Friction Reducer Additives for High Salinity Hydraulic Fracturing
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Solution Overview
Problem
Hydraulic fracturing operations face challenges in maintaining viscosity of frac fluids in high salinity environments due to the degradation of traditional polymers like hydrolyzed polyacrylate sodium acrylamide, which leads to increased costs and environmental concerns related to water disposal and recycling, especially in areas with limited fresh water resources and high salinity produced water.
Innovation Solution
A chemical additive formulation comprising mineral oil, soy protein isolate, paraffin wax, emulsifiers, and hydrogel polymers is used to enhance the viscosity of frac fluids, providing salt tolerance and thermal stability, allowing for the effective use of both fresh and produced water in frac fluid systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If traditional polyanionic polymers (hydrolyzed polyacrylate sodium acrylamide) are used as friction reducers, then pumping pressure is reduced and hydrocarbon extraction is improved, but viscosity is lost (90-95% loss) in high salinity environments due to cationic ions
Solution Approach 1:
The patent modifies the polymer chemistry by using partially hydrolyzed polyacrylonitrile instead of hydrolyzed polyacrylate sodium acrylamide, changing the chemical parameters to resist cationic ion interference. This parameter change allows the polymer to maintain its viscosity and friction reduction properties in high salinity conditions with cationic ions like NaCl, CaCl2, MgCl2, and FeCl3.
Solution Approach 2:
The invention creates a composite friction reducer system by combining partially hydrolyzed polyacrylonitrile with crosslinking agents and other functional chemicals. This composite approach enhances the polymer's stability and performance in high salinity environments while maintaining pumping pressure reduction capabilities.
2Quantity of substance
If produced water with high salinity is used to reduce costs and environmental impact, then fresh water consumption is reduced and disposal costs are lowered, but frac fluid viscosity deteriorates due to cationic ions
Solution Approach 1:
The patent changes the polymer parameters to use partially hydrolyzed polyacrylonitrile, which has inherent resistance to cationic ions found in produced water. This allows the use of high salinity produced water without significant viscosity loss, enabling cost-effective and environmentally friendly fracking operations.
Solution Approach 2:
The invention enables the use of produced water (a readily available, low-cost resource) by making the friction reducer polymer resistant to its harmful components (cationic ions). This eliminates the need for expensive fresh water while maintaining operational effectiveness.
3Stability of the object's composition
If more hydrolyzed polyacrylate sodium acrylamide polymer is added to maintain viscosity in high salinity, then frac fluid viscosity is improved, but pumping cost increases and the polymer degrades more rapidly
Solution Approach 1:
The patent changes the polymer type to partially hydrolyzed polyacrylonitrile, which maintains viscosity stability in high salinity without requiring higher dosages. This parameter change improves pumping efficiency and reduces costs compared to using more traditional polymer.
Solution Approach 2:
The invention extracts the problematic hydrolyzed polyacrylate sodium acrylamide polymer from the system and replaces it with partially hydrolyzed polyacrylonitrile, which does not suffer from the same cationic ion sensitivity issues. This extraction of the problematic component eliminates the need for excessive polymer addition.
4Power
If traditional friction reducer chemicals are used in high temperature environments, then friction reduction is achieved, but thermal stability is poor and polymers degrade above 60°C
Solution Approach 1:
The patent changes the polymer parameters to use partially hydrolyzed polyacrylonitrile, which has superior thermal stability compared to hydrolyzed polyacrylate sodium acrylamide. This allows the friction reducer to maintain its properties at elevated temperatures typical of deep well fracking operations.
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 additive formulation significantly increases the viscosity of frac fluids, reducing the need for fresh water, lowering operational costs, and enhancing the efficiency of hydraulic fracturing operations in high salinity conditions while maintaining performance at elevated temperatures.
Implementation Method 1
emulsifier or non-ionic surfactants as encapsulated shell or control release agent in a range from 0.001% to 20%
Implementation Method 2
emulsifier or non-ionic surfactants
Implementation Method 3
hydrogel polymers as suspending agents in a range of 0.00% to 35%
Implementation Method 4
providing salt tolerance and thermal stability
Implementation Method 5
mineral oil or other hydrophobic solvent
Data Source
AI summary
Chemical additives useful for hydraulic fracturing operation are comprising of lubricant/nonpolar solvents; hydro-dual-phobic domains as core encapsulated by emulsifiers as shell, suspended in water by hydrogel polymers as hydrophilic domains; soy protein isolate (SPI) and sweet rice flour were modified with crosslinking polymers of isocyanate as hydrophobic domains, which is incorporated into the frac fluid as a standard alone friction reducer solution or as an enhancer of frac fluid viscosity of the final frac fluid products in high salinity brines having a concentration as high as 25.0% at an ambient temperature at a downhole well temperature from 30 to 180° F.