Chemically Modified Cellulose Nanofibrils for Wellbore Fluids
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Solution Overview
Problem
There is a need for wellbore treatment fluids with improved thermal stability and fluid properties, such as viscosity and fluid loss control, which are not adequately addressed by existing additives.
Innovation Solution
Chemically modified cellulose nanofibrils or nanocrystals are used as additives in wellbore treatment fluids, providing enhanced thermal stability, shear thinning behavior, and low fluid loss, with modifications such as carboxymethylation or TEMPO oxidation affecting their properties and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional additives are used in wellbore treatment fluids, then basic fluid functions are maintained, but thermal stability and fluid loss control are insufficient at high temperatures
Solution Approach 1:
The patent applies parameter changes by chemically modifying cellulose nanofibrils through carboxymethylation to introduce negative charges, changing the chemical parameters of the additive. This modification enables the additive to maintain thermal stability up to 600°F and effectively control fluid loss, resolving the contradiction between basic fluid function and high-temperature performance
Solution Approach 2:
The patent uses composite materials by combining chemically modified cellulose nanofibrils with other wellbore treatment fluid components. The modified cellulose nanofibrils form a composite system that provides both thermal stability and fluid loss control, addressing the insufficiency of conventional single-function additives
2Quantity of substance
If viscosity is increased to improve fluid carrying capacity, then fluid loss control improves, but pumpability and flow characteristics deteriorate
Solution Approach 1:
The patent applies dynamics by utilizing the shear-thinning behavior of chemically modified cellulose nanofibrils. The additive provides high viscosity at low shear rates for fluid loss control, but viscosity decreases at high shear rates during pumping, enabling both effective fluid loss control and good pumpability without contradiction
Solution Approach 2:
The chemically modified cellulose nanofibrils change their rheological parameters based on shear rate conditions. At static or low-flow conditions, they maintain high viscosity for fluid loss control; during high-speed pumping, viscosity reduces to improve flow characteristics, dynamically resolving the contradiction between fluid loss control and pumpability
3Temperature
If chemical modification is applied to enhance thermal stability, then thermal performance improves, but additive complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies parameter changes through controlled chemical modification of cellulose nanofibrils using carboxymethylation. This specific chemical transformation introduces negative charges that provide thermal stability up to 600°F, achieving high thermal performance through a well-defined chemical process rather than complex formulations
Solution Approach 2:
The patent extracts and isolates the key functional property (thermal stability) through specific chemical modification of cellulose nanofibrils. By focusing on carboxymethylation as the primary modification, the patent simplifies the manufacturing approach compared to using multiple different additives, reducing overall additive complexity while achieving the desired thermal performance
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 chemically modified cellulose additives offer improved thermal stability up to 600°F (316°C) and reduced fluid loss, enhancing the fluid's viscoelastic properties and pumpability, while maintaining desirable rheological characteristics.
Implementation Method 1
The additive can be made of chemically-modified cellulose nanofibrils or cellulose nanocrystals
Implementation Method 2
providing enhanced thermal stability, shear thinning behavior, and low fluid loss
Implementation Method 3
reduced fluid loss, enhancing the fluid's viscoelastic properties and pumpability
Implementation Method 4
enhancing the fluid's viscoelastic properties and pumpability, while maintaining desirable rheological characteristics
Data Source
AI summary
A wellbore treatment fluid comprising: a base fluid; and additive comprising a first polymer bundle selected from the group consisting of cellulose nanofibrils, cellulose nanocrystals, and combinations thereof, wherein one or more functional groups of the first polymer are chemically modified A method of treating a portion of a wellbore comprising: introducing the treatment fluid into the wellbore.