Metal Vee Seal Shoulders With Pressure-Testable Dual Sealing
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Solution Overview
Problem
Current oil and gas wellheads, particularly flangeless types, lack a method to test the integrity of metal seals, whereas flange type connections rely on crush gaskets that require additional subassemblies for pressure testing.
Innovation Solution
The development of two metal-to-metal seals with circumferential shoulders or protrusions, where the protrusions are made of higher yield strength material than the mating surface, allowing for a variable axial load to form a barrier and provide a fluid pathway for pressure testing to verify seal integrity, with optional additional axial load for enhanced sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal to metal seals are used in flangeless wellheads, then sealing effectiveness is improved, but the ability to test seal integrity is lost
Solution Approach 1:
The seal interface is segmented into multiple protrusions distributed around the circumference, allowing individual or collective engagement with the mating surface. This segmentation enables both effective sealing through multiple contact points and testing capability by allowing selective engagement patterns that can be verified through fluid pathway access.
Solution Approach 2:
The protrusions act as intermediaries between the two tubulars, providing both sealing function and testing capability. The protrusions engage with the mating surface to create the seal, while simultaneously providing a defined interface that allows fluid pathways to access the seal location for integrity verification without requiring additional subassemblies.
2Reliability
If crush gaskets are used in flange type connections, then sealing capability is achieved, but device complexity increases due to required subassemblies for testing
Solution Approach 1:
The testing capability is extracted from a separate subassembly and integrated directly into the seal structure itself. The protrusions and mating surface configuration inherently provide both sealing and testing functions, eliminating the need for additional subassemblies that would otherwise be required to verify seal integrity in flange type connections.
Solution Approach 2:
The sealing function and testing function are merged into a single integrated structure. The protrusions serve dual purposes: creating the seal through engagement with the mating surface and enabling integrity verification through defined fluid pathways, thereby combining multiple functions into one component system.
3Ease of operation
If elastomeric seals are used in flangeless wellheads, then ease of sealing is improved, but reliability of metal-to-metal sealing is reduced
Solution Approach 1:
The material parameter is changed from elastomeric to metal for the protrusions, fundamentally altering the sealing mechanism from elastic deformation to plastic deformation. This parameter change enables the protrusions to penetrate and permanently deform the mating surface, creating a more reliable metal-to-metal seal that maintains integrity under high pressure and temperature conditions.
Solution Approach 2:
The seal system utilizes composite material properties by combining protrusions of higher yield strength material with a mating surface of lower yield strength material. This material combination enables the softer mating surface to be permanently deformed by the harder protrusions, creating a reliable metal-to-metal seal while maintaining ease of installation through the protrusion engagement mechanism.
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
Enables reliable testing and formation of a fluid-tight seal between tubulars, ensuring the seal's effectiveness and allowing for adjustments to improve the seal's integrity if initial testing indicates a leak.
Implementation Method 1
the protrusions on the first shoulder, having a higher yield strength than the material of the first tubular mating surface or the second tubular mating surface, will penetrate the material of the second shoulder forming a barrier to fluid passage
Implementation Method 2
a variable axial load is provided to force the first shoulder into closer proximity to the second shoulder
Implementation Method 3
The fluid pathway can be pressurized in order to determine whether or not a seal has been formed between the first and second protrusions
Data Source
AI summary
A system to provide at least two circumferential metal to metal seals between coaxial tubulars. Where a first tubular includes a circumferential shoulder having a circumferential first metal seal and a circumferential second metal seal. A second tubular has a circumferential shoulder that matches and abuts the first tubular circumferential shoulder. Each metal seal is of a material having a higher yield strength than the second tubular shoulder such that the first metal seal and the second metal seal will penetrate the material of the second tubular shoulder thereby providing a seal. Additionally a test port is provided from the exterior of the exterior tubular to a point on either the first or second tubular between the first and second metal seals.