Articulated Debris Barrier Locking Mechanism for Subterranean Tools

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Solution Overview

Problem

Existing debris barriers for subterranean tools, such as packers, face issues with maintaining extension and locking in place due to variable loading and thermal effects, leading to potential retraction and debris jamming, which can prevent packer release and require costly milling operations for retrieval.

Innovation Solution

An articulated debris barrier that selectively extends and locks radially to span an annular gap when a tool is set, using a snap ring or body lock ring mechanism to secure the position, allowing for reliable extension and retraction synchronized with the tool's operation, ensuring the barrier does not hang up or get damaged during retrieval.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the debris barrier is held extended by set down weight, then the barrier spans the annular gap to prevent debris entry, but the barrier may retract when loading changes or thermal effects eliminate the set down weight

Engineering Contradiction:

Improvedebris barrier extension maintenanceVSAvoiddebris admission to moving parts

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A lock ring is positioned in advance to engage with a groove on the piston. When the piston moves to extend the debris barrier, the lock ring engages the groove to preliminarily secure the extended position before any potential loading changes or thermal effects occur, preventing retraction and debris admission.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The lock ring acts as an intermediary mechanism between the piston and the debris barrier. It transfers and maintains the extended position of the barrier independently of the variable set down weight, mediating the connection between the piston movement and the barrier position to ensure reliable extension maintenance.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the debris barrier is locked in extended position during service, then the barrier remains stable against debris, but the barrier cannot retract for tool retrieval without jamming or damage

Engineering Contradiction:

Improvedebris barrier stability during serviceVSAvoidtool retrieval operation

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The locking system is designed to be dynamic rather than fixed. The lock ring can engage with the groove to secure the extended position during service, but can also disengage when retrieval is needed. This dynamic behavior allows the system to adapt between the stable locked state during operation and the retractable state during retrieval, avoiding jamming or damage.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS10329868B2Releasably locked debris barrier for a subterranean tool

Publication Date: 2019.06.25 BAKER HUGHES CO

AI summary

An articulated debris barrier folds on itself to extend radially to span a surrounding annular gap when the tool associated with it is set. The debris barrier can be used with a packer or bridge plug. The set position of the packer or plug is locked and another lock holds the extended position of the debris barrier. The debris barrier lock can be a snap ring that extends into a groove brought into alignment with it during the setting. Alternatively the lock for the debris barrier can be a body lock ring. In either case, release and retrieval of the packer or plug involves undermining of the locking feature for the debris barrier so that the debris barrier can extend while retracting from the borehole wall so that the barrier and the associated packer or plug can be removed together.