Degradable Wellbore Isolation Device Coating
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Solution Overview
Problem
Traditional methods for removing retrievable wellbore isolation devices are time-consuming and costly, and can result in premature dissolution, especially when using acidic fluids, which is undesirable in oil and gas well operations.
Innovation Solution
A degradable wellbore isolation device coated with a non-metallic material that degrades upon contact with wellbore fluid, delaying the exposure of a degradable core or mandrel, which can be made from materials that undergo galvanic corrosion, allowing for controlled dissolution without the need for retrieval tools or milling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional retrieval methods (retrieval tools or milling) are used to remove isolation devices, then the isolation device can be removed, but the process becomes time-consuming and costly
Solution Approach 1:
The isolation device is designed as a disposable component with a degradable core that dissolves in wellbore fluids, eliminating the need for complex retrieval operations. The device performs its isolation function and then degrades naturally, replacing expensive retrieval tools and milling operations with a simple chemical dissolution process.
Solution Approach 2:
The patent replaces mechanical retrieval systems (retrieval tools, milling equipment) with a chemical dissolution mechanism. The degradable core material dissolves through chemical interaction with wellbore fluids, substituting mechanical removal processes with a chemical process that is both simpler and faster.
2Ease of operation
If the isolation device is made fully degradable to enable easy removal, then retrieval becomes simple, but the device may dissolve prematurely before completing its isolation function
Solution Approach 1:
The isolation device is segmented into two functional parts: a stable outer structure (casing, sealing elements) that maintains isolation reliability, and an inner degradable core that enables easy removal. This segmentation allows each component to fulfill its specific function without compromising the other.
Solution Approach 2:
The degradable core acts as an intermediary between the stable outer structure and the wellbore environment. It provides a controlled dissolution mechanism that allows the device to be removed without requiring complex retrieval operations, while the stable outer structure ensures the device maintains its isolation function until removal is desired.
3Speed
If acidic fluids are used to accelerate dissolution of the isolation device, then removal speed increases, but premature dissolution occurs which is undesirable
Solution Approach 1:
The patent changes the chemical parameters of the degradable core material to enable controlled dissolution at normal wellbore fluid conditions. By selecting materials with specific degradation rates that match typical wellbore fluid chemistry, the device dissolves at a predictable speed without requiring aggressive acidic fluids that could cause premature dissolution.
Solution Approach 2:
The degradable core is designed as a temporary, disposable component that naturally dissolves in wellbore fluids over a predetermined period. This eliminates the need to introduce acidic fluids that would accelerate dissolution uncontrollably, allowing the device to self-regulate its dissolution timing based on its material composition and the normal wellbore environment.
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
The solution allows for controlled and delayed dissolution of the isolation device, maintaining zonal isolation for a desired period and facilitating removal without the use of costly retrieval methods, thereby improving operational efficiency and reducing the risk of premature dissolution.
Implementation Method 1
The coating surrounds at least a portion of the isolation device that includes a degradable material. The coating degrades upon contact with a wellbore fluid.
Implementation Method 2
which can be made from materials that undergo galvanic corrosion, allowing for controlled dissolution without the need for retrieval tools or milling
Data Source
AI summary
A wellbore isolation device comprising: one or more materials, wherein the one or more materials degrade after contact with a fluid; and a non-metallic coating, wherein the coating covers the one or more materials of the wellbore isolation device, and wherein the coating partially or wholly degrades after contact with a wellbore fluid. A method of removing the wellbore isolation device comprising: degrading the coating via contact with a wellbore fluid; and contacting the portion of the wellbore isolation device with a fluid, wherein the portion of the wellbore isolation device comprises one or more materials that degrade after contact with the fluid.