Wellhead Valve Override Locking for Stuck Valve Recovery
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Solution Overview
Problem
Wellhead valves in wellbore operations can become stuck in an open or closed configuration, making it difficult to control fluid flow, necessitating a contingency override mechanism.
Innovation Solution
A wellhead module with a housing, valve member, actuator assembly, and locking mechanism that allows the actuator assembly to be unlocked and translated within the housing to override the stuck valve, using mechanisms such as shearable members, pistons, or hydraulic systems to facilitate movement between locked and unlocked states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the actuator assembly is locked to the housing to maintain stable valve control, then reliability is improved, but the ability to override stuck components is lost
Solution Approach 1:
The locking mechanism transitions between locked and unlocked states dynamically. During normal operation, the locking mechanism secures the actuator assembly to the housing for stable control. When override is needed, the locking mechanism releases, allowing the actuator assembly to be moved to alternative positions to override stuck valve components.
Solution Approach 2:
The locking mechanism is designed with preliminary release capability. Before override operation, the locking mechanism can be selectively released to prepare the actuator assembly for repositioning. This preliminary action enables the transition from stable locked operation to override capability without requiring complete system disassembly.
2Adaptability or versatility
If the actuator assembly is unlocked to enable override of stuck valve, then adaptability is improved, but control stability is reduced
Solution Approach 1:
The system dynamically switches between locked and unlocked states based on operational needs. The locking mechanism provides stable connection during normal operation and enables temporary release for override operations, then returns to locked state after override, maintaining stability when needed while providing adaptability when required.
3Reliability
If the valve components are made robust to prevent sticking, then reliability is improved, but the complexity of the override mechanism increases
Solution Approach 1:
The override mechanism is segmented into distinct functional components: the locking mechanism for securing the actuator assembly, the actuator assembly itself for moving the valve member, and the housing structure. This segmentation allows each component to be optimized independently and simplifies the overall override mechanism by breaking it into manageable, specialized parts.
Solution Approach 2:
The locking mechanism acts as an intermediary between the actuator assembly and the housing. It provides a controlled interface that enables both stable operation and override capability without requiring complex direct connections. This intermediary component simplifies the overall system by providing a single point of control for both locking and unlocking operations.
Data Source
AI summary
A wellhead module, comprising: a housing, a valve member, an actuator assembly, and a locking mechanism. The valve member extends through an opening at an end of the housing and is translatable between an open position and a closed position. The actuator assembly is disposed within the housing and is configured to translate the valve member between the open position and the closed position. The locking mechanism is convertible from a first state to a second state, the actuator assembly is axially locked to the housing at a first axial position in the first state, and the actuator assembly is unlocked from the housing in a second state and thus movable to a second axial position within the housing.