Dual String Section Mill Radial Cutting Mechanism
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current downhole milling tools for dual-string wellbores require multiple trips and operations to remove cement and casing strings, which are time-consuming and costly, and are prone to failure due to high shear and torsional loads from larger diameter blades.
Innovation Solution
A dual-string casing mill with a cutting block and milling blade configuration that extends radially outward and inward, allowing simultaneous removal of the cement layer and casing string, reducing loads on the blades and improving tool reliability through distinct cutting structures for efficient cement and casing removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If larger diameter milling blades are used to remove cement layer and casing strings simultaneously, then productivity is improved, but reliability deteriorates due to increased shear and torsional loads causing blade failure
Solution Approach 1:
The milling tool divides the cutting function into separate components: cutting blocks for cement removal and milling blades for casing string removal. This segmentation allows each component to be optimized for its specific function, with cutting blocks handling cement layer removal and smaller milling blades handling casing string removal, thereby avoiding the reliability issues of using oversized blades for dual purposes
Solution Approach 2:
The patent combines multiple cutting elements (cutting blocks and milling blades) into a single integrated milling tool assembly that can perform both cement removal and casing milling operations simultaneously during one trip, achieving the productivity benefit of simultaneous removal while maintaining reliability through proper functional division
2Productivity
If larger diameter milling blades are used to remove cement layer and casing strings, then productivity is improved, but device complexity increases due to difficulty in collapsing blades into tool body
Solution Approach 1:
The cutting blocks and milling blades are designed to nest within the tool body when not in use. The cutting blocks can be retracted into axial recesses in the tool body, and the milling blades can be collapsed into the cutting blocks or tool body, creating a compact configuration that simplifies the collapse mechanism and eliminates the need for complex deployment systems
3Productivity
If larger diameter milling blades are used for simultaneous removal operations, then productivity is improved, but ease of operation deteriorates due to blades hanging up in smaller diameter casing
Solution Approach 1:
The milling tool employs dynamic blade deployment and retraction mechanisms that allow the cutting blocks and milling blades to be extended when needed for cutting operations and collapsed into a compact configuration for tripping in and out of the wellbore. This dynamic capability ensures the tool can navigate through smaller diameter casing without the blades hanging up, while still providing simultaneous removal capability when deployed
4Reliability
If multiple trips are made to remove cement layer and casing strings separately, then reliability is improved by using appropriately sized blades for each operation, but productivity deteriorates due to time-consuming multiple operations
Solution Approach 1:
The patent merges the cement removal function and casing milling function into a single tool assembly that can perform both operations simultaneously during one trip. The cutting blocks handle cement removal while the milling blades handle casing string removal, allowing both operations to be completed in a single deployment and eliminating the need for multiple trips while maintaining reliable performance
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 single-trip operation for simultaneous cement and casing removal, reducing operational costs and improving tool durability by optimizing cutting structures for efficient performance and extended service life.
Implementation Method 1
The cutting block is configured to remove a cement layer in a wellbore
Implementation Method 2
The milling blade is configured to cut and mill a section of a casing string in a wellbore
Data Source
AI summary
A dual string section milling tool includes a cutting block deployed in an axial recess in a tool body. The cutting block is configured to extend radially outward from and retract radially inward towards the tool body. The cutting block is further configured to remove a cement layer in a wellbore. The dual string section milling tool further includes a milling blade deployed in an axial slot disposed in the cutting block. The milling blade is configured to extend radially outward from and inwards towards the cutting block. The milling blade is further configured to cut and mill a section of casing string. The dual string section milling tool may be further configured to simultaneously remove cement and mill a wellbore tubular.