Retractable Cutting Tool with Uphole Milling Capability
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Solution Overview
Problem
Existing cutting tools face challenges in efficiently cutting through tubular strings and milling in an uphole direction without requiring continuous fluid pressure and a return spring, as they often rely on complex blade orientations and mechanisms that restrict continuous drilling operations.
Innovation Solution
A cutting and pulling tool design that uses a fluid-actuated piston to extend and maintain cutter blades, eliminating the need for a return spring by employing a lock ring and shear pins, allowing blades to extend radially and retract with a bias or plug-assisted mechanism, enabling cutting through tubular walls and milling in an uphole direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a return spring is used to retract the blades, then the blades can automatically retract after cutting, but the device complexity and cost increase
Solution Approach 1:
The patent removes the return spring from the system entirely. Instead of using a spring to retract the blades, the design relies on the natural retraction mechanism where the blades are held extended only during cutting operation, and automatically retract when fluid pressure is removed, eliminating the need for a return spring and reducing device complexity
Solution Approach 2:
The cutting tool performs its own retraction function without external assistance. The blades retract automatically through the designed mechanism that uses fluid pressure control - when pressure is applied, blades extend; when pressure is removed, blades retract, making the system self-sufficient without requiring additional components like return springs
2Reliability
If continuous fluid pressure is applied to hold blades extended, then cutting performance is maintained, but energy consumption and operational complexity increase
Solution Approach 1:
Instead of continuous fluid pressure, the system uses periodic or intermittent pressure application. Fluid pressure is applied only when blade extension is needed for cutting, and removed when retraction is required, converting a continuous energy-consuming operation into a periodic one that reduces energy consumption while maintaining cutting reliability
Solution Approach 2:
The patent ensures that the useful action of cutting is maintained continuously when needed, while eliminating continuous fluid pressure by using a locking mechanism or natural retraction design that maintains blade position without ongoing energy input, allowing the system to hold blades extended during cutting without continuous pressure
3Strength
If blades extend below the tubular to be milled, then cutting capability is achieved, but the tool cannot be removed through the cut tubular
Solution Approach 1:
The blade system is designed to be dynamic rather than static. The blades can extend below the tubular during cutting operations when needed, and then retract above the tubular when the cutting is complete, allowing the tool to pass through the cut tubular. This dynamic extension and retraction capability resolves the contradiction between achieving cutting strength and enabling tool removal
4Manufacturing precision
If a complex blade orientation system is used to cut through tubular walls, then cutting precision is improved, but device complexity increases
Solution Approach 1:
The cutting tool is designed with multi-functionality, where the same blade system performs both cutting through the tubular wall and milling operations. By integrating these functions into a single blade assembly that can extend and retract, the design eliminates the need for separate complex orientation mechanisms for different cutting tasks, reducing overall device complexity while maintaining cutting precision
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 and economical cutting and milling operations without continuous fluid pressure, allowing for efficient removal of tubular strings and supporting the cut string with reduced stress, facilitating continuous drilling and plug-and-abandonment procedures.
Implementation Method 1
The actuating piston is flow actuated to shift and extend the cutting blades and to retain the extended blade position even after the flow is cut off
Implementation Method 2
The blades are retracted with pressure on a landed plug on the piston so that a return spring is not required
Data Source
AI summary
Cutter blades extend and stay extended as long as pressure on a piston is continued. The blades either open fully in open hole or cut through the wall of a tubular and then mill in an uphole direction to take out a piece of the tubular. The piston that held out the blades when pressure was applied is acted on by a return bias when the pressure is removed so that the blades can retract and the tool removed through the cut tubular. As a backup a plug can be dropped to obstruct a through passage in the piston so that pressure from the surface can be used to force the piston back to retract the blades. Continued drilling operations or the cut and milled portion can be then blocked off such as with cement for a plug and abandonment of the well.