Pressure-Operated Dimple Lockout Tool for Sub-Surface Safety Valves
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Solution Overview
Problem
Sub-Surface Safety Valves (SSSVs) can become damaged or clogged, making it difficult to operate them properly, and existing methods for locking them in an open position are complex and unreliable, especially when dealing with debris and corrosive fluids.
Innovation Solution
A lockout tool is used to form multiple dimples in the flow tube of the SSSV using a mechanism driven by pressurized fluid, ensuring the flow tube remains extended and locked open, preventing the flapper from closing, and providing feedback and emergency removal options.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lockout tool is used to form dimples in the flow tube, then the reliability of locking the SSSV in open position is improved, but the device complexity increases
Solution Approach 1:
The lockout tool is designed with nested components where the piston is disposed inside the cam housing, and the cam mechanism is integrated within the piston assembly. This nesting allows the complex dimple-forming mechanism to be contained within a compact structure that can be deployed through the production tubing, resolving the contradiction by organizing complexity in a space-efficient manner while maintaining reliable locking function.
Solution Approach 2:
The tool uses pressurized fluid introduced through the production tubing to drive the piston, which in turn actuates the cam mechanism to form dimples in the flow tube. This hydraulic/pneumatic actuation provides reliable and controlled dimple formation without requiring complex mechanical linkages or manual intervention, improving reliability while using fluid pressure as the energy source.
2Manufacturing precision
If multiple dimples are formed simultaneously in the flow tube, then the manufacturing precision of the locking mechanism is improved, but the device complexity increases
Solution Approach 1:
The cam mechanism is designed with multiple cam surfaces that actuate in a periodic sequence as the piston moves downward. Each cam surface corresponds to a specific dimple location, and as the piston progresses, each cam sequentially deforms the flow tube to create a dimple. This periodic action ensures precise positioning of multiple dimples around the flow tube circumference while using a relatively simple reciprocating piston motion.
Solution Approach 2:
The cam mechanism is segmented into multiple independent cam surfaces, each responsible for forming one dimple at a specific location. This segmentation allows each cam to be optimized for its specific dimple-forming function while working in coordination with the others, achieving precise multi-point deformation through a modular approach that manages complexity.
3Stability of the object's composition
If the flow tube is deformed to lock in extended position, then the stability of the locked open position is improved, but the ease of operation decreases
Solution Approach 1:
The lockout tool performs the dimple-forming action as a preliminary step before withdrawing from the flow tube. By creating the dimples that lock the flow tube in the extended position before the tool is removed, the system ensures stable locking without requiring the operator to manually manipulate or hold the flow tube in position during the locking process. The preliminary deformation action establishes the locked state autonomously.
Solution Approach 2:
The cam mechanism automatically deforms the flow tube into the locked position through the piston's downward motion, without requiring external manipulation of the flow tube. The tool itself performs the locking action through its internal cam-piston mechanism, making the operation self-contained and eliminating the need for complex manual positioning or holding of the flow tube during the locking process.
Data Source
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AI summary
The disclosure describes a lockout tool including a cam housing configured to fit within a flow tube of a safety valve that is coupled to production tubing and has a longitudinal up-down axis. The lockout tool further includes a piston disposed within the cam housing and configured to move within the cam housing parallel to the longitudinal up-down axis and form a plurality of dimples in the flow tube upon provision within the production tubing of a pressurized fluid.