Fracturing Gel Hydration via Diffusion and Concentration Control
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Solution Overview
Problem
Current hydraulic fracturing methods face inefficiencies in hydrating polymers for fracturing fluids, leading to suboptimal viscosity and flow rates, which can limit hydrocarbon production from subterranean formations.
Innovation Solution
A method and system for preparing a fracturing slurry by creating a concentrated gel from polymers and water, with a control system that regulates the hydration and dilution process to achieve a predefined downhole concentration and maximum slurry rate, ensuring efficient polymer hydration and viscosity development.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mechanical mixing processes with moving parts are used to hydrate polymer, then hydration rate increases, but device complexity and energy consumption increase
Solution Approach 1:
The patent replaces mechanical mixing mechanisms (paddles, moving parts) with a chemical/physical process where polymer granules hydrate through diffusion and osmosis in water. The hydration occurs naturally without mechanical agitation, substituting mechanical energy with molecular-level processes driven by concentration gradients and water absorption properties of the polymer.
Solution Approach 2:
The polymer granules perform self-hydration by absorbing water through their own molecular structure without external mechanical assistance. The process leverages the inherent hygroscopic properties of the polymer to drive water uptake and gel formation autonomously, eliminating the need for powered mixing equipment.
2Reliability
If large volume hydration tanks are used to allow sufficient residence time for polymer hydration, then hydration completeness improves, but equipment volume and operational time increase
Solution Approach 1:
The patent changes the concentration parameter by using highly concentrated polymer granule suspensions (e.g., 10-20% or higher) instead of dilute solutions. This concentration change accelerates the hydration kinetics and allows complete hydration to occur in smaller volumes and shorter times, as the higher polymer content promotes faster water absorption and gel network formation.
Solution Approach 2:
The polymer granules are pre-processed to optimize their hydration characteristics before entering the tank, such as controlling granule size, surface area, and initial moisture content. This preliminary preparation ensures that hydration proceeds rapidly and completely during the residence time in the tank, maximizing efficiency without requiring excessive volume or time.
3Strength
If high polymer concentration is used in fracturing fluid, then viscosity increases, but flow rate and pumpability decrease
Solution Approach 1:
The patent utilizes the time-dependent and shear-dependent rheological properties of the hydrated polymer gel. The fluid exhibits dynamic viscosity that changes with shear rate and time, allowing it to maintain high viscosity at low shear rates (providing fracture support) while becoming more pumpable under high shear conditions during injection. This dynamic behavior reconciles the contradiction between viscosity and flow rate.
Solution Approach 2:
The patent optimizes the polymer concentration within a specific range (e.g., 10-20% or higher) and controls hydration time and temperature to achieve the desired rheological profile. By precisely controlling these parameters, the system achieves sufficient viscosity for fracture propping while maintaining adequate flow characteristics for pumpability through adjustment of concentration and hydration conditions.
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
This approach enhances the hydration rate and viscosity of fracturing fluids, allowing for improved hydrocarbon flow and production by optimizing the concentration and rate of the fracturing slurry, thereby increasing well productivity.
Implementation Method 1
A high level of viscosity of a hydrophilic polymer is reached when the polymer is properly hydrated. In general, the hydration of a polymer is performed in hydration tanks with large volumes that accept a polymer phase gel and water mixture so as to produce a hydrated fluid
Implementation Method 2
hydration tanks have focused primarily on mechanical mechanism movement or paddle based mixing processes which involve moving parts, as well as horse power to produce shear forces that increase the hydration rate of the hydratable polymer and establish the desired hydrated fluid viscosity
Data Source
AI summary
A method of preparing a fracturing slurry comprising a concentrated gel and water, the method comprising preparing a concentrated gel from a polymer and water, diluting the concentrated gel with additional water to form a fracturing carrier fluid at a predefined downhole concentration, preparing a fracturing slurry comprising the fracturing carrier fluid, and pumping the fracturing slurry downhole at or below a predefined maximum slurry rate. The fracturing carrier fluid is formed upon allowing the concentrated gel sufficient residence time to at least partially hydrate.