HDS Polysaccharide Gel Breaking for Metal-Crosslinked Polymer Viscosity
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Solution Overview
Problem
Conventional breaker agents used to reduce the viscosity of metal-crosslinked polymer fluids in subterranean treatments are ineffective in breaking the metal-crosslinking bonds, leading to incomplete breakdown and potential plugging issues during well completion operations.
Innovation Solution
The introduction of a polysaccharide with a high degree of substitution (HDS polysaccharide) that selectively removes metal ions from the polymer, combined with a conventional breaker agent to degrade polymer chains, effectively breaking the metal-crosslinking bonds and reducing viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional breaker agents are used to reduce viscosity, then polymer chains are degraded, but metal-crosslinked portions remain intact causing incomplete breaking
Solution Approach 1:
The breaking process is divided into two distinct mechanisms: (1) polymer chain degradation by conventional breaker agents, and (2) metal ion removal by HDS polysaccharide. This segmentation allows each component to target specific aspects of the gel structure, achieving complete breaking where neither agent alone would suffice.
Solution Approach 2:
The invention uses a composite approach by combining HDS polysaccharide with conventional breaker agents. The HDS polysaccharide acts as a specialized component that complements the conventional breaker, creating a synergistic system that addresses both polymer chains and metal crosslinks simultaneously.
2Reliability
If HDS polysaccharide is used to remove metal ions, then complete gel breaking is achieved, but additional materials and process complexity are introduced
Solution Approach 1:
HDS polysaccharide serves as an intermediary substance that facilitates metal ion removal from the gel structure. Rather than directly breaking the gel, it mediates the process by chelating metal ions, which then allows the polymer network to collapse and break naturally.
Solution Approach 2:
The invention changes the chemical parameter of the polysaccharide by using a high degree of substitution variant. This parameter change enables the polysaccharide to effectively compete for metal ions, transforming it from a typical viscosity-enhancing agent into an effective gel-breaking agent.
3Device complexity
If conventional breaker agents alone are used, then the process is simple, but plugging issues occur due to incomplete breakdown
Solution Approach 1:
The invention converts the potential harm of metal ion presence (which causes plugging) into a benefit by using those same metal ions as targets for the HDS polysaccharide. The metal ions that would otherwise cause problems are specifically removed by the polysaccharide, transforming a harmful factor into the mechanism for complete gel breaking.
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
This method achieves complete or substantial degradation of metal-ion crosslinked polymer fluids, allowing for predictable and efficient removal of viscous treating fluids from subterranean formations, preventing plugging and ensuring fluid flow.
Implementation Method 1
The HDS polysaccharide removes the metal ion from the polymer to thus uncrosslink the polymer
Implementation Method 2
Acids, enzymes, and oxidizers are commonly used to reduce the viscosity of metal-crosslinked polymer fluids. These known breakers are somewhat effective to reduce viscosity by degrading polymer chains
Data Source
AI summary
A method is provided for improved degradation of metal-crosslinked polymer gels, which are useful in oil and gas treating operations. In this method a polysaccharide having a higher degree of substitution than the polymer in the polymer gel is added to the gel. The polysaccharide removes the crosslinking metal ion from the gel to thus break down the gel and reduce its viscosity.