Downhole Disconnect Shear Mechanism for Stuck Tool Retrieval
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Solution Overview
Problem
Existing wellbore tools, particularly retrievable packers, often become stuck in the wellbore due to a robust connection mechanism that prevents disconnection, even when stuck, leading to operational challenges during retrieval.
Innovation Solution
A disconnect system comprising a shear mechanism that separates the upper and lower sections of a stinger upon application of a threshold tension, allowing for safe retrieval of stuck tools without requiring rotation or torque, utilizing a shear member and collar for separable connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a robust connection mechanism is used to ensure secure connection with the retrievable packer, then the connection strength is improved, but the ability to disconnect from the packer deteriorates
Solution Approach 1:
The stinger is divided into upper and lower sections connected by a shear mechanism. The shear member is positioned within a shear cavity, creating a separable connection that maintains strength during normal operation but allows controlled separation when needed. This segmentation enables the robust connection to be temporarily weakened for disconnection purposes.
Solution Approach 2:
The connection mechanism transitions from a static, permanent connection to a dynamic, controllable connection. The shear mechanism allows the connection strength to be adjusted based on operational needs - maintaining full strength during packing operations and enabling controlled separation when the packer becomes stuck or needs retrieval.
2Ease of operation
If the disconnect mechanism is designed to release the tool easily, then the ease of operation is improved, but the reliability of maintaining secure connection deteriorates
Solution Approach 1:
The shear member is pre-positioned within the shear cavity during manufacturing, creating a predetermined failure plane. This preliminary arrangement ensures that under normal operational tensions, the connection remains reliable, but when excessive tension is applied, the shear member will cleanly separate at the predetermined location, enabling reliable disconnection.
3Reliability
If a permanent connection is used to ensure tool security in the wellbore, then the reliability is improved, but the ability to retrieve the tool deteriorates
Solution Approach 1:
The shear mechanism acts as an intermediary element between the upper and lower stinger sections. During normal operation, the shear member maintains a secure intermediary connection that ensures tool security. When retrieval is needed, applying tension causes the shear member to separate, enabling the lower section to be retrieved from the wellbore while maintaining the integrity of the upper section.
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
Enables reliable disconnection of stuck tools from the wellbore by applying tension to the shear member, ensuring safe retrieval and preventing damage to the packer or other tools, thereby overcoming the issue of stuck tools and enhancing operational efficiency.
Implementation Method 1
a shear mechanism interconnecting the upper sub and the lower sub, wherein the shear mechanism parts upon the application of a threshold tension on the upper sub
Data Source
AI summary
A release device includes a first sub, a second sub, and a connector separably connecting the first and the second sub, wherein the connector includes a shear member disposed with the first sub and a collar connected between the second sub and the shear member.