Downhole Swivel Sub Sliding Sleeve Mechanism
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Solution Overview
Problem
Existing swivel subs for the oil and gas industry either apply torque to delicate screens or liners, risk damaging them due to friction, or require compression/tension to enable selective rotation, which is not suitable for all drilling applications.
Innovation Solution
A swivel sub with a sliding sleeve mechanism that allows relative rotation between a workstring and downhole apparatus without compression or tension, using a pressure differential to switch between engaged and disengaged positions, enabling selective transmission of rotation to the drill-pipe string and downhole tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the workstring is rotated to break friction during screen insertion, then the drag is reduced and measured down weight can be applied, but torque is applied to the screen which may cause buckling and damage
Solution Approach 1:
The swivel sub divides the drill string into two independent rotating sections: an upper body connected to the workstring and a lower body connected to the screen. The telescopic sleeve can slide within the lower body, allowing the upper body to rotate independently while the screen remains stationary, thus eliminating torque transmission to the screen during insertion operations.
2Adaptability or versatility
If existing swivel subs use compression or tension to enable selective rotation, then rotation control is achieved, but the mechanism is not suitable for all drilling applications and may damage delicate screens
Solution Approach 1:
The telescopic sleeve is designed to slide dynamically within the lower body along the longitudinal axis. This dynamic movement allows the sleeve to engage or disengage from the upper body as needed, providing selective rotation control without requiring compression or tension mechanisms that could stress delicate screens.
3Stability of the object's composition
If the sliding sleeve is held in position by shear pins, then the engaged position is maintained, but the pins must be sheared to release which requires additional operational complexity
Solution Approach 1:
The shear pins are designed to fail under specific periodic conditions (such as applying a predetermined torque or using a release tool). This periodic action allows the pins to remain intact during normal operation, maintaining stability, and then fail on demand to enable release, simplifying the overall release mechanism compared to complex locking 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
Enables the rotation of the drill-pipe string above the sub while maintaining the downhole apparatus stationary, or rotating both together, without applying torque or stress, thus preventing damage and facilitating the deployment of screens or liners in challenging wellbore conditions.
Implementation Method 1
a pressure differential to switch between engaged and disengaged positions
Data Source
AI summary
The present invention provides a swivel sub for connection in a work string between a workstring and a downhole apparatus. The swivel sub includes a first substantially cylindrical body, including a sleeve portion having one or more teeth and a second substantially cylindrical body being partially located within the sleeve portion. The bodies are arranged to rotate relative to each other. The swivel sub also includes a sliding sleeve, having one or more teeth arranged mutually engage with the first teeth is axially moveable between disengaged and engaged positions, in one embodiment by a pressure differential being created in the sub. Further, the present invention provides methods for of running the tool, with particular application to setting and hanging of liners and screens.