Thru-Casing Section Mill for Dual String Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current well abandonment procedures require multiple operations to remove dual-string casing and cement, which is inefficient and time-consuming, especially when removing a significant length of casing string and cement layer from oil and gas wells.
Innovation Solution
A downhole tool with radially movable cutting blocks and milling blades that can extend and retract, coupled with a link mechanism, allows for simultaneous milling of both inner and outer casing strings and cement, enabling efficient removal of casing sections through a combination of rotational and axial movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple separate operations are used to remove dual-string casing and cement, then each operation can be performed with specialized equipment, but the overall process becomes time-consuming and inefficient
Solution Approach 1:
The patent combines multiple separate milling operations into a single integrated tool that can simultaneously mill both the inner and outer casing strings along with the cement layer. The downhole tool incorporates cutting blocks with milling blades that can extend radially to engage both casing strings, eliminating the need to trip and reconfigure equipment between operations.
Solution Approach 2:
The downhole tool is designed with universal functionality to perform multiple tasks: milling inner casing, milling outer casing, and removing cement layers. The cutting blocks can be positioned and extended to accommodate different well configurations, allowing a single tool to replace multiple specialized tools and operations.
2Productivity
If a single downhole tool mills both inner and outer casing simultaneously, then operational efficiency improves, but the device complexity increases
Solution Approach 1:
The tool is segmented into modular components including a tool body, multiple cutting blocks, and retractable milling blades. Each cutting block can be independently positioned and controlled, allowing the complex function of dual-casing milling to be broken down into manageable, coordinated segments that simplify the overall system architecture.
Solution Approach 2:
The cutting blocks and milling blades are designed to be dynamically adjustable rather than fixed. The blades can extend and retract radially, and the cutting blocks can be positioned at different locations along the tool body, allowing the tool to adapt to various well configurations and reducing the need for multiple specialized fixed-tools.
3Productivity
If the milling blade extends radially to cut both casing strings, then the cutting capability is improved, but the risk of blade damage from excessive radial load increases
Solution Approach 1:
The milling blades are designed to be retractable rather than fixed, allowing them to extend radially only when needed for cutting and retract when encountering excessive resistance or during non-cutting phases. This dynamic capability protects the blades from damage while maintaining cutting effectiveness during normal operation.
Solution Approach 2:
The tool allows for adjustment of the radial extension position of the cutting blocks and milling blades. By controlling the extent of radial extension, the system can optimize cutting performance while avoiding excessive radial loads that could damage the blades, effectively managing the trade-off between cutting capability and blade protection.
Data Source
AI summary
A milling tool includes a cutting block in a recess in a tool body. The cutting block is configured to extend radially outward from and retract radially inward toward the tool body. The milling tool further includes a milling blade in a recess or cut-out in the cutting block. The milling blade is configured to extend radially outward from and inwards toward the cutting block. One or more links may couple the milling blade to the tool body to cause the milling blade to move radially relative to the cutting block when the cutting block moves radially relative to the tool body. The milling tool may be used as a dual string section mill to remove any of an inner casing, an outer casing, or cement between the inner and outer casings.