Labile-Link Vinyl Polymers for Subterranean Fluid Degradation
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Solution Overview
Problem
In subterranean applications, synthetic polymers used in treatment fluids often persist due to their stability, leading to formation damage and the need for costly clean-up operations, as existing breakers like oxidative agents and enzymes are inefficient or ineffective at high temperatures and extreme pH levels, resulting in incomplete polymer degradation and deposition on oil-bearing rock surfaces.
Innovation Solution
Development of water-soluble degradable synthetic vinyl polymers with labile groups in their backbone, produced through redox polymerization, which can be tailored to degrade under specific conditions, such as high temperatures, allowing for complete breakdown into smaller, soluble components that do not accumulate and form deposits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If synthetic polymers are used in treatment fluids, then viscosity and fluid control are improved, but polymer stability causes accumulation and formation damage
Solution Approach 1:
The patent divides the polymer chain into segments connected by labile groups (hydrolyzable bonds such as ester, amide, or carbamate linkages). These labile groups act as weak points that allow the polymer to break down into smaller segments under downhole conditions, preventing accumulation and formation damage while maintaining high molecular weight for adequate viscosity during the treatment process.
2Stability of the object's composition
If oxidative breakers are used to degrade polymers, then polymer breakdown is achieved, but breakers are lost due to fluid loss and may prematurely decrease viscosity
Solution Approach 1:
The patent makes the polymer self-degradable by incorporating labile groups directly into the polymer backbone that can hydrolyze under downhole conditions (elevated temperature and pH). The polymer degrades itself without requiring external oxidative breakers, eliminating breaker loss due to fluid loss and avoiding premature viscosity decrease. The degradation is triggered automatically by the downhole environment.
3Stability of the object's composition
If enzymes are used to break polymers, then degradation occurs under mild conditions, but enzymes are ineffective at high temperatures and extreme pH levels
Solution Approach 1:
The patent changes the chemical nature of the polymer backbone to include labile groups (ester, amide, carbamate linkages) that are specifically designed to hydrolyze at elevated temperatures and extreme pH levels typical of downhole conditions. This allows the polymer to degrade effectively in the high-temperature, high-pH environment where enzymes would be inactive, expanding the operational temperature and pH range for polymer degradation.
4Strength
If high molecular weight polymers are used, then viscosity and proppant transport are improved, but polymer persistence in the formation increases
Solution Approach 1:
The patent incorporates labile groups at regular intervals along the polymer backbone, creating predetermined weak points. The polymer maintains high molecular weight between these labile groups to provide adequate viscosity for proppant transport, but the labile groups enable controlled degradation into smaller segments after the treatment, reducing retention time and preventing formation damage.
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
These polymers effectively degrade into smaller, soluble pieces, reducing the risk of formation damage and facilitating easier recovery, while maintaining viscosity control and avoiding impurity deposition, thus enhancing the efficiency and sustainability of subterranean treatments.
Implementation Method 1
The polymers of the present invention have a labile group in the backbone such as, but not limited to, an ester, amide, or carbamate linkage that can be degraded in the downhole environment
Implementation Method 2
Oxidative breakers may be dissolved in the fluid, but may be lost due to fluid loss
Data Source
AI summary
Of the many embodiments presented herein, one is a subterranean treatment fluid comprising: an aqueous fluid; and a water-soluble degradable synthetic vinyl polymer having a labile link in its backbone. Also provided in one instance is a water-soluble degradable synthetic vinyl polymer with labile group in its backbone made by a redox polymerization, the redox polymerization reaction comprising these reactants: a macroinitiator that comprises a labile link, an oxidizing metal ion, and a vinyl monomer.