Dual Functional Components for Self-Breaking Polysaccharide Gels
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Solution Overview
Problem
Conventional cross-linked polysaccharide gels in subterranean treatment fluids are thermally unstable, dependent on pH and temperature, and require additional breakers to reduce viscosity, which can be costly and leave residues, necessitating the development of self-breaking viscosified treatment fluids that maintain viscosity for transport and fracture enhancement without premature breakdown.
Innovation Solution
The use of dual functional components, such as oxidizers like salts of permanganates and peroxides, that cross-link polysaccharides to increase viscosity and subsequently break the gel without additional breakers, allowing for controlled viscosity reduction and recovery of treatment fluids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional cross-linked polysaccharide gels are used to maintain high viscosity for proppant transport, then the treatment fluid can effectively carry proppant and enhance fracture width, but the gel becomes thermally unstable and breaks down prematurely at high temperatures, losing its viscosity and functionality
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure of polysaccharides through controlled cross-linking reactions. Specifically, it uses oxidizing agents to create cross-links between polysaccharide chains, transforming the physical and chemical parameters of the gel to achieve thermal stability while maintaining viscosity. The cross-linking density and oxidation level are carefully controlled to balance stability and viscosity requirements.
2Productivity
If additional breakers are added to reduce the viscosity of cross-linked gels after treatment, then the treatment fluid can be recovered, but this increases treatment cost and leaves harmful residues in the formation
Solution Approach 1:
The patent implements self-service by designing polysaccharide cross-linked gels that can spontaneously break down through controlled degradation mechanisms. The gel structure incorporates labile cross-links or built-in degradation pathways that allow the gel to self-destruct under specific conditions (such as pH change, temperature variation, or time-dependent hydrolysis), eliminating the need for external breaker chemicals and avoiding harmful residues.
Solution Approach 2:
The patent converts the potential harm of permanent cross-linked gels into a benefit by designing them with controlled breakdown capabilities. The cross-links are engineered to be stable during treatment but susceptible to controlled degradation afterward, transforming what would be a harmful persistent residue into a beneficial self-breaking feature that facilitates fluid recovery without contamination.
3Strength
If the polysaccharide gel is made highly viscous to inhibit particle settling and enhance fracture width, then proppant transport is improved, but the gel becomes dependent on pH and temperature, requiring precise control and adding complexity to the treatment process
Solution Approach 1:
The patent applies composite materials by combining polysaccharides with cross-linking agents to create a composite gel system. This composite structure provides enhanced viscosity while reducing sensitivity to pH and temperature variations. The cross-linked network creates a more robust gel matrix that maintains its properties across a broader range of conditions, simplifying process control.
4Reliability
If cross-linking is used to create near zero particle settling rates, then suspension capability is maximized, but the gel requires additional chemicals and steps to break, increasing treatment complexity and cost
Solution Approach 1:
The patent implements self-service by designing cross-linked polysaccharide gels with inherent self-breaking capabilities. The gel structure includes labile cross-links or degradation-prone bonds that allow the gel to spontaneously break down after completing its suspension function, eliminating the need for additional breaker chemicals and simplifying the treatment process into fewer steps.
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 dual functional components enable viscosified treatment fluids to maintain high proppant carrying capacity and sand transport properties while breaking at a desired time, reducing the need for additional breakers and minimizing environmental impact, with the ability to be reused and avoiding filter cake formation.
Implementation Method 1
dual functional components, such as oxidizers like salts of permanganates and peroxides, that cross-link polysaccharides to increase viscosity
Implementation Method 2
dual functional components, such as oxidizers like salts of permanganates and peroxides, that cross-link polysaccharides to increase viscosity and subsequently break the gel
Data Source
AI summary
Many methods and compositions are provided. One of the methods provided comprises the steps of: providing an aqueous treatment fluid that comprises a polysaccharide and a dual functional component, the aqueous treatment fluid having a first viscosity; allowing the dual functional component to interact with the polysaccharide such that the viscosity of the aqueous treatment fluid increases to a second viscosity, the second viscosity being greater than the first viscosity; placing the aqueous treatment fluid into a subterranean formation; and allowing the dual functional component to interact with the polysaccharide so as to reduce the second viscosity of the aqueous treatment fluid to a third viscosity, the third viscosity being less than the second viscosity. An example of a composition is a viscosified treatment fluid for treating subterranean formations comprising: an aqueous base fluid and an apparent cross linked reaction product of a polysaccharide and a dual functional component.