Viscosifying Non-Ionic Associative Polymer for Fracturing Fluids
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Solution Overview
Problem
Hydraulic fracturing operations face challenges with crosslinked polymeric networks that are damaged by high shear rates, reducing their ability to transport proppant, and water frac methods limit proppant size and concentration due to low viscosity, affecting fracture conductivity and production rates.
Innovation Solution
A viscosifying non-ionic associative polymer is used, which includes hydrophilic and hydrophobic blocks, providing viscosity without crosslinkers or surfactants, maintaining viscosity under shear and in non-ideal aqueous solutions, allowing for increased proppant carrying capacity and deeper fracture penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If crosslinked polymeric networks are used to generate highly viscous fluids, then viscosity is improved, but the network is permanently damaged by high shear rates, reducing proppant transport ability
Solution Approach 1:
The polymer is segmented into hydrophilic and hydrophobic blocks that can associate and disassociate dynamically. This segmentation allows the polymer to form transient structures that provide viscosity while remaining flexible enough to withstand shear rates without permanent damage to the polymeric network.
Solution Approach 2:
The patent changes the chemical composition parameters of the polymer by incorporating specific hydrophobic blocks (such as polypropylene oxide or polyester units) into the polymeric structure. This compositional change enables the polymer to maintain viscosity through hydrophobic associations while resisting permanent structural damage under shear stress.
2Productivity
If water frac methods are used with ungelled water, then pumping rates can be increased, but proppant size and concentration are limited due to low viscosity, affecting fracture conductivity
Solution Approach 1:
The patent changes the rheological parameters of the fracturing fluid by using non-ionic associative polymers that provide significant viscosity enhancement at low concentrations. This allows the fluid to carry higher proppant concentrations while maintaining pumpability, effectively resolving the trade-off between pumping rate and proppant loading.
Solution Approach 2:
The patent creates a composite fluid system combining water with non-ionic associative polymers that have both hydrophilic and hydrophobic segments. This composite structure provides the dual benefit of water-like pumpability combined with enhanced viscosity for proppant suspension and transport capability.
3Duration of action of stationary object
If crosslinkers and surfactants are used to achieve viscosity, then viscosity is improved, but the composition becomes more sensitive to water quality and temperature
Solution Approach 1:
The patent extracts and eliminates the need for crosslinkers and surfactants by using non-ionic associative polymers that provide viscosity through their inherent amphiphilic structure. The hydrophobic blocks associate through hydrophobic interactions, which are less sensitive to water quality variations and temperature changes compared to ionic crosslinking mechanisms.
Solution Approach 2:
The patent replaces complex crosslinking systems with simpler non-ionic associative polymers that achieve viscosity through transient hydrophobic associations. These associations are dynamic and reversible, providing robust viscosity that is less sensitive to environmental variations without requiring additional chemical additives.
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 polymer achieves constant viscosity over a wide range of shear rates, effectively transporting larger proppants deeper into fractures, enhancing fracture conductivity and production rates while being less sensitive to water quality and temperature.
Implementation Method 1
The polymer achieves constant viscosity over a wide range of shear rates
Implementation Method 2
maintaining viscosity under shear
Implementation Method 3
effectively transporting larger proppants deeper into fractures
Data Source
AI summary
Various embodiments relate to compositions including a viscosifying non-ionic associative polymer for treatment of subterranean formations. In various embodiments, the present invention provides a method of treating a subterranean formation. The method includes placing in the subterranean formation a composition including a viscosifying non-ionic associative polymer including at least one hydrophilic block and at least one hydrophobic group that is at each occurrence an independently selected substituted or unsubstituted (C5-C50)hydrocarbyl group.