Dissolvable Isolation Device with Surface Treatment for Controlled Corrosion
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Solution Overview
Problem
Traditional methods for removing retrievable isolation devices in oil and gas well operations are time-consuming and costly, and often result in premature dissolution due to acidic fluids, which can compromise the integrity of the device and its ability to maintain zonal isolation.
Innovation Solution
A wellbore isolation device with a surface treatment that alters its corrosion resistance, featuring a degradable sealant filling pores to delay corrosion, allowing controlled dissolution via galvanic corrosion, and a metal alloy composition that includes magnesium as the primary anode, with embedded cathode pieces to manage the dissolution rate.
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 is time-consuming and costly
Solution Approach 1:
The isolation device is designed as a disposable component with a controlled service life. After performing its zonal isolation function, the device is intended to dissolve automatically through galvanic corrosion without requiring retrieval operations. This transforms a permanent/retrievable device into a temporary/disposable one, eliminating the need for time-consuming removal operations.
Solution Approach 2:
The patent replaces mechanical retrieval systems (retrieval tools, milling equipment) with a chemical dissolution system. Instead of mechanically removing the isolation device through complex toolstrings or milling operations, the device is designed to chemically dissolve via galvanic corrosion in the wellbore environment, substituting a complex mechanical removal process with a simpler chemical dissolution process.
2Productivity
If the isolation device dissolves prematurely due to acidic fluids, then removal is achieved, but the zonal isolation integrity is compromised
Solution Approach 1:
The isolation device incorporates a passivation layer as a preliminary protective action before the device is exposed to wellbore fluids. This passivation layer is applied in advance during manufacturing to create a protective barrier that prevents premature dissolution. The layer is designed to provide initial corrosion resistance until the device reaches its intended dissolution time, ensuring zonal isolation integrity is maintained during the service period.
Solution Approach 2:
The patent controls the dissolution rate by changing material parameters - specifically using a metal alloy with controlled composition (e.g., magnesium-based alloys with specific element ratios) and controlling the thickness and properties of the passivation layer. These parameter changes allow the device to resist dissolution during the desired service period while ensuring complete dissolution after the intended timeframe, resolving the contradiction between premature dissolution and delayed dissolution.
3Duration of action of stationary object
If a passivation layer is applied to delay dissolution, then zonal isolation is maintained, but the device complexity increases
Solution Approach 1:
The isolation device uses composite material construction, combining a metal alloy base material with a passivation layer coating. This composite structure integrates two materials with different functions: the metal alloy provides structural integrity and controlled dissolution properties, while the passivation layer provides corrosion resistance. This composite approach extends the isolation duration without requiring complex mechanical structures or multiple components.
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 effectively delays corrosion for a desired period, maintaining zonal isolation and allowing for controlled removal of the isolation device without the need for costly retrieval tools or milling, ensuring structural integrity and efficient well operation.
Implementation Method 1
The isolation device includes at least an anode that is capable of dissolving via galvanic corrosion
Implementation Method 2
a surface of the anode is altered via a surface treatment, wherein the altered surface contains pores and a sealant and wherein the sealant is a degradable substance and is placed over the altered surface and fills the pores
Data Source
Figure 1
Figure 2
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AI summary
A wellbore isolation device comprising: a material that dissolves via corrosion when in contact with a wellbore fluid, a surface of the material, wherein the surface of the material is altered via a surface treatment, and wherein the altered surface delays corrosion of the material for a desired amount of time. A method of removing the wellbore isolation device comprising: contacting or allowing the wellbore isolation device to come in contact with a wellbore fluid; and causing or allowing at least the portion of the material to dissolve.