Release Sub for Wireline Retrieval Using Electric Motor Decoupling
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Solution Overview
Problem
Existing methods for retrieving downhole tools and wirelines from a wellbore are often unsafe and can result in complications, especially when the tools become stuck and require overpulling the wireline, which can lead to breakage at weak points.
Innovation Solution
The implementation of a release sub mechanism within the downhole tool, comprising a first portion with a threaded pin and an electric motor, and a second portion with a threaded box, allowing for decoupling of the tool sections by rotating the threaded pin relative to the threaded box, facilitated by an electric motor and shear pins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If overpull is applied to the wireline to release a stuck downhole tool, then the tool may be released, but the wireline may break at a weak point causing safety issues and wellbore complications
Solution Approach 1:
The downhole tool is divided into multiple sections that can be independently retrieved. The release sub contains a threaded pin and box mechanism that allows one section to be detached from another, enabling the upper section with the wireline to be pulled out separately without requiring excessive force that would break the wireline.
Solution Approach 2:
The release sub acts as an intermediary mechanism between the stuck tool section and the wireline. It provides a controlled detachment interface where the threaded pin can be rotated to uncouple sections, serving as a mediator that allows tool release without transmitting damaging forces to the wireline.
2Strength
If the downhole tool is designed as a single integrated unit, then structural strength is maintained, but retrieval becomes difficult when stuck
Solution Approach 1:
The downhole tool is segmented into multiple sections connected by release subs. Each section maintains its structural integrity through proper design, while the segmented structure allows individual sections to be detached and retrieved separately, improving overall retrieval efficiency when the tool becomes stuck.
Solution Approach 2:
The release sub mechanism transforms the static integrated structure into a dynamic system where sections can be selectively coupled or decoupled. The threaded pin and box assembly allows controlled movement and separation, enabling the tool to transition from an integrated operational unit to separable retrieval units.
3Ease of operation
If a release mechanism is added to the downhole tool, then controlled detachment is enabled, but device complexity increases
Solution Approach 1:
The release sub mechanism is designed to be self-contained and self-actuating. The threaded pin and box assembly forms an integrated unit where the pin threads into the box to couple sections and can be rotated to decouple them, providing controlled detachment without requiring external complex actuation systems.
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
This solution enables safe and controlled detachment of the downhole tool sections, allowing for the retrieval of the first section and wireline while leaving the second section in the wellbore, which can then be safely retrieved using stronger equipment.
Implementation Method 1
The the release sub includes: a first portion including a threaded pin and an electric motor, and a second portion including a threaded box where the threaded pin is threaded into the threaded box to couple the first portion to the second portion
Data Source
AI summary
Methods, devices, and systems are discussed. In some cases, the methods may include conveying a downhole tool into a wellbore. The downhole tool includes a release sub disposed between a first section of the downhole tool and a second section of the downhole tool. The release sub includes: a first portion including a threaded pin and an electric motor, and a second portion including a threaded box where the threaded pin is threaded into the threaded box to couple the first portion to the second portion. The methods may further include causing the electric motor to rotate the threaded pin relative to the threaded box to decouple the first portion from the second portion, such that the first section of the downhole tool is at least partially detached from the second section of the downhole tool.