Hydraulically Actuated Isolation Sleeve for Subsea Wellhead Sealing
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Solution Overview
Problem
In subsea wellhead assemblies, uncontrolled releases of oil or gas (blowouts) are challenging to manage due to high pressures and potential damage to components, necessitating an efficient sealing mechanism to regain control.
Innovation Solution
A hydraulically actuated isolation sleeve with a piston is used to create a seal between the capping system and wellhead or blowout preventer stack, even if primary gaskets are damaged, ensuring effective fluid containment during blowout conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a primary gasket sealing area is used to create a seal between components, then the sealing mechanism is simple, but the reliability is reduced when the gasket becomes damaged during a blowout condition
Solution Approach 1:
The sealing mechanism is divided into two independent sealing systems: a primary gasket sealing area and a secondary sealing area with an isolation sleeve. Each sealing area can function independently, allowing the system to maintain reliability even if one sealing mechanism fails. The isolation sleeve with its piston and seal creates a secondary barrier that segments the overall sealing function.
Solution Approach 2:
The isolation sleeve and seal are pre-positioned within the wellhead assembly, ready for immediate deployment. The piston is pre-configured to be movable between retracted and extended positions. In the event of gasket damage, the secondary sealing mechanism can be activated without requiring external components or complex assembly procedures, enabling rapid response to blowout conditions.
2Reliability
If a hydraulically actuated piston is used to energize the seal, then the sealing effectiveness is improved, but the device complexity increases
Solution Approach 1:
A hydraulically actuated piston is employed to energize the seal element. Hydraulic actuation provides high force multiplication, allowing the seal to be firmly pressed against the sealing surface with sufficient force to withstand high-pressure blowout conditions. The hydraulic system can be integrated with existing well control hydraulic infrastructure, reducing overall system complexity.
Solution Approach 2:
The piston is designed to be movable between retracted and extended positions, allowing the sealing mechanism to adapt to different operational states. When extended, the piston energizes the seal for high-reliability sealing; when retracted, the seal is de-energized for component removal or installation. This dynamic capability provides operational flexibility without requiring multiple separate components.
3Adaptability or versatility
If the isolation sleeve is designed to seal against damaged equipment, then the adaptability is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The secondary sealing area is designed with localized sealing features that concentrate sealing force on specific contact surfaces. The isolation sleeve includes a seal element that makes localized contact with the wellhead or blowout preventer stack sealing surface. This localized sealing approach allows the system to accommodate general surface irregularities and damage while maintaining effective sealing at the critical contact points.
Solution Approach 2:
The sealing mechanism can adapt to varying sealing surface conditions by changing the pressure parameter applied by the hydraulic piston. When the sealing surface is relatively intact, lower piston pressure may suffice. When damage or irregularities are present, the hydraulic system can increase pressure to ensure adequate seal engagement and compensate for surface imperfections, thereby maintaining sealing effectiveness across different conditions.
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 solution enables rapid and reliable re-establishment of control over wellhead fluid flow, preventing leaks and protecting equipment from damage during high-pressure events.
Implementation Method 1
The sealing mechanism includes an isolation sleeve with a hydraulically actuated piston to energize a sealing element and effect a seal between the isolation sleeve and another component
Data Source
AI summary
Sealing mechanisms are provided. In one embodiment, a system includes a connector configured to couple one or more flow-control valves to equipment installed at a well and an isolation sleeve configured to be retained by the connector. The isolation sleeve may include a seal and a hydraulically actuated piston disposed adjacent one another about a body of the isolation sleeve such that actuation of the piston engages the seal. The isolation sleeve may also include a mechanically driven actuator ring, where the actuator ring energizes a seal against the bore of a tubing hanger. Additional systems, devices, and methods are also disclosed.