Smart Collet Locking Mechanism for Selective Downhole Support
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Solution Overview
Problem
In multiple zone completions, the Smart® Collet's alignment with predetermined support locations is uncertain, leading to potential unintended support and misalignment issues during gravel packing, as the spacing between zones is unknown, and existing technologies fail to selectively prevent the collet from supporting loads until it reaches the intended location.
Innovation Solution
A lock system that works in conjunction with a mandrel to selectively enable or disable the Smart® Collet's operation by using a lower housing with an external dog and an upper housing that cams the collet heads into a mandrel groove, allowing relative rotation to lock or unlock the collet, preventing support when not at the desired location and enabling it when aligned correctly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the Smart® Collet is used in multiple zone completions with unknown spacing between zones, then the collet may inadvertently find support at unintended locations, but adding a locking mechanism increases device complexity
Solution Approach 1:
The lock system is segmented into distinct functional components: a lock ring with locking elements, a mandrel with grooves, and interaction surfaces. This segmentation allows the locking function to be added as a modular component rather than redesigning the entire collet system, thereby improving reliability while minimizing the increase in overall device complexity.
Solution Approach 2:
The lock ring acts as an intermediary component between the collet assembly and the mandrel. It mediates the interaction by providing controlled engagement through its locking elements that interact with the mandrel grooves, enabling selective locking and unlocking without requiring direct complex interactions between the collet and mandrel themselves.
2Reliability
If a lock system is added to prevent premature support, then the tool can operate selectively at intended locations, but the ease of operation is reduced due to additional locking and unlocking steps
Solution Approach 1:
The lock system is designed to be self-actuating through the interaction between the lock ring's locking elements and the mandrel grooves. As the inner string is lowered, the locking elements automatically engage with the grooves to prevent premature support, and automatically disengage when the collet reaches the intended location, eliminating the need for manual locking and unlocking operations.
Solution Approach 2:
The locking elements are pre-positioned on the lock ring and the grooves are pre-formed on the mandrel during manufacturing. This preliminary configuration ensures that when the tool is deployed, the locking and unlocking actions occur automatically based on the relative positions, without requiring operators to perform additional steps during operation.
3Ease of operation
If the collet is continuously unlocked to allow free operation, then the tool is easy to operate, but the collet may inadvertently find support at wrong locations causing misalignment
Solution Approach 1:
The lock ring with locking elements provides preliminary anti-action by preventing the collet from finding support at unintended locations before the collet reaches its designated support point. This preemptive locking mechanism counteracts the potential harmful effect of inadvertent support, ensuring that the collet remains in a controlled state until the correct alignment is achieved.
Solution Approach 2:
The system dynamically transitions between locked and unlocked states based on the collet's position. The locking elements engage with the mandrel grooves to restrict movement when the collet is in unauthorized positions, and disengage to allow free operation when the collet reaches the intended location, thereby maintaining manufacturing precision while preserving operational freedom at the correct time.
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 lock system ensures the Smart® Collet operates only at intended locations, preventing premature support and ensuring proper gravel crossover, allowing for efficient operation in multiple zones by automatically locking and unlocking based on the collet's position, thus eliminating unintended support issues.
Implementation Method 1
An upper housing cams the collet heads into a respective groove in the mandrel
Implementation Method 2
The rotation to unlock and then lock is accomplished by dog interaction with shaped internal profiles in a surrounding tubular assembly at strategic locations
Implementation Method 3
Reversal of such relative rotation between the upper and lower housings allows the collet heads to spring out of the mandrel groove for the unlocked position
Data Source
AI summary
A lock system works in combination with a mandrel to allow selective operation and disabling of a downhole tool. In the specific situation of a Smart Collet® the tool is locked from being able to find support when engaged to a mating profile as the tool is moved between landing locations. A lower housing features an external dog that in response to rotation takes with it a collet ring with circumferentially oriented fingers. An outer housing cams the collet heads into a respective groove in the mandrel. Reversal of such relative rotation between the upper and lower housings allows the collet heads to spring out of the mandrel groove for the unlocked position. The lock is adapted for use in a variety of tools. The rotation to unlock and then lock is accomplished by dog interaction with shaped internal profiles in a surrounding tubular assembly at strategic locations where needed.