Surfactant Concentration Gradient in Hydraulic Fracturing
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Solution Overview
Problem
In hydraulic fracturing, high surfactant concentrations are required to maintain effectiveness in low permeability formations like shale, leading to excessive surfactant usage and costs, as surfactants adsorb to the fracture face, reducing their concentration at the leading edge of the fracturing fluid.
Innovation Solution
A method involving a surfactant concentration gradient is introduced, with a high initial concentration in the first portion of the fracturing fluid followed by a gradual reduction, optimized using adsorption coefficient calculations and frac simulation to minimize total surfactant volume while maintaining effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high surfactant concentrations are used throughout the fracturing treatment, then the desired cleanup effect is maintained, but the total surfactant volume and cost increase significantly
Solution Approach 1:
The patent applies parameter changes by varying the surfactant concentration over time during the fracturing treatment. The concentration is highest at the beginning to ensure adequate surfactant reaches the fracture face, then gradually reduced as the treatment progresses. This dynamic parameter adjustment maintains the cleanup effect while minimizing total surfactant usage.
Solution Approach 2:
The patent implements dynamics by transitioning from a static surfactant concentration approach to a dynamic one. The surfactant concentration is continuously adjusted during the fracturing process based on the amount of surfactant already adsorbed to the fracture face, ensuring optimal performance at each stage of the treatment.
2Reliability
If high surfactant concentrations are used to compensate for adsorption losses, then adequate surfactant reaches the fracture face, but the cost and surfactant volume required increase
Solution Approach 1:
The patent applies feedback by using calculations based on adsorption coefficients to determine the actual surfactant concentration reaching the fracture face. This information feeds back into the treatment design, allowing optimization of the surfactant concentration profile to minimize adsorption losses while maintaining effectiveness.
Solution Approach 2:
The patent implements preliminary action by calculating the expected adsorption losses before the fracturing treatment begins. Using laboratory measurements of adsorption coefficients and frac simulation, the treatment is pre-optimized to determine the precise surfactant concentration needed at each stage, preventing excessive surfactant addition.
3Ease of operation
If uniform surfactant concentration is used throughout the fracturing fluid, then the treatment is simple to implement, but the leading edge of the fracture receives inadequate surfactant
Solution Approach 1:
The patent applies parameter changes by transitioning from a uniform surfactant concentration to a gradient concentration profile. The concentration is highest in the initial portion of the fracturing fluid and decreases in subsequent portions, ensuring adequate surfactant is available at the leading edge of the fracture where it is most needed for surface energy modification.
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 reduces the overall surfactant volume required, leading to significant cost savings while maintaining the desired cleanup effect, as the surfactant concentration is strategically maintained throughout the fracturing process.
Implementation Method 1
Performance of the surface-active materials is generally based on cost to provide reduction in interfacial tension
Implementation Method 2
facilitate the removal of water from a porous media (for example, a proppant packed fracture) with mixtures of gas or oil by preventing or breaking emulsion formation
Implementation Method 3
the leading front of the fracture will be greatly reduced in the concentration of surfactant that is in the fluid at that point owing to the fact that surfactants tend to adsorb to the fracture face
Data Source
AI summary
Fracturing methods include introducing a relatively high concentration of a surfactant in an initial portion of one or more fluids used in a fracturing treatment and then cutting or ramping back to a relatively low concentration of the surfactant in the remaining fluid used in the treatment. By using such a method, the volume of surfactant to provide superior treatment can be reduced significantly from the normal recommendations, leading to a high cost savings while still obtaining the desired effect upon cleanup.