Downhole Disconnect Tool Inner Sleeve Rotation Control
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Solution Overview
Problem
Current methods for disconnecting tubular strings in subterranean wells are inefficient, particularly when the bottom hole assembly or lower portion becomes stuck, as they lack effective mechanisms for safe and reliable separation and retrieval of upper and lower portions during drilling and other well operations.
Innovation Solution
A downhole disconnect tool with upper and lower outer housing sections connected by threads, featuring an inner sleeve that limits relative rotation in the connect position and allows unthreading by creating a pressure differential with a plug, enabling safe separation of the tubular string portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional disconnect methods are used, then tubular strings can be disconnected, but the process is inefficient and lacks reliable separation mechanisms
Solution Approach 1:
The disconnect tool is divided into upper and lower outer housing sections that can be separated, with an inner sleeve that controls the connection state. This segmentation allows the tool to transition between connected and disconnected states reliably, solving the problem of inefficient and unreliable conventional disconnect methods.
Solution Approach 2:
The inner sleeve acts as an intermediary component between the upper and lower outer housing sections. By controlling the engagement between these sections, the inner sleeve provides a reliable mechanism for separation, addressing the lack of effective separation mechanisms in conventional methods.
2Reliability
If the inner sleeve is designed to limit rotation for secure connection, then connection reliability improves, but the complexity of the device increases
Solution Approach 1:
The inner sleeve combines multiple functions: it limits rotation between outer housing sections to ensure reliable connection, transmits torque during drilling operations, and controls the disconnection process. By merging these functions into a single component, the design achieves high connection reliability without excessive complexity.
Solution Approach 2:
The inner sleeve serves multiple purposes: providing rotational limitation for secure connection, transmitting torque, and enabling controlled disconnection through pressure differential response. This multi-functionality allows the tool to achieve reliable connection without adding unnecessary structural complexity.
3Strength
If threaded connection is used for joining sections, then connection strength is sufficient, but unthreading becomes difficult when stuck
Solution Approach 1:
The inner sleeve is pre-configured to respond to pressure differentials by moving axially. This preliminary action mechanism allows the sleeve to automatically facilitate unthreading when activation pressure is applied, solving the problem of difficult unthreading when sections become stuck together.
Solution Approach 2:
The disconnection mechanism uses hydraulic pressure differentials to activate the inner sleeve's movement. By applying pressure across the plug and inner sleeve, the system overcomes the friction and interference that prevent unthreading, making separation easy even when sections are stuck.
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 efficient disconnection and retrieval of tubular string portions by allowing controlled unthreading of the upper from the lower section, facilitating the removal of stuck components and improving overall well operation efficiency in drilling and other well operations.
Implementation Method 1
applying a differential pressure across the plug while the plug is engaged with the plug seat, thereby displacing the inner sleeve relative to first and second outer housing sections
Data Source
AI summary
A downhole disconnect tool can include outer housing sections connected to each other with threads, and an inner sleeve received in at least one of the outer housing sections, whereby the inner sleeve limits relative rotation between the outer housing sections in a connect position, and permits relative rotation between the outer housing sections in a disconnect position. A method of disconnecting portions of a tubular string can include connecting a downhole disconnect tool between the tubular string portions, deploying a plug into the tubular string, thereby engaging the plug with an inner sleeve in the downhole disconnect tool, applying a differential pressure across the plug, thereby displacing the inner sleeve relative to outer housing sections of the downhole disconnect tool, and then unthreading the outer housing sections from each other in the well.