Mill Catch Mechanism for Redundant Downhole Tool Retrieval
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Solution Overview
Problem
Current downhole operations face challenges in retrieving milling tools after connection failures between the mill and the drill string, leading to inefficiencies and resource wastage due to the need for fishing operations to recover broken components.
Innovation Solution
Incorporating a catch mechanism that acts as a secondary load path to support the mill or bit, allowing it to be tripped out of the wellbore even after primary connection failure, thereby eliminating the need for additional fishing operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single load path is used to support the mill, then the device complexity is reduced, but the reliability decreases due to connection failure risk
Solution Approach 1:
A catch mechanism is pre-installed on the mill before deployment into the wellbore. This mechanism includes catch elements positioned to engage with corresponding features on the drill string, creating a backup support system that activates only upon primary connection failure, thus improving reliability without requiring complex active monitoring or control systems.
Solution Approach 2:
The catch mechanism serves as a pre-prepared safety net that activates automatically when the primary connection fails. By having this backup load path already in place before any failure occurs, the system ensures continuous support capability without requiring complex real-time decision-making or activation sequences.
2Loss of time
If fishing operations are performed to retrieve broken tools, then the loss of time is increased, but the loss of substance is reduced by recovering valuable equipment
Solution Approach 1:
The catch mechanism is pre-configured on the mill to automatically engage with the drill string upon connection failure, maintaining support capability and enabling immediate tripping out of the wellbore. This eliminates the need for time-consuming fishing operations while ensuring complete recovery of the expensive mill and associated equipment.
Solution Approach 2:
The catch mechanism provides self-activating backup support that automatically engages when the primary connection fails, without requiring external intervention or specialized fishing operations. The mill essentially retrieves itself by maintaining its own support capability through the pre-installed catch elements.
Data Source
AI summary
Systems, tools, and methods include using a milling assembly with a catch mechanism configured to maintain a connection between the drill string and the mill in the event a primary connection between the mill and catch mechanism fails. A primary connection may support the weight of the mill by using a connection between the drill string and the mill. The catch mechanism may operate as a back-up or redundant connection and may support the weight of the mill by coupling the catch mechanism to both the mill and the drill string.