pressure wellbore operations.
2Ease of manufacture
If conventional threaded connections are used, then assembly is simple, but the tensile load capacity is limited and efficiency is reduced
Solution Approach 1:
The pin end features a varying inner diameter with a 'V' shaped configuration and curved profile, while the box end has a corresponding thicker curved geometry. These curved, non-linear geometries optimize stress distribution during radial expansion, enabling the connection to withstand significantly higher tensile loads while maintaining thread engagement integrity and assembly simplicity.
3Adaptability or versatility
If radial expansion is performed on threaded connections, then wellbore zonation is achieved, but the threaded connection efficiency decreases and load-bearing capacity is reduced
Solution Approach 1:
The threaded connection is pre-configured with a pin end having varying inner diameter and wall thickness, along with corresponding box end geometry, before radial expansion. This preliminary geometric configuration ensures that during radial expansion, the threads maintain optimal engagement and the metal sealing surfaces remain in sufficient contact, preserving both connection efficiency and load-bearing capacity throughout the expansion process.
Solution Approach 2:
The pin end and box end feature localized variations in wall thickness and inner diameter geometry at specific regions. The pin end has increased wall thickness at the threaded portion compared to the body, and the box end has corresponding localized thickening. This local quality enhancement provides targeted strength where threads engage, maintaining connection integrity during radial expansion while enabling wellbore zonation.
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 configuration enhances the efficiency and load-bearing capacity of expandable threaded connections, enabling them to handle increased tensile loads and maintain sealing integrity under high pressure differentials, outperforming conventional connections by allowing expansion with various expansion ratios while maintaining a metal-to-metal seal.
Implementation Method 1
A threaded connection is provided including a pin end and a box end. The pin end includes a varying inner diameter and wall thickness. The box end is engaged with the pin end in a metal-to-metal seal configuration.
Implementation Method 2
A connection that utilizes a metal-to-metal seal forms a seal between two abutting surfaces of the threaded connections that contact with sufficient compressive force to form a seal between the surfaces.
Implementation Method 3
radially expanding and plastically deforming tubular members that are coupled to one another by threaded connections
Implementation Method 4
radially expanding and plastically deforming tubular members
Data Source
Figure 1~3
AI summary
An expandable connection is configured such that a metal-to-metal seal is created upon expansion, even under different expansion ratios. The creation of the metal-to-metal seal can rely on a spring-back effect after expansion. A high pressure rating of the metal-to-metal seal that is created can be achieved with an oversized box face thickness. The expandable connection can also be configured to achieve a high tensile efficiency.