Galvanic Port Plug for Cemented Wellbore Tools
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Solution Overview
Problem
Existing port plugs in well systems fail to effectively prevent cement composition from entering undesirable spaces and maintaining pressure differential, and often require unreliable dissolution methods, such as hydrolysis, which can lead to premature degradation or incomplete degradation due to insufficient water or extreme temperatures.
Innovation Solution
A port plug made of two metals or metal alloys that form a galvanic couple, allowing controlled dissolution via corrosion, with the anode material dissolving in the presence of an electrolyte, such as a cement composition, to maintain pressure and enable timely fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrolysis is used to dissolve the port plug, then the plug can be removed after cementing, but the plug may degrade prematurely or incompletely due to insufficient water or extreme temperatures
Solution Approach 1:
The invention changes the dissolution mechanism from hydrolysis to galvanic corrosion by selecting metal materials with different electrochemical potentials. The port plug is constructed with an anodic metal (e.g., zinc, aluminum, magnesium) and a cathodic metal (e.g., stainless steel, copper, nickel), creating a galvanic couple that dissolves reliably through electrochemical corrosion controlled by the cement composition's electrolyte content, rather than being dependent on water availability or temperature for hydrolysis.
2Productivity
If the port plug is made of dissolvable material, then the port can be opened after cementing, but the plug may not effectively prevent cement intrusion during the cementing process
Solution Approach 1:
The port plug is constructed as a composite structure combining an anodic metal matrix (e.g., zinc, aluminum, or magnesium alloy) with embedded cathodic metal particles or wires (e.g., stainless steel, copper, or nickel). This composite galvanic couple structure provides both immediate cement blocking capability through the intact multi-material construction and controlled dissolution through galvanic corrosion, where the cement composition acts as the electrolyte to dissolve the anodic metal while leaving the cathodic metal framework intact to maintain structural integrity during the cementing process.
3Device complexity
If a single metal is used for the port plug, then the structure is simple, but the dissolution rate cannot be controlled and may be too slow or too fast
Solution Approach 1:
The port plug uses a composite galvanic couple structure with an anodic metal (e.g., zinc, aluminum, magnesium) and a cathodic metal (e.g., stainless steel, copper, nickel). The galvanic corrosion rate is controlled by the electrochemical potential difference between the two metals, allowing predictable and controlled dissolution. The anodic metal dissolves preferentially while the cathodic metal remains intact, providing a controlled dissolution timeframe that matches the cementing operation requirements, neither too fast nor too slow.
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 galvanic corrosion-based port plug effectively prevents cement intrusion, maintains specified pressure differentials, and dissolves within a desired timeframe, ensuring reliable fluid flow and tool operation.
Implementation Method 1
A port plug can be removed by dissolving the plug via galvanic corrosion
Implementation Method 2
the cement composition is the electrolyte
Data Source
Figure 1
Figure 2~3
AI summary
A method of performing an operation in a wellbore comprising: introducing a tool into the wellbore, wherein the tool comprises: (A) a mandrel comprising a port; and (B) a plug, wherein the plug is located within the port, and wherein the plug comprises at least a first material, wherein the first material partially or wholly dissolves via corrosion; introducing a cement composition into an annulus located between the outside of the tool at least at the location of the port and the inside of the wellbore; and causing or allowing at least a portion of the first material to dissolve, wherein the step of causing or allowing is performed after the step of introducing the cement composition.