CO2-Responsive Multi-Scale Gel for Tight Oil Channeling Control
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Solution Overview
Problem
Tight oil reservoirs with low permeability and complex fracture networks face challenges in CO2 flooding due to premature breakthrough and low sweep efficiency, requiring a more effective channeling control system that is temperature-resistant and cost-efficient.
Innovation Solution
A multi-scale channeling control system combining nanoscale CO2 responsive worm-like micelles and micron-scale CO2 responsive dispersion gel, prepared with specific components and methods, enhances viscosity and plugging strength, and exhibits reversible CO2 responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If foam or gel is used to control fractures, then channeling control capability is improved, but matrix damage and stability deteriorate
Solution Approach 1:
The patent uses CO2-responsive materials that change their physical parameters (viscosity, molecular size) in response to CO2 concentration. The worm-like micelles and dispersion gel particles transform from compact states to extended states when exposed to CO2, enabling dynamic channeling control without permanent matrix damage. This reversible parameter change allows the system to adapt to different CO2 concentrations while maintaining matrix integrity.
Solution Approach 2:
The invention combines multiple components into a composite system: CO2-responsive monomers, hydrophobic/hydrophilic balance modifiers, crosslinking agents, and dispersion gel particles. This composite structure integrates the advantages of different materials while mitigating their individual disadvantages, achieving both strong channeling control and matrix protection through synergistic effects.
2Productivity
If CO2 is injected into fractured reservoirs, then productivity is improved, but premature breakthrough and low sweep efficiency occur
Solution Approach 1:
The patent introduces CO2-responsive worm-like micelles and dispersion gel particles as intermediary substances between the injected CO2 and the fracture network. These intermediaries selectively plug high-permeability fracture channels by transforming in response to CO2, forcing the CO2 flood to sweep through lower-permeability matrix regions. This mediation improves sweep efficiency while maintaining productivity enhancement.
Solution Approach 2:
The invention creates local quality differences in the flood system by using CO2-responsive materials that transform preferentially in high-CO2 concentration zones (fractures). The worm-like micelles and dispersion gel particles exhibit different properties in different locations: they remain compact in low-CO2 zones allowing flow, but extend and plug in high-CO2 zones where needed, achieving spatially selective channeling control.
3Productivity
If conventional fracturing is performed, then productivity increases, but water rises rapidly and recovery efficiency remains low
Solution Approach 1:
The patent employs dynamic CO2-responsive materials that can change their properties in real-time based on CO2 concentration. The worm-like micelles and dispersion gel particles dynamically transform from compact to extended states and back, enabling adaptive channeling control throughout the flooding process. This dynamic behavior allows the system to maintain productivity while progressively improving recovery efficiency as CO2 distributes through the reservoir.
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 system significantly increases flood control capability and recovery efficiency by transforming micelles in response to CO2, improving plugging strength and long-term stability, with enhanced CO2 displacement and reversibility, thereby increasing the swept volume and recovery factor in tight oil reservoirs.
Implementation Method 1
nanoscale CO2 responsive worm-like micelle system
Implementation Method 2
transforming micelles in response to CO2
Implementation Method 3
micron-scale CO2 responsive dispersion gel
Implementation Method 4
enhances plugging strength and long-term stability
Implementation Method 5
enhances viscosity and plugging strength
Implementation Method 6
enhanced CO2 displacement and reversibility, thereby increasing the swept volume
Data Source
AI summary
A tight oil reservoir CO2 flooding multi-scale channeling control system and a preparation method, including nanoscale CO2 responsive worm-like micellar systems and micron-scale CO2 responsive dispersion gel, are provided. The nanoscale CO2 responsive worm-like micelle system is prepared by CO2 reactive monomers and organic anti-ion monomers stirred in water. The micron-scale CO2 responsive dispersion gel is made of acrylamide, a responsive monomer, a silane coupling agent modified hydroxylated multi-walled carbon nanotubes as raw materials, cross-linked in water. The tight oil reservoir CO2 multi-scale channel control system, has strong flow control ability during CO2 displacement, and high-strength carbon nanotubes are introduced into the micro-scale CO2 responsive dispersion gel, which effectively improves the strength and long-term stability of the dispersion gel, significantly enhances the sealing effect on cracks, and after displacement of the CO2 of the system, the worm-like micelles revert to spherical micelles with good responsive reversibility.