PVA-Magnesium Composite Downhole Tools for High Salinity
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Solution Overview
Problem
Current degradable downhole tools and components face challenges in high salinity environments, where they either degrade slowly or produce sticky residues, and existing materials require high temperatures or are expensive, limiting their effectiveness in hydraulic fracturing operations.
Innovation Solution
A composite material comprising polyvinyl alcohol (PVA) and a degradable metal, such as magnesium or its alloys, is used to create tools and components that can degrade efficiently in high salinity conditions, with the addition of fiberglass reinforcing material and mineral fills to enhance strength and degradability, allowing for rapid corrosion in aqueous fluids with high salinity and moderate temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional degradable materials are used in high salinity environments, then the tools can be degraded, but the degradation rate is slow and sticky residues are produced
Solution Approach 1:
The patent uses a composite material system consisting of PVA polymer matrix combined with degradable metal particles (magnesium, zinc, or their alloys). This composite structure allows the metal particles to catalyze and accelerate the degradation of PVA in high salinity environments through galvanic corrosion and electrochemical reactions, achieving rapid degradation without sticky residues while the PVA provides structural integrity during operation.
Solution Approach 2:
The patent modifies the chemical composition parameters of the degradable material by incorporating specific metal particles with controlled size distributions (0.1-10 micrometers) and concentrations (1-50 wt%). These parameter changes enable the material to respond differently to high salinity conditions, accelerating degradation through electrochemical mechanisms while preventing residue formation through controlled breakdown products.
2Productivity
If degradable tools are used in hydraulic fracturing, then operational efficiency is improved, but the tools require high temperatures to degrade which is not always available
Solution Approach 1:
The patent replaces thermal degradation mechanisms with electrochemical degradation mechanisms. Instead of relying on heat to break down the polymer structure, the degradable metal particles initiate and accelerate chemical degradation through electrochemical reactions with the PVA matrix in the presence of formation water, enabling degradation at moderate temperatures (20-100°C) typical of hydraulic fracturing operations.
Solution Approach 2:
The degradable metal particles act as intermediaries that facilitate the degradation process. These metal particles (magnesium, zinc, or their alloys) serve as catalysts and reaction sites that accelerate the breakdown of PVA through electrochemical mechanisms, allowing degradation to proceed at lower temperatures than would be required for pure thermal degradation of the polymer.
3Ease of operation
If degradable materials are used to create tools, then the tools can be dissolved after use, but the strength and structural integrity during operation are reduced
Solution Approach 1:
The patent creates a composite structure where the PVA polymer matrix provides structural integrity and mechanical strength during tool operation, while the embedded degradable metal particles (1-50 wt%) provide the degradation functionality. The synergistic combination allows the tool to maintain sufficient strength for hydraulic fracturing operations while ensuring complete degradation after use through the metal-catalyzed breakdown of the polymer matrix.
Solution Approach 2:
The patent applies different properties to different components of the composite material. The PVA matrix provides structural quality and mechanical strength where needed for tool function, while the degradable metal particles are distributed throughout to provide localized degradation initiation sites. This local differentiation of material qualities allows the tool to simultaneously achieve strength during operation and dissolvability after use.
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 PVA-degradable metal composite tools exhibit desirable strength and degradability, capable of dissolving at a high rate in high-salinity environments at low temperatures, avoiding sticky residues and maintaining operational efficiency in hydraulic fracturing processes.
Implementation Method 1
capable of dissolving at a high rate in high-salinity environments at low temperatures
Implementation Method 2
A composite material comprising polyvinyl alcohol (PVA) and a degradable metal, such as magnesium or its alloys, is used to create tools and components that can degrade efficiently in high salinity conditions
Implementation Method 3
capable of dissolving at a high rate in high-salinity environments at low temperatures
Data Source
AI summary
Degradable downhole tools, tool components, and balls are formed from a processed polyvinyl alcohol (PVA) compound that is degradable in a high-salinity environment. The PVA compound exhibits strength and elasticity properties that are comparable to existing degradable downhole polymers and further exhibits degradability properties that are superior to existing degradable downhole polymers, particularly in high-salinity fluids. For different components, the PVA compound may include a reinforcing material such as fiberglass. The PVA compound also includes a loading of degradable metal, such as a degradable magnesium alloy, rendering the material degradable at high salinity. Usage of tools, tool components, and balls formed from the disclosed materials eliminates the requirement that such equipment be drilled out after use as the PVA compound quickly degrades in high-salinity downhole fluids.