Metal-to-Metal Sealed Sub-Surface Safety Valve for Cold Temperatures
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Solution Overview
Problem
Standard wireline retrievable safety valves (WRSVs) used in carbon capture and storage (CCS) fail due to material brittleness and damage from low temperatures, particularly when injecting carbon dioxide, as they rely on elastomeric seals that become brittle and crack in extreme cold environments.
Innovation Solution
Implementing a WRSV with metal-to-metal seals and non-elastomeric components, including metal-to-metal premium threads and thermoplastic seals, to maintain integrity and prevent damage in low temperature conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If elastomeric seals are used in WRSV, then sealing effectiveness is improved under normal conditions, but the seals become brittle and crack in low temperature environments
Solution Approach 1:
The patent changes the material parameter of the seals from elastomeric to metal-to-metal or thermoplastic materials that maintain their sealing properties at low temperatures. This parameter change allows the valve to operate reliably in cold temperature environments where elastomeric seals would become brittle and fail.
Solution Approach 2:
The patent employs composite material construction for the valve body and components, using materials specifically selected for their low-temperature performance characteristics. The combination of metal components with appropriate sealing materials creates a composite structure that maintains integrity and sealing effectiveness across extreme temperature ranges.
2Ease of manufacture
If standard WRSV components are used, then manufacturing ease is improved, but the components become damaged and brittle in extreme cold temperatures
Solution Approach 1:
The patent changes the material composition and thermal properties of the components to maintain strength and ductility at low temperatures. By selecting materials with appropriate transition temperatures and mechanical properties, the components retain their structural integrity and resistance to brittle failure in extreme cold environments.
3Reliability
If metal-to-metal seals are used instead of elastomeric seals, then low temperature reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent extracts the elastomeric sealing function and replaces it with metal-to-metal sealing surfaces or thermoplastic seals integrated into the valve structure. This eliminates the need for separate elastomeric seal components and their associated installation and maintenance complexities, while achieving reliable low-temperature sealing through the primary structural components.
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 WRSV with metal-to-metal seals and non-elastomeric components effectively prevents seal brittleness and cracking, ensuring reliable operation and reducing downtime in cold temperature environments during carbon dioxide injection.
Implementation Method 1
In case of catastrophic failures to the well's integrity above the SSSV, the Jules Thompson effect will cause rapid cooling of the tubing within the well to as low as −78° C.
Data Source
AI summary
A sub-surface safety valve (SSSV) for use in a low temperature downhole environment. The low temperature environment can be created by injection of fluid such as carbon dioxide. The low temperature downhole environment may be detrimental to the SSSV by damaging elastomer seals. The disclosed SSSV utilizes non-elastomeric seals and metal-to-metal seals between components. The SSSV utilizes metal-to-metal thread between body joints eliminating the need for an elastomers in the thread between body joints. Creating a SSSV with an elastomer seal reduces fatigue and damage in a low temperature environment.