Downhole Tool Body Controlled Degradation via Galvanic Cell
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Solution Overview
Problem
Current methods for removing downhole components are inefficient and seek alternatives for enabling fluid flow or releasing locks/anchors without the need for pumping, milling, or using chemicals.
Innovation Solution
A downhole assembly with controlled degradation, where a body with a more negative electrode potential is electrically coupled with an insert of a less negative potential, forming an electrochemical cell that corrodes the body for controlled removal, utilizing cathodic protection principles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If current removal methods (pumping, milling, chemical dissolution) are used, then downhole components can be removed, but the process is inefficient and requires complex mechanical or chemical intervention
Solution Approach 1:
The patent replaces mechanical removal methods (pumping, milling) with an electrochemical system. By creating a galvanic cell with sacrificial anodes and cathodic compartments, the tool body is corroded electrochemically rather than mechanically removed, eliminating the need for complex mechanical intervention equipment.
Solution Approach 2:
The downhole tool performs its own removal by utilizing the surrounding downhole environment (electrolyte solution) to create a galvanic cell. The sacrificial anodes automatically corrode to protect the tool body, and the tool body subsequently corrodes in a controlled manner, eliminating the need for external removal equipment or chemical injection systems.
2Reliability
If sacrificial anodes are used for cathodic protection, then the tool body is protected from corrosion, but the anodes are consumed and require replacement or monitoring
Solution Approach 1:
The patent intentionally designs the sacrificial anodes to be consumable and discarded. After the anodes are depleted, the tool body is left in a controlled state ready for electrochemical removal. The system transitions from protection mode to removal mode, where the previously protected body becomes the target for controlled corrosion.
Solution Approach 2:
The sacrificial anodes perform preliminary corrosion protection during the tool's service life, preparing the tool body for subsequent controlled removal. This preliminary protective action ensures the body remains intact and structurally sound until removal is desired, at which point the body can be uniformly corroded without having suffered differential corrosion during service.
3Productivity
If electrochemical removal is used, then controlled degradation is achieved, but the process requires specific electrode potential differences and material selections
Solution Approach 1:
The patent utilizes changes in electrode potential parameters to control the removal process. By selecting materials with specific electrochemical properties (sacrificial anodes with more negative potential than the tool body), the system achieves controlled corrosion. The electrochemical parameters (electrode potentials, electrolyte composition) are adjusted to control the rate and uniformity of degradation.
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 predictable and controlled removal of downhole components by selectively corroding the body, allowing fluid flow or releasing locks/anchors without mechanical intervention, while preserving the inserts.
Implementation Method 1
the body formed from a first material having a first electrode potential; and an insert disposed in the cavity, the insert electrically coupled to the body and formed from a second material having a second electrode potential, the first electrode potential being more negative than the second electrode potential
Data Source
AI summary
A downhole assembly with controlled degradation including a body having a cavity therein and is formed from a first material having a first electrode potential. An insert is disposed in the cavity, the insert electrically coupled to the body and formed from a second material having a second electrode potential, with the first electrode potential being more negative than the second electrode potential.