Smart Collet Selective Locking Mechanism for Multi-Zone Gravel Packing
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Solution Overview
Problem
In multiple zone completions, determining proper alignment of the inner string assembly for a Smart® Collet is challenging due to unknown support location spacing, leading to potential unintended support and misalignment issues during gravel packing operations.
Innovation Solution
A selective lock mechanism that prevents the Smart® Collet from supporting loads until it reaches the intended location, using a rotating sleeve with spirally meshing profiles to align and misalign a tab with a slot, allowing relative axial movement for proper operation at desired zones while locking the tool away from undesired locations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the Smart® Collet is allowed to support load at any location, then the tool can operate freely during movement, but the collet may prematurely support load at unintended locations causing misalignment
Solution Approach 1:
The lock assembly applies a preliminary restraining force to prevent the collet from supporting load before reaching the intended location. The tab engages with the slot to create mechanical interference that actively prevents premature engagement, ensuring the collet remains disabled until the exact moment it reaches the designated support location.
Solution Approach 2:
The system prepares the lock assembly in advance with the tab positioned to engage the slot only at the intended location. The spiral groove geometry is pre-configured so that rotation of the outer assembly automatically brings the tab and slot into alignment at the precise moment the collet reaches the correct position, enabling seamless transition from locked to unlocked state.
2Reliability
If a lock mechanism is added to prevent premature support, then accurate location control is achieved, but the device complexity increases
Solution Approach 1:
The lock assembly merges the locking function with the existing rotational movement mechanism of the outer assembly. The tab and slot are integrated into the normal operational components rather than being separate locking devices. The spiral groove that drives rotation also simultaneously controls the engagement and disengagement of the tab with the slot, combining two functions into one coordinated system.
Solution Approach 2:
The lock mechanism is self-actuating through the rotational movement of the outer assembly. The tab automatically engages with the slot when the collet reaches the intended location and disengages when moving away, without requiring external control systems. The spiral groove geometry inherently controls the timing of lock and unlock events based purely on the rotational position of the outer assembly.
3Reliability
If the collet is locked to prevent operation, then premature support is prevented, but the tool cannot function when moved away from desired location
Solution Approach 1:
The lock assembly transitions from a static locked state to a dynamic unlocked state based on the rotational position of the outer assembly. The tab and slot engagement is not fixed but varies with rotation, allowing the system to automatically adapt its locking state. This dynamic behavior enables the collet to be locked during movement between zones and unlocked only at the intended support locations within each zone.
Solution Approach 2:
The lock mechanism operates periodically as the outer assembly rotates through different zones. The tab engages with the slot at specific intervals corresponding to the intended support locations, creating a rhythmic pattern of locked and unlocked states. This periodic engagement allows the collet to function at multiple discrete locations while remaining locked during transit between them.
Data Source
AI summary
A collet system is disabled from gaining profile support when moved between profiles that will be used ultimately to support an inner string at a desired plurality of locations. It is when the collet reaches a desired location that it is unlocked by virtue of inner string movement so that a profile on the outer assembly is engaged by a sleeve to induce relative rotation of the sleeve with respect to the mandrel that supports the sleeve. The relative rotation moves a tab into alignment with a slot to permit relative axial movement between the mandrel and the tool so that the tool can function as intended. The sleeve is engaged by another profile for further relative rotation to misalign the tab and the slot to lock the tool. The tool is preferably a support collet for a crossover in a multi-zone gravel pack.