Expandable Metal Sleeve for Self-Sealing Control Lines
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Solution Overview
Problem
Traditional plugging and abandonment techniques using cement struggle to effectively seal control lines in subterranean wells, leading to fluid/gas migration through vertical leak paths, which contaminates the seabed and requires frequent workovers.
Innovation Solution
Incorporating expandable metal in control lines that react with specific reactive fluids to form self-sealing barriers, either intentionally or accidentally, providing a more reliable sealing method compared to traditional cementing techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional cementing techniques are used to seal control lines, then the sealing process is simple and straightforward, but the sealing reliability is insufficient leading to fluid/gas migration
Solution Approach 1:
The expandable metal sleeve is designed to automatically expand and seal the control line when exposed to reactive fluids like formation water or brine, without requiring external activation or complex control systems. The metal reacts chemically with the fluid to generate hydrogen gas pressure that forces the sleeve to expand radially and seal the leak path, making the system self-activating and self-sealing
Solution Approach 2:
The sealing system combines multiple materials with complementary properties: an expandable metal alloy sleeve (providing structural integrity and sealability), a corrosion-resistant outer casing (protecting the metal from premature reaction), and potentially a catalyst layer (accelerating the reaction with reactive fluids). This composite structure achieves both reliability and controlled activation
2Reliability
If expandable metal is incorporated in control lines to provide self-sealing, then sealing reliability improves, but the device complexity increases
Solution Approach 1:
The expandable metal seal mechanism is nested within the existing control line tubular structure. The metal sleeve is positioned inside the control line, surrounded by cement or other sealing materials, creating a nested configuration where the expandable metal acts as an internal self-sealing element within the larger control line assembly
Solution Approach 2:
The system exploits changes in physical and chemical parameters (volume expansion of metal during reaction, pressure generation from hydrogen gas evolution, radial force development) to transform the seal from a passive structure to an active self-sealing barrier. The metal undergoes phase and property changes when exposed to reactive fluids, enabling automatic seal activation
3Object-affected harmful factors
If expandable metal is used to prevent fluid migration, then protection against contamination improves, but the manufacturing complexity increases
Solution Approach 1:
The expandable metal seal components are pre-installed and positioned within the control line during manufacturing, but remain in a dormant, non-expanded state. The actual sealing action is postponed until the metal is exposed to reactive fluids downhole, allowing the control line to be manufactured and installed without requiring the complex expansion mechanism to be activated during assembly
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 expandable metal effectively prevents undesired fluid communication, self-heals leaks, and enhances the robustness of the downhole system, reducing the need for workovers and ensuring more reliable pressure isolation.
Implementation Method 1
a sleeve of expandable metal positioned within the control line tubular, the sleeve of expandable metal comprising a metal configured to expand in response to hydrolysis to seal the control line tubular when contacting a reactive fluid
Data Source
AI summary
Provided is a control line, a method for sealing a control line, and a well system including a control line. The control line, in one aspect, includes a control line tubular, the control line tubular having a length (Lt), a width (Wt) and wall thickness (Tt). The control line, in accordance with at least this aspect, further includes a sleeve of expandable metal positioned within the control line tubular, the sleeve of expandable metal comprising a metal configured to expand in response to hydrolysis to seal the control line tubular when contacting a reactive fluid.