Modular Downhole Milling for Electrolytic Tubing Removal
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Solution Overview
Problem
Current downhole milling tools are limited in their ability to efficiently remove entire sections of metal tubing and cement in wellbores, often requiring multiple operations and equipment, and lack the capability to operate independently without a rig for well abandonment and side-tracking operations.
Innovation Solution
A modular downhole tool combining electrolytic milling with electromechanical milling, featuring expandable rails with conductive elements and abrasive components, capable of corroding and grinding metal tubing, and optionally integrating logging, anchoring, and electromechanical modules for standalone operation or as part of a modular system, allowing for controlled corrosion and material removal without the need for a rig.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional electromechanical milling tools are used to remove metal tubing sections, then material removal capability is achieved, but operational complexity increases and rig-based installation is required
Solution Approach 1:
The patent combines electrolytic milling and electromechanical milling into a single integrated downhole tool. The electrolytic milling module uses conductive elements and electrolyte circulation to corrode metal tubing, while the electromechanical milling module uses rotating blades with cutting elements. Both modules can operate simultaneously or sequentially to remove metal tubing sections and cement, eliminating the need for multiple separate operations and rig-based installations.
Solution Approach 2:
The downhole tool is designed as a modular system that can perform multiple functions: electrolytic milling of metal tubing, electromechanical milling of metal tubing and cement, and potential logging operations. This multi-functional capability allows a single tool to replace multiple specialized tools, reducing operational complexity and eliminating the requirement for rig-based installation for different operations.
2Productivity
If multiple separate operations are used to remove metal tubing and cement, then comprehensive material removal is achieved, but time consumption and operational complexity increase
Solution Approach 1:
The patent integrates both electrolytic milling and electromechanical milling capabilities into a single downhole tool that can operate simultaneously or sequentially. The electrolytic milling module targets metal tubing while the electromechanical milling module handles both metal tubing and cement removal. This combined approach allows comprehensive material removal in a single operation rather than requiring separate operations for different materials.
Solution Approach 2:
The tool enables continuous material removal operations by combining chemical corrosion (electrolytic milling) with mechanical cutting (electromechanical milling). The electrolytic process continuously corrodes metal tubing while the electromechanical blades simultaneously or sequentially cut through metal and cement, maintaining continuous productive action without requiring multiple separate operations and reducing total operational time.
3Productivity
If traditional milling tools are deployed on tool strings, then material removal is achieved, but the need for rig-based installation reduces operational flexibility
Solution Approach 1:
The downhole tool is designed to be self-contained with all necessary components for material removal: electrolyte circulation systems, conductive elements for electrolytic milling, rotating mechanisms with cutting elements for electromechanical milling, and potential logging equipment. This self-service capability allows the tool to perform comprehensive operations independently once deployed, providing operational flexibility without requiring continuous rig-based installation or support equipment.
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 removal of metal tubing and cement sections with reduced operational complexity, allowing for standalone operation and integration with other modules to perform well abandonment and side-tracking tasks, enhancing operational efficiency and reducing the need for rig-based installations.
Implementation Method 1
an electric current is applied through the tool and adjacent pipe or casing and salt water is circulated around the tool and inner wall of the casing and serves as an electrolyte
Implementation Method 2
electrochemical machining or grinding
Implementation Method 3
an abrasive material (cutting element) so that they can mechanically cut or mill through the cement layers between casings
Data Source
Figure 1
Figure 1a
Figure 2
AI summary
The present invention relates to a downhole tool (23), for removing sections of metal tubing, comprising: at least one conductive element (1) being arranged to corrode a section of metal tubing using an electrolytic process, said conductive element (1) being a tube or a pipe which is made of electric conductive material, an apparatus (4) to establish a connection to the metal tubing (2), and a milling apparatus with cutting or abrasive elements (3) arranged to remove byproducts from the electrolytic process. The invention also relates to a modular downhole tool (45), comprising an elongated main shaft (8) with several modules for insertion in a wellbore.